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Solid States Devices => solid state devices => Topic started by: tinman on May 08, 2016, 10:42:41 AM
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I have started this thread to solve MileHighs question below.
Please keep the insults down,and the language clean.
MH's question.
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts. Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts. Then after that the voltage is zero volts.
What happens from T=0 when the ideal voltage is connected to the ideal coil?.
My answer to this question is--you cannot place an ideal voltage across an ideal inductor.
The reason being,at T=0,when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity. The reason this cannot happen,is because an ideal inductor dose not dissipate any power in the form of heat,due to the fact that it has no resistance or hysteresis loss,as it is an ideal inductor. If an ideal voltage was placed across an ideal inductor(in theory),it would result in an explosion the likes the universe has not seen since the creation of it-the big bang all over again.
All are welcome to have a go at answering MHs question.
MH
For the record,could you please post your answer to your question above?
Brad
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Brad:
Your answer is wrong and I already answered a more difficult version of the question on the other thread and I already told you I won't answer this question.
You are one strange egg Brad because you think you are "running the show" now but in fact the show is running you.
Re: This posting from the other thread: http://overunity.com/8341/joule-thief-101/msg483350/#msg483350 (http://overunity.com/8341/joule-thief-101/msg483350/#msg483350)
As I already stated, you make reference to an "R" resistance but there is none in the example being discussed. You also make reference to a divide-by-zero for a time constant and state that it is "instantaneous" when it is infinity or undefined. You are told these two things are wrong in a later posting but like the Pope you pretend that you are infallible and can just "waive" past these two glaring errors because you are Brad.
Re: This posting from the other thread: http://overunity.com/8341/joule-thief-101/msg483376/#msg483376 (http://overunity.com/8341/joule-thief-101/msg483376/#msg483376)
You are all in a tizzy because I mention a "'trick' question." But unfortunately you have another case of crossed signals in your head. It's not my question in that posting that is the "trick," it's actually ION's follow-up question to my question that is the "trick." I say in jest to ION that his question is a "trick" question but that flies right over your head. Lo and behold, the signals get crossed in your head and you accuse me of asking a "trick" question when I did no such thing.
But the most mind-blowing thing about that posting of yours is that you completely gloss over the extremely important and relevant technical information that is contained in that posting.
For me, there are only two outstanding issues and I will mention them again and I will put them in a better sequence this time:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
You are stating that you want to try to answer the question. That's a good thing and your first try is wrong, good luck.
MileHigh
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author=MileHigh link=topic=16589.msg483392#msg483392 date=1462705232]
MileHigh
Your answer is wrong and I already answered a more difficult version of the question on the other thread and I already told you I won't answer this question.
OK
If my answer is wrong,then it is now up to you to prove that by supplying the correct answer.
I have given my answer to your question,and you cannot just say it's wrong without being able to support that claim by supplying what you believe to be the correct answer.
We are only discussing the original question here ATM.
As I already stated, you make reference to an "R" resistance but there is none in the example being discussed.
MH
My reference to resistance is a value of 0 ohms.
Is not 0 ohms resistance no resistance? Your statement makes no sense ,as i do not state any resistance ,as 0 is none. I only say that,so as others reading the question understand that an ideal coil has 0 ohms of resistance--no resistance.
You are one strange egg Brad because you think you are "running the show" now but in fact the show is running you.
I am providing an answer to your question,and now you have to disprove my answer by way of supplying the one you think is correct.
You also make reference to a divide-by-zero for a time constant and state that it is "instantaneous" when it is infinity or undefined. You are told these two things are wrong in a later posting but like the Pope you pretend that you are infallible and can just "waive" past these two glaring errors because you are Brad.
I am told i am wrong by who MH?
You are all in a tizzy because I mention a "'trick' question." But unfortunately you have another case of crossed signals in your head. It's not my question in that posting that is the "trick," it's actually ION's follow-up question to my question that is the "trick." I say in jest to ION that his question is a "trick" question but that flies right over your head. Lo and behold, the signals get crossed in your head and you accuse me of asking a "trick" question when I did no such thing.
OK,so lets say that your question above is not a !trick! question as i have stated.
So now i will ask you (as you think i have it wrong)to calculate the time from T=0 in your question,it takes the ideal inductor to reach it's maximum current flow value,once the ideal voltage of 4 volts is placed across that coil.
But the most mind-blowing thing about that posting of yours is that you completely gloss over the extremely important and relevant technical information that is contained in that posting.
You mean IONs response to your question?,once again referring to an ideal voltage from an ideal power supply,being placed over an ideal inductor?.
Well let's leave ION out of this for a while,and let you answer the questions,as it is your question we are talking about here,and so you are the one that should be providing the required answers.
For me, there are only two outstanding issues and I will mention them again and I will put them in a better sequence this time:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
I have answered your question,and i stand by my answer.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
We are discussing your original question above only, in this thread at the moment.
You are stating that you want to try to answer the question. That's a good thing and your first try is wrong, good luck.
Regarding the question we are discussing in this thread(your original question to EMJ and Wattsup),i have answered the question correctly. If you believe i am wrong,then you must provide the evidence to show that.
So the questions i have for you MH are
1-how is the current time constant calculated for your ideal inductor/
2-What is the time taken for the current to rise to peak value from T=0,that moment when the ideal voltage of 4 volts is placed across the ideal inductor?.
Lets start with those two question's,and take it from there.
Brad
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If there is no resistor in the schematic then you do not discuss an imaginary zero-ohm resistor that you want to force into the schematic. It's a non-starter.
I told you Brad to try to work it out with your peers or work it out by yourself. I am not going to supply you with the correct answer. If I did that you would balk anyway and fight over it for 100 postings. I am not doing that.
"You are wrong."
"Okay, now give me the right answer."
It's not going to work like that.
You should say, "Okay, I will discuss it with my peers and go do more research and learn more and improve my skills so that I can answer the question successfully by myself."
You clearly have no understanding at all about how an inductor actually works. That is the essence of the question. Why don't you start there?
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Stop trolling Webby. Don't ruin a brand new thread.
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If there is no resistor in the schematic then you do not discuss an imaginary zero-ohm resistor that you want to force into the schematic. It's a non-starter.
I told you Brad to try to work it out with your peers or work it out by yourself. I am not going to supply you with the correct answer. If I did that you would balk anyway and fight over it for 100 postings. I am not doing that.
"You are wrong."
"Okay, now give me the right answer."
It's not not going to work like that.
."
You clearly have no understanding at all about how an inductor actually works. That is the essence of the question. Why don't you start there?
So you are not here to debate or discuss your question,but only to leave it to me to do all the work.
So much for you insisting on debating things ::) ::)
You should say, "Okay, I will discuss it with my peers and go do more research and learn more and improve my skills so that I can answer the question successfully by myself
My skills are fine thank you MH.
My answer to your question above is correct,and as you have provided no answer other than to say mine is incorrect,we can safely say your answer is incorrect,as i believe mine is correct,and you disagree with my answer.
As you have not provided any proof that my answer is incorrect,nor have you attempted to answer a couple of simple questions,we can assume that you cannot answer them,nor can you provide evidence that my answer is incorrect.
So as you do not wish to be a part of this debate,or help others find the answer to your question,i will post some answers for you.
Q1-can a voltage exist across an ideal inductor that has a DC current flowing through it.
Your answer MH (if you know your stuff)will be no,a voltage cannot exist across an ideal inductor that has a DC current flowing through it.
Have you ticked this box in the pole question?--seems not.
So now that you agree that a voltage cannot exist across an ideal inductor that has a DC current flowing through it,how can you have a voltage of 4 volts existing across an ideal inductor for 3 second's--an inductor that has no resistance?.
Brad
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<<< no,a voltage cannot exist across an ideal inductor that has a DC current flowing through it. >>>
And that's probably the only thing that you have stated about this subject so far that is correct.
I will repeat to you: I already answered a variation on the question that is actually more difficult to answer. I gave a complete and full answer. It's up to you and your peers to try to answer the simpler question if you want to.
I am just waiting and hoping for a successful conclusion. I will repeat: You clearly have no understanding at all about how an inductor actually works. That is the essence of the question. Why don't you start there?
If you don't get a guru parachuting in to help you and you and your peers are unable to answer a question about one of the simplest circuits possible, so be it.
These are the only two things I am interested in hopefully seeing a successful resolution to:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
MileHigh
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<<< no,a voltage cannot exist across an ideal inductor that has a DC current flowing through it. >>>
And that's probably the only thing that you have stated about this subject so far that is correct.
I will repeat to you: I already answered a variation on the question that is actually more difficult to answer. I gave a complete and full answer. It's up to you and your peers to try to answer the simpler question if you want to.
I am just waiting and hoping for a successful conclusion. I will repeat: You clearly have no understanding at all about how an inductor actually works. That is the essence of the question. Why don't you start there?
If you don't get a guru parachuting in to help you and you and your peers are unable to answer a question about one of the simplest circuits possible, so be it.
These are the only two things I am interested in hopefully seeing a successful resolution to:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
MileHigh
MH
I would suggest at this point in time,you review your question,and not treat your inductor as a normal inductor that !dose! have a series/parallel resistance.
You clearly defined the inductor and voltage as being !ideal!.
You said your question was not a trick question,so i think you need to go and calculate the L/R time constant for your ideal inductor--some how ???
Once you have that L/R time constant value,we then only need multiply that by 5 to get a close approximation for the time it takes that 5 henry ideal inductor to reach it's steady state current value after T=0-->the ideal voltage is applied across the ideal inductor.
All i ask is that you calculate the L/R time constant of your 5 henry ideal inductor.
Brad.
How are you to work out the L/R time constant when there is no R ???
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MH,
does the question ask for when T=0
It does not start when T>0 the question is for when T=0
T=0 is the start of the cycle --> the instant the ideal voltage is placed across the ideal inductor
Brad
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You are lost Brad and you should take my advice and start from scratch. And like usual you are completely baffling because some big clues were presented to you and they passed right through you like you weren't even there. I am giving you a 10% chance to get it right.
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A post from Magneticitist on the JT 101 thread
What I find curious about the whole 'Ideal' scenario no matter how useful it may be in real world applications.. An Ideal inductor is said to dissipate or radiate 0 energy, so technically it only passes current by putting faith in Ohms law's ability to handle the number 0.
I would think that in an ideal voltage source, connecting to an ideal inductor, nothing at all would happen because the voltage cannot waver, and the lack of resistance in the inductor would cause an infinite current were it not for an ideal inductor being unable to dissipate energy. If it cannot dissipate energy it perfectly contains on faith, we cannot possibly observe this energy and it might as well be at rest with no charge.
So even in the fantasy realm of imaginary voltage sources and coils that are ideal, an inductor can do no work unless it actually becomes something we cannot call 'ideal'. further evidence against this paradox of passing infinite current at 0 resistance.
MHs response to some one posting there thought's--and good ones at that.
I am just letting you know as a courtesy that you clearly have no idea what you are talking about.
So now myself,EMJ,Wattsup and Magneticitist are wrong,and MH is yet to post an answer to his own question,nor seems that he is willing to provide any information or answers to other simple questions asked of him.
Brad
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You are lost Brad and you should take my advice and start from scratch. And like usual you are completely baffling because some big clues were presented to you and they passed right through you like you weren't even there. I am giving you a 10% chance to get it right.
Quote:
The time constant τ is an indicator of how long current takes to increase from zero to its steady-state value.
Here is a useful rule of thumb:
For most practical purposes, we may assume that all quantities in a DC RL circuit have reached their steady-state values after five time constants.
So if a circuit has a time constant of 1 millisecond, then it will take about 5 milliseconds for the circuit's currents and voltages to reach their steady-state values.
Since one time constant is equal to L÷R, we can write this rule of thumb as an equation:
Time to reach steady state ≈ 5×L÷R
So MH,if your !very large! 5 henry coil had a resistance value of say 5 ohms,then it would take 1 second to reach it's time constant,and 5 seconds to reach a steady state current flow.
If your 5 henry coil had just .0001 ohms resistance,then it would take 50,000 seconds to reach it's time constant,and 250,000 seconds to reach a steady state of current flow.
As your coil is ideal,it has no resistance.
So i ask again--how are you going to calculate the time constant of your ideal coil>?
Brad
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The answer is that there is no time constant. A variation on the same question was already answered.
That's it, from this point on you can moan and groan and whine and complain all you want. A better scenario is you tasking yourself with this:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
If you try and make a good sincere effort of it but don't get there, then good show. If you get there then great show. But if you just whine for an answer and sit on your fanny and complain then you are going to have to hope that a guru comes along and spoon feeds you. But of course if you are spoon fed then chances are in two weeks you will be a blank slate.
It's up to you.
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In an ideal voltage source the source Emf would be fixed and an ideal inductor would have virtually no losses. It seems to me no current could flow because the moment a charge tried to moved due to the ideal voltage source Emf the ideal inductor would produce an equal and opposite Cemf to oppose it. Ideally if the source Emf is always instantaneously opposed by the inductors Cemf then nothing can move, a stalemate.
AC
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@AllCanadian seems a reasonable deduction that follows logic. welcome to the club of having no idea.
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@Magneticists
seems a reasonable deduction that follows logic. welcome to the club of having no idea.
Logically, the fact that I expressed my idea here indicates I must have one and the presumption that just because my idea may not agree with yours that it's incorrect is false. However I have no indication that you have any idea which is why grown ups need to use "their words" and convey what they mean in an intelligent manner... such as technical debate on the issue at hand.
AC
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Brad,
Here are two small but significant hints:
1) brush up on what it means mathematically when any number is divided by 0 (don't assume you are correct, verify it).
2) MH's question is regarding what happens at t=0, i.e. the instant the Vsource is connected (MH, please confirm).
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@Magneticists
Logically, the fact that I expressed my idea here indicates I must have one and the presumption that just because my idea may not agree with yours that it's incorrect is false. However I have no indication that you have any idea which is why grown ups need to use "their words" and convey what they mean in an intelligent manner... such as technical debate on the issue at hand.
AC
Well said
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Poynt:
Here is the question again:
<<<
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts. Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts. Then after that the voltage is zero volts.
What happens starting from t=0.
>>>
So the time frame is from 0 seconds to "beyond 13 seconds."
MileHigh
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Brad,
Here are two small but significant hints:
1) brush up on what it means mathematically when any number is divided by 0 (don't assume you are correct, verify it).
2) MH's question is regarding what happens at t=0, i.e. the instant the Vsource is connected (MH, please confirm).
OK look I have to ask you out of genuine respect for this conversation.. How did you come to ask Brad those questions? In the beginning of this thread he stated:
"My answer to this question is--you cannot place an ideal voltage across an ideal inductor.
The reason being,at T=0,when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity."
with his own words he said he understands that MH's T=0 was in reference to the initial connection of the vsource.
the issue is an ideal source being placed across 0 resistance. whether it's a coil or straight wire doesn't really matter in this context.
to answer the question of what happens the very instant the ideal vsource is connected to the ideal coil?
T=0 THE VOLTAGE CONNECTS TO THE COIL, THAT'S WHAT HAPPENS.
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Look at this posting: http://overunity.com/8341/joule-thief-101/msg483361/#msg483361
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Thanks MH for correcting me.
Although the question involves t=0 to t=13s, knowing what happens right at t=0 (the moment Vsource connects the inductor) is important.
It's also important to know what results when a number is divided by 0.
Let's see if examining this causes Brad to come to a different answer.
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Somebody has to go back to basics, it might as well be me.
The definition of an ideal inductor is a two-terminal device that obeys the current/voltage relationship:
V = L dI/dt where V is the applied voltage, L is the inductance in Henries and dI/dt is the rate of change of the current with time. The impedance of the voltage source and the resistance of the inductor are both assumed to be zero.
This definition can be rewritten as dI.dt = V/L. Given an initial current of zero, applying 4 V to a 5 H inductor leads to a current through the inductor that increases at 0.8 amps per second. After three seconds the current will be 2.4 amps. If the supply is not turned off the current will increase indefinitely at 0.8 A/second. There are no time constants involved.
For completeness, a capacitor is a two-terminal device the current through which is given by the equation:
I = C dV/dt where C is the capacitance in Farads. The current through the capacitor is proportion to the rate of change in the applied voltage times the capacitance. In this case applying a fixed current results in a voltage across the capacitor that increases indefinitely.
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Thanks MH for correcting me.
Although the question involves t=0 to t=13s, knowing what happens right at t=0 (the moment Vsource connects the inductor) is important.
It's also important to know what results when a number is divided by 0.
Let's see if examining this causes Brad to come to a different answer.
I just googled a few math sites and they all said that you can not divide any number by 0. It is impossible and incorrect to do so.
So, now my question is...why is that? One site said that you would get infinity by doing this which is why you can't do this. Gee, and I thought I understood simple math, ha ha.
The intuitive answer, at least for me, would have been that division means breaking something into a certain number of equal parts and if there are no divisions into equal parts, then you are left with the original amount undivided. But, this fails the multiplication test when you multiply the answer to double check it....
10 divided by 0 = 10. Then 10 times 0 should equal 10, and of course it does not. So, 10 divided by 0 either equals infinity, 0 or, it is undefined. Some say it can't be done. All of this depends upon which math sites you want to believe.
Bill
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In an ideal voltage source the source Emf would be fixed and an ideal inductor would have virtually no losses. It seems to me no current could flow because the moment a charge tried to moved due to the ideal voltage source Emf the ideal inductor would produce an equal and opposite Cemf to oppose it. Ideally if the source Emf is always instantaneously opposed by the inductors Cemf then nothing can move, a stalemate.
AC
Lol. I said that a few times on this site. Just did yesterday. ;) ;)
Like are we taking about an ideal inductor that has no magnetic fields? Like I said yesterday, it could be just the field charge before the ideal switch connects that could set up an ideal BEMF standoff and no current would ever flow, inductor or even a straight wire Im glad someone here is on the same level of thinking as I am on this. ;) ;)
Mags
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I just googled a few math sites and they all said that you can not divide any number by 0. It is impossible and incorrect to do so.
So, now my question is...why is that? One site said that you would get infinity by doing this which is why you can't do this. Gee, and I thought I understood simple math, ha ha.
The intuitive answer, at least for me, would have been that division means breaking something into a certain number of equal parts and if there are no divisions into equal parts, then you are left with the original amount undivided. But, this fails the multiplication test when you multiply the answer to double check it....
10 divided by 0 = 10. Then 10 times 0 should equal 10, and of course it does not. So, 10 divided by 0 either equals infinity, 0 or, it is undefined. Some say it can't be done. All of this depends upon which math sites you want to believe.
Bill
Maybe we wouldnt have to worry with the 0 value for resistance, where it may be replaced by a time of electron travel over a distance. Can an electron move faster than the speed of light? Is the speed of light infinity or instantaineous? So there would still be a time thing to work with as I dont think T=0 can even exist. It means no time, nothing happened because that time didnt exist. ;)
Mags
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Thanks MH for correcting me.
Although the question involves t=0 to t=13s, knowing what happens right at t=0 (the moment Vsource connects the inductor) is important.
It's also important to know what results when a number is divided by 0.
Let's see if examining this causes Brad to come to a different answer.
When you divide one number !x! by another number !y!,it is asking you to work out how many !y's! will fit into !x!,so how many 0's in 10?.
So to work out the L/R time constant,when the value of R is 0,then the answer is infinity,and so inductance in this case with the inductor being ideal, dose not play a part in current rise time. That being the case,you are placing an ideal voltage across a perfect dead short.
All L/R time constants are based around the ideal inductor where the resistance value is added in series with the inductor ,by way of a resistor that is external to the inductor. As the current rises,the voltage across the inductor drop's until it reaches a value of 0 volts. The problem here is that we have an ideal voltage that dose not drop,and there for the current will continue to rise to an infinite amount. If we remove the series resistor from our ideal inductor,we have a dead short due to the L/R time constant being infinite,and playing no part in current rise time.
Like MH said--there is !no! time constant,as it is infinite.
And so we now have an ideal voltage-->a voltage that will not change,being placed across a short that will not allow a voltage potential to exist across it.
So i stand by my answer-->you cannot place an ideal voltage across an ideal inductor.
If you did(theoretically),the current would rise instantly to an infinite value.
Brad
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When you divide one number !x! by another number !y!,it is asking you to work out how many !y's! will fit into !x!,so how many 0's in 10?.
So to work out the L/R time constant,when the value of R is 0,then the answer is infinity,and so inductance in this case with the inductor being ideal, dose not play a part in current rise time. That being the case,you are placing an ideal voltage across a perfect dead short.
All L/R time constants are based around the ideal inductor where the resistance value is added in series with the inductor ,by way of a resistor that is external to the inductor. As the current rises,the voltage across the inductor drop's until it reaches a value of 0 volts. The problem here is that we have an ideal voltage that dose not drop,and there for the current will continue to rise to an infinite amount. If we remove the series resistor from our ideal inductor,we have a dead short due to the L/R time constant being infinite,and playing no part in current rise time.
Like MH said--there is !no! time constant,as it is infinite.
And so we now have an ideal voltage-->a voltage that will not change,being placed across a short that will not allow a voltage potential to exist across it.
So i stand by my answer-->you cannot place an ideal voltage across an ideal inductor.
If you did(theoretically),the current would rise instantly to an infinite value.
Brad
You may wish to exercise a few examples to see if your conclusion is correct. Your conclusion being that if the time constant (Tau) is infinite, the load immediately presents itself as a perfect short, meaning the current will be infinite and instantaneous.
Here are a few: (in all cases, L=6H)
1) R=1, Tau=6s
2) R=0.1, Tau=60s (1min)
3) R=1m Ohm, Tau=60ks (16.6 hours)
4) R=1u Ohm, Tau=6M(million)s (1667 hours)
5) etc.
What is happening to Tau as R decreases?
If R could be 0, Tau must be infinite.
What happens to the inductor current after t=0 when Tau=infinity?
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then we have the extra confusing idea that whether a real coil or ideal coil, at T=0 the current is at absolute 0 because there is absolutely no resistance to yield a voltage drop, it's at a maximum across the coil. there is absolutely no current flow to yield a magnetic field, because the magnetic field that will not be created without current is opposing the current flow. hmm.
a superconductive coil will yield no external field because it perfectly contains it within the conductor resisting current change, perfectly. with absolute 0 resistance we are approaching an infinite magnetic field force and thus an infinite reactance. since infinity cannot overpower infinity, they simply cancel each other out in practice.
resistance is the factor that prevents a conductor from perfectly resisting an exterior magnetic field because its the factor that resists current.. with 0 resistance there is perfect opposition like a super cooled conductor opposing a magnet. in essence, can't an absolute 0 resistance in a conductor/inductor be considered both a dead short AND open circuit at the same time?
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then we have the extra confusing idea that whether a real coil or ideal coil, at T=0 the current is at absolute 0 because there is absolutely no resistance to yield a voltage drop, it's at a maximum across the coil. there is absolutely no current flow to yield a magnetic field, because the magnetic field that will not be created without current is opposing the current flow. hmm.
a superconductive coil will yield no external field because it perfectly contains it within the conductor resisting current change, perfectly. with absolute 0 resistance we are approaching an infinite magnetic field force and thus an infinite reactance. since infinity cannot overpower infinity, they simply cancel each other out in practice.
resistance is the factor that prevents a conductor from perfectly resisting an exterior magnetic field because its the factor that resists current.. with 0 resistance there is perfect opposition like a super cooled conductor opposing a magnet. in essence, can't an absolute 0 resistance in a conductor/inductor be considered both a dead short AND open circuit at the same time?
There ya go. ;) Resistance is a necessity for current to flow. ;D Lol ;D
Mags
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There ya go. ;) Resistance is a necessity for current to flow. ;D Lol ;D
Mags
I have actually always believed this and it's hard for me to think otherwise.
I can't help it no matter how foolish it may seem.
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In all this, we havnt considered a load to be included. If we have the ideal supply and ideal wires and just a normal dc motor, then what? The ideal supply produces 12v and the normal motor is rated at 12v. So if current flows, we could run those wires a very long distance with no loss. So if we had the ideal supply and ideal say twisted pair run out to say 10miles, would there be 12v potential available at the end of those wires and would the motor run? Now I might think that the twisted pair would act like a cap, so there should be potential at the end, 10 miles down the road.
lol, soo if we twisted our wire first and then connected it to the ideal supply, would there be the end of the universe event? And even if we ran 1 wire N 10 miles and the other S 10 miles to reduce the capacitance as much as possible(and lets idealize that it was done in an ideally empty universe ::) will it ever end) there would still be a capacity. So Boom I suppose. ::)
There must be a need for ideal current limiters?? ??? ::) ;) Gees. Im going to think about this stuff every time I see or hear the word 'Ideal' ::)
Mags
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I have actually always believed this and it's hard for me to think otherwise.
I can't help it no matter how foolish it may seem.
I have said it before also, considering... ;) Im just lol that someone else finally said it. ;) ;D
Mags
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So the questions i have for you MH are
1-how is the current time constant calculated for your ideal inductor/
Like any other inductor.
2-What is the time taken for the current to rise to peak value from T=0,that moment when the ideal voltage of 4 volts is placed across the ideal inductor?.
Indeed this question is germane to the original question, What is your answer?
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the question has 5H , time secs and +/- volts given , and zero volt crossing
1H = current changing @ 1 A per SECOND resulting in emf of 1V across an inductor
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@Magneticitist
I have actually always believed this and it's hard for me to think otherwise. [/size]I can't help it no matter how foolish it may seem.
Think of space, charges move producing a magnetic field and there is no resistance. Supposedly empty space conducts just like a vacuum tube thus in 99% of the universe a complete lack of resistance is in fact the norm. The only problem with understanding nature seems to be human nature and their odd preoccupation with math, numbers and equations... the proverbial rabbit hole.
AC
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Like any other inductor.
Indeed this question is germane to the original question, What is your answer?
How do you calculate the L/R time constant, when there is no R
My answer has already been posted--the current rise is instant-or at the speed of light-close enough,as there is no resistance to appose the current flow.
You posted a comment on th JT thread not long ago Poynt,and it was-- @T=0,one would think the universe would blow up.
Brad
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T=0 is The Big Bang.
Think about it. There was no time prior to that event so it had to be 0.
Bill
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You may wish to exercise a few examples to see if your conclusion is correct. Your conclusion being that if the time constant (Tau) is infinite, the load immediately presents itself as a perfect short, meaning the current will be infinite and instantaneous.
Here are a few: (in all cases, L=6H)
1) R=1, Tau=6s
2) R=0.1, Tau=60s (1min)
3) R=1m Ohm, Tau=60ks (16.6 hours)
4) R=1u Ohm, Tau=6M(million)s (1667 hours)
5) etc.
What is happening to Tau as R decreases?
If R could be 0, Tau must be infinite.
What happens to the inductor current after t=0 when Tau=infinity?
As i said before,if Tau is infinite,there is no inductance,and so there is nothing to create the BEMF that apposes the applied EMF,and so now the applied EMF is across a dead short,as an ideal inductor has no resistance.
This results in an instant current rise to an infinite value.
Brad
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T=0 is The Big Bang.
Think about it. There was no time prior to that event so it had to be 0.
Bill
The big bang at T=0 was the creation of the universe. Poynt said that the universe would blow up at T=0,meaning that the universe was already in existance.
Brad
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Come on tinman, the answer's in the question.
John.
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the time constant for the inductor is based upon the concept that an inductor can never actually reach infinity, but never actually has a 'maximum' throttle. it just starts to become too difficult to distinguish the differences between the mathematical volumes of natural logarithm after the 5th time constant.
this does not help the hypothetical non resistant coil situation supplied with an infinite current/voltage ratio.
I personally do not quite understand the initial question as it seems vague, or I simply am not interpreting it properly being that as Brad said these types of exercises usually involve a series resistance. MH has made it clear a resistance is not required to run the test but even if our coil reaches a discernible infinity limit in 20 seconds that still doesn't change the basic principle of the question Brad has an issue with, the general idea of a proposed ideal voltage source meeting a proposed 0 resistance conductor, and substituting R=0 with R=1.
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Come on tinman, the answer's in the question.
John.
The answer is not in the question,as the question is based around an inductor that dose not exist,and a voltage source that also dose not exist--that being the !!ideal! part of the question.
There for,the answer to this question will only be a theoretical answer,as the circuit cannot be tested to obtain the correct answer.
I dont think MH gave much thought to his question,or the outcome of installing the !ideal! parts to this !so called! simple circuit. As soon as you add things that do not exist,the question becomes far from simple,as there are no results obtained from such a circuit in test before.
It's much the same as those that theorize that anything that travels at the speed of light,will have infinite mass--a theory that !as yet! cannot be backed up by a practical test. Light travels at the speed of light,and it dose not have infinite mass :o.
So when i say that you cannot hook an ideal voltage across an ideal coil,you actually cannot do it,as both the ideal coil and ideal voltage do not exist,so i am technically correct.
Then comes the theoretical conundrum of trying to work out the question.
MH states that there is no time constant for current rise within the inductor,and i agree on this. But here is the conundrum.
The time constant is either 0 or infinite for maximum current flow through the inductor at T=0-->the moment the ideal voltage is placed across the ideal coil.
If the time constant is 0,that means that the current through the ideal inductor will rise instantly to an infinite value--as we have an ideal voltage source across the ideal inductor.
If the time constant is infinite for maximum current through the ideal inductor,then that means that no current flows through the inductor--ever,because if it takes an infinite amount of time to reach maximum current flow through the coil,then it also takes an infinite amount of time to reach a 10% value of maximum current flow through the ideal inductor,and it takes an infinite amount of time to reach 1% of the maximum amount of current flow through the ideal inductor--and so on. So it will take an infinite amount of time before current even starts to flow--so there will never be any current flow through the ideal inductor.
Now here comes the conundrum part. The ideal inductor has no resistance,and so now our ideal voltage is placed across a dead short,and that means an infinite amount of current will flow instantly.
At T=0,an ideal voltage of 4 volts is placed across the ideal inductor,for a period of 3 second's.
Either way you look at it,this is something that cannot happen--as i have stated many times now in my answer to the question.
The next problem is this.
I can claim my answer to be correct,and no one can disprove it,as the ideal inductor and ideal voltage source do not exist.
MH could say his answer is correct,and i could not prove it to be wrong,as i have no way of testing his theory.
MH stated that the question is not a trick question,but based on the fact that he is using an inductor that dose not exist,being supplied a voltage from a source that also dose not exist,how is any body to answer the question correctly,when such a circuit cannot be tested?.
Brad
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Just answer the question.
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Brad,
Here are two small but significant hints:
2) MH's question is regarding what happens at t=0, i.e. the instant the Vsource is connected (MH, please confirm).
1) brush up on what it means mathematically when any number is divided by 0 (don't assume you are correct, verify it).
The only time 0 is used as a divisional number(that im aware of),is in computer arithmetic. But even then,it must be assigned with either a + or- value,and even then,the resultant value of the division is either negative infinity,or positive infinity.
There are no other cases i know of,or could find,where anything can be divided by 0,and result in a defined number or amount. Every attempt at explaining that a number remains unchanged when divided by zero failed.
Brad
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Just answer the question.
I have answered the question many times.
Where are you reading?.
Brad
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Just answer the question.
Here is an idea John.
Instead of posting pictures of your farm animals,and non related comments--post your answer to the question here on this thread :D
Brad
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I think the confusion lies in the general ridiculousness of the intended point.
The question is apparently geared to asses your knowledge of circuit operation by seeing how institutionalized you are regarding EE fundamentals as they are taught in a classroom setting.
no matter the logic you provide, until you work out some mathematical answer in detail based upon the numbers given your answer will not be considered. If you worked out the math to please them it would be pointless because as you have already stated you are in disagreement with the general nature of the question.
it's kind of like walking up to a mechanic who can take an engine apart and put it back together in better working condition than it started and saying "hey, work out how long this engine is going to last in minutes assuming I drove it 24hrs a day at at 50 mph, and there's no friction anywhere in the mechanical operation.. do it on paper and show me your entire work... oh? you can't? you clearly have no idea what you're doing then and should probably learn how to use a wrench before putting that engine back together"
MH and others want the question to be answered in the same form it would if you were a student in their EE class and it was assigned as a piece of homework. I'm not entirely sure the specifics of what they even want worked out, but I'd imagine a detailed explanation of the near characteristics of the coil over a scale of time given L is 5H. but is that even a common kind of EE question the way it was asked? Right now I'm in the position of just being curious as to how they want the question answered. I feel like I can actually learn something from this exercise but it's being made more difficult than it needs to be.
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I don't want to spoil the fun, you'll get there in the end!
John.
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Yes, all this does not detract from the ideal voltage source not being able to drop to anything else but its ideal voltage even in time. There would not be an eventual drop to 0 volts because the source would not care about an ideal inductor in any case, infinity or not. So............. even if the current rose to infinity and the inductor was totally destroyed, you would still have your source voltage unchanged. And there in lies the chicken and egg rub.
As well, you can analyze this until the cow jumps over the moon, but you will still not know what actually happens inside a coil and @MH, that includes you. Just because you can rationalize or try to rationalize these mind games, not one iota will be discovered on the coils true function, you are still stuck with only the mind effect.
Actually this is a good comparison for me because in SC current is the number of atoms active in energy conveyance and voltage is the depth at which conveyance occurs. Put 1 volt in a 5H coil that has a cvr tapped in the coil center and wait. The current having a finite number of atoms in the inductor, ideal or not, would be the limiting factor so you would not have any need to ponder ideal conditions to actually know what is happening inside your coil. Hence why I asked the question of wire gauge tables not defining their complete tests. Meanwhile you guys would still be scratching your heads wondering how a coil can handle infinite current.
So the question for you guys is simple. How can an ideal voltage provide infinite current. That is like saying a 46AWG wire should be able to render an infinite AWG wire red hot for infinity. hahaha And this is the same EE that calls OUers out-of-the-box crazy.
Maybe it's better to just chew on ideal gum with ideal jaws.
wattsup
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I think the confusion lies in the general ridiculousness of the intended point.
The question is apparently geared to asses your knowledge of circuit operation by seeing how institutionalized you are regarding EE fundamentals as they are taught in a classroom setting.
no matter the logic you provide, until you work out some mathematical answer in detail based upon the numbers given your answer will not be considered. If you worked out the math to please them it would be pointless because as you have already stated you are in disagreement with the general nature of the question.
There is nothing ridiculous about the intended points. One point is to understand how an inductor works. Another point is to be able to look at a schematic diagram and have a better preliminary sense of what what might be going on in the schematic. Another point would be to be better able to design a circuit to do what you want it to do. Another point would be to be better able to analyze a circuit that you have built. Another point would be to be able to look at a scope trace as a passive observer vs. looking at a scope trace and relating it directly back to your circuit and understanding the waveform and why it is shaped the way it is.
Who says you have to give a mathematical answer for starters? Why not just try to answer the question on a conceptual level for starters and then see if you can move on to a more formal answer? The field is entirely wide open to you but I am not seeing much movement on that field.
On the other thread I clearly showed you how close an ideal inductor can be to a real-world inductor in an actual working circuit. I showed you that ideal voltage sources are available right now, and anybody can play with one.
What I an seeing from you so far is that you are just blindly believing what Brad is saying. The problem is that Brad is wrong. So why don't you try to brainstorm and come up with something new?
The simple truth is this: Brad has stuck with his wrong answer for a few days. Instead of sticking to the wrong answer he could have been researching this stuff over the past few days and who knows he could have already made a breakthrough and then he could have started moving towards the actual answer.
I will repeat, this question is valid and very important if you want to experiment with coils and make pulse motors, the whole nine yards. I admit it's a bit stark to come face to face with the fact that you play with coils all the time on your bench but you don't understand how they work. Do do you remain sour and suck on bitter lemons all day, or do you try to turn lemons into lemonade?
Certainly, just refusing to do anything except repeat the same thing is not productive.
MileHigh
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I think the confusion lies in the general ridiculousness of the intended point.
The question is apparently geared to asses your knowledge of circuit operation by seeing how institutionalized you are regarding EE fundamentals as they are taught in a classroom setting.
no matter the logic you provide, until you work out some mathematical answer in detail based upon the numbers given your answer will not be considered. If you worked out the math to please them it would be pointless because as you have already stated you are in disagreement with the general nature of the question.
it's kind of like walking up to a mechanic who can take an engine apart and put it back together in better working condition than it started and saying "hey, work out how long this engine is going to last in minutes assuming I drove it 24hrs a day at at 50 mph, and there's no friction anywhere in the mechanical operation.. do it on paper and show me your entire work... oh? you can't? you clearly have no idea what you're doing then and should probably learn how to use a wrench before putting that engine back together"
MH and others want the question to be answered in the same form it would if you were a student in their EE class and it was assigned as a piece of homework. I'm not entirely sure the specifics of what they even want worked out, but I'd imagine a detailed explanation of the near characteristics of the coil over a scale of time given L is 5H. but is that even a common kind of EE question the way it was asked? Right now I'm in the position of just being curious as to how they want the question answered. I feel like I can actually learn something from this exercise but it's being made more difficult than it needs to be.
Like i said,i dont think MH thought about his question very well when he included ideals in it.
Do we even have an inductor in the question?.
Well from an EEs view ,they may think they do,but from an outsiders view,there may be no inductor at all.
What are the properties of an ideal inductor?
An ideal inductor has no resistance,no capacitance,but only inductance ???
How can it have inductance if it has no resistance?
Well before the EE guys go--what the hell are you talking about,lets look at the meaning of resistance and inductance.
Resistance-->Resistance is the friction in an electrical circuit that controls the flow of current
Inductance--> Inductance is typified by the behavior of a coil of wire in resisting any change of electric current through the coil
So a resistor controls the flow of current,and inductance resist any change in current. So it would seem that the inductor also tries to control the flow of current by resisting any change to it.
So inductance is a resistance,and an ideal coil has no resistance.
So dose this mean that it has no inductance?
MH and others want the question to be answered in the same form it would if you were a student in their EE class and it was assigned as a piece of homework.
Im not interested in there !theoretical! answers,im looking for the correct answer to the question.
All circuits are modeled using a resistor in series with the ideal inductor,so as to represent real world inductors. We need to model this circuit without the resistor,and i know just the man for the job.
Poynt
This will be one of very few times you hear me say this ;D
Can you use your sim to model the circuit :o
I believe you have tried this before ;)
Now,you have said on many occasions that the sim will produce actual result's,so lets see it produce some results regarding MHs ideal inductor with an ideal voltage across it-->lets see what happens.
No need to post the answer--just tell us if your sim was able to show real world results based around MHs parameters--that being a 5 Henry ideal coil,with a 4 volt ideal voltage across it for 3 seconds-->the first part of the cycle in MHs question.
Brad
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There is nothing ridiculous about the intended points. One point is to understand how an inductor works. Another point is to be able to look at a schematic diagram and have a better preliminary sense of what what might be going on in the schematic. Another point would be to be better able to design a circuit to do what you want it to do. Another point would be to be better able to analyze a circuit that you have built. Another point would be to be able to look at a scope trace as a passive observer vs. looking at a scope trace and relating it directly back to your circuit and understanding the waveform and why it is shaped the way it is.
Who says you have to give a mathematical answer for starters? Why not just try to answer the question on a conceptual level for starters and then see if you can move on to a more formal answer? The field is entirely wide open to you but I am not seeing much movement on that field.
What I an seeing from you so far is that you are just blindly believing what Brad is saying. The problem is that Brad is wrong. So why don't you try to brainstorm and come up with something new?
The simple truth is this: Brad has stuck with his wrong answer for a few days. Instead of sticking to the wrong answer he could have been researching this stuff over the past few days and who knows he could have already made a breakthrough and then he could have started moving towards the actual answer.
I will repeat, this question is valid and very important if you want to experiment with coils and make pulse motors, the whole nine yards. I admit it's a bit stark to come face to face with the fact that you play with coils all the time on your bench but you don't understand how they work. Do do you remain sour and suck on bitter lemons all day, or do you try to turn lemons into lemonade?
Certainly, just refusing to do anything except repeat the same thing is not productive.
MileHigh
On the other thread I clearly showed you how close an ideal inductor can be to a real-world inductor in an actual working circuit. I showed you that ideal voltage sources are available right now, and anybody can play with one.
No such voltage or inductor exist--not even close.
The fact is MH,and this is an absolute fact,you cannot back up your answer with a real world test to show you are correct.
There is no such thing as an ideal inductor,nor is there any such thing as an ideal voltage.
An ideal inductor has no resistance,and inductance it self produces resistance-a resistance to the change in current. So an ideal inductor dose not exist for that very reason,and there for your question cannot be answered-well maybe in MH fairy land.
An ideal voltage also dose not exist. There is no device that can provide an infinite amount of current to maintain an ideal voltage across a dead short that is also ideal-being a short that will never collapse under any load.
"Can God create a stone so heavy that even God is not strong enough to lift it?" God, being almighty, should be able to create this stone but if He does, he cannot move it meaning he is not almighty. However, if God cannot create this stone, the same problem arises.
Brad
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Yes, all this does not detract from the ideal voltage source not being able to drop to anything else but its ideal voltage even in time. There would not be an eventual drop to 0 volts because the source would not care about an ideal inductor in any case, infinity or not. So............. even if the current rose to infinity and the inductor was totally destroyed, you would still have your source voltage unchanged. And there in lies the chicken and egg rub.
As well, you can analyze this until the cow jumps over the moon, but you will still not know what actually happens inside a coil and @MH, that includes you. Just because you can rationalize or try to rationalize these mind games, not one iota will be discovered on the coils true function, you are still stuck with only the mind effect.
Hence why I asked the question of wire gauge tables not defining their complete tests. Meanwhile you guys would still be scratching your heads wondering how a coil can handle infinite current.
So the question for you guys is simple. How can an ideal voltage provide infinite current. That is like saying a 46AWG wire should be able to render an infinite AWG wire red hot for infinity. hahaha And this is the same EE that calls OUers out-of-the-box crazy.
Maybe it's better to just chew on ideal gum with ideal jaws.
wattsup
Lots of unproductive sour grapes. You have got to be kidding about the "mind games." The intention behind this question is to understand how a coil works in the real world. For many experimenters it's possible that mastering this will open up a whole new world of true understanding for them, and instead of just being passive builders and observers, they will become active designers and analyzers. What's the classic question among builders? "What wire gauge and how many turns?" They think that if they are mindless replicators then some magic will happen. For a given project, who says the wire gauge is that important? For a given project, who says the number of turns is that important? Well if you have no clue you may as well just replicate and do what you are told to do, right?
The issue of "infinite current" is irrelevant. The question of a certain wire gauge getting too hot at a certain current level is irrelevant.
There was a time when I explained to some beginners that the simple model for a battery that you use every day on your bench is an ideal voltage source in series with a resistor. That explains why the battery voltage drops under load. Look at that, an appearance of the dreaded ideal voltage source. They were aghast just by the notion of "There is a resistor inside the battery!!??" So for some people it's "radical" to actually try to understand how an inductor works. The wiser people will want to understand this and they will be able to apply it to the work they do on their bench.
MileHigh
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No need to post the answer--just tell us if your sim was able to show real world results based around MHs parameters--that being a 5 Henry ideal coil,with a 4 volt ideal voltage across it for 3 seconds-->the first part of the cycle in MHs question.
The sim will work perfectly and I am glad that you don't want to see it. The way you have to "see it" is to use your intellect to understand how an inductor works.
You are clearly still stuck like glue to your mistake. The only question is what do you do? Do you stick it out and refuse to explore other options until at the end you are spoon fed the answer? If you agree the answer is correct then you will have a rather embarrassing little apology to offer up. Or, do you do what I suggested to you: Assume for the sake of argument that I am right and for your own benefit start working and researching so that you come to a complete understanding on your own? Which of the two scenarios do you think will ultimately be better for you?
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No such voltage or inductor exist--not even close.
The fact is MH,and this is an absolute fact,you cannot back up your answer with a real world test to show you are correct.
There is no such thing as an ideal inductor,nor is there any such thing as an ideal voltage.
An ideal inductor has no resistance,and inductance it self produces resistance-a resistance to the change in current. So an ideal inductor dose not exist for that very reason,and there for your question cannot be answered-well maybe in MH fairy land.
An ideal voltage also dose not exist. There is no device that can provide an infinite amount of current to maintain an ideal voltage across a dead short that is also ideal-being a short that will never collapse under any load.
Brad
A real inductor can be 99.99% identical to an ideal inductor. Ideal voltage sources exist right now within certain limitations. A good bench power supply is an ideal voltage source. A car audio amplifier is an ideal voltage source that can output The Star Spangled Banner as an ideal voltage. I explain that all on the other thread.
The real-world test can easily be done as explained on the other thread. The only limitation is that the real-world inductor will behave a tiny smidgen differently from the ideal inductor.
You are just making phony dismissive arguments that take you off track. The point of the exercise is perfectly clear: To understand how an inductor works.
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The way you have to "see it" is to use your intellect to understand how an inductor works.
The only question is what do you do? Do you stick it out and refuse to explore other options until at the end you are spoon fed the answer? If you agree the answer is correct then you will have a rather embarrassing little apology to offer up. Or, do you do what I suggested to you: Assume for the sake of argument that I am right and for your own benefit start working and researching so that you come to a complete understanding on your own? Which of the two scenarios do you think will ultimately be better for you?
The sim will work perfectly and I am glad that you don't want to see it.
I think you will find that it will not,well at least it did not on the thread i read on OUR.
Poynt had to add a resistance in series with the ideal inductor,and as your question dose not include a resistance,then the sim must represent your ideal inductor that has no resistance.
You are clearly still stuck like glue to your mistake.
As you ,nor anyone else has proven that i have made a mistake,then my answer stands-you cannot connect an ideal voltage across an ideal inductor.
Brad
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Considering a sim to provide an answer here is a good thing because all simulators I've used will not allow an inductor with zero resistance. Some low value will be assigned if the operator fails to fill in the blank. So, what we have to consider is what happens as the resistance approaches zero.
For example, what will the current be at T=0 when we apply the assumed ideal voltage source of 4 volts to the 5 henry inductance with a dc resistance of 1 ohm? Will it be 4 amps? How about .01 ohm, will it be 400 amps or? How about 1e-10 ohms, will it be 4e10 amps?
Looking at the problem from another angle, if we assume we had somehow achieved a current level of 2.4 amps in our ideal inductor with zero resistance and we then shorted it with a perfect conductor having zero resistance, what happens to the inductor current?
partzman
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Somebody has already posted on this thread very recently how an ideal inductor behaves. I am sure that you can sense that Poynt is in agreement with me.
The best course of action for you would be to understand what inductance really is an how it behaves. You are arguing that there is a radical discontinuity between how an ideal inductor behaves and a real-word inductor with a 0.0000000001 ohm wire resistance behaves. Nature does not like discontinuities at all. Just that fact should get you thinking again and hopefully find you going in the right direction.
"Nature does not like discontinuities at all."
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I am really surprised that a sim program would balk at an ideal inductor but if that's the case there must be a circuit condition where there is a problem. However, in my my example I can't see the sim encountering a problem like a divide-by-zero error or whatever.
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author=MileHigh link=topic=16589.msg483533#msg483533 date=1462796493]
You are just making phony dismissive arguments that take you off track. The point of the exercise is perfectly clear: To understand how an inductor works.
No MH. You are making claims you cannot back up,as you do not have access to an ideal inductor.
A real inductor can be 99.99% identical to an ideal inductor.
99.99% of infinity is an infinite amount away from ideal MH. This may shock you ,but the difference between 99.99% and absolute can be extremely large.
When i asked what the L/R time constant was,you said there isnt one.
With your non ideal coil(being the one that is 99.99% close to ideal)there is an L/R time constant,and so that coil has a finite L/R time constant,where as the ideal coil has either a time constant of 0,or it is infinite. These two values are far from your 99.99% close enough is near enough coil,as it is not even close.
Like i said,you should have thought about your question a little better.
Ideal voltage sources exist right now within certain limitations. A good bench power supply is an ideal voltage source. A car audio amplifier is an ideal voltage source that can output The Star Spangled Banner as an ideal voltage. I explain that all on the other thread.
They are not ideal at all.
An ideal voltage dose not change--at all,when a load is placed across it-not even by .0000001 of a volt. The ideal power supply would need an ideal transformer,and ideal FWBR,and all other components would have to be ideal--including the power station,the grid supply,and the meter on your house.
All these factors you fail to take into account when you stated an ideal voltage and an ideal inductor.
The real-world test can easily be done as explained on the other thread.
You cannot do a real world test on fictional components and values.
The only limitation is that the real-world inductor will behave a tiny smidgen differently from the ideal inductor.
No-the difference is !infinite!--you just dont get this,do you ?.
Brad
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If the time constant is infinite for maximum current through the ideal inductor,then that means that no current flows through the inductor--ever,because if it takes an infinite amount of time to reach maximum current flow through the coil,then it also takes an infinite amount of time to reach a 10% value of maximum current flow through the ideal inductor,and it takes an infinite amount of time to reach 1% of the maximum amount of current flow through the ideal inductor--and so on. So it will take an infinite amount of time before current even starts to flow--so there will never be any current flow through the ideal inductor.
;)
My blown universe post was a bit of a ruse. In fact it implied the opposite of what would theoretically happen, that is, "nothing".
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How do you calculate the L/R time constant, when there is no R
L/0=infinite
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A sim of an ideal V source across an ideal inductor will crash the sim.
A tiny bit of resistance must be added as the computational resolution is finite.
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Brad:
<<< No-the difference is !infinite!--you just dont get this,do you ?. >>>
You are just getting belligerent for no reason and you are twisting your logic and not really making sense.
I said that a real-world coil can be 99.99% identical in behaviour to an ideal coil. That means the difference in their behaviour on the bench will be one part in 10,000. That's pretty damn similar.
Any good bench power supply with a big capacitor on the output, a huge transformer or huge switching power supply, and a well-designed negative feedback control system to maintain a constant output voltage will be 99.99% identical to an ideal voltage source so the same argument applies.
The point being again that discussing ideal coils or ideal voltage sources is not far fetched at all.
This is the real topic of discussion: a) What is inductance? b) Demonstrate your understanding of inductance by solving for the current for an ideal inductor in a simple circuit.
That is what you need to focus on.
MileHigh
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You may wish to exercise a few examples to see if your conclusion is correct. Your conclusion being that if the time constant (Tau) is infinite, the load immediately presents itself as a perfect short, meaning the current will be infinite and instantaneous.
Here are a few: (in all cases, L=6H)
1) R=1, Tau=6s
2) R=0.1, Tau=60s (1min)
3) R=1m Ohm, Tau=60ks (16.6 hours)
4) R=1u Ohm, Tau=6M(million)s (1667 hours)
5) etc.
What is happening to Tau as R decreases?
If R could be 0, Tau must be infinite.
What happens to the inductor current after t=0 when Tau=infinity?
This is the very reason that MHs question cannot be answered,as i have stated before.
The conundrum kicks in at T=0.
If R = 0,which id dose,as the inductor is ideal,then no current flows through the ideal inductor.
If Tau is infinite,then 10% of maximum current flow is also an infinite amount of time,and so is 1% of maximum current flow,and so is .1% of maximum current flow-ETC. This means that it will also take an infinite amount of time before current start to flow,as there is no division of infinite that it self is not infinite. This means that there is no inductance,as there is no current flow to create a magnetic field,and there for no CEMF to resist the change in current that isnt flowing anyway :o
But there is also no resistance in an ideal coil,and so the ideal voltage is now across a dead short.
So now we have an infinite amount of current flow :o
MH quoted him self--Quote: there is no time constant--post 14
So,the current either rises instantly,or the current rise time is infinite,which means there is no current flowing through the ideal coil.
Brad
-
L/0=infinite
As i thought
Brad
-
A sim of an ideal V source across an ideal inductor will crash the sim.
A tiny bit of resistance must be added as the computational resolution is finite.
So this means we cannot sim MHs question as it is defined ?
Brad
-
<<< So,the current either rises instantly,or the current rise time is infinite,which means there is no current flowing through the ideal coil. >>>
Sorry but I have to lol, when the "answer" is two completely contradictory answers.
-
author=MileHigh link=topic=16589.msg483543#msg483543 date=1462799110]
That is what you need to focus on.
MileHigh
[/quote]
You are just getting belligerent for no reason and you are twisting your logic and not really making sense.
No i am not MH. I am working on your question using the values and components you described.
I said that a real-world coil can be 99.99% identical in behaviour to an ideal coil. That means the difference in their behaviour on the bench will be one part in 10,000. That's pretty damn similar.
I think you will find that there is a huge difference between an ideal inductor,and a real world inductor MH. And once this is resolved,then you will find that your near enough to ideal power supply is not even close to being ideal.
The point being again that discussing ideal coils or ideal voltage sources is not far fetched at all.
If we are going to be accurate and true to our selves in this discussion,then i think you are going to find that there is an infinite gap between real and ideal.
This is the real topic of discussion: a) What is inductance? b) Demonstrate your understanding of inductance by solving for the current for an ideal inductor in a simple circuit.
Your simple circuit requires resistance,and is normally a resistor added in series with an ideal inductor. But your question and comments that follow say there is no resistance,and so, it cannot be resolved,as poynt has just stated in regards to the sim test.
Brad
-
<<< So,the current either rises instantly,or the current rise time is infinite,which means there is no current flowing through the ideal coil. >>>
Sorry but I have to lol, when the "answer" is two completely contradictory answers.
Exactly MH.
As i said,you did not think about your question to well when you added ideals to it.
It is also the reason i stated that an ideal voltage cannot be placed across an ideal inductor.
You did see the word conundrum attached to that post-along with several other posts--didnt you?.
Your question cannot be answered,as it is a contradiction to it self.
You stated as well that there is no time constant. What dose that mean?--dose the current rise instantly,or is the L/R time constant infinite?.
Brad
-
@ MH
for many years Poynt has told me that a sim can simulate any real world circuit. Poynt also knows how much i hate the use of sim's when dealing with real world circuit's. But time after time ,Poynt has shown me that the sim has been successful 100% of the time in replicating anything i (and others) have built,and has come to more exacting results than i could obtain on the bench with real world devices.
Poynt has just stated that your circuit as defined cannot be simulated,and so your circuit dose not represent a real world device.
But i would like to continue with this discussion ,as it has really made me (and others here)think of what the outcome of your defined circuit would be.
At this point in time,i am sticking to my answers given-both the real world answer-->you cannot place an ideal voltage across an ideal inductor,and also my theoretical answer,being the current would rise instantly,to an infinite value.
The reason for my theoretical answer is because of the resistance value of zero when calculating the L/R time constant.
I have found no math that allows for any value to be divided by zero without the answer being infinite. If the current rise time is infinite,then there is no rise in current as far as the inductor side of it go's. This means that there is no inductor. But as there is an ideal resulting in a zero value of resistance,the ideal voltage is now placed across a dead short--the big conundrum of the whole question using your ideal values.
And so my answer of an instant current rise of an infinite value.
Brad
-
;)
My blown universe post was a bit of a ruse. In fact it implied the opposite of what would theoretically happen, that is, "nothing".
So you are saying that at T=0--the instant the ideal voltage is placed across the ideal inductor,nothing would happen?--no voltage would appear across the ideal inductor?.
Brad
-
<<< Poynt has just stated that your circuit as defined cannot be simulated,and so your circuit dose not represent a real world device. >>>
Of course it can be simulated. To my surprise in this case he has to add a resistor. We have seen him add little phantom resistors many times in the past to get the simulator to run so ultimately there is no real surprise.
The place to simulate this setup is in your head, like I explained before. Then there are no issues. I am attaching the "short answer that solves everything" again to this posting.
-
Brad:
How about this: Take the identical question and add a 0.00000000001 ohm resistor in series with the 5 Henry ideal coil. Now you have a real-world coil.
Can you answer the question now? If you answer that properly then as far as I am concerned your answer will be perfectly legitimate.
MileHigh
-
Brad:
How about this: Take the identical question and add a 0.00000000001 ohm resistor in series with the 5 Henry ideal coil. Now you have a real-world coil.
Can you answer the question now? If you answer that properly then as far as I am concerned your answer will be perfectly legitimate.
MileHigh
Yes MH,now that question can be answered,as we have the needed value to calculate the L/R time constant.
But first i want to resolve your original question-the one this thread is about,as i have done nothing but think about the situation that could exist in this ideal case,and the outcome of such an event.
I am hoping that Poynt will keep working on this with the rest of us here,as i have a feeling that even he may not be sure of the outcome,due to the result of the attempted simulation.
At this point in time,i will stick with my theories and answers given,but it is not yet resolved,and so will continue research toward the answer.
Brad
-
<<< Poynt has just stated that your circuit as defined cannot be simulated,and so your circuit dose not represent a real world device. >>>
Of course it can be simulated. To my surprise in this case he has to add a resistor. We have seen him add little phantom resistors many times in the past to get the simulator to run so ultimately there is no real surprise.
The place to simulate this setup is in your head, like I explained before. Then there are no issues. I am attaching the "short answer that solves everything" again to this posting.
Your short answer dose not solve your question.
Below you can see what i mean that a small difference in resistance value can have an infinite difference in the end resulting value. One has a finite value,and the other has an infinite value,even though the two resistance values are very close. This is the difference between a real world inductor and an ideal inductor.
Brad
-
Brad:
How about this: Take the identical question and add a 0.00000000001 ohm resistor in series with the 5 Henry ideal coil. Now you have a real-world coil.
Can you answer the question now? If you answer that properly then as far as I am concerned your answer will be perfectly legitimate.
MileHigh
So using your resistance value MH,i have calculated the L/R time constant to be 500,000,000,000.00 seconds or 1388888888.88 hours.
So we can safely say(as poynt did),that next to nothing will happen when the ideal voltage is placed across the inductor and series resistor-->!OR!,the inductor having a very low resistance value,will causes the current to rise to 63% of 400000000 kiloamps,keeping in mind that we still have our ideal voltage that will drop to a value of 0 across the inductor,but remain at 4 volts acros the resistor /inductor ,now that we have the series resistor,as it dose when using real world circuits.
Brad
-
I've attached an LtSpice sim of a 5 henry inductor with a dc resistance of 1e-11 connected to a 4 volt ideal voltage source for 3 secs.
At the end of three secs we see the inductor current has reached 2.4 amps. This is as close to a perfect inductor as one could want.
Using the formula that MH supplied that is, delta I = Et/L, this results in delta I = 4*3/5 = 2.4 amps.
What happens if we increase the dc resistance to a higher resistance? The peak current reached will simply be lower than the above depending on the value of the resistance under otherwise the same conditions.
partzman
-
Brad,
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever. (You can't have both answers.)
Now, replace the ideal inductor with an ideal discharged capacitor, what is the outcome at t=0?
Do you still think with the inductor scenario current instantly going to infinity is a possibility?
-
I've attached an LtSpice sim of a 5 henry inductor with a dc resistance of 1e-11 connected to a 4 volt ideal voltage source for 3 secs.
At the end of three secs we see the inductor current has reached 2.4 amps. This is as close to a perfect inductor as one could want.
Using the formula that MH supplied that is, delta I = Et/L, this results in delta I = 4*3/5 = 2.4 amps.
What happens if we increase the dc resistance to a higher resistance? The peak current reached will simply be lower than the above depending on the value of the resistance under otherwise the same conditions.
partzman
Unfortunately partzman,it is no where near an ideal inductors outcome,as an ideal inductor never has any current passing through it.
Brad
-
Brad,
Now, replace the ideal inductor with an ideal discharged capacitor, what is the outcome at t=0?
Do you still think with the inductor scenario current instantly going to infinity is a possibility?
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V across it and zero current through it for ever and ever. (You can't have both answers.)
Well this as you know,was one of my answers. My other answer is because there is no resistance with an ideal inductor,and there for it is a dead short.
Your self,verpies,MH and ION have all stated that there is no voltage across an ideal inductor that has a steady DC current flowing through it. So if it is as you say-nothing will happen when an ideal voltage is placed across an ideal inductor--no current will flow,how can you then say that no voltage will be across an ideal inductor when there is a DC current flowing through it. How did the current flow take place if no current flow will take place when the ideal voltage was placed across it?.
In regards to the ideal capacitor,would we not have the same conundrum?
Brad
-
Brad:
You have actually been given part of the answer, and you see that you were dead wrong. Turn that into a learning experience.
These are the two challenges for you:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
I will repost my answer to the harder version of the question on this thread.
MileHigh
-
Here is the harder version of the question and the answer:
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
-
I've attached an LtSpice sim of a 5 henry inductor with a dc resistance of 1e-11 connected to a 4 volt ideal voltage source for 3 secs.
At the end of three secs we see the inductor current has reached 2.4 amps. This is as close to a perfect inductor as one could want.
Using the formula that MH supplied that is, delta I = Et/L, this results in delta I = 4*3/5 = 2.4 amps.
What happens if we increase the dc resistance to a higher resistance? The peak current reached will simply be lower than the above depending on the value of the resistance under otherwise the same conditions.
partzman
Thank you partzman for running the simulation. I am hoping that this gives Brad and others enough information to answer the full question and demonstrate that they understand the concepts and show competence in the subject matter. In that sense please refrain from providing further answers to the complete question that defines a multi-part voltage waveform. The hope is that the interested parties undertake to teach themselves as apposed to being spoon fed the answers.
MileHigh
-
I just want to point out this argument started over an actual inductor. like, a non imaginary, real world, coil that is part of a real circuit.
The argument began when the group was discussing just how the circuit operated. Now I'm no expert, but I'm fairly sure
this inductor has an inductance and a resistance, and I'm sure some capacitance in the windings.. I'm also pretty sure we can track down
the rest of the factors in the circuit such as source voltage.. frequency.. etc.. I have seen no one do that. Instead days have been spent
arguing over a completely fictitious scenario that basically boils down to a basic philosophical argument about duality or the chicken and the egg.
At this point I don't see how we are any closer to agreeing just how the JT circuit originally in question fires below 300mV.
Instead we have moved to the fantasy realm of an ideal hypothetical scenario because MH want's to prove that
Brad just blindly threw the circuit together and has no idea how it works.
At least I learned something.. I learned that even though one can understand the characteristics of an inductor, how to use it
in a circuit, how it behaves in comparison to other components, and how to work out its role in a circuit over time.. none of that
has absolutely anything to do with how an inductor really works unless you can answer some ambiguous question about a
hypothetical coil.
what happens after T=0? well, there's a dog somewhere that probably took a dump, someone's favorite tv show probably came on,
somewhere along the lines the inductor started charging.. oh and it also continued to display characteristics of any other inductor even though
we have to assume that entirely of faith.
I'm assuming since MH has finished his little test exercise, can we go ahead and start figuring out
what's going on in the actual circuit now?
-
Here is the harder version of the question and the answer:
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
look.. I'm just some dude that loves electronics tinkering and never claimed to be any kind of electrical engineer, but this version actually seems a simpler question. Though I'm extremely confused as to how there is 0 voltage at 0 seconds when at 0 seconds the coil is connected to the source.
For those of us who are trying to interpret your original question properly out of simple respect, any more details as to 'how' you wanted the question answered would be of great help.
-
Magneticitist:
You are way off. For starters, you threw a lot of mumbo-jumbo talk at this subject earlier when discussing this test. You are talking more mumbo-jumbo talk now.
Like I already clearly stated to you in an earlier posting, this example has many applications in the real world of your bench. What we are talking about is real, and there are no philosophical arguments to be made.
We are not interested in the resistance or the capacitance between the windings, at all. That just makes everything more complicated. We are not talking about frequency at all. Nor are we talking about a Joule Thief. Forget about the usual buzz words and the usual box of tricks, time to get real.
At least I learned something.. I learned that even though one can understand the characteristics of an inductor, how to use it in a circuit, how it behaves in comparison to other components, and how to work out its role in a circuit over time.. none of that has absolutely anything to do with how an inductor really works unless you can answer some ambiguous question about a hypothetical coil.
It has every damn thing to do with how an inductor really works. Your problem is that you have been taken out of your comfort zone. You like to fire off philosophical musings when it comes to coils and circuits, it gives the impression that you have a "higher order" discussion going on about electronics. The problem here is that we were trying to figure out how a very simple circuit works and you had no idea yourself. Don't be dismissive of real solid knowledge and make silly cracks about a dog taking a dump.
The message to you is to come down to Earth and if you want to do better work on your bench, then you want to understand this stuff and have complete mastery over it. Pay attention and try to learn something important. Drop the mumbo-jumbo talk and be real.
The question still has not been answered, do you want to take a shot at it?
MileHigh
-
well at least we can agree, that both sides of this argument feel as if they are speaking to a brick wall that's reading a magazine.
(btw that was sarcasm about the inductor..)
-
look.. I'm just some dude that loves electronics tinkering and never claimed to be any kind of electrical engineer, but this version actually seems a simpler question. Though I'm extremely confused as to how there is 0 voltage at 0 seconds when at 0 seconds the coil is connected to the source.
For those of us who are trying to interpret your original question properly out of simple respect, any more details as to 'how' you wanted the question answered would be of great help.
The formula for the voltage source that connects to the coil is v = 20*t^2. Therefore when t=0 the voltage is zero. This is like setting the voltage on your bench power supply to zero and connecting up a coil. Then you turn the knob to increase the voltage, and you turn it faster as time progresses. So the question is what is the current through the coil when you do this?
Do you perhaps think that is a dumb thing to do? Millions would disagree with you. What if you play the Star Spangled Banner across the coil? Well, there will be a current waveform in that case also, and it would not be that hard to determine. Notice that I say "determine" and NOT "measure." You don't need to measure the current when the Star Spangled Banner is playing across the coil, you can determine what it is using your brain and a few tools. That's the whole point in this discussion. Note that sometimes you simply can't measure the current, you need to use your wits instead to determine the current.
At this point how to answer the original question should be pretty obvious to most. Please check with Brad first and get his take on how to answer the question. He should know how to respond to that. If it is still not clear after that then I will answer you.
The way the question was posed was intentional. You are supposed to have the electronics aptitude and experience to know what to say for the answer. I am not saying this to give you a hard time. Rather, I am just stating this to illustrate how far many bench experimenters have to go to get to a better and more productive place. There is no point in playing with coils if you don't really know what you are doing. It might be tough medicine to say that but it is good medicine. And that brings us full circle back to the question that I asked EMJunkie being repeated here. He had been playing with coils on his bench for ten years and he couldn't answer the question either.
MileHigh
-
Brad,
Now, replace the ideal inductor with an ideal discharged capacitor, what is the outcome at t=0?
Do you still think with the inductor scenario current instantly going to infinity is a possibility?
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever. (You can't have both answers.)
Ok,in this point in time,i will provide my real world answer,along with my !two! theoretical answers.
My real world answer is(and has been throughout this thread)that you cannot place an ideal voltage across an ideal inductor,as an ideal inductor dose not -and never will exist.
Theoretical answer 1--> As R = 0,then the L/R time constant is infinite-as you have just stated is correct Poynt. The first thing this means is that the question asked by MH with the values given in that question,results in nothing at all happening--as you also just stated would be the situation.
What we now need to do to understand my second theoretical answer, is define the properties of an ideal inductor. An ideal inductor has no resistance or capacitance,but only inductance. This is now when we find out that the ideal inductor has no inductance at all-regardless of the inductance value of that ideal inductor. For inductance to occur,current must flow into that inductor,and as we have both just established,no current will into that inductor ,regardless of the voltage across that ideal inductor,or the time the voltage is across that inductor,as the current rise time is infinite,and there for there is an infinite time before current starts to flow-->there is no current flowing into that inductor-ever,as we know know.
As we have no capacitance value,then the voltage across the inductor is not stored across the inductor,so this is omitted. But what we do have,due to there being no resistance,is a dead short across the inductors terminals,which brings rise to my theoretical answer 2.
Theoretical answer 2-->. As it has now been concluded that there is no current flowing into the ideal inductor,then there is no inductance taking place. We are now left with an ideal voltage across a dead short,due to the zero value of resistance. This leads to an instant current rise to an infinite value due to the ideal voltage now being across a dead short. I will define instant being the ideal speed at which current can flow,that being the speed of light.
So you see now why i called this a conundrum theory.
But what these two theories prove,is my real world answer,and that is,as you know-->that you cannot place an ideal voltage across an ideal inductor,as an ideal inductor dose not -and never will exist.
There is also a second conundrum,and that being that we all agree that a voltage cannot exist across an ideal inductor that has a steady DC current flowing through it. If an ideal inductor,with an ideal voltage placed across it,never has current flowing into or through it,how did the steady state current get induced into the ideal inductor,that dose not allow a voltage to be seen across it?.
We have worked out that current will never flow into an ideal inductor,and now all we have to do is work out the rest of what i posted--or should i say Poynt,have your opinion toward what i have posted above.
Brad
-
Brad:
You have actually been given part of the answer, and you see that you were dead wrong. Turn that into a learning experience.
These are the two challenges for you:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
I will repost my answer to the harder version of the question on this thread.
MileHigh
MH
Did you not see Poynts post (80)
Quote: Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever.
This in itself says that the results to your question will be-nothing happens. It also shows that one of my theoretical answers was correct,and my real world answer was also correct--when you read my last pots,you may start to understand the complications with your !original! question.
To quote your post 69-- Sorry but I have to lol, when the "answer" is two completely contradictory answers.,i think once again,you have laughed at me to soon.
Brad
-
Here is the harder version of the question and the answer:
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
As i clearly stated MH,we are not resolving your modified version until your original question is answered.
Please stop trying to confuse people in this thread,that is dedicated to resolving your original question.
Brad
-
Here is the harder version of the question and the answer:
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
Your original question clearly states an ideal voltage of 4 volts for 3 seconds.
The rest of your answer is not related to the original question,as the voltage is not 4 volts for 3 seconds.
https://en.wikipedia.org/wiki/Voltage_source
An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.
Brad
-
Brad:
Re: Poynt's comment:
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever.
I am not sure of the context for that or he may simply have been sarcastic.
What I can say to you is this:
The question was posed to you with an ideal inductor and you objected to that. So I then reposed the question to you and added a resistor that gives you a time constant of 158,440 years and you agreed in principle that that variant of the question can be answered. On top of that, you have already been given a partial correct answer.
So what you (or anyone else) need to do is try to answer either question, the original or the variant. Both answers will essentially be the same.
So there is only one real answer, even if you use the variant question. And the answer is still not forthcoming from you or from anyone else. That means you have an opportunity to shine and demonstrate that you understand what is going on, you understand inductance, and you understand how an inductor works.
So forget about your long and complicated answer in post #91. A simple question can be answered with a simple answer, and then also demonstrate your competence on the subject matter. Give it your best shot.
MileHigh
-
author=MileHigh link=topic=16589.msg483572#msg483572 date=1462810403]
Thank you partzman for running the simulation.
MileHigh
Partzmans answer dose not represent your original question.
If partzman runs the same simulation with the resistance value removed,so as the circuit represents your ideal inductor,he will derive the same answer as myself and Poynt.
I am hoping that this gives Brad and others enough information to answer the full question and demonstrate that they understand the concepts and show competence in the subject matter.
The rest of us are hoping that MH learns that when you add ideals into questions,it changes everything drastically,and the situation in no way represents real worl outcomes.
In that sense please refrain from providing further answers to the complete question that defines a multi-part voltage waveform. The hope is that the interested parties undertake to teach themselves as apposed to being spoon fed the answers.
All the information i have provided has been under my own understandings and research. There has been no spoon feeding thank you very much MH.
Brad
-
Brad:
<<< If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time. >>>
Actually, that's a "rule" that you seem to have made up for yourself. An ideal voltage source can be a function of time. i.e.; v(t) = 7*sin(omega*t).
That's a +/-7-volt sine wave at the angular frequency omega that has a zero output impedance.
I can't fathom how you "lock" yourself sometimes. An ideal voltage source is a voltage source that has a zero output impedance. It has nothing to do with it possibly varying in time.
Like I said before, you can have an ideal voltage source that outputs an Ozzy Osbourne song or The Star Spangled Banner - it's still an ideal voltage source.
MileHigh
-
I just want to point out this argument started over an actual inductor. like, a non imaginary, real world, coil that is part of a real circuit.
The argument began when the group was discussing just how the circuit operated. Now I'm no expert, but I'm fairly sure
this inductor has an inductance and a resistance, and I'm sure some capacitance in the windings.. I'm also pretty sure we can track down
the rest of the factors in the circuit such as source voltage.. frequency.. etc.. I have seen no one do that. Instead days have been spent
arguing over a completely fictitious scenario that basically boils down to a basic philosophical argument about duality or the chicken and the egg.
At this point I don't see how we are any closer to agreeing just how the JT circuit originally in question fires below 300mV.
Instead we have moved to the fantasy realm of an ideal hypothetical scenario because MH want's to prove that
Brad just blindly threw the circuit together and has no idea how it works.
At least I learned something.. I learned that even though one can understand the characteristics of an inductor, how to use it
in a circuit, how it behaves in comparison to other components, and how to work out its role in a circuit over time.. none of that
has absolutely anything to do with how an inductor really works unless you can answer some ambiguous question about a
hypothetical coil.
what happens after T=0? well, there's a dog somewhere that probably took a dump, someone's favorite tv show probably came on,
somewhere along the lines the inductor started charging.. oh and it also continued to display characteristics of any other inductor even though
we have to assume that entirely of faith.
I'm assuming since MH has finished his little test exercise, can we go ahead and start figuring out
what's going on in the actual circuit now?
MH ask this question to a couple of members of this forum,and he has been ranting on ever since how they could not answer his question correctly.
I decided to have a go at answering the question,which is posted in the first post of this thread.
I opened this thread to discuss this original question,and not MHs modified version that now has a non ideal inductor.
I told MH that his question is more complicated than he believes it is.
It has already been established that from T=0 to T=13 seconds,nothing will happen,as current will not flow through an ideal inductor. This opens cans of worms all over the place,as you can see in my previous 4 to 5 posts.
Brad
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MH you have to understand, the problems I have with your 'ideal' argument and your test question are entirely based upon the context in which you are using them..
As I said I totally understand the entire use of this circuit theory. Why would I argue that? Of course, by knowing the nature of what you are playing with, you can use certain tools to approximate possible outcomes.. essentially design a functioning circuit on paper and know how it will work before even having to wire it.. I get it.. The argument I have against the 'ideal' 0 resistance situation is simple.. we don't know for sure how a circuit would act with 0 resistance. we just don't. we lie to ourselves and say once we get to a point where from our perspective things become far too 'small' to say they matter anymore, we can just go ahead and say they don't exist.
Anyway like I said it seemed as if you had presented this question like it somehow related to the circuit that was originally being discussed. I'm trying to explain how your pop quiz had entirely nothing to do with the real world circuit in question and you take that as me trying to crap on the basic circuit theory you had to learn and have grown to respect as a useful tool in EE, all talks of 0 resistance aside.
If it would make you feel any better we can dispense with the trivial motions we are sure to play out.. I'm dumb, you're smart. I have absolutely no idea what an inductor is and you're the master of the electronic universe. I resign to the fact that I am utterly incapable of designing even the simplest functional circuit so long as it contains an inductor, and you know them inside out, top to bottom, with no mysteries to uncover.
Now that we have all that out of the way, I'd really like to get back to the joule thief discussion myself.. Didn't you and Brad have a disagreement about the circuit operation?
Is there some further explanation that proves your reasoning somewhere buried underneath this pop quiz question we have spent pages and pages discussing?
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The formula for the voltage source that connects to the coil is v = 20*t^2. Therefore when t=0 the voltage is zero. This is like setting the voltage on your bench power supply to zero and connecting up a coil. Then you turn the knob to increase the voltage, and you turn it faster as time progresses. So the question is what is the current through the coil when you do this?
Do you perhaps think that is a dumb thing to do? Millions would disagree with you. What if you play the Star Spangled Banner across the coil? Well, there will be a current waveform in that case also, and it would not be that hard to determine. Notice that I say "determine" and NOT "measure." You don't need to measure the current when the Star Spangled Banner is playing across the coil, you can determine what it is using your brain and a few tools. That's the whole point in this discussion. Note that sometimes you simply can't measure the current, you need to use your wits instead to determine the current.
Please check with Brad first and get his take on how to answer the question. He should know how to respond to that. If it is still not clear after that then I will answer you.
The way the question was posed was intentional. You are supposed to have the electronics aptitude and experience to know what to say for the answer. I am not saying this to give you a hard time. Rather, I am just stating this to illustrate how far many bench experimenters have to go to get to a better and more productive place. There is no point in playing with coils if you don't really know what you are doing. It might be tough medicine to say that but it is good medicine. And that brings us full circle back to the question that I asked EMJunkie being repeated here. He had been playing with coils on his bench for ten years and he couldn't answer the question either.
MileHigh
At this point how to answer the original question should be pretty obvious to most.
Except to you MH.
The first answer we have so far is--nothing will happen.
I am awaiting Poynts review on the reasons for my second theoretical answer-and my theories on the rest of it.
Brad
Brad
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Brad:
Partzmans answer dose not represent your original question.
If partzman runs the same simulation with the resistance value removed,so as the circuit represents your ideal inductor,he will derive the same answer as myself and Poynt.
I will repeat this a second and last time. The addition of the resistance to the simulation is to solve a constraint in the way the software works. It has nothing whatsoever to do with what you are referring to.
You are in for an unpleasant surprise when Poynt comes back. You think that both of you are on the same page but you are not. Like I said, I can't explain his quote but in due time we will find out.
You literally have been given a partial correct answer from partzman in two forms. Someone else earlier in the thread described an ideal inductor behaviour perfectly. It looks like it's going to take a few more days before you come round and it may have to end up being a forced spoon feeding session from a guru.
MileHigh
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MH ask this question to a couple of members of this forum,and he has been ranting on ever since how they could not answer his question correctly.
I decided to have a go at answering the question,which is posted in the first post of this thread.
I opened this thread to discuss this original question,and not MHs modified version that now has a non ideal inductor.
I told MH that his question is more complicated than he believes it is.
It has already been established that from T=0 to T=13 seconds,nothing will happen,as current will not flow through an ideal inductor. This opens cans of worms all over the place,as you can see in my previous 4 to 5 posts.
Brad
one thing that majorly confused me, and apparently you as well, was the 'ideal voltage' source also being a variable supply. so not only does this magic power supply provide infinite current with 0 vdrop it can change voltage at any time. I was under the impression an ideal vsource was a fixed source for all intents and purposes, though apparently not. this is why I was saying that kind of question is more what you would expect from your EE professor, in class. without being primed with the basics of that class, it's quite hard to know where one is supposed to start answering, or how.
IMO that does not mean a person is completely void of electronics knowledge of circuit building capability.
people still make fun of Ed Leedskalnin but could he not manipulate magnetic current to do his bidding? sure, maybe he could have done so much more had he earned a degree, but his lack of degree by no means made him a clueless idiot.
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Magneticitist:
The question defines a voltage source connected to an inductor. It defines the voltage waveform.
The only unknown in the setup is the current. You have to solve for the current.
MileHigh
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Brad:
Re: Poynt's comment:
I am not sure of the context for that or he may simply have been sarcastic.
What I can say to you is this:
The question was posed to you with an ideal inductor and you objected to that. So I then reposed the question to you and added a resistor that gives you a time constant of 158,440 years and you agreed in principle that that variant of the question can be answered. On top of that, you have already been given a partial correct answer.
So what you (or anyone else) need to do is try to answer either question, the original or the variant. Both answers will essentially be the same.
So there is only one real answer, even if you use the variant question. And the answer is still not forthcoming from you or from anyone else. That means you have an opportunity to shine and demonstrate that you understand what is going on, you understand inductance, and you understand how an inductor works.
So forget about your long and complicated answer in post #91. A simple question can be answered with a simple answer, and then also demonstrate your competence on the subject matter. Give it your best shot.
MileHigh
As i have now stated 3 times MH,we will first answer your original question,and then we will look at your modified question,which now includes a resistance,and so is no longer related to the original question,as the inductor is no non ideal. The two answers and outcomes will be infinitely different--that you can be assured.
I do not believe Poynt is being sarcastic,as this is a very important subject as far as im concerned.
I am no longer interested in proving you wrong,as your original question has me fired up like i have not been in a long time. My brain has gone into overdrive on this one,and it has been a long time since i have had so much interest in a subject. It is now 2.15 am,and i cant sleep. I just lye in been thinking about this subject--going over and over my thoughts on it. I have to start a 9 hour shift in 4 hours,but i cant sleep.
The ramifications of my theories being correct,change everything as far as what is believed to be an ideal inductor. If Poynt was being sincere with his answer about there being no current flow through an ideal inductor,which as you know,was also !one! of my answers,then we have started to travel down a road no one has traveled yet.
I have to wait for Poynts view on my answers i provided.
Maybe even PW,Vortex1,verpies would like to join in on the discussion?.
Brad
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Brad:
Re: Poynt's comment:
I am not sure of the context for that or he may simply have been sarcastic.
I'm not being sarcastic at all.
Unless I'm overlooking something, or don't correctly understand the question, there will be no current, and the voltage across the inductor will be whatever the voltage source is at any one time, from t=0 to the end of time.
Given that tau=infinity, there can be no change in either I or V. Indeed if R is non-zero, there will be a current and the voltage change over time.
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one thing that majorly confused me, and apparently you as well, was the 'ideal voltage' source also being a variable supply. so not only does this magic power supply provide infinite current with 0 vdrop it can change voltage at any time. I was under the impression an ideal vsource was a fixed source for all intents and purposes, though apparently not.
That's an ironic twist for you. The supposedly "open-minded researchers that go where conventional scientists don't dare go" can sometimes be so closed-minded that they can't conceive of something as simple as an ideal voltage source that varies in time.
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That's an ironic twist for you. The supposedly "open-minded researchers that go where conventional scientists don't dare go" can sometimes be so closed-minded that they can't conceive of something as simple as an ideal voltage source that varies in time.
it's quite simple.. having not invested any real time into learning about 'ideal' components, I had to look up what constituted an ideal voltage source.. The information I gathered stated an ideal voltage source was a fixed source that can supply infinite current without dropping.. Obviously that was an incorrect or incomplete description.
(i will say that yes, the possibility of a variable supply did indeed fly over my head. I won't cry about it!)
Now you're just being spiteful.
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I'm not being sarcastic at all.
Unless I'm overlooking something, or don't correctly understand the question, there will be no current, and the voltage across the inductor will be whatever the voltage source is at any one time, from t=0 to the end of time.
Given that tau=infinity, there can be no change in either I or V. Indeed if R is non-zero, there will be a current and the voltage change over time.
I am going to have to assume that you don't understand the question. Before t=0 the voltage source and the coil are disconnected. The only reason for putting it that way is to implicitly establish that the current through the coil is zero at the start of the test. At t=0 you then have a 4-volt source connected to a 5-Henry inductor, and then the voltage varies in time as described.
When it is reworded as above, is it clear now?
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Brad,
I don't support your answer regarding the inductor acting like an instantaneous short. Just because there is no current flow, doesn't mean the load presented to the voltage source is no longer "inductive".
There is only one answer, that being the inductor will essentially look like a perpetual "open" to the voltage source. At least that is my thinking on this until MH corrects me, and I welcome being corrected if I am in fact wrong on this.
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it's quite simple.. having not invested any real time into learning about 'ideal' components, I had to look up what constituted an ideal voltage source.. The information I gathered stated an ideal voltage source was a fixed source that can supply infinite current without dropping.. Obviously that was an incorrect or incomplete description.
Now you're just being spiteful.
They say fixed source meaning that the voltage will not change under load. They don't say anything else.
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Brad:
I will repeat this a second and last time. The addition of the resistance to the simulation is to solve a constraint in the way the software works. It has nothing whatsoever to do with what you are referring to.
You literally have been given a partial correct answer from partzman in two forms. Someone else earlier in the thread described an ideal inductor behaviour perfectly. It looks like it's going to take a few more days before you come round and it may have to end up being a forced spoon feeding session from a guru.
MileHigh
MH
Maybe you can work out the L/R time constant of an ideal coil.
As Poynt stated,and as i stated,it will then be 5/0=infinity.
You have already stated that there is no time constant,and the value could be infinity or undefined-correct?,or do i have that wrong?.
If it is infinity,then there is going to be no current flow into the ideal inductor-correct?
So unless you know some sort of math that allows a division of 5/0,and provides a value we can work with,then i will stick with my claim.
You are in for an unpleasant surprise when Poynt comes back. You think that both of you are on the same page but you are not. Like I said, I can't explain his quote but in due time we will find out.
Well i dont believe that Poynt would lead me down the garden path,or post sarcastic results,just because that is what i believe. Sure,we have had our moments,but we have also had our times where we get along just fine,like in the Lewin topic not long ago. I listened to what he was saying,and carried out the test as he stated,and it resulted in being exactly what he said it would be. There is always going to be times when we dont agree on something,but when it comes time to work on thing's like this,then we should both be striving toward a correct answer and outcome.
Brad.
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Brad:
<<< If it is infinity,then there is going to be no current flow into the ideal inductor-correct? >>>
Here is something for you to ponder: A straight line is a circle with a radius of infinity.
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I also want to point out in a non sarcastic manner, that this is what it's all about. despite our little beefs we are trying to put our minds together to debate and brainstorm what's going on here... From the EE professionals to the casual tinkerers it's not so cut and clear... this is how complex electricity can be..
I'm not saying a simple agreeable answer is impossible... but clearly if one 'side' has yet to clearly come to an agreeable conclusion then it must be, at the very least, a little confusing.
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They say fixed source meaning that the voltage will not change under load. They don't say anything else.
well in all honestly my mistake then.. but I took 'fixed source' as being utterly fixed.
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Brad,
I don't support your answer regarding the inductor acting like an instantaneous short. Just because there is no current flow, doesn't mean the load presented to the voltage source is no longer "inductive".
There is only one answer, that being the inductor will essentially look like a perpetual "open" to the voltage source. At least that is my thinking on this until MH corrects me, and I welcome being corrected if I am in fact wrong on this.
OK,so here is the part in that reply i dont understand.
If the inductor looks like a perpetual open (circuit i guess?)to the voltage source,then what is the load?
Brad
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Brad:
<<< If it is infinity,then there is going to be no current flow into the ideal inductor-correct? >>>
Here is something for you to ponder: A straight line is a circle with a radius of infinity.
A straight line is not a circle,as it has a beginig and end-unless it is infinitely long. A circle is an infinite loop.
Brad
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OK,so here is the part in that reply i dont understand.
If the inductor looks like a perpetual open (circuit i guess?)to the voltage source,then what is the load?
Brad
Zero current means no load. So we have an infinite load, i.e. an "open" circuit.
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I'm not being sarcastic at all.
Unless I'm overlooking something, or don't correctly understand the question, there will be no current, and the voltage across the inductor will be whatever the voltage source is at any one time, from t=0 to the end of time.
Given that tau=infinity, there can be no change in either I or V. Indeed if R is non-zero, there will be a current and the voltage change over time.
Thanks Poynt
I did not believe that you would answer questions this important in a sarcastic manner -as i pointed out to MH.
So this would mean that MHs original question would result in the applied voltage being seen across the ideal inductor,and nothing more than that.
So rather that slam all my theories in one post,maybe a step at a time would be better.
So,if there is no current flowing through the inductor,that would mean no inductance/no resulting rising magnetic field?--correct?
Brad
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<<< You have already stated that there is no time constant,and the value could be infinity or undefined-correct?,or do i have that wrong?. >>>
Here is the reason I am saying there is no time constant: It's because in the ideal coil case you will never have a situation that meets the standard definition of a time constant. So in that sense there is no time constant.
Take the example of a car that is front wheel drive. A car with front-wheel drive will not handle the same way as a car with rear-wheel drive. So there is no point in talking about handling problems with rear-wheel drive cars to someone driving a front-wheel drive car.
And yes, the time constant is infinity. It's another way of saying the same thing. The real question is what does that mean for this test?
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Poynt, I hope you did not miss my reply #108.
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Zero current means no load. So we have an infinite load, i.e. an "open" circuit.
Ok,im going to need help understanding this Poynt
The zero current meaning no load is no problem,but having an infinite load(a load of infinite proportions),would this not require a current flow of infinite magnitude?,and we have no current flow.
Brad
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MH,
For your test (13s of a few different voltages), the different voltages have no affect on the outcome.
So the question could have been asked with one voltage and still have the same answer, correct?
I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.
I think we can conclude from these results that my answer is correct.
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I am going to have to assume that you don't understand the question. Before t=0 the voltage source and the coil are disconnected. The only reason for putting it that way is to implicitly establish that the current through the coil is zero at the start of the test. At t=0 you then have a 4-volt source connected to a 5-Henry inductor, and then the voltage varies in time as described.
When it is reworded as above, is it clear now?
Im going to have to correct that MH.
At T=0,an ideal voltage of 4 volts is placed across an ideal inductor of 5 Henrys for 3 seconds. This is how your question reads.
To quote again,An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.
Brad
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MH,
For your test (13s of a few different voltages), the different voltages have no affect on the outcome.
So the question could have been asked with one voltage and still have the same answer, correct?
I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.
I think we can conclude from these results that my answer is correct.
Poynt
Thank you for your time on this,i am really enjoying this topic.
But i have to get some sleep--work in 3 hour time ::)
I hope we can look into this further together,along with anyone else that is interested.
Cheers
Brad
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Ok,im going to need help understanding this Poynt
The zero current meaning no load is no problem,but having an infinite load(a load of infinite proportions),would this not require a current flow of infinite magnitude?,and we have no current flow.
Brad
Don't get too hung up on my use of the term "infinite load". In electronics when we say that we mean an "open circuit", not a "short circuit". I know it seems counter intuitive. If we mean to say a "short", we say "short, "short circuit" or "zero Ohm" load.
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MH,
For your test (13s of a few different voltages), the different voltages have no affect on the outcome.
So the question could have been asked with one voltage and still have the same answer, correct?
I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.
I think we can conclude from these results that my answer is correct.
Poynt, I am really surprised and I suspect that you are a victim of GIGO from your simulator. You put in a resistance value that was too low for the sim and it got scrambled brains. (a bug!) That affected you also I am afraid! lol I almost suspect you may have worked 36 hours non-stop or something.
Perhaps forget about the sim and do it in your head?
Hold on, I will find the posting number of another sim also. ===>>> Please look at post #79.
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wait, are we now saying that the answer MH was looking for, was to clarify that no current would flow and it would act like an open circuit?
this is confusing because I recall at least a couple of us saying that and it was some ol whackadoo or crazy stuff, or whatever.
edit- nevermind I see MH is in disagreement, now idk what is going on
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wait, are we now saying that the answer MH was looking for, was to clarify that no current would flow and it would act like an open circuit?
this is confusing because I recall at least a couple of us saying that and it was some ol whackadoo or crazy stuff, or whatever.
edit- nevermind I see MH is in disagreement, now idk what is going on
It could be sleep deprivation, you never know. It's like the old cliche that when you factor in all of the rewrites and recompiles and bug fixes, a software engineer can only write 10 lines of code a day.
However, the other issue is that we are getting way off the beaten track. We still haven't really scratched the surface when it comes to actually understanding the how and why of what is going on in this trivial circuit. I suppose we need to actually get it answered also. The how and why is the real point in this whole exercise.
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Poynt, I am really surprised and I suspect that you are a victim of GIGO from your simulator. You put in a resistance value that was too low for the sim and it got scrambled brains. (a bug!) That affected you also I am afraid! lol I almost suspect you may have worked 36 hours non-stop or something.
Perhaps forget about the sim and do it in your head?
Hold on, I will find the posting number of another sim also. ===>>> Please look at post #79.
I saw that post.
His R value is too big. I can obtain similar results as I increase the resistor value. 1p Ohm is nowhere near 0 Ohms. Have Partzman try 0.00000000000000000000000000000000000001f Ohms. He will see a flatline of current (0A) for at least 100 seconds.
I did work this out in my head first, and the sim supports my conclusion.
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Well now I feel like I am in the Twilight Zone.
Poynt: The current is one over "L" integral v dt.
That's 1/5 * integral (4) dt.
That's 1/5 * 4t.
That's 4/5*t.
When t = 3 seconds that's 12/5 = 2.4 amps.
Can we get out of the Zone now?
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What does old Lewin think?
YT Kirchoffs rule is for the birds. Stripey shirt 16.01.
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Perhaps the sim skids out at these lower R settings, and defaults to 0 rather than crashing as it does with no resistor at all.
It does seem to settle at the 2.4A point when R is relatively small though. So, yeah it must be right.
It doesn't makes sense to me from the infinite tau perspective though.
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The Tau business is fairly simple to explain.
When you transition from a finite Tau to an infinite Tau the current waveform goes from an inverse exponential curve to a straight line. Note that it is a straight line with a constant slope of V/L.
So Tau at infinity just means the current trace is a perfectly straight line. Since it is a straight line the concept of "reaching 63% of the maximum value" does not apply anymore because that concept does not exist when the current waveform is a perfectly straight line. i.e.; "There is no time constant."
So Tau being infinity does not mean stopping current flow, it means linearly increasing current flow.
Since we are discussing limits, the only possible way for the current to flat-line at zero "forever" would be for the inductance to be infinity. Then you have a "more real" Tau = infinity because this time L/R becomes infinity/R.
So when Tau = infinity/R that gives you the horizontal current trace stuck at zero with a slope of zero (V/infinity), whereas when Tau = L/0, you get a current trace that is a straight line with with a slope of V/L.
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Thanks for the explanation MH. ;)
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My idea was to stick in a series resistor of 1-66666666 Ohms.
John.
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For Brad:
Don't get put off with what may look like a bunch of Engineering mumbo-jumbo talk. I never intended to go in this direction. All of the mumbo-jumbo talk can be expressed in ordinary simple English that anybody that wants to learn can truly learn. I am glad that you are all fired up about this subject.
So I am going to ask you again to rethink your stance. Accept the fact that at 3 seconds the current has climbed to 2.4 amps in a perfectly straight line. Assuming that you do accept this fact, then the next step for you and your peers is to figure out how and why, and how you can apply this to real life.
I am still hoping that you and your peers will be able to answer the question and explain why. At this point the thread has been littered with clues. The best-case scenario would be for you to leverage off of this information and brainstorm with your friends and answer the simple question about the current waveform and demonstrate that you understand the how and why of what's going on.
MileHigh
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Oh, when I do 4/1.66666 I get something like 2.4A. Amazing!
John.
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The Tau business is fairly simple to explain.
When you transition from a finite Tau to an infinite Tau the current waveform goes from an inverse exponential curve to a straight line. Note that it is a straight line with a constant slope of V/L.
So Tau at infinity just means the current trace is a perfectly straight line. Since it is a straight line the concept of "reaching 63% of the maximum value" does not apply anymore because that concept does not exist when the current waveform is a perfectly straight line. i.e.; "There is no time constant."
So Tau being infinity does not mean stopping current flow, it means linearly increasing current flow.
Since we are discussing limits, the only possible way for the current to flat-line at zero "forever" would be for the inductance to be infinity. Then you have a "more real" Tau = infinity because this time L/R becomes infinity/R.
So when Tau = infinity/R that gives you the horizontal current trace stuck at zero with a slope of zero (V/infinity), whereas when Tau = L/0, you get a current trace that is a straight line with with a slope of V/L.
is it really that simple to you? how can this not be construed as utterly confusing and even contradictory? I suppose I just have it completely backwards, but isn't our ability to calculate the current at a given time based upon the constant? but yet we remove the constant and un-tether it to infinity like what would happen to any normal inductor without a time constraint with which to calculate it? how do we know the rate of charge would follow a straight line incline, isn't the magnetic field supposed to be able to follow an equally opposing one making it just a flatline forever?
if you were to 'zoom in' at roughly the 99.5% point of the inductors charge you may see that you have only just begun charging it. it would almost be like looking at this examples straight incline with an infinite or 'no time constraint'. the idea of 'infinity' or 'zero' seem to introduce some natural 'stalemate' as another user put it. we are expected to look at 0 as a balance of opposing forces, or a neutral. an at-rest. yet in this case the 0 is just supposed to represent a lack thereof as if there is a difference. it's not something I'm tying to argue to death it's just very counter intuitive in my opinion sorry of that offends you.
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Ok,im going to need help understanding this Poynt
The zero current meaning no load is no problem,but having an infinite load(a load of infinite proportions),would this not require a current flow of infinite magnitude?,and we have no current flow.
Brad
Personally I think the term: "infinite load" is just silly.
I would prefer the term: "infinite resistance" as Current (I) is directly proportional to the Resistance (R) of the load and the Voltage (V) applied accross the Load. Ohms Law Exquation: V/R = Current (I)
With: "infinite resistance", no current can flow.
I know this is what Poynt meant, but this mix in words is confusing for others that dont know.
Chris Sykes
hyiq.org
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is it really that simple to you? how can this not be construed as utterly confusing and even contradictory? I suppose I just have it completely backwards, but isn't our ability to calculate the current at a given time based upon the constant? but yet we remove the constant and un-tether it to infinity like what would happen to any normal inductor without a time constraint with which to calculate it? how do we know the rate of charge would follow a straight line incline, isn't the magnetic field supposed to be able to follow an equally opposing one making it just a flatline forever?
if you were to 'zoom in' at roughly the 99.5% point of the inductors charge you may see that you have only just begun charging it. it would almost be like looking at this examples straight incline with an infinite or 'no time constraint'. the idea of 'infinity' or 'zero' seem to introduce some natural 'stalemate' as another user put it. we are expected to look at 0 as a balance of opposing forces, or a neutral. an at-rest. yet in this case the 0 is just supposed to represent a lack thereof as if there is a difference. it's not something I'm tying to argue to death it's just very counter intuitive in my opinion sorry of that offends you.
For starters, just forget about all of the talk about an inductor being an infinite value. The take away from this is as follows: As the resistance gets lower and lower, the time constant gets longer and longer, and the inverse exponential curve for the current waveform gets flatter and flatter. When the resistance drops to zero it becomes a straight line and then the concept of a time constant becomes invalid.
So, how much of a mind bender is it really to go from a sloped current waveform that is nearly perfectly flat and you only start to detect a slight curve in the waveform after five hours and a sloped current waveform that is perfectly straight?
What you really want to do if you are interested is work with your peers and focus on trying to understand what the circuit is doing and and answering the question. Focus on doing the research and trying to answer the question. If you know what you are talking about, this is a very simple problem with a very simple explanation.
Also as a side note, if you are serious, you have to work on your language and start using commonly accepted terms and phrases to describe electronic circuits. You need to reign in the meaningless expressions and the mixing up of variables and concepts and use the proper term for the proper concept.
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Well this is what I wanted to do from the start, but not with this imaginary test circuit.
How about we do that with the original circuit in question, with your input included?
no offense but I didn't come here to simulate how your test circuit may possibly function.
I don't really want to argue what 0 means in the real world either.
if we were to let's say, graph out the joule thiefs inductor voltage to current ratio over time until
we can see how many seconds it takes to become what we can consider fully charged, is that going to show us what's firing the transistor? according to what it seems like you were originally alluding to, then no. in order to really make use of this lesson on inductors and how we can understand what may be happening in let's say, our joule thief circuits, we need to add more information into the scenario than inductance and voltage in ideal terms. there are a lot of different ways inductors can act under varying circumstances and to assume some simple ideal DC over an ideal inductor of 5H scenario really paints some kind of picture as to 'how we should proceed' fine tuning our joule thief seems like a lesson tailored more toward spiteful cerebral-measuring than genuine intentions of shedding light on the topic (that was) at hand.
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Brad:
I am going to do a preemptive strike to get you off of your fixation so that you start to move forward and both answer the question but more importantly understand the answer and the underlying concepts.
For the first part of the question the cat is out of the bag and the formula for the current is i = 0.8*t.
It seems crazy doesn't it? All that arguing and anguish and wild imaginary theories and the answer for the first three seconds is i = 0.8*t.
Okay, so after one second the current is 0.8 amperes.
I attached the formula from Hyperphysics for a voltage source energizing an RL circuit. You can see the red trace for the current and the formula. You can see the "V/R" in the formula and that might tempt you to say that that's proof that the current goes to infinity but that would be dead wrong. The red formula does not work when the resistance becomes zero because the term "V/0" is invalid and undefined.
So now I am going to prove to you that the first part of the answer given to you is correct. We are going to solve the formula for t=1 second, L=5 Henrys and R=0.001 ohms. Sound fair enough? If I am correct the two answers for the current value at one second should be very close to each other.
From the red formula:
i = 4/0.001 * (1 - 2.7182818^(-0.001/5))
i = 4000 * (1 - 2.7182818^-0.0002)
i = 4000 * (1 - 0.99980001999866673333)
i = 4000 * 0.000199980013332666693332
i = 0.799920005333 amperes.
So as you can see, when we introduced a resistor of 0.001 ohms, after one second the current was just a tiny tiny smidgen less than the 0.8 amperes you get when there is no resistor. You note that the calculation for when there is no resistor is 10 times easier as compared to when there is a resistor.
So there is your proof in the pudding. It's time for you to move on and try to answer the question and more importantly understand the how and the why.
MileHigh
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The Tau business is fairly simple to explain.
When you transition from a finite Tau to an infinite Tau the current waveform goes from an inverse exponential curve to a straight line. Note that it is a straight line with a constant slope of V/L.
So Tau at infinity just means the current trace is a perfectly straight line. Since it is a straight line the concept of "reaching 63% of the maximum value" does not apply anymore because that concept does not exist when the current waveform is a perfectly straight line. i.e.; "There is no time constant."
So Tau being infinity does not mean stopping current flow, it means linearly increasing current flow.
Since we are discussing limits, the only possible way for the current to flat-line at zero "forever" would be for the inductance to be infinity. Then you have a "more real" Tau = infinity because this time L/R becomes infinity/R.
So when Tau = infinity/R that gives you the horizontal current trace stuck at zero with a slope of zero (V/infinity), whereas when Tau = L/0, you get a current trace that is a straight line with with a slope of V/L.
Im sorry MH,but that dose not work either,as the V has no slope ,due to that fact that the voltage is ideal.
I will once again post the definition of an ideal voltage.
Quote: An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.
This is the definition that is used to define behaviours in circuits such as yours.
The voltage of 4 volts from your ideal voltage supply,will not alter during the 3 seconds after T=0.
Regardless of whether it is L/0 or R/0,Tau is always infinite,meaning that the current will not rise in the case of an ideal inductor.
You are trying to use real world calculations to define outcomes in an ideal situation that dose not exist,and then you are surprised by the outcome.
Poynts simulation shows the results expected,and if he ran that simulation for !lets say! 100 years,we would see the current rise expected for such a low value of resistance--there is nothing wrong with his sim.
Brad
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Well this is what I wanted to do from the start, but not with this imaginary test circuit.
How about we do that with the original circuit in question, with your input included?
no offense but I didn't come here to simulate how your test circuit may possibly function.
I don't really want to argue what 0 means in the real world either.
if we were to let's say, graph out the joule thiefs inductor voltage to current ratio over time until
we can see how many seconds it takes to become what we can consider fully charged, is that going to show us what's firing the transistor? according to what it seems like you were originally alluding to, then no. in order to really make use of this lesson on inductors and how we can understand what may be happening in let's say, our joule thief circuits, we need to add more information into the scenario than inductance and voltage in ideal terms. there are a lot of different ways inductors can act under varying circumstances and to assume some simple ideal DC over an ideal inductor of 5H scenario really paints some kind of picture as to 'how we should proceed' fine tuning our joule thief seems like a lesson tailored more toward spiteful cerebral-measuring than genuine intentions of shedding light on the topic (that was) at hand.
I will repeat to you, the circuit is only "imaginary" if you have a bad attitude and refuse to open up your mind and learn something new and you refuse to apply your knowledge. I will repeat to you, that there is almost no difference between an inductor with zero ohms resistance and an inductor with 0.001 ohms resistance and I just proved it to you and Brad in my previous posting where I did the "real" calculation.
If you can't understand how closely an ideal inductor matches a real inductor and how much can be learned from trying to understand how an ideal inductor works then read over the thread again. I am not here to argue that anymore.
<<< if we were to let's say, graph out the joule thiefs inductor voltage to current ratio over time until
we can see how many seconds it takes to become what we can consider fully charged >>>
The quoted sentence above does not really make any sense and that is the whole point of this exercise. Understand how an inductor works so you can talk about using one sensibly and also understand how a Joule Thief works and then build better Joule Thieves.
Yes there are different ways of using inductors in circuits. A good start is right here. This example applies directly to the energizing phase of a Joule Thief. If you understand the basics then moving to regular inductors is easier. And like I told you in many circuits real inductors for all practical intents and purposes act exactly like ideal inductors.
"Spiteful cerebral-measuring" is you just being defensive because you are in the realm of real electronics here, not the usual throwing around of meaningless catch phrases.
The best thing you could do for yourself is have the same spark as Brad and follow it through and learn something real and substantial about electronics. I will remind you, you read the question and you did not have the slightest idea what to do. I am hoping that you and Brad arrive at a successful conclusion to this debate.
I am not going to touch any Joule Thief thread, sorry.
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Brad:
I am going to do a preemptive strike to get you off of your fixation so that you start to move forward and both answer the question but more importantly understand the answer and the underlying concepts.
For the first part of the question the cat is out of the bag and the formula for the current is i = 0.8*t.
It seems crazy doesn't it? All that arguing and anguish and wild imaginary theories and the answer for the first three seconds is i = 0.8*t.
Okay, so after one second the current is 0.8 amperes.
I attached the formula from Hyperphysics for a voltage source energizing an RL circuit. You can see the red trace for the current and the formula. You can see the "V/R" in the formula and that might tempt you to say that that's proof that the current goes to infinity but that would be dead wrong. The red formula does not work when the resistance becomes zero because the term "V/0" is invalid and undefined.
So now I am going to prove to you that the first part of the answer given to you is correct. We are going to solve the formula for t=1 second, L=5 Henrys and R=0.001 ohms. Sound fair enough? If I am correct the two answers for the current value at one second should be very close to each other.
From the red formula:
i = 4/0.001 * (1 - 2.7182818^(-0.001/5))
i = 4000 * (1 - 2.7182818^-0.0002)
i = 4000 * (1 - 0.99980001999866673333)
i = 4000 * 0.000199980013332666693332
i = 0.799920005333 amperes.
So as you can see, when we introduced a resistor of 0.001 ohms, after one second the current was just a tiny tiny smidgen less than the 0.8 amperes you get when there is no resistor. You note that the calculation for when there is no resistor is 10 times easier as compared to when there is a resistor.
So there is your proof in the pudding. It's time for you to move on and try to answer the question and more importantly understand the how and the why.
MileHigh
I have filled in the blanks in your diagram,and also noted that there will be no voltage curve when the voltage is ideal,and set at 4 volts for 3 seconds-as per your original question.
I am pretty sure Poynt has not yet finished looking into this,and i think you will find that i am correct when i say that your ideal voltage of 4 volts across the ideal inductor for the first 3 seconds from T=0 ,remains 4 volts,as an ideal voltage dose not change in value over time-regardless of the load,and so there is no such voltage curve as you have depicted in your diagram .
Brad
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<<< Im sorry MH,but that dose not work either,as the V has no slope ,due to that fact that the voltage is ideal. >>>
There is no slope associated with the voltage so I don't know what you are talking about. Forget the Tau business for now, it's not relevant.
Read again, Poynt stated that his sim did not run right the first time and when he tweaked the R value it ran as expected and he is in agreement with me now.
The best thing you could do for yourself is follow-though and answer the complete question and demonstrate competence in the subject matter. You have been given a very generous start, now it's up to you and your peers to follow through. You still have a long way to go.
The question still has not been answered....
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I will repeat to you, the circuit is only "imaginary" if you have a bad attitude and refuse to open up your mind and learn something new and you refuse to apply your knowledge. I will repeat to you, that there is almost no difference between an inductor with zero ohms resistance and an inductor with 0.001 ohms resistance and I just proved it to you and Brad in my previous posting where I did the "real" calculation.
If you can't understand how closely an ideal inductor matches a real inductor and how much can be learned from trying to understand how an ideal inductor works then read over the thread again. I am not here to argue that anymore.
<<< if we were to let's say, graph out the joule thiefs inductor voltage to current ratio over time until
we can see how many seconds it takes to become what we can consider fully charged >>>
The quoted sentence above does not really make any sense and that is the whole point of this exercise. Understand how an inductor works so you can talk about using one sensibly and also understand how a Joule Thief works and then build better Joule Thieves.
Yes there are different ways of using inductors in circuits. A good start is right here. This example applies directly to the energizing phase of a Joule Thief. If you understand the basics then moving to regular inductors is easier. And like I told you in many circuits real inductors for all practical intents and purposes act exactly like ideal inductors.
"Spiteful cerebral-measuring" is you just being defensive because you are in the realm of real electronics here, not the usual throwing around of meaningless catch phrases.
The best thing you could do for yourself is have the same spark as Brad and follow it through and learn something real and substantial about electronics. I will remind you, you read the question and you did not have the slightest idea what to do. I am hoping that you and Brad arrive at a successful conclusion to this debate.
I am not going to touch any Joule Thief thread, sorry.
why do you always do that? is this sentence REALLY that hard for you to understand?
"<<< if we were to let's say, graph out the joule thiefs inductor voltage to current ratio over time until we can see how many seconds it takes to become what we can consider fully charged >>>"
is that really such a laymans way of stating it that you simply refuse to attempt comprehending it?
What are we doing in this exercise? Are we not basically graphing an inductor charging according to a time constant? (which in this case doesn't exist) you just happen to use a 5H inductor, nowhere near what the JT inductor is in Brads circuit, and a 0 resistance which has caused a conundrum you are still not understanding the nature of. And yet and still you are claiming to know how an inductor with 0 resistance will act.
I'm literally stating what we just did in practice by analyzing this exercise, and am comparing it to how we can use this same circuit theory analysis to gain an understanding about what is going on
with the joule thief circuit you no longer wish to shed light on.
I'm not going to keep telling you that I'm not attacking your reasoning for using such theoretical models.. It's common practice for even the greenest of EE students. I keep telling you it's not helping us understand the confusion with Brads circuit. You could have easily generated a different question that was more tailored to that specific circuit if you had some revelation you wished to portray in lesson form.
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Below i have added the correct voltage and current traces as would be seen using an ideal voltage,and an ideal inductor.
You will note that it is also the same as what Poynt's sim showed during his 100 second run time.
Brad
P.S
I have incorrectly worded current trace !across! inductor,when it should be current through inductor-as im sure you are well aware of.
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I have filled in the blanks in your diagram,and also noted that there will be no voltage curve when the voltage is ideal,and set at 4 volts for 3 seconds-as per your original question.
I am pretty sure Poynt has not yet finished looking into this,and i think you will find that i am correct when i say that your ideal voltage of 4 volts across the ideal inductor for the first 3 seconds from T=0 ,remains 4 volts,as an ideal voltage dose not change in value over time-regardless of the load,and so there is no such voltage curve as you have depicted in your diagram .
Brad
Read my posting again and understand it, I solved for R=0.001 ohm so I was not discussing an ideal inductor there.
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Magneticitist:
Sorry for being picky but I am not going to discuss Joule Thieves on this thread. For the main coil in a Joule Thief, there is no such thing as a "inductor voltage to current ratio" and I am making a point to you about communicating effectively. How can you expect to talk shop about Joule Thieves if the person you are talking to is a beginner that would not have a clue what you are saying when you say "inductor voltage to current ratio" which itself doesn't really make sense. I won't go after you anymore about this but now you are fully aware.
Note, this thread is all about the energizing of an inductor. My advice to you is to forget about Joule Thieves on this thread and focus on trying to answer the question and understand what is going on.
MileHigh
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Read my posting again and understand it, I solved for R=0.001 ohm so I was not discussing an ideal inductor there.
Good Lord man... did you not just ever so thoroughly stress there is no real difference?
What is the point of this? Why would you even continue to prod him into solving for R=.001 if you are
satisfied with his answer for R=0? We are now practicing an exercise in futility.
I see maybe you are trying to prove a point? show that there is no real difference?
but once again, it wouldn't. you cannot compare two things by only having one of them.
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<<< Im sorry MH,but that dose not work either,as the V has no slope ,due to that fact that the voltage is ideal. >>>
The best thing you could do for yourself is follow-though and answer the complete question and demonstrate competence in the subject matter. You have been given a very generous start, now it's up to you and your peers to follow through. You still have a long way to go.
The question still has not been answered....
Read again, Poynt stated that his sim did not run right the first time and when he tweaked the R value it ran as expected and he is in agreement with me now.
That is correct,his sim ran correct the second time when he placed a very small resistance in with the ideal inductor,and the result was no flow of current.
I have not seen Poynt agree with you. I read- This dose not agree with the Tau being infinity,and--thank you for the explanation.
There is no slope associated with the voltage so I don't know what you are talking about. Forget the Tau business for now, it's not relevant.
Your diagram shows a clear slope in the voltage across the inductor.
How can Tau not be relevant?.
Brad
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Read my posting again and understand it, I solved for R=0.001 ohm so I was not discussing an ideal inductor there.
Please solve for R=0,so as we are defined to the parameters of your original question,as i have shown you already the infinite difference this makes even at a resistance far less than .001 ohms
Brad
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Good Lord man... did you not just ever so thoroughly stress there is no real difference?
What is the point of this? Why would you even continue to prod him into solving for R=.001 if you are
satisfied with his answer for R=0? We are now practicing an exercise in futility.
I see maybe you are trying to prove a point? show that there is no real difference?
but once again, it wouldn't. you cannot compare two things by only having one of them.
If you read the posting again you will see that I compared the 5 Henry coil with no resistor (ideal) and the 5 Henry coil with a 0.001 ohm resistor (real) and I clearly show that the behaviour between the two coils is nearly identical at t=1 second.
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Magneticitist:
Sorry for being picky but I am not going to discuss Joule Thieves on this thread. For the main coil in a Joule Thief, there is no such thing as a "inductor voltage to current ratio" and I am making a point to you about communicating effectively. How can you expect to talk shop about Joule Thieves if the person you are talking to is a beginner that would not have a clue what you are saying when you say "inductor voltage to current ratio" which itself doesn't really make sense. I won't go after you anymore about this but now you are fully aware.
Note, this thread is all about the energizing of an inductor. My advice to you is to forget about Joule Thieves on this thread and focus on trying to answer the question and understand what is going on.
MileHigh
well this is the golden point we have both made now. this thread was made out of respect to your question.. a question Brad never had to make any attempt at answering.. A question that was conceived by you to somehow prove your view on his circuit was correct and superior. That was a joule Thief circuit. at least, a circuit using a transformer. Why you decided to then go into an inductors 101 is obviously beyond me as we have clearly discussed I am out of my element just here to throw around catch phrases and impress total strangers.
I have been trying to figure your reason for bringing up this inductor lesson since I first read about
your question and I still don't get how it could possibly relate to the original conversation.
I understand you want to knit pick such statements as 'voltage to current ratio' but I don't see how that is confusing.. at the time it seemed a fairly straightforward way to word it. I'm pretty sure I could come up with a number of ways to literate an inductor charging, and how it has a voltage unit and current unit we could measure.. I don't think you realize saying such things to me doesn't offend me. I can only gather that conclusion since you so frequently want to point out that all of my thoughts here are just random things I pulled out of my buttcrack on the spot for jollies that not even the most remedial of minds can understand.
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Please solve for R=0,so as we are defined to the parameters of your original question,as i have shown you already the infinite difference this makes even at a resistance far less than .001 ohms
Brad
You are shooting blanks, we are not discussing resistors. What I did was compare the behaviour of the ideal 5 Henry coil and a real 5 Henry coil (0.001 series resistance) and showed you that their behaviour is nearly identical at t=1 second. Do you get that?
If you get that then it proves to you that the formula for the current through the ideal coil of i = 0.8*t is correct.
In other words the explained behaviour for the ideal coil is not a short circuit or an open circuit, it's i = 0.8t. Do you get that?
If you get all of this then you should move forward and try to answer the full question and demonstrate that you know what you are doing.
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Magneticitist:
Stop the psychobabble and the drama, ok? The thread is here and Brad started it and that's all there is to it.
Do you want to contribute to it and learn? Then work with Brad and see what you can come up with. Try to answer the question and use that as a vehicle to learn.
MileHigh
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You are shooting blanks, we are not discussing resistors. What I did was compare the behaviour of the ideal 5 Henry coil and a real 5 Henry coil (0.001 series resistance) and showed you that their behaviour is nearly identical at t=1 second. Do you get that?
If you get that then it proves to you that the formula for the current through the ideal coil of i = 0.8*t is correct.
In other words the explained behaviour for the ideal coil is not a short circuit or an open circuit, it's i = 0.8t. Do you get that?
If you get all of this then you should move forward and try to answer the full question and demonstrate that you know what you are doing.
Tau=L/R is how the time constant for the rise of current flow is determined,and that time constant has a value of infinity,and only changes to a finite value when a small amount of resistance is added to the inductor.
The second thing to ask your self,is how is the inductor defined as being a value of 5 Henry's when you have no resistive value to make that definition?. As you can see,the inductance in all three example in the link below,rely on measuring a voltage drop across a resistance to obtain the current flow to obtain inductive value. So how is this done when there is no resistance? When you work this out,you may begin to understand as to why an ideal inductor dose not dissipate any power,which also lines up with your very own statement that a voltage cannot be measured across an ideal inductor when a DC current if flowing through it,as current alone is not power,and hence the reason that an ideal inductor dose not dissipate power. But now your question also posses the problem that we !do! have an ideal voltage across the ideal inductor that you say has a DC current flowing through it. It can only have a voltage across it if there is no current flowing through it-and visa versa .
http://www.wikihow.com/Measure-Inductance
It is like my answer says it is--you cannot place an ideal voltage across an ideal inductor,as an ideal inductor dose not exist.
I have also shown that regardless of how little the resistance value may be,it will lead to a value that is infinitely different to that of an ideal inductor that has no R value.
Brad
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What does DC current have to do with anything when you put voltage across an ideal coil? You will have to contemplate that.
You have been given more than enough information to do some hunting and researching on your own so that you answer the question correctly. You still haven't taken a stab at the full question.
After all this, it still feels to me like there is faint hope that you are going to achieve those two tasks I listed for you with your current attitude. You never know though like I already said. I think that you are going to have to hope a guru comes in to help you because I am jumping off the train and switching to passive observer mode.
I hope one day in the not too distant future to see you follow-up on both tasks successfully and demonstrate full competence in this very important subject matter.
MileHigh
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I'm just an oaf but I get what you're saying.. an inductor requires at least some form of 'resistance' to have a measurable inductance otherwise we are just saying "hey this is a 5H inductor" and base that entirely off of speculation.
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What does DC current have to do with anything when you put voltage across an ideal coil? You will have to contemplate that.
You have been given more than enough information to do some hunting and researching on your own so that you answer the question correctly. You still haven't taken a stab at the full question.
After all this, it still feels to me like there is faint hope that you are going to achieve those two tasks I listed for you with your current attitude. You never know though like I already said. I think that you are going to have to hope a guru comes in to help you because I am jumping off the train and switching to passive observer mode.
I hope one day in the not too distant future to see you follow-up on both tasks successfully and demonstrate full competence in this very important subject matter.
MileHigh
The fact that you have dismissed the L/R time constant to answer your original question is troubling.You have dismissed using this method-which is used in any other situation,based on the fact that there is no R value. You know that if you did use this conventional method,that the result would be exactly as myself and Poynt said it would be--there would be no flow of current,due to the infinite time constant value. You have dismissed the method that gives us the time constant required to answer your question correctly. This method (Tau=L/R) is the correct method to use in regards to your question. The fact that it results in no current flowing through the ideal inductor ,is inline with the fact that an ideal inductor dose not dissipate energy. Also to back it up is the fact that we have an ideal voltage of 4 volts across that inductor for a period of 3 seconds. This also states that during this time,no current can be flowing through that inductor,as there is a voltage across it,and as you your self have stated,if a DC current was flowing through that inductor,then there would be no voltage across it--but we have 4 volts across it,and so no current is flowing through it. This also falls in line with Poynts sim test.
All circuits used to make this definition are based around an ideal inductor,but with an added series resistor to simulate the resistance that would exist in a real world inductor. If we are to define the outcome of placing an ideal voltage across an ideal inductor,then there is no reason at all that the series resistor just be removed to obtain the correct evaluation for an ideal inductor.
The only reason you do not wish to use this method of Tau=L/R,is because that then puts you in a position of being incorrect. this being the case,i find that a sad time indeed in the history of this forum,where people come to learn and solve such problems using what we know and undderstand to be correct.
Quote: http://www.learnabout-electronics.org/ac_theory/dc_ccts45.php
When a current is applied to an inductor it takes some time for the current to reach its maximum value, after which it will remain in a "steady state" until some other event causes the input to change. The time taken for the current to rise to its steady state value in an LR circuit depends on:
•The resistance (R)
This is the total circuit resistance, which includes the DC resistance of the inductor (RL) itself, plus any external circuit resistance.
• The inductance of L
Which is proportional to the square of the number of turns, the cross sectional area of coil and the permeability of the core.
I am standing firm on my answers,and i hope Poynt(and others) takes the time to have another look at this,and not just accept your example as a reality.
Brad
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guys let's just make a deal and be honest. MH wants to act like you are a complete loony for believing what you do, but I'm fairly sure this is not some extremely rare argument and has been argued before, probably to this very day by many others.. there are others in this thread that share Brads view as well. does that mean MH is wrong? of course not. but until some kind of all ending smoking gun evidence can be presented (which it cannot) what is the point? ok let's say we're using a real R value then. still, what's the point? even plugging in the numbers and calculating for current or the rate of current change, or the voltage, or whatever.. at this point it's just going through the motions.
How about we agree to make a real conscious effort learning about inductors the same way MH did when he was being indoctrinated so long as he agrees to stop using circuit examples with values of 0 and expect a real provable formulaic outcome or omitting variables from formulas altogether.
Then hopefully we can go back to the original topic loool. I'm genuinely interested I mean when do you see me here, that's what I came for and for like 10 pages there it looked like you guys were creeping ever closer to a real provable answer which is what I thought MH had up his sleeve with this whole question thing but oh well can we move on now.
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guys let's just make a deal and be honest. MH wants to act like you are a complete loony for believing what you do, but I'm fairly sure this is not some extremely rare argument and has been argued before, probably to this very day by many others.. there are others in this thread that share Brads view as well. does that mean MH is wrong? of course not. but until some kind of all ending smoking gun evidence can be presented (which it cannot) what is the point? ok let's say we're using a real R value then. still, what's the point? even plugging in the numbers and calculating for current or the rate of current change, or the voltage, or whatever.. at this point it's just going through the motions.
How about we agree to make a real conscious effort learning about inductors the same way MH did when he was being indoctrinated so long as he agrees to stop using circuit examples with values of 0 and expect a real provable formulaic outcome or omitting variables from formulas altogether.
Then hopefully we can go back to the original topic loool. I'm genuinely interested I mean when do you see me here, that's what I came for and for like 10 pages there it looked like you guys were creeping ever closer to a real provable answer which is what I thought MH had up his sleeve with this whole question thing but oh well can we move on now.
I started this thread to remove the debate on MHs ideal coil and voltage question from the JT 101 thread,so as discussion on the topic of JTs could continue without unrelated topics being discussed there,and splitting up the thread. But it seems that now capacitors has also taken hold in that thread--perhaps a dedicated thread on capacitors should also be opened.
Brad
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I will drop in and say this out of frustration:
1. Talking about DC current through an ideal coil and no resultant voltage drop is meaningless and has nothing to do with this exercise.
2. When you apply voltage across an ideal coil you get changing and increasing current. This simple fact is escaping you and as a result you are leading yourself down a garden path. Just like when you apply voltage across a real coil you get changing and increasing current until the current levels off.
It's pull yourself up by your own bootstraps time, or stick in mud and be wrong and go nowhere time, or wait for a guru to save you time.
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This is true I don't mean to disrespect this thread or MH's wishes to avoid further JT discussion... but I have to ask since you two are honestly the best people to ask at this point.. I was eagerly reading
your discussion in the JT thread before this topic and didn't quite realize how far off topic it was actually leading. I guess I may have to try to steal the JT thread back on topic but then I don't want to interrupt the capacitor talk after it has gained some charge. this topic actually has merit too though I suppose, I just don't see how one side could really disprove the other.
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Ideal inductors do exist in our society today. I am certainly no expert in the subject but examine the superconducting electromagnets used in MRI. Once below their critical superconducting temperature, certain materials exhibit zero resistance and yet maintain inductance. The inductive fields exist outside the confines of the wire but they do exist. A 5 henry superconducting coil is still 5 henries even with zero resistance and they will "store" their current with zero voltage drop for extremely long periods of time. There are qualifications for these ideal conductors to work as they do but they are in use everyday.
Resistance of a coil does not determine it's inductance, it simply hinders pure inductance.
I have attached another sim using a coil resistance of 1e-110. This parameter may have passed a preset limit in LtSpice however.
partzman
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The Tau business is fairly simple to explain.
When you transition from a finite Tau to an infinite Tau the current waveform goes from an inverse exponential curve to a straight line. Note that it is a straight line with a constant slope of V/L.
So Tau being infinity does not mean stopping current flow, it means linearly increasing current flow.
Since we are discussing limits, the only possible way for the current to flat-line at zero "forever" would be for the inductance to be infinity. Then you have a "more real" Tau = infinity because this time L/R becomes infinity/R.
So when Tau = infinity/R that gives you the horizontal current trace stuck at zero with a slope of zero (V/infinity), whereas when Tau = L/0, you get a current trace that is a straight line with with a slope of V/L.
MH
Your explanation above only explains the trace or wave form seen on the scope. It dose not explain away the actual resultant math value. The math is precise,and defines the actual time taken for the current to rise,and mathematically that time is infinite--you cannot redefine math at your will.
So Tau at infinity just means the current trace is a perfectly straight line. Since it is a straight line the concept of "reaching 63% of the maximum value" does not apply anymore because that concept does not exist when the current waveform is a perfectly straight line. i.e.; "There is no time constant."
Tau at infinity dose not just mean the current trace is just a flat line. Tau at infinity is a mathematical calculated value using the the equation that is always used to calculate the Tau time constant--> Tau=L/R.
There is a time constant,and that time constant is infinity. A flat line on a scope dose not just dismiss this mathematically calculated time constant. In fact,that flat line seen on the scope ,represents the infinite flat line that would be seen as an infinite time value. If the scope had an infinitely long screen,then you would see that trace remain flat at a zero value throughout the entire time a voltage is placed across the ideal inductor.
Brad
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So I guess the question is how much time does it take for an ideal inductor to reach a particular current over time if resistance was not an obstacle. This would mean that the ideal inductor is functional as an inductor.....
Well the ideal inductors current rise when the ideal input voltage is applied will be a straight line increase and not a curve because the absence of voltage division because of no resistance. So the current could rise indefinitely over time, directly related to time and the resistance value does not need to be in the equation L/R. Correct?
That is if the ideal inductors bemf ends up not being equal to the input and the ideal inductor actually works.
Mags
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the superconductors are a good example but they are like comparing 0 resistance with .0000001 or any of the other ridiculously low resistances mentioned to sim with.
and how do we know if R was 0 that line wouldn't be level flat or plumb straight up.
when we super cool the conductors we are probably just reallocating that resistive variable elsewhere. maybe much less measurable resistance but maybe a much less hindered ability to create
a field. idk I'm no expert either lol. at any rate it makes me think of how the curie point is sort of like
the opposite effect and maybe we can take magnetic inductor with very little resistance and heat it to a point where it has very high resistance and has a harder time creating a field if that doesn't sound stupid.
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So I guess the question is how much time does it take for an ideal inductor to reach a particular current over time if resistance was not an obstacle. This would mean that the ideal inductor is functional as an inductor.....
Well the ideal inductors current rise when the ideal input voltage is applied will be a straight line increase and not a curve because the absence of voltage division because of no resistance. So the current could rise indefinitely over time, directly related to time and the resistance value does not need to be in the equation L/R. Correct?
That is if the ideal inductors bemf ends up not being equal to the input and the ideal inductor actually works.
Mags
yea my beef is if the ideal coil aka absolute 0 R coil cannot dissipate or radiate anything whatsoever, then to me that's like another way of saying it has immeasurable current. infinite, 0, immeasurable either way and might as well be non existent. you would never have the field or current to begin with and the lack of a time constant would just basically make all the equations equal 0 since progress over time is out of the window and no longer even discernible from 0 time progression at all. it's like we are talking about trying to apply current to something that can perfectly and absolutely resist current change aren't we?
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Ideal inductors do exist in our society today. I am certainly no expert in the subject but examine the superconducting electromagnets used in MRI. Once below their critical superconducting temperature, certain materials exhibit zero resistance and yet maintain inductance. The inductive fields exist outside the confines of the wire but they do exist. There are qualifications for these ideal conductors to work as they do but they are in use everyday.
Resistance of a coil does not determine it's inductance, it simply hinders pure inductance.
I have attached another sim using a coil resistance of 1e-110. This parameter may have passed a preset limit in LtSpice however.
partzman
A 5 henry superconducting coil is still 5 henries even with zero resistance and they will "store" their current with zero voltage drop for extremely long periods of time.
Partzman
A super conductor that has a steady DC current flowing through it,has no voltage across it. If it did,then it would be dissipating power,and super conductors do not dissipate power.
Brad
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So I guess the question is how much time does it take for an ideal inductor to reach a particular current over time if resistance was not an obstacle. This would mean that the ideal inductor is functional as an inductor.....
Well the ideal inductors current rise when the ideal input voltage is applied will be a straight line increase and not a curve because the absence of voltage division because of no resistance. So the current could rise indefinitely over time, directly related to time and the resistance value does not need to be in the equation L/R. Correct?
That is if the ideal inductors bemf ends up not being equal to the input and the ideal inductor actually works.
Mags
You have nailed it on the head-or near to Mag's.
Unfortunately MH is just not getting it,and he is trying to use a math function that dose not account for the voltage and inductor on being ideal.
Well now I feel like I am in the Twilight Zone.
Poynt: The current is one over "L" integral v dt.
That's 1/5 * integral (4) dt.
That's 1/5 * 4t.
That's 4/5*t.
When t = 3 seconds that's 12/5 = 2.4 amps.
The above is not applicable to an ideal inductor with an ideal voltage across it.
The math above is based on the premise that the inductor will eventually reach a maximum current value in Tau x 5s. We already know that by using the L/R time constant,that Tau is infinity.
We can also solve this a second way. That is to place the ideal voltage across the ideal inductor,and time how long it takes for the maximum current value to be reached. We then divide this time by 5 to obtain our Tau time constant. This also results in an infinite time,as the voltage is ideal,and the inductor has no resistance. It also means once again that there will be no current flowing through the ideal inductor :o.
As i said,and have all along--you cannot place an ideal voltage across an ideal inductor,because as you see,you are left with a paradox.
If an ideal voltage is placed across an ideal inductor(that has no resistance to control the flow of current),then the current would take an infinite amount of time to reach it's peak level.
This then means that the current would also take an infinite amount of time to start to flow into that inductor at T=0,as when you divide an infinite amount of time by any other amount of time,you end up with an answer that is also infinite.
So that is the paradox,but it is also correct,and once again backs up all my answers i have given in regards to the original question.
Even MH cannot deny that it would take an infinite amount of time for the current to reach maximum value,when an ideal voltage(a voltage that dose not change over time) is placed across an ideal inductor that has no resistance(dose not limit or control the flow of current)
If he understands this,then he may also understand the conundrum/paradox associated with his!so called! simple circuit,being that,from the above,we also know it would also take an infinite amount of time for the current to start to flow through the ideal inductor.
This will lead to the point where he now understands my answer--you cannot place an ideal voltage across an ideal inductor
Can i explain both of my theoretical answers?--yes i can,and i am surprised Poynt did not pick up on it-the paradox. MH laughed at my two theoretical answers being totally different.
1-being that there is no current flowing through the inductor--that Poynt did agree with--not sure what he thinks now after MH threw in his wobbly mathematics.The reason being-->as above. If it takes an infinite time for the current to reach it's maximum,then it also takes an infinite amount of time before the current starts to flow.
2-@ T=0,when the ideal voltage is placed across the ideal inductor,the current will rise instantly to an infinite value. Answer one makes answer two also correct,in that,as the current is going to rise for an infinite time to an infinite value,then at the very start of that infinite time ,T=0,the current will also be at an infinite amount. As i said,no matter how many parts you divide an infinite value by,each part in itself will also have an infinite value.
This all sounds crazy i know,and hence the reason i included the word conundrum and/or paradox with my answers.
This also shows that MHs question cannot be answered,as it cannot exist.
Changing values around,and changing from an ideal to a non ideal,and using math that is based around non ideal situations,is not going to make the original question answerable.
Brad
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electric field moves at light speed doesn't it? how would we know it lagged over distance without resistance.
yet a graph can somehow show some kind of change over time when time has already been omitted due to there
being no relative way to measure it.
one day they'll get a super conductor 100% ideal with absolute 0 resistance, and it will be when the entire universe
is one giant solid piece of silver, and there's absolutely nothing else in the universe to compare it to.
to agree with Albert Einstein, or to disagree with Albert Einstein?..
That is the question.
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OK, it's 2:30 AM and I am sleepy so here goes nothing.
The ideal business is just a show piece. You have this ideal voltage meaning it provides anywhere from none to infinite current. As long as your wire is fat enough and let's say 200 turns, that fixed voltage will be applied and you will have enough current in the source to heat up those fat wires. Since those wires of the coil as so fat, the resistance is almost nothing even though nothing can be at an absolute zero resistance.
Now put that same ideal voltage into a coil of thinner wire and only 20 turns. Now that wire has some resistance because it is much thinner then that fat wire coil. Now the voltage is applied and the current, even though it could go to infinity if your wire was of infinite diameter, the current will stabilize at a given level and stay there. The wire determines the current because in any case, the wire has x number of copper atoms and cannot invent or materialize any more so there are only an x amount of atoms conveying and hence x current in the coil. With only 20 turns that 4 volts has a chance to make it to the end of the coil so that whole coil with have current conveyed. I am saying conveyed because I do not believe in flow but that should not detract from this.
Now take that same thin wire coil that now has 2000 turns hence higher henries. Apply your ideal voltage of 4 volts. Even if the current can go to infinity, the coil is only hit with 4 volts and 4 volts in a 2000 turn coil is nothing, probably won't even be conveyed to the end of the coil so the current will be greater at the start of the coil and very weak by the time it gets to the end of the coil hence the current at the start will be greater then the current at the end of the coil. Yes this is counter andwould need to be tested with a multi tapped coil.
Yes this is not an ideal coil. Unfortunately yes, @MH did not need to include an ideal coil in this question and that is a mistake he needs to man up to but that's his business not mine. It would have saved 100 pages of nullisms.
Just for the record I actually do know that DC does not work like that in our coils but that's another topic and should again not detract from this subject as an EE discourse goes.
So again, what @MH just wants to explain is actually very rudimentary but by using the ideal voltage construct just makes the none to infinite current available to match the coils wire AWG and length and topology. Just apply the voltage and the current will find its own level. Yes a DC power supply will do that for you as well. Even if the coil had wire the diameter of the sun and the length of our solar system it will still have resistance so it would be better to remove the ideal from the coil and leave it with the voltage source.
But I still think @MH needs to concede that the original question should not have employed two ideal subjects in the same question. One is enough to explain the process which is again so rudimentary that is is sort of insulting but again, maybe guys take is for granted that you really do not need to always measure currents to know what's going on going your coils.
I rarely use anything to measure watts. My LEDs or bulbs say it all already. When one of them blows, I'll know something is really good. hahahahahaha You don't need to be so obsessed with measurements as I have found it takes time, it already shows what you should already know and it especially eats away at your bench time, patience and distracts you from the most important part of testing a build and that is.................... working the variables. You make a build and test it. You learned one thing. You then test variables on the build as comparisons and now you are learning multiples more on effects. That's where the gold is.
GGGGGGHHHHHHHHHHHHHHHH.
wattsup
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We can also solve this a second way. That is to place the ideal voltage across the ideal inductor,and time how long it takes for the maximum current value to be reached. We then divide this time by 5 to obtain our Tau time constant. This also results in an infinite time,as the voltage is ideal,and the inductor has no resistance. It also means once again that there will be no current flowing through the ideal inductor :o .
Since an ideal inductor must have a zero resistance, this means that it must be shorted (if it ain't shorted, it ain't ideal) and it becomes physically impossible to connect any real voltage sources in series with it.
Otherwise, I agree with the above statement. Not only an ideal inductor is devoid of an asymptotic V/R current limit but also the current through an inductor of infinite inductance, that is somehow connected to an ideal voltage source, could never change because of the implied zero di/dt at any voltage.
Of course, it is debatable whether an ideal inductor must have an infinite inductance. Some would say that it is enough for it to have zero resistance and zero parasitic capacitance.
However it is possible to externally change the magnetic flux penetrating a shorted ideal inductor. Doing so will instantaneously cause a current to circulate through it *, in order to maintain the previous flux level penetrating its windings. This is a voltageless current! - it cannot be measured by a voltmeter and it was not caused by a voltage source.
Last but not least - inductors are current devices and voltage creates no effects in them. Voltage cannot even be measured in shorted ideal inductors (neither practically nor theoretically!). Measurement of voltage (emf) is meaningful only for non-ideal inductors (e.g. open inductors or inductors with series resistances). Open inductors or inductors without current flowing though them are dummy inductors - they create no effects on the environment. Voltmeter deflection notwithstanding.
P.S.
I'm just replying to Tinman's post and I have not read what others wrote in this thread.
* (without delay and regardless of its inductance)
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@All - Dont forget, Impedance has two different types of Resistance, Real and Imaginary.
Imaginary consists of Inductive Reactance and Capacitive Reactance - This is considered to be a Resistance also.
For DC, it does not apply unless youre looking at the rise and fall times as a Frequency Component. So youre pretty safe to say DC there is none.
However, at any frequency there will be a value of Impedance even if the Real Resistance is 0.
Chris Sykes
hyiq.org
see: https://www.researchgate.net/figure/237776087_fig9_Figure-9-Impedance-and-ESR-vs-Frequency-for-T520-vs-T528-equal-parts
P.S: Impedance (Z) and Equivalent Series Resistance (ESR) run the same race, they are parts of the samething. So, really, at any Frequency, there can be no Ideal Inductor with Zero Resistance. At least according to theory. Only at DC. Which some have already explained.
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@All - Dont forget, Impedance has two different types of Resistance, Real and Imaginary.
To be technically correct it should've been written:
"Impedance has two different types of Ohms - Real and Imaginary"
OR
"Impedance has two different components - Real and Imaginary"
...because the word "Resistance" is reserved for the real component of Impedance.
This is just a terminological correction - not a conceptual one.
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To be technically correct it should've been written:
"Impedance has two different types of Ohms - Real and Imaginary"
OR
"Impedance has two different components - Real and Imaginary"
...because the word "Resistance" is reserved for the real component of Impedance.
This is just a terminological correction - not a conceptual one.
Yes, of course, thanks Verpies, both are measured in Ohms: Ω-jΩ or Ω+jΩ
If you see something like:
Z = 10-j10 (-j = Inductive Reactance)
or
Z = 10+j10 (+j = Capacitive Reactance)
This is where 10 Ohms of Real Resistance and 10 Ohms of Reactance: (XL Reactive Iductance or XC Reactive Capacitive).
See: http://www.saylor.org/site/wp-content/uploads/2011/07/ME301-vol-2.pdf
http://www.allaboutcircuits.com/textbook/alternating-current/chpt-4/series-resistor-capacitor-circuits/
Chris Sykes
hyiq.org
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Otherwise, I agree with the above statement. Not only an ideal inductor is devoid of an asymptotic V/R current limit but also the current through an inductor of infinite inductance, that is somehow connected to an ideal voltage source, could never change because of the implied zero di/dt at any voltage.
Of course, it is debatable whether an ideal inductor must have an infinite inductance. Some would say that it is enough for it to have zero resistance and zero parasitic capacitance.
However it is possible to externally change the magnetic flux penetrating a shorted ideal inductor. Doing so will instantaneously cause a current to circulate through it *, in order to maintain the previous flux level penetrating its windings. This is a voltageless current! - it cannot be measured by a voltmeter and it was not caused by a voltage source.
Last but not least - inductors are current devices and voltage creates no effects in them. Voltage cannot even be measured in shorted ideal inductors (neither practically nor theoretically!). Measurement of voltage (emf) is meaningful only for non-ideal inductors (e.g. open inductors or inductors with series resistances). Open inductors or inductors without current flowing though them are dummy inductors - they create no effects on the environment. Voltmeter deflection notwithstanding.
P.S.
I'm just replying to Tinman's post and I have not read what others wrote in this thread.
* (without delay and regardless of its inductance)
Since an ideal inductor must have a zero resistance, this means that it must be shorted (if it ain't shorted, it ain't ideal) and it becomes physically impossible to connect any real voltage sources in series with it.
Thank you verpies for joining in on this discussion.
You have confirmed my real world answer--an ideal voltage cannot be applied to/placed across an ideal inductor.
Last but not least - inductors are current devices and voltage creates no effects in them. Voltage cannot even be measured in shorted ideal inductors (neither practically nor theoretically!). Measurement of voltage (emf) is meaningful only for non-ideal inductors (e.g. open inductors or inductors with series resistances). Open inductors or inductors without current flowing though them are dummy inductors - they create no effects on the environment. Voltmeter deflection notwithstanding.
I only hope Poynt reads what both you and i have stated,and revisits his thoughts on the question presented by MH,and understands that the math MH is using to make his calculations do not apply when dealing with ideal inductor's.
Just another proof that placing a voltage across an ideal inductor dose not create a current flow through that ideal inductor.
Being an ideal inductor,means that it dose not dissipate power,and that also means the CEMF is also ideal,--> equal to that which creates it,and thus no current flows when a voltage is placed across that ideal inductor.
A non ideal inductor dose have an R value,and this means it dose dissipate power. This also means that the CEMF value is not as high as the EMF that created it,and so current will flow through a non ideal inductor--as we know.
Brad
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To be technically correct it should've been written:
"Impedance has two different types of Ohms - Real and Imaginary"
OR
"Impedance has two different components - Real and Imaginary"
...because the word "Resistance" is reserved for the real component of Impedance.
This is just a terminological correction - not a conceptual one.
Verpies
Would you care to answer the question below,and give the reason for your answer.
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts. Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts. Then after that the voltage is zero volts.
What happens from T=0 when the ideal voltage is connected to the ideal coil?.
Brad
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However it is possible to externally change the magnetic flux penetrating a shorted ideal inductor. Doing so will instantaneously cause a current to circulate through it *, in order to maintain the previous flux level penetrating its windings. This is a voltageless current! - it cannot be measured by a voltmeter and it was not caused by a voltage source.
Better yet, the current induced in the above scenario is independent of the rate of change of flux (dΦ/dt) penetrating that inductor.
On the other hand, the emf induced across an open inductor is not independent of the rate of change of flux (dΦ/dt) penetrating that inductor.
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Brad,
To be clear, I am in agreement with MH. It makes sense to me now, and apparently when I answered the question years back on OUR, I also got the answer correct.
Regarding my simulation, when using such small resistance values without changing some settings in SPICE (LT Spice must already be set to handle this), the simulation engine runs out of computational precision, which is why it "flatlines" with very low values. When the value is too low, the sim runs out of gas and starts making gross approximations, which is evident below with R=1f Ohm. But you do see that it is honing in on the 2.4A value? Any smaller in value and the trace just flatlines.
For an ideal inductor, yes Tau is infinite, but this has does not preclude current flow through the inductor. If however the inductance was an unrealistically large value like 1 million Henries, then yes the current would essentially be zero for a relatively long duration of time. That was my confusion. Tau simply determines the rise time, and since it is infinitely long, the trace becomes a nice straight line rather than the curve we normally see.
I was wrong in my analysis, but it is clear to me now.
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Better yet, the current induced in the above scenario is independent of the rate of change of flux (dΦ/dt) penetrating that inductor.
On the other hand, the emf induced across an open inductor is not independent of the rate of change of flux (dΦ/dt) penetrating that inductor.
That is because one is closed,and the other open.
If-as in the question i posted in my last post,the inductor is a closed loop,in that it has an ideal voltage source that completes the loop. Being an !ideal! voltage source,it too must be void of resistance and resistive losses,and so becomes part of the ideal inductor.
So now that the inductor and voltage source are a complete ideal loop,void of resistance,across no two points in that loop can a voltage exist.
And hence,once again,you cannot place a voltage across an ideal inductor,when current is flowing through that closed inductor loop.
Brad
So the question asked is referring to a closed loop scenario.
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Brad,
To be clear, I am in agreement with MH. It makes sense to me now, and apparently when I answered the question years back on OUR, I also got the answer correct.
Regarding my simulation, when using such small resistance values without changing some settings in SPICE (LT Spice must already be set to handle this), the simulation engine runs out of computational precision, which is why it "flatlines" with very low values. When the value is too low, the sim runs out of gas and starts making gross approximations, which is evident below with R=1f Ohm. But you do see that it is honing in on the 2.4A value? Any smaller in value and the trace just flatlines.
For an ideal inductor, yes Tau is infinite, but this has does not preclude current flow through the inductor. If however the inductance was an unrealistically large value like 1 million Henries, then yes the current would essentially be zero for a relatively long duration of time. That was my confusion. Tau simply determines the rise time, and since it is infinitely long, the trace becomes a nice straight line rather than the curve we normally see.
I was wrong in my analysis, but it is clear to me now.
Rise time is an actual value,not a trace on a scope.
Is verpies also wrong? Quote: Since an ideal inductor must have a zero resistance, this means that it must be shorted (if it ain't shorted, it ain't ideal) and it becomes physically impossible to connect any real voltage sources in series with it.
Otherwise, I agree with the above statement. Not only an ideal inductor is devoid of an asymptotic V/R current limit but also the current through an inductor of infinite inductance, that is somehow connected to an ideal voltage source, could never change because of the implied zero di/dt at any voltage.
How long will it take for the current to reach it's peak in an ideal inductor(regardless of inductance value),when that inductor has no resistance,and is supplied with an ideal voltage?
Once you have this value,you can divide it by 5 to obtain your time constant for the rise of current in that ideal inductor. Mh is using math that applies to an inductor on the understanding that that inductor will reach a maximum current value in a finite time. This cannot be applied to an ideal inductor,where the current will never reach a maximum value when an ideal voltage is placed across it.
Brad
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. . . “Mad Hatter: “Why is a raven like a writing-desk?”
“Have you guessed the riddle yet?” the Hatter said, turning to Alice again.
“No, I give up,” Alice replied: “What’s the answer?”
“I haven’t the slightest idea,” said the Hatter”
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Brad,
I don't understand what verpies is trying to say, so I can't say if he is in agreement with MH or not.
You could ask him.
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hmm, I thought the EMF followed current. It's the electric field that's the precursor. No EMF if the current is not allowed to change. Electric field see's whats going on the entire time tho.
- question:
is a rise in current a change in current, or not?
the inverse exponential curve to straight line makes perfect sense though..
that is, if current were allowed to flow or change. we have to assume that
is the case first.
*unlike a capacitor, imaginarily we have started at source voltage in our scenario across the inductor. well, again, unlike the capacitor, mission accomplished. no need for current flow because no lenz effect.
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is a rise in current a change in current, or not?
It is
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Magneticitist
hmm, I thought the EMF followed current. It's the electric field that's the precursor. No EMF if the current is not allowed to change. Electric field see's whats going on the entire time tho.
You may want to rethink your statement. The Electro-Motive Force is the force which causes the charges to move and this motion is called an electric current. The EMF is a Force on the charges and without a force acting on something it has no reason to move.
I cannot even begin to explain how completely messed up your post is... review Coulombs Law, Faradays Law, Electron flow notation, an Electro-Motive Force (Emf).
AC
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I don't understand what you mean. I'm saying EMF is a result of current. Well, 'result of' is not quite what I mean but it's hard for me to word it otherwise.
How can there be an electromagnetic field without current? There is however an electric field, the voltage.
-maybe I have this wrong but I think you may be missing that we are essentially saying the same thing. damn maybe MH is right and I need to start honing my word choices but can see how I was confusing EMF magnetic field, but I thought I was being clear by also mentioning the electric field as being the established circuit voltage. I believe someone else put it, a currentless voltage.
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I don't understand what you mean. I'm saying EMF is a result of current. Well, 'result of' is not quite what I mean but it's hard for me to word it otherwise.
How can there be an electromagnetic field without current? There is however an electric field, the voltage.
-maybe I have this wrong but I think you may be missing that we are essentially saying the same thing. damn maybe MH is right and I need to start honing my word choices.
EMF=Electro-Motive Force not electromagnetic field...maybe this will help your confusion?
Bill
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EMF=Electro-Motive Force not electromagnetic field...maybe this will help your confusion?
Bill
you are right thank you I was just realizing that
(i will admit I really need to brush up on what to call certain things MH! but in theory I feel
I understand what is going on.. for example I want to call the voltage the electric field in nature when that's not even correct after checking)
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you are right thank you I was just realizing that
(i will admit I really need to brush up on what to call certain things MH! but in theory I feel
I understand what is going on.. for example I want to call the voltage the electric field in nature when that's not even correct after checking)
No problem. This can be very confusing...and...just when I think I am starting to understand something...I find out that I really am not, ha ha.
Bill
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No problem. This can be very confusing...and...just when I think I am starting to understand something...I find out that I really am not, ha ha.
Bill
it is indeed very confusing and hard to convey thoughts without looking like an idiot if you're like
me and have not dedicated enough time to properly learning the right terminology for everything.
but in an even harder way to explain it seems like this argument involves a basic paradox that
was at least evident enough to warrant many pages of debate. at the end of it all while I personally
struggle to convey my thoughts, I just think the damn thing will do absolutely nothing. Sit at source voltage and act as if it wasn't even there to begin with.
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I thought the EMF followed current.
An EMF measured across an open inductor is proportional to the rate of change of flux penetrating that inductor (dΦ/dt).
EMF measured across an inductor is not proportional to the current flowing through it and in an open inductor the current cannot flow at all.
It's the electric field that's the precursor.
Precursor of what?
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Brad,
To be clear, I am in agreement with MH. It makes sense to me now, and apparently when I answered the question years back on OUR, I also got the answer correct.
Regarding my simulation, when using such small resistance values without changing some settings in SPICE (LT Spice must already be set to handle this), the simulation engine runs out of computational precision, which is why it "flatlines" with very low values. When the value is too low, the sim runs out of gas and starts making gross approximations, which is evident below with R=1f Ohm. But you do see that it is honing in on the 2.4A value? Any smaller in value and the trace just flatlines.
For an ideal inductor, yes Tau is infinite, but this has does not preclude current flow through the inductor. If however the inductance was an unrealistically large value like 1 million Henries, then yes the current would essentially be zero for a relatively long duration of time. That was my confusion. Tau simply determines the rise time, and since it is infinitely long, the trace becomes a nice straight line rather than the curve we normally see.
I was wrong in my analysis, but it is clear to me now.
I dont think it is clear Poynt,and your original thought (current will not flow)is correct.
If your sim can replicate any real electrical event in a circuit,why dose it crash when you use an ideal inductor that no resistance?. Why is your sim unable to carry out a simple analysis such as you think MH has successfully done?.
The answer is simple,and as i stated. MH is using math that is based on the premise that the inductor will reach a maximum current level. !!Can you calculate what the maximum current level will be of an ideal inductor using MHs calculations? Will this answer (When t = 3 seconds that's 12/5 = 2.4 amps) then be correct?.
When modeling a circuit ,an ideal inductor is used--along with a series resistor that mimics the resistance that would exist in a real world inductor. This is why you have to place some resistance in series with your ideal inductor in your sim to stop it crashing.
Why dose your sim crash without it?
Because your using an ideal inductor. An ideal inductor has ideal inductance,no resistance,no capacitance,and dose not dissipate power. This means that the CEMF is also ideal,and so is equal to the EMF ,and so an equal current will flow in the opposite direction to that of the current produced by the EMF.
Here is verpies statement.
Since an ideal inductor must have a zero resistance, this means that it must be shorted (if it ain't shorted, it ain't ideal) and it becomes physically impossible to connect any real voltage sources in series with it.Not only an ideal inductor is devoid of an asymptotic V/R current limit but also the current through an inductor of infinite inductance, that is somehow connected to an ideal voltage source, could never change because of the implied zero di/dt at any voltage.
Remember-it is only the resistance and parasitic capacitance that allows the EMF to be greater than the CEMF,and allow the flow of current,something that an ideal inductor is void of.
Brad
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An EMF measured across an open inductor is proportional to the rate of change of flux penetrating that inductor (dΦ/dt).
EMF measured across an inductor is not proportional to the current flowing through it and in an open inductor the current cannot flow at all.
Precursor of what?
well, look.. I hadn't thought about this kind of stuff in a while and in this debate tried to quickly brush up on my terminology online, and read how the EMF is actually the potential. I was thinking the electric field was the voltage when apparently that's not a metaphor. Now I don't really know what to call what at the moment because I am getting more confused at the terminology other people are using that seems to contradict what I just read. I need to spend some more time reading this in detail before I know exactly what do call what here but I think of it like electric- voltage, magnetic - current. maybe that is a complete falsehood that has emerged from too much misinterpreted tinkering and not enough reading. at any rate the point I was trying to make is that any magnetic force that is present is present when there is current flowing and if not we just have voltage from the source.
there's no di/dt to even consider, no magnetic field to consider, no lenz to consider, because it's all perfectly working against itself in theory and pretty much just not existing at all. like any inductor the voltage is the precursor unlike the opposite in a capacitor.
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@Tinman
Remember-it is only the resistance and parasitic capacitance that allows the EMF to be greater than the CEMF,and allow the flow of current,something that an ideal inductor is void of.
I would agree and if the resistance is defined as zero in the question then Ohms law has no application... let's move on. No resistance and no capacitance which leaves an Electro-Motive Force from the source which are Coulomb forces due to the Ideal voltage source electric field. The source Emf acts forward however the moment something tries to move a magnetic field evolves producing an equal and opposite Counter-Force, our Cemf, which opposes the charges motion.
Logic suggest that if nothing can dissipate and energy is perfectly conserved then the Cemf must balance perfectly with the source Emf... remember these are perfectly conserved forces. If an ideal superconductor produces a perpetual loss-less current closed loop then an ideal superconducting coil must also produce a perpetual loss-less Cemf countering our source Emf. One cannot say the rules always apply then change the rules simply because they do not like the answer. Either the forces balance perfectly and energy is conserved or energy is not conserved in a loss-less system and we have problems. Ideally it must be ideal because we have already defined it as such.
AC
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@Tinman
I would agree and if the resistance is defined as zero in the question then Ohms law has no application... let's move on. No resistance and no capacitance which leaves an Electro-Motive Force from the source which are Coulomb forces due to the Ideal voltage source electric field. The source Emf acts forward however the moment something tries to move a magnetic field evolves producing an equal and opposite Counter-Force, our Cemf, which opposes the charges motion.
Logic suggest that if nothing can dissipate and energy is perfectly conserved then the Cemf must balance perfectly with the source Emf... remember these are perfectly conserved forces. If an ideal superconductor produces a perpetual loss-less current closed loop then an ideal superconducting coil must also produce a perpetual loss-less Cemf countering our source Emf. One cannot say the rules always apply then change the rules simply because they do not like the answer. Either the forces balance perfectly and energy is conserved or energy is not conserved in a loss-less system and we have problems. Ideally it must be ideal because we have already defined it as such.
AC
Absolutely AC
Ideal means perfect-a losless conversion between EMF-forward current-counterEMF-reverse current.of the same amount.
So that would mean a dead short when an ideal voltage from an ideal source is placed across the ideal inductor,as as much current would be trying to flow back into the ideal voltage source,as the ideal voltage source is trying to deliver.
My answer stands--you cannot place an ideal voltage across an ideal inductor.
Brad
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@Tinman
I would agree and if the resistance is defined as zero in the question then Ohms law has no application... let's move on. No resistance and no capacitance which leaves an Electro-Motive Force from the source which are Coulomb forces due to the Ideal voltage source electric field. The source Emf acts forward however the moment something tries to move a magnetic field evolves producing an equal and opposite Counter-Force, our Cemf, which opposes the charges motion.
Logic suggest that if nothing can dissipate and energy is perfectly conserved then the Cemf must balance perfectly with the source Emf... remember these are perfectly conserved forces. If an ideal superconductor produces a perpetual loss-less current closed loop then an ideal superconducting coil must also produce a perpetual loss-less Cemf countering our source Emf. One cannot say the rules always apply then change the rules simply because they do not like the answer. Either the forces balance perfectly and energy is conserved or energy is not conserved in a loss-less system and we have problems. Ideally it must be ideal because we have already defined it as such.
AC
I don't see why we should have to take it further than "perfectly and absolutely resists current change". This automatically means no EMF or counter EMF doesn't it?
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Absolutely AC
Ideal means perfect-a losless conversion between EMF-forward current-counterEMF-reverse current.of the same amount.
This would more so describe an ideal inductor that also has an infinite amount of inductance. As such, when connected across a voltage source, no current would ever flow as the time constant would also be infinite. An ideal inductor with infinite inductance would appear to be a continuous open circuit when connected in parallel with a voltage source.
Consider the superconducting magnet used in an MRI machine. Typically, they have a total inductance of around 6000Hy. They are "charged" very slowly to a couple hundred amps or so with an adjustable current limited source to prevent an excessive overvoltage condition.
So that would mean a dead short when an ideal voltage from an ideal source is placed across the ideal inductor,as as much current would be trying to flow back into the ideal voltage source,as the ideal voltage source is trying to deliver.
My answer stands--you cannot place an ideal voltage across an ideal inductor.
You seem to be describing an ideal capacitor with an infinite amount of capacitance. An ideal capacitor with an infinite amount of capacitance would have an infinite time constant and appear to be a continuous short circuit when connected in parallel with a voltage source.
That's my 2 cents for now. I've been away and will try to catch up on this thread as time allows. Very busy...
PW
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This would more so describe an ideal inductor that also has an infinite amount of inductance. As such, when connected across a voltage source, no current would ever flow as the time constant would also be infinite. An ideal inductor with infinite inductance would appear to be a continuous open circuit when connected to a voltage source.
Consider the superconducting magnet used in an MRI machine. Typically, they have a total inductance of around 6000Hy. They are "charged" very slowly to a couple hundred amps or so with an adjustable current limited source to prevent an excessive overvoltage condition.
You seem to be describing an ideal capacitor with an infinite amount of capacitance. An ideal capacitor with an infinite amount of capacitance would have an infinite time constant and appear to be a continuous short circuit when a voltage is applied across it.
That's my 2 cents for now. I've been away and will try to catch up on this thread as time allows. Very busy...
PW
let's say this is true, and it honestly makes a degree of sense even though I disagree in principle..
Wouldn't this mean the inductor is 'perfectly' accomplishing the exact opposite of what it's supposed to be perfectly doing in nature? Wouldn't the EMF and *CEMF be increasing against each other the entire time to infinity? And wouldn't that have to mean a continuously rising current?
How does that not constitute current change?
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This photo is for the Tinman.
Basically we get too much overunity and have to hand-rear the triplets.
These are a few of this years pets.
How about this for a business idea Tinman? Start the manufacture of
braking systems for overunity machines.
The one thing Wayne Travis got right on his early plans for his church
was the provision of a cooling system!!!
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I don't see why we should have to take it further than "perfectly and absolutely resists current change".
This automatically means no EMF or counter EMF doesn't it?
What it means ,is that there can be no voltage across the ideal inductor--so yes.
It also means,as i said before,the current would be instant,and infinite--but no current flow. It would be much like supplying each end of a water pipe with water at 40psi. You would have pressure,but no flow.
Brad
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Consider the superconducting magnet used in an MRI machine. Typically, they have a total inductance of around 6000Hy. They are "charged" very slowly to a couple hundred amps or so with an adjustable current limited source to prevent an excessive overvoltage condition.
You seem to be describing an ideal capacitor with an infinite amount of capacitance. An ideal capacitor with an infinite amount of capacitance would have an infinite time constant and appear to be a continuous short circuit when connected in parallel with a voltage source.
That's my 2 cents for now. I've been away and will try to catch up on this thread as time allows. Very busy...
PW
This would more so describe an ideal inductor that also has an infinite amount of inductance. As such, when connected across a voltage source, no current would ever flow as the time constant would also be infinite. An ideal inductor with infinite inductance would appear to be a continuous open circuit when connected in parallel with a voltage source.
Thanks for joining PW.
I have to say that i dont agree with the ideal inductor needing to have an infinite inductance value.
Any iductor that is ideal is loss less -dose not dissipate power,due to having no resistance or capacitance. It converts or stores 100% of the energy it receives--ideal. Being the case,the current created when the v ideal voltage is placed across the ideal inductor,would create an CEMF and current of the same value--100% conversion--ideal.
Due to the fact that the voltage is also ideal,the source of that voltage must also be ideal.
Lets say it's an ideal battery,meaning that that battery could deliver 4 volts across any load without a voltage drop. The battery would also have to be ideal,and there for would have no internal resistance,and would not dissipate power by way of waste heat,or radiated energy of any type.
Once this ideal voltage source is hooked across the ideal inductor,as soon as any magnetic field started to form,it would produce an exact opposite,in the way of CEMF and current--ideal conversion. We know this to be true in an ideal situation,as everything has an equal and opposite reaction. In a non ideal situation,some of that equal and opposite is lost to heat due to resistance and parasitic capacitance--but not in an ideal situation,which is what the original question states the inductor and voltage source is--ideal.
The result would be an instant and infinite current build up between the ideal voltage source,and the ideal inductor,but no current would flow.And as there is no resistance throughout the circuit,no voltage would appear anywhere across that loop.
It is hard for some to understand what !ideal! mean's,but think about it long enough,and you begin to put all the pieces together.
Every action has an equal and opposite reaction--this dose not change.
And so,in this ideal situation,the CEMF must be equal and opposite to the EMF,and the current produced by the CEMF that apposes the current produced by the EMF must also be equal and opposite,as an ideal inductor dose not dissipate power.
Brad
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This photo is for the Tinman.
Basically we get too much overunity and have to hand-rear the triplets.
These are a few of this years pets.
How about this for a business idea Tinman? Start the manufacture of
braking systems for overunity machines.
The one thing Wayne Travis got right on his early plans for his church
was the provision of a cooling system!!!
Seems you have hit the bottle again John.
Any chance you could provide useful input into this thread?.
Brad
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let's say this is true, and it honestly makes a degree of sense even though I disagree in principle..
Wouldn't this mean the inductor is 'perfectly' accomplishing the exact opposite of what it's supposed to be perfectly doing in nature? Wouldn't the EMF and CMF be increasing against each other the entire time to infinity? And wouldn't that have to mean a continuously rising current?
How does that not constitute current change?
Because the current produced by the inductor is equal and opposite to that being provided by the ideal voltage source,and so no current flows,but it dose rise to an infinite amount.
I have asked this question before--what happens when an unstoppable force meets an unmovable object?.
Brad
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Well now I feel like I am in the Twilight Zone.
Poynt: The current is one over "L" integral v dt.
That's 1/5 * integral (4) dt.
That's 1/5 * 4t.
That's 4/5*t.
When t = 3 seconds that's 12/5 = 2.4 amps.
Can we get out of the Zone now?
And when t= 20 seconds that's 9714.05 amps.
Poynt ran his sim for 100 second's (what would be the current then ?),and still he had no voltage drop :D
Brad
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Because the current produced by the inductor is equal and opposite to that being provided by the ideal voltage source,and so no current flows,but it dose rise to an infinite amount.
I have asked this question before--what happens when an unstoppable force meets an unmovable object?.
Brad
Like I said before...
The Big Bang. Then, it all starts all over again. An endless cycle.
Of course, this is just a theory.
Bill
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tinman,I've had a great find.
Have a look at Electronics-Tutorials w.s.
With all the crap you've been coming out with lately you're like me and
really need to start from the very beginning.
There's a lot about inductors and it's very basic and even I've been able
to inch forward, albeit very slowly.
Good luck,John.
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Because the current produced by the inductor is equal and opposite to that being provided by the ideal voltage source,and so no current flows,but it dose rise to an infinite amount.
I have asked this question before--what happens when an unstoppable force meets an unmovable object?.
Brad
right, in that scenario it could be said there was never any current at all. infinite is the same thing as none at all in practice.
however, if we were to assume this infinitely rising current without any curvature continues to infinity, that in itself is a current change, therefore how can it be function as an ideal coil? In the very nature of how its operation is described it seems as if it should be infinitely resting with 0 current flow or infinite current flow.. which as I say is the same thing so we might as well just say none at all.
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@Magneticitist
I don't see why we should have to take it further than "perfectly and absolutely resists current change". This automatically means no EMF or counter EMF doesn't it?
An Electro-Motive Force relates to electric fields and a Magneto-Motive Force relates to the Magnetic fields. The Electric field is the cause or the source of the force which initially acts on the charges causing them to move... a current. If a charge tries to move it instantly produces a magnetic field which opposes it's motion which we call a Cemf. We call it a Cemf because the conductor contains billions of (+) and (-) charges and the moment one tries to move the rest oppose it because they are linked by electric fields.
So yes the Emf is present as an electric field of force... before... anything moves such as a current. The Emf is the cause of the current not vice versa.
@Picowatt
This would more so describe an ideal inductor that also has an infinite amount of inductance. As such, when connected across a voltage source, no current would ever flow as the time constant would also be infinite. An ideal inductor with infinite inductance would appear to be a continuous open circuit when connected in parallel with a voltage source.
First we should ask what is inductance?, Inductance: the property of an electrical conductor by which a change in current through it induces an electromotive force in both the conductor itself and in any nearby conductors. Inductance is not something but a property of something which is actually self-inductance which relates to a Cemf. So when we say Inductance what we really mean is self-inductance or the generation of a Cemf which opposes the source Emf.
In this case we are speaking of an Ideal Inductor, a perfect inductor with no losses of any kind hence the term "ideal". Now if a charge tries to move it must instantaneously invoke an equal and opposite Cemf because we have defined action and reaction occurring under ideal conditions, no losses. Thus any inductance (self-inductance) of any kind in an ideal inductor qualifies as infinite (however not an infinitely large field) because the term inductance relates solely to the Cemf which must oppose the source Emf. An ideal closed loop superconductor produces a continuous current at zero voltage and an ideal closed loop super-inductor should produce a continuous electric field opposition or Emf/Cemf at zero current. Can you see the symmetry here?.
I know this seems difficult to understand because this leads to questions which many find deeply disturbing. What is an Electric Field, what is a Magnetic Field fundamentally?. You see it's like trying to describe a bike without knowing what a wheel is. This is why everyone tends to throw about terminology never knowing what the terms actually mean or what they are supposed to describe in reality.
AC
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@Magneticitist
An Electro-Motive Force relates to electric fields and a Magneto-Motive Force relates to the Magnetic fields. The Electric field is the cause or the source of the force which initially acts on the charges causing them to move... a current. If a charge tries to move it instantly produces a magnetic field which opposes it's motion which we call a Cemf. We call it a Cemf because the conductor contains billions of (+) and (-) charges and the moment one tries to move the rest oppose it because they are linked by electric fields.
So yes the Emf is present as an electric field of force... before... anything moves such as a current. The Emf is the cause of the current not vice versa.
@Picowatt
First we should ask what is inductance?, Inductance: the property of an electrical conductor by which a change in current through it induces an electromotive force in both the conductor itself and in any nearby conductors. Inductance is not something but a property of something which is actually self-inductance which relates to a Cemf. So when we say Inductance what we really mean is self-inductance or the generation of a Cemf which opposes the source Emf.
In this case we are speaking of an Ideal Inductor, a perfect inductor with no losses of any kind hence the term "ideal". Now if a charge tries to move it must instantaneously invoke an equal and opposite Cemf because we have defined action and reaction occurring under ideal conditions, no losses. Thus any inductance (self-inductance) of any kind in an ideal inductor qualifies as infinite (however not an infinitely large field) because the term inductance relates solely to the Cemf which must oppose the source Emf. An ideal closed loop superconductor produces a continuous current at zero voltage and an ideal closed loop super-inductor should produce a continuous electric field opposition or Emf/Cemf at zero current. Can you see the symmetry here?.
I know this seems difficult to understand because this leads to questions which many find deeply disturbing. What is an Electric Field, what is a Magnetic Field fundamentally?. You see it's like trying to describe a bike without knowing what a wheel is. This is why everyone tends to throw about terminology never knowing what the terms actually mean or what they are supposed to describe in reality.
AC
thanks for the explanation.. but I'm not in disagreement that EMF is the cause of the current. I'm saying I don't see how there would be any current, EMF, CEMF, or any kind of interaction I would consider a Lenz Law interaction that would require more current to overpower an equal opposition.
That would be the scenario I see played out were current actually flowing into this inductor with infinite rise time and no curvature.
but I personally can't get past the sheer logical aspect of the argument. I don't see the need to have to get into the complex details of charges and opposing forces when the ideal coil is said to no dissipate energy and perfectly resist change in current. I don't see how that doesn't imply no current at all, unless we are approaching this imaginary scenario adding the parameter that this ideal inductor is already partially charged and just accept that as imaginary scientific parameters.
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There's a lot about inductors and it's very basic and even I've been able to inch forward, albeit very slowly.
Did you discover yet, that inductance is the amount of magnetic flux that is generated by a given electric current ?
In other words, Henry = Weber / Ampere.
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Thanks for joining PW.
I have to say that i dont agree with the ideal inductor needing to have an infinite inductance value.
An ideal inductor does not have to have an infinite inductance.
What I said was your description of an inductor whose EMF and CEMF are in perfect balance would be descriptive of an inductor with infinite inductance. An inductor with infinite inductance, when connected across a V source, would forever appear as an open circuit.
It is hard for some to understand what !ideal! mean's,but think about it long enough,and you begin to put all the pieces together.
A straight length of ideal conductor, such as a straight wire with no resistance or capacitance, would be an ideal inductor. Just like its less ideal real world counterpart, a finite amount of time is required for current to flow thru the wire because of the wire's inductance.
Wrapping that same straight length of ideal (or normal) wire into a helix increases the coupling between sections (turns) of the wire and increases its inductance.
I do not understand why you believe that an ideal inductor would cause an instantaneous and infinite amount of current to flow when connected across a voltage source. As I said, that would be more descriptive of an ideal capacitance.
Gotta' go...
PW
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Because the current produced by the inductor is equal and opposite to that being provided by the ideal voltage source, and so no current flows, but it dose rise to an infinite amount.
It is true only for an ideal inductor that has an infinite inductance.
In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.
Anyway, that statement above is so awkwardly worded.
First you write about two currents flowing and at the end you write about currents not flowing - that sounds contradictory.
I think you wanted to write about two currents, that would flow if they were not opposing each other.
Specifically, one current, that would flow due to the nature of a shorted voltage source and a second current, that would flow in a shorted ideal inductor (shorted by the voltage source).
That's all, that I was able to decode, so far.
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An ideal inductor does not have to have an infinite inductance.
True. An infinite ideal inductor is a special case of an ideal inductor.
What I said was your description of an inductor whose EMF and CEMF are in perfect balance would be descriptive of an inductor with infinite inductance. An inductor with infinite inductance, when connected across a V source, would forever appear as an open circuit.
I agree and I think Tinman was stating the same thing but in terms of opposing hypothetical currents instead of opposing EMFs.
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until some form of 'distance' or 'length' is brought into the equation, which has a direct relation with resistance in the real world (I think?) isn't 'time' out of the window altogether because without anything to slow electron drift velocity (pardon if that makes no sense I just read some stuff and thought I made some sense of it) wouldn't the current technically travel at light speed? what about collisions? would that be meeting a resistance? if we have nothing with which to truly factor a Tau
into the equation then why can't 'current infinitely rising' be synonymous with 'no current flow at all'.
the real problem here is nobody want's to come out and say Ohm's law needs to be thrown out
of the window in this situation isn't it? and we are supposed to be trained to rely on Ohms Law.
Brad was trying to show extremely high amps calculated at extremely low resistance as a metaphor for approaching "infinite" using Ohms Law. But as we have been discussing, and maybe do not all agree on it, but infinite=0.
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Ohm's Law applies to resistors, it does not apply to inductors or capacitors. I am keeping it simple and with that in mind forget about Ohm's Law, we are discussing an inductor.
So you are correct, for this discussion we can throw out Ohm's Law.
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The inductor is impeding current flow but when I look up impedance it
refers to ac circuits and reactance doesn't seem to fit the bill either.
It's all good fun and the whole thing proves that not many of us know
that much!
You've got to hand it to the Henrys and Faradays and Maxwells for
figuring it out so well in the first place.
John.
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Ohm's Law applies to resistors, it does not apply to inductors or capacitors. I am keeping it simple and with that in mind forget about Ohm's Law, we are discussing an inductor.
So you are correct, for this discussion we can throw out Ohm's Law.
I believe the twin brother to the issue of Ohms law being a factor or not, is the possibility
that an absolute 0 resistance removes the characteristics of an inductor/capacitor/conductor/resistor altogether so they might as well all be considered ideal conductors at 0 resistance. Does that sound like insane mumbo jumbo cause by freaking golly it makes a degree of sense to me.
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It's mostly mumbo jumbo talk.
But here is the clue: Even if "the resistance is zero," in other words there is no resistance in the circuit, it does not necessarily mean that something isn't impeding the current flow.
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It's mostly mumbo jumbo talk.
But here is the clue: Even if "the resistance is zero," in other words there is no resistance in the circuit, it does not necessarily mean that something isn't impeding the current flow.
:D :D :D
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...an absolute 0 resistance removes the characteristics of an inductor/capacitor/conductor/resistor altogether so they might as well all be considered ideal conductors at 0 resistance.
"Absolute 0 resistance" removes the characteristic of resistance but it does not remove "inductive reactance (https://en.wikipedia.org/wiki/Electrical_reactance#Inductive_reactance)" of inductors nor "capacitive reactance (https://en.wikipedia.org/wiki/Electrical_reactance#Capacitive_reactance)" of capacitors (despite all three being measured in Ohms).
Impedance = Resistance + Reactance.
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"Absolute 0 resistance" removes the characteristic of resistance but it does not remove "inductive reactance (https://en.wikipedia.org/wiki/Electrical_reactance#Inductive_reactance)" of inductors nor "capacitive reactance (https://en.wikipedia.org/wiki/Electrical_reactance#Capacitive_reactance)" of capacitors (despite all three being measured in Ohms).
Impedance = Resistance + Reactance.
But can we say for sure that our understanding of those 2 forms of reactance is not derived from
some existing level of resistance? were we in some alternate universe where we never
even had a variable to call R in the first place, can we say all our circuit theory would be exactly
the same using the same math? and sheesh it's like, definitely ultra confusing, when we have different variables measures in the same unit but they are somehow working entirely independent
from that unit. not trying to be difficult it just this type of thought pattern seems to be expected
when it's almost inherent in the forum name.
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It is true only for an ideal inductor that has an infinite inductance.
In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.
Specifically, one current, that would flow due to the nature of a shorted voltage source and a second current, that would flow in a shorted ideal inductor (shorted by the voltage source).
That's all, that I was able to decode, so far.
Anyway, that statement above is so awkwardly worded.
First you write about two currents flowing and at the end you write about currents not flowing - that sounds contradictory.
No,i said currents being produced,not flowing.
I think you wanted to write about two currents, that would flow if they were not opposing each other.
And that is what i wrote.
The current produced by the EMF of our ideal voltage,would meet the equal and opposite from the CEMF produced by the ideal inductor.
When dealing with ideals,we deal with absolutes,and there for the CEMF is ideal,meaning that it is equal and opposite to that of the EMF.
Brad
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author=verpies link=topic=16589.msg483812#msg483812 date=1462987219]
It is true only for an ideal inductor that has an infinite inductance.
In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.
And how would it do that if the CEMF is equal to the EMF that created it?
Brad
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And how would it do that if the CEMF is equal to the EMF that created it?
The current would not increase if CEMF = -EMF, but they would be so only in the case when the ideal inductor had infinite inductance.
Note that I was explicitly writing about the current increase through an ideal inductor with finite inductance.
-
But can we say for sure that our understanding of those 2 forms of reactance is not derived from
some existing level of resistance?
No, the resistance behaves significantly different from inductive reactance. The former converts current to heat and the latter converts current to magnetic flux.
...and sheesh it's like, definitely ultra confusing, when we have different variables measures in the same unit but they are somehow working entirely independent.
They both have the same units, but mathematically they are in different complex dimensions which are orthogonal.
You don't seem to have a problem with distances in different orthogonal dimensions, that are not affecting each other despite being expressed by the same units: meters or feet.
-
What a silly thing this has turned out to be. Ideal seems to have caused total confusion.
The whole thing is just a matter of a bit of maths,which I can't do!
I would love to do the experiment, a good quality choke and a couple of forklift LA. cells
would make an ideal power supply. I can see smoke in the equation.
I don't see superconductors as the equivalent zero resistance.
Another point I'd like to make is the continual appearance of things like "You lied MH."
to me lying is deliberate fraud whereas misinformation due to incomprehension
isn't lying.
I lied when I said I knew the answer when in reality I didn't.
Have a great day you all,warmest regards, John.
-
Note that I was explicitly writing about the current increase through an ideal inductor with finite inductance.
The current would not increase if CEMF = -EMF, but they would be so only in the case when the ideal inductor had infinite inductance.
And so the reverse would apply.
The moment an EMF is placed across the ideal inductor,and a current started to flow,then the CEMF produced would be the same as the EMF that created it. That being the case,then the inductor would act as though it had infinite inductance.
Just thoughts :)
Brad
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author=minnie link=topic=16589.msg483887#msg483887 date=1463045835]
I don't see superconductors as the equivalent zero resistance.
I lied when I said I knew the answer when in reality I didn't.
Have a great day you all,warmest regards, John.
I would love to do the experiment, a good quality choke and a couple of forklift LA. cells
would make an ideal power supply. I can see smoke in the equation.
Of course you will get smoke,as you will have resistance,and be far from an ideal inductor.It is the resistance that causes the heat loss,no resistance=no heat.
Remember,the ideal inductor dose not dissipate power. The ideal inductor is wound from ideal conducting wire.
I don't see superconductors as the equivalent zero resistance.
https://en.wikipedia.org/wiki/Meissner_effect
In Type II superconductors, raising the applied field past a critical value Hc1 leads to a mixed state (also known as the vortex state) in which an increasing amount of magnetic flux penetrates the material, but there remains no resistance to the flow of electric current as long as the current is not too large. ;)
Another point I'd like to make is the continual appearance of things like "You lied MH."
to me lying is deliberate fraud whereas misinformation due to incomprehension
isn't lying.
You mean like making an absolute claim about there being no resonant systems in or around an ICE in any way,shape ,or form--only to later say-->well i dont know that much about ICEs :o
So you have given only two option's,fraud,or misinformation.
As much as myself and MH may not get along at times,due to nothing more that a difference in opinion,i would think more-a mistake would be a better word to use--which we have all made.
Brad
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Perhaps we can actually carry out this experiment :o
Will insulated copper wire become super conductive if submerged in liquid nitrogen ?.
If not,what kind of wire would we need to achieve our super conductive windings at liquid nitrogen temperatures.
Brad
-
Or this one: https://www.youtube.com/watch?v=PIvZJ9xGutI (https://www.youtube.com/watch?v=PIvZJ9xGutI)
Hear the: Sorry about the light, and welcome in mine Labrborattorry (Nicky''''''s, kitchen table)!?
-
Or this one: https://www.youtube.com/watch?v=PIvZJ9xGutI (https://www.youtube.com/watch?v=PIvZJ9xGutI)
Hear the: Sorry about the light, and welcome in mine Labrborattorry (Nicky''''''s, kitchen table)!?
That almost sounds like TK lol.
Brad
-
That almost sounds like TK lol.
Brad
Hole D-base with different Cookie's remarks collected!
What do you think about:
Always, Independent 3e party validation, all less is don't pay attention, except for: Nasa, Mit, Lewin sometimes, .............
Sweet dreams, and go to bed!
-
PW
This would more so describe an ideal inductor that also has an infinite amount of inductance. As such, when connected across a voltage source, no current would ever flow as the time constant would also be infinite.
The time constant is infinite.
Tau=L/R. There is no R,as it's an ideal inductor.
Tau=L/0 = infinity.
Brad
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the ball, shopping cart, whatever.. floats through the perfect vacuum unimpeded. ok.
well how do we know this if there is absolutely nothing else in this vacuum to compare
its relative motion to. the presence of something else, anything else, could
be considered a resistance. a way to set a Tau. For all intents and purposes, it's at rest.
To say otherwise would be to simply assume it in test parameters. Newtonian Physics
really don't much belong in quantum mechanics anyhow do they? This seems more of
a time paradox. I understand I provide nothing to the convo without being able
to at least properly explain it, but maybe possibly someone else can see where I'm coming
from here. The 'ground' as Webby put it imo seems like light speed. Resistance is what keeps
our energy from traveling at light speed right? Whether, electric current, or whatever?
-
The time constant is infinite.
Tau=L/R. There is no R,as it's an ideal inductor.
Tau=L/0 = infinity.
Brad
Tau has no bearing on whether current can/will flow or not. The effect it has is how "curvy" the rise of current is, relative to the timing of your test. With an infinite tau, the curve is going to be a straight line, not only because the time is infinite, but also because the beginning part of the curve is almost straight anyway.
-
the ball, shopping cart, whatever.. floats through the perfect vacuum unimpeded. ok.
well how do we know this if there is absolutely nothing else in this vacuum to compare
its relative motion to. the presence of something else, anything else, could
be considered a resistance. a way to set a Tau. For all intents and purposes, it's at rest.
To say otherwise would be to simply assume it in test parameters. Newtonian Physics
really don't much belong in quantum mechanics anyhow do they? This seems more of
a time paradox. I understand I provide nothing to the convo without being able
to at least properly explain it, but maybe possibly someone else can see where I'm coming
from here. The 'ground' as Webby put it imo seems like light speed. Resistance is what keeps
our energy from traveling at light speed right? Whether, electric current, or whatever?
Electrons move at the speed of light even through resistors as far as I know.
Bill
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Electrons move at the speed of light even through resistors as far as I know.
Bill
That is where things get even more complicated and the atomic structure of conductors come into play. The EM waves can propagate at typically light speed, or just under, but the electron's have a
velocity we call the electron drift that is actually much much slower.
(in a way it's analogous to how slowly a magnet falls through the copper pipe demonstration)
-
That is where things get even more complicated and the atomic structure of conductors come into play. The EM waves can propagate at typically light speed, or just under, but the electron's have a
velocity we call the electron drift that is actually much much slower.
(in a way it's analogous to how slowly a magnet falls through the copper pipe demonstration)
The magnet slowing through a copper pipe is a demonstration of Lenz Law due to the fact that copper can be diamagnetic. Electrons move at the speed of light...you can limit the number of them moving through a circuit but not slow them down.
Bill
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The magnet slowing through a copper pipe is a demonstration of Lenz Law due to the fact that copper can be diamagnetic. Electrons move at the speed of light...you can limit the number of them moving through a circuit but not slow them down.
Bill
It's definitely not something that can be so thoroughly explained in a short comment, but essentially this is true, electrons are traveling chaotically at near light speed. This is the Fermi velocity. But when we bring current flow into the equation the drift velocity of the electron particle through a conductor can become analogous to the magnet in the copper pipe, simply in the context of the magnet moving much much slower than you would intuitively imagine without understanding Lenz Law and eddy currents.
-
Tau has no bearing on whether current can/will flow or not. The effect it has is how "curvy" the rise of current is, relative to the timing of your test. With an infinite tau, the curve is going to be a straight line, not only because the time is infinite, but also because the beginning part of the curve is almost straight anyway.
Poynt.
;)
Brad
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Tau has no bearing on whether current can/will flow or not. The effect it has is how "curvy" the rise of current is, relative to the timing of your test. With an infinite tau, the curve is going to be a straight line, not only because the time is infinite, but also because the beginning part of the curve is almost straight anyway.
edit
-
The magnet slowing through a copper pipe is a demonstration of Lenz Law due to the fact that copper can be diamagnetic. Electrons move at the speed of light...you can limit the number of them moving through a circuit but not slow them down.
Bill
No
It's because the shorted single turn copper coil is producing a magnetic field that apposes that which created it.
Brad
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yes, with inertia supplied by gravity.. in this case metaphorically, the ideal voltage/infinite current.
without a time constant, we can say this magnet is falling forever and ever and the pipe is an infinite length. (edit, infinite in both directions... with no 'starting point'.. so how is it moving?) Since we have no relative way of knowing if it's moving other than counting the seconds and
using some constitutive equation to solve for current, we are left to assume it's actually moving
based upon the equation and the implication that it's moving because it is being acted upon by
a force. it is, however as I have thought, more complicated than newtonian physics because we
are dealing with a kind of special relativity that we still do not understand the full nature of despite
the amazing things that engineers are capable of doing as this time. R seems like it can mathematically be represented in nature in a variety of ways. Excluding R from all
of eternity and assuming our understanding of Inductance would remain absolute doesn't
seem like something we can prove.
-
No
It's because the shorted single turn copper coil is producing a magnetic field that apposes that which created it.
Brad
MIT video demonstrating Lenz Law: https://www.youtube.com/watch?v=N7tIi71-AjA (https://www.youtube.com/watch?v=N7tIi71-AjA)
Lenz Law:
"If an induced current flows, its direction is always such that it will oppose the change which produced it."
You are basically saying the same thing...except for the diamagnetic business.
Bill
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MIT video demonstrating Lenz Law: https://www.youtube.com/watch?v=N7tIi71-AjA (https://www.youtube.com/watch?v=N7tIi71-AjA)
Lenz Law:
"If an induced current flows, its direction is always such that it will oppose the change which produced it."
You are basically saying the same thing...except for the diamagnetic business.
Bill
lol basically, I have no doubt both of you understand Lenz Law. The term Diamagnetic
can be confusing though and I'm not even sure as to whether that's a 'proper' way to
say it although I perfectly understand what you mean because the copper essentially
does become 'diamagnetic' as far as I can tell. seems like the same explanation.
However I also thought diamagnetic materials referred more to materials that naturally
exhibit a strong diamagnetism, much more so than what may be found in normal conductors like
copper. For example Bismuth. still, confusing.
-
lol basically, I have no doubt both of you understand Lenz Law. The term Diamagnetic
can be confusing though and I'm not even sure as to whether that's a 'proper' way to
say it although I perfectly understand what you mean because the copper essentially
does become 'diamagnetic' as far as I can tell. seems like the same explanation.
However I also thought diamagnetic materials referred more to materials that naturally
exhibit a strong diamagnetism, much more so than what may be found in normal conductors like
copper. For example Bismuth. still, confusing.
Aluminum, another good conductor, is also diamagnetic. I have seen videos of a magnet slowly sliding down an Al plate. Is Bismuth diamagnetic or paramagnetic? I can't remember...it has been a while.
Bill
PS Here is just one of the aluminum vids: https://www.youtube.com/watch?v=-7IzlnFH7ww (https://www.youtube.com/watch?v=-7IzlnFH7ww)
-
Aluminum, another good conductor, is also diamagnetic. I have seen videos of a magnet slowly sliding down an Al plate. Is Bismuth diamagnetic or paramagnetic? I can't remember...it has been a while.
Bill
hell it's been a while myself, I'd have to look up 'paramagnetic' but i'd imagine it's the opposite effect.
I'm pretty sure Bismuth is diamagnetic though. It would certainly seem counter intuitive to say
that copper is not diamagnetic when it does seem to behave that way, like aluminum. I have
never heard that word used to describe the Lenz effect however which is why I can imagine
there is some scientific separation. I'm not one to nitpick over terminology as long as I can understand you of course, but if there IS some separation in the physical explanation of Lenz
law and diamagnetism then I suppose Brad would be correct in excluding the word Diamagnetic.
I suppose the difference lies in the changing magnetic field vs a non changing. Bismuth requires no lenz interaction to get the opposition. (at least from the newtonian side of things to the quantum side of things lol)
edit- ok so copper and aluminum are diamagnetic like many other metals. However their
naturally occurring diamagnetism is quite negligible when compared to Bismuth.
So you could say, yes, the magnet acts the way it does in the pipe because copper is a diamagnetic. But to give that explanation also requires that we explain the diamagnetic interaction between the magnet and the copper is a direct result of the Lenz effect, the opposing fields.
so long as a changing magnetic field is brought into the explanation it seems totally proper.
It only becomes confusing when someone can think that copper is naturally diamagnetic like
Bismuth and will yield that field opposition without any changing field interacting with it.
-
hell it's been a while myself, I'd have to look up 'paramagnetic' but i'd imagine it's the opposite effect.
I'm pretty sure Bismuth is diamagnetic though. It would certainly seem counter intuitive to say
that copper is not diamagnetic when it does seem to behave that way, like aluminum. I have
never heard that word used to describe the Lenz effect however which is why I can imagine
there is some scientific separation. I'm not one to nitpick over terminology as long as I can understand you of course, but if there IS some separation in the physical explanation of Lenz
law and diamagnetism then I suppose Brad would be correct in excluding the word Diamagnetic.
I suppose the difference lies in the changing magnetic field vs a non changing. Bismuth requires no lenz interaction to get the opposition. (at least from the newtonian side of things to the quantum side of things lol)
edit- ok so copper and aluminum are diamagnetic like many other metals. However their
naturally occurring diamagnetism is quite negligible when compared to Bismuth.
So you could say, yes, the magnet acts the way it does in the pipe because copper is a diamagnetic. But to give that explanation also requires that we explain the diamagnetic interaction between the magnet and the copper is a direct result of the Lenz effect, the opposing fields.
so long as a changing magnetic field is brought into the explanation it seems totally proper.
It only becomes confusing when someone can think that copper is naturally diamagnetic like
Bismuth and will yield that field opposition without any changing field interacting with it.
If the pipe is cooled down enough,so as it became superconductive,would the magnet still fall?
Think about that,and how it relates to the ideal coil,which is also made of many superconductive loops.
Brad
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If the pipe is cooled down enough,so as it became superconductive,would the magnet still fall?
Think about that,and how it relates to the ideal coil,which is also made of many superconductive loops.
Brad
hmm good question, I don't see why it would. but even those scenarios involve an observable magnetic field. which means it's still radiating.
-
If the pipe is cooled down enough,so as it became superconductive,would the magnet still fall?
Think about that,and how it relates to the ideal coil,which is also made of many superconductive loops.
Brad
Brad:
No! No...
Please do not introduce an ideal pipe into the mix, ha ha. My head is about to explode from all of the other ideal items we have already.
Bill
PS No, the magnet would not fall as Lenz would be increased proportionally to the increased conductivity of the copper pipe.
-
Brad:
No! No...
Please do not introduce an ideal pipe into the mix, ha ha. My head is about to explode from all of the other ideal items we have already.
Bill
PS No, the magnet would not fall as Lenz would be increased proportionally to the increased conductivity of the copper pipe.
almost spit my mountain dew out at that one
-
ok, now think about what would happen if you dropped a suitably sized magnet
down a pipe of pure bismuth.
now super cool the bismuth.
lmfao
-
Can you have a fixed finite inductance from an inductor that has resistance=0 and capacitance=0
Yes
-
If the pipe is cooled down enough,so as it became superconductive,would the magnet still fall?
Think about that,and how it relates to the ideal coil,which is also made of many superconductive loops.
As well, think about the large number of inductors in use everyday all over the world made just that way...
PW
-
Brad:
No! No...
Please do not introduce an ideal pipe into the mix, ha ha. My head is about to explode from all of the other ideal items we have already.
Bill
PS No, the magnet would not fall as Lenz would be increased proportionally to the increased conductivity of the copper pipe.
Lol-sorry Bill :D
What about this-as we are talking about the magnet falling through the copper pipe.
Now lets say the leading field(the one on the bottom of the PM as we place it in the pipe) of the PM is the north field,and the trailing field is the south field. The magnet will induce a field in that copper pipe that apposes that of the magnet,ans so apposes the motion of the magnet. So just below the falling magnet,the copper pipe will be producing a north field--that apposes the motion of the magnet. But dose that mean that a north field is also produced just above the falling magnet--so just above the south field of the magnet,that wants to also appose the motion of the magnet.
Dose this mean that the copper pipe now has produced a mono magnetic field? :o--north below the falling magnet-pushing against the falling magnet,and north above the falling magnet-pulling on the falling magnet.
This is the way it would work with a shorted coil.
A north field approaches the shorted coil,and the shorted coil produces a magnetic field that apposes the north field of the magnet. Then if we turn the magnet around,and we pull the south field away from the shorted coil,then that shorted coil will produce a north field that wants to pull the magnet back toward it.
Sorry in advance Bill :D
Brad
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almost spit my mountain dew out at that one
At least your not drinking the cool aid ;)
Brad
-
Kool-aid is good, as long as it is cherry flavour. ;)
-
Kool-aid is good, as long as it is cherry flavour. ;)
We dont have cool aid over here--we have lemon aid of all flavours --is that the same?
Brad
-
If it is a flavoured powder you add to sugar and water, then probably same thing. ;)
-
If it is a flavoured powder you add to sugar and water, then probably same thing. ;)
Oh no
Lemonaid is like coca cola or pepsi.
Sounds more like our Staminade--thats a powder you mix with water to get a fizzy soft drink.
Brad
-
If it is a flavoured powder you add to sugar and water, then probably same thing. ;)
Have you tried our famous vegimite Poynt?
You have it on toast
Brad
-
The time constant is infinite.
Tau=L/R. There is no R,as it's an ideal inductor.
Tau=L/0 = infinity.
Good God, Brad! - you are doing a mathematical analysis. Your experimental skills mixed with that one will accomplish wonders.
Anyway, you are correct that when R=0 then Tau=∞ , ...however Tau is not inductance.
Infinite Tau does not mean that current through an ideal inductor cannot change or that it is always constant (i.e. zero) ...like it would be with an infinite ideal inductor.
This is because if you insert R=0 into the formula for inductor's current i(t)=(V/R)*( 1- (e^(-t*R/L)) ) you do not get a constant current function ...because there are two competing limits in this formula, one for V/R=∞ and another for (1-e^0)=0. If you multiply them together you get ∞ * 0 ...:o
Which limit wins out or how the two limits combine requires higher level of math analysis. Do you want me to go into it?
-
.
-
Tau has no bearing on whether current can/will flow or not. The effect it has is how "curvy" the rise of current is, relative to the timing of your test. With an infinite tau, the curve is going to be a straight line,
That is correct.
Making the resistance R=0 "turns off" the real component of impedance but leaves the imaginary part (the inductive reactance (X) ) unaffected.
Their magnitudes combine according to SQRT(R2+X2)
-
It's because the shorted single turn copper coil is producing a magnetic field that apposes that which created it.
I agree and this can be observed in this this video (https://www.youtube.com/watch?v=wUaqXk6axOo).
If the pipe is cooled down enough,so as it became superconductive,would the magnet still fall?
Depends how large the inner diamaeter of the pipe is compared to the magnet. If it is small enough then the magnet would bounce forever.
This video (https://www.youtube.com/watch?v=uL4pfisCX14) illustrates how a falling magnet behaves when it is released from the middle of a single shorted turn that has zero resistance.
P.S.
Again, I remind everyone that the magnitude of the current induced in a perfectly conducting ring does not depend on how fast that magnet is moving.
Also copper cooled by liquid nitrogen does not become superconductive, but the YBCO ceramic does.
Niobium metal becomes superconductive when cooled by liquid helium.
-
@Magneticist
You should look at that post (http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692) of mine from another thread.
-
Aluminum, another good conductor, is also diamagnetic. I have seen videos of a magnet slowly sliding down an Al plate. Is Bismuth diamagnetic or paramagnetic? I can't remember...it has been a while.
Yes Bismuth is one of the best diamagnets.
The difference between Copper or Aluminum pipe/sheet and Bismuth is that Bismuth will always oppose and repel permanent magnets, while Copper/Aluminum will do so only when these magnets are moving.
-
No, the magnet would not fall as Lenz would be increased proportionally to the increased conductivity of the copper pipe.
If the superconducting ring or plate is "frozen" while the magnet is away then:
the magnet will fall through a superconductive ring that is much larger than the magnet and if the ring's diameter is sufficiently small compared to the diameter of the magnet, then the magnet will bounce.
And if small superconducting ring or a large plate is "frozen" while the magnet is nearby, then:
the magnet will hover over or under the superconducting ring/plate.
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@Magneticist
You should look at that post (http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692) of mine from another thread.
I have no issue with that representation because it helps to explain a mathematical
way we can calculate charge/discharge using the constant, at the very least. It also
seems like a great presentation so I will definitely give it a look and thank you for
providing it.
I also have no issue with Poynt99's statement :
"Tau has no bearing on whether current can/will flow or not.
The effect it has is how "curvy" the rise of current is, relative to
the timing of your test. With an infinite tau, the curve is going to
be a straight line,"
the issue I have is when trying to imagine what would 'actually'
happen if this 'ideal inductor' question was suddenly made reality.
It gets into the atomic model and the more detailed aspects of ultra
complicated quantum physics where I am so lost in the grand scheme of things
I can't say I really know how to make heads or tails of it..
I see a more paradoxical issue where we just wouldn't be able to
'see' or 'observe' the current in any way in the real world so it might
as well not exist as 'flowing'. My position is almost agreeing that current
will flow, but flow just as much as it wouldn't. I know this doesn't seem
to make any logical sense to others but what am I left to do? beat my
head against the wall until I no longer see it that way? You can't quite
prove to me that current would flow over 0 resistance unless we are
talking mathematical constructs. and even then, you say you can use
that math to prove this theory but with R=0 I don't see how it could
possibly result in any answer that is not 'undefined', even if you claim
we are using formulas that do not even require a relationship with a unit
of resistance. Somewhere along the lines, a unit of resistance has to matter
in quantum mechanics. The only 'constant' which I see available for us to
make the determination that current will flow, is the assumption it would
do so because it does indeed flow with very little resistance.
In all honestly I don't wholeheartedly believe in hardly any of this
electron theory. I give it the respect it deserves by not completely
dismissing it and attempting to gain an understanding of it because
as far as I know it retains a complex level of mathematical continuity
across the board but that doesn't mean I'm ready to completely
and absolutely accept every aspect of these theories.
they are not totally tangible to me and a lot of times
just flat out go against my better judgement and intuition.
if I had a specific capacitor charged to a certain voltage
and said it had discharged to x volts over a period of time,
and someone was to tell me they did the math and that wasn't
possible.. chances are I was wrong somewhere because as I said
it's been figured out to a complex level of mathematical continuity.
but what if I wasn't wrong? what if all my units were correct?
what would be the real reality of my capacitor? would that need
investigation or should it be immediately dismissed as wrong?
what if I so immediately dismissed it as wrong only to overlook
a possibility that the math was not accounting for an additional
variable? what if? an important discovery or revelation could be
made, or a lot of freaking time could be wasted having a severe
brain fart cause a decimal was where it shouldn't be. to each his own.
-
@Magneticist
You should look at that post (http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692) of mine from another thread.
this is great stuff and really the 'gist' of what we should be focusing on regarding
inductor charging.
-
oops repeat
-
I thought that the self-inductance was a physical property,
On the most basic level it is a simple ratio that tells you how many Webers you get per Ampere.
L=Φ/i
-
How about trying to state inductance in something a bit more tangible that people can relate to? It's all basically the inertia of the current flow when passing through an inductor.
If you have one Henry of inductance and you put a voltage of one volt across it, you get one amp of current after one second.
If you have two Henrys of inductance and you put a voltage of one volt across it, you get one-half amp of current after one second.
If you have one Henry of inductance and you put a voltage of two volts across it, you get two amps of current after one second.
More Henrys = less amps.
More voltage = more amps.
When you think about that hard you realize that one Henry is one volt-second per amp.
It's perhaps easier to think about the inverse of that, which is one amp per volt per second.
So, one Henry of inductance gives you one amp per volt per second.
One-half of a Henry of inductance is less inertia, so you get two amps per volt per second.
Two Henrys of inductance is more inertia, so you get one-half of an amp per volt per second.
It's really as simple as that. It's like pushing on a bloody shopping cart, the lighter the shopping cart, the faster it will accelerate, the heavier the shopping cart, the slower it will accelerate. The speed of the shopping cart is the current flow. The mass of the shopping cart is the inductance.
It's all very simple and very understandable if you choose friendly concepts like inertia and friendly units like amps per volt per second.
But unfortunately this simplicity was destroyed by a positively insane argument that no current would flow in an ideal inductor. It's a travesty.
Travesty: 1. a false, absurd, or distorted representation of something. 2. represent in a false or distorted way.
-
How about trying to state inductance in something a bit more tangible that people can relate to? It's all basically the inertia of the current flow when passing through an inductor.
If you have one Henry of inductance and you put a voltage of one volt across it, you get one amp of current after one second.
If you have two Henrys of inductance and you put a voltage of one volt across it, you get one-half amp of current after one second.
If you have one Henry of inductance and you put a voltage of two volts across it, you get two amps of current after one second.
More Henrys = less amps.
More voltage = more amps.
When you think about that hard you realize that one Henry is one volt-second per amp.
It's perhaps easier to think about the inverse of that, which is one amp per volt per second.
So, one Henry of inductance gives you one amp per volt per second.
One-half of a Henry of inductance is less inertia, so you get two amps per volt per second.
Two Henrys of inductance is more inertia, so you get one-half of an amp per volt per second.
Travesty: 1. a false, absurd, or distorted representation of something. 2. represent in a false or distorted way.
It's really as simple as that. It's like pushing on a bloody shopping cart, the lighter the shopping cart, the faster it will accelerate, the heavier the shopping cart, the slower it will accelerate. The speed of the shopping cart is the current flow. The mass of the shopping cart is the inductance.
It's all very simple and very understandable if you choose friendly concepts like inertia and friendly units like amps per volt per second.
But unfortunately this simplicity was destroyed by a positively insane argument that no current would flow in an ideal inductor. It's a travesty.
It's really not that simple MH. And the travesty is you have not taken the time to draw out your own circuit,or realize what you have described. Most every other EE guy has just followed your lead,without thinking or doing the same.
It is like i said,you cannot place an ideal voltage from an ideal voltage source across an ideal inductor. The reason you dont understand this,is because you dont understand your own two component circuit.
Verpies was the only one to touch on why you cannot have or place an ideal voltage across an ideal inductor(quote: Since an ideal inductor must have a zero resistance, this means that it must be shorted (if it ain't shorted, it ain't ideal) and it becomes physically impossible to connect any real voltage sources in series with it.),but i think that your circuit may have past him by as well. Your circuit is an oxymoron-a paradox,and cannot work in reality,as one cancels out the other. If you took the time to draw out your own circuit,and write down all the values of that circuit,and applied all that you have stated in this(and the JT)thread,then you would see the error of your ways.
But as you continue to try and relate ideal coils to non ideal coils,and ideal voltage sources with non ideal sources,you havnt a hope in hell in seeing what your circuit represents.
I can debunk your circuit in just 5 lines of text,but i will give you and the other EE guys here say-4 to 8 weeks lol,--just kidding,say 4 days to think about it.
Brad
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The travesty continues.
Unfortunately Brad you are not understanding what Verpies is stating or you simply are not reading his actual text properly and/or it is not registering in your brain.
He does NOT say that you cannot place an ideal voltage source across an ideal inductor. He clearly states that you cannot place a real voltage source across an ideal inductor. This is the second time I am telling you what he said in an attempt to correct your misunderstanding.
If you are still confused, then please take it up with Verpies.
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I have no issue with that representation because it helps to explain a mathematical
way we can calculate charge/discharge using the constant, at the very least. It also
seems like a great presentation so I will definitely give it a look and thank you for
providing it.
I also have no issue with Poynt99's statement :
"Tau has no bearing on whether current can/will flow or not.
The effect it has is how "curvy" the rise of current is, relative to
the timing of your test. With an infinite tau, the curve is going to
be a straight line,"
beat my
head against the wall until I no longer see it that way? You can't quite
prove to me that current would flow over 0 resistance unless we are
talking mathematical constructs. and even then, you say you can use
that math to prove this theory but with R=0 I don't see how it could
possibly result in any answer that is not 'undefined', even if you claim
we are using formulas that do not even require a relationship with a unit
of resistance. Somewhere along the lines, a unit of resistance has to matter
in quantum mechanics. The only 'constant' which I see available for us to
make the determination that current will flow, is the assumption it would
do so because it does indeed flow with very little resistance.
In all honestly I don't wholeheartedly believe in hardly any of this
electron theory. I give it the respect it deserves by not completely
dismissing it and attempting to gain an understanding of it because
as far as I know it retains a complex level of mathematical continuity
across the board but that doesn't mean I'm ready to completely
and absolutely accept every aspect of these theories.
they are not totally tangible to me and a lot of times
just flat out go against my better judgement and intuition.
if I had a specific capacitor charged to a certain voltage
and said it had discharged to x volts over a period of time,
and someone was to tell me they did the math and that wasn't
possible.. chances are I was wrong somewhere because as I said
it's been figured out to a complex level of mathematical continuity.
but what if I wasn't wrong? what if all my units were correct?
what would be the real reality of my capacitor? would that need
investigation or should it be immediately dismissed as wrong?
what if I so immediately dismissed it as wrong only to overlook
a possibility that the math was not accounting for an additional
variable? what if? an important discovery or revelation could be
made, or a lot of freaking time could be wasted having a severe
brain fart cause a decimal was where it shouldn't be. to each his own.
the issue I have is when trying to imagine what would 'actually'
happen if this 'ideal inductor' question was suddenly made reality.
It gets into the atomic model and the more detailed aspects of ultra
complicated quantum physics where I am so lost in the grand scheme of things
I can't say I really know how to make heads or tails of it..
I see a more paradoxical issue where we just wouldn't be able to
'see' or 'observe' the current in any way in the real world so it might
as well not exist as 'flowing'. My position is almost agreeing that current
will flow, but flow just as much as it wouldn't. I know this doesn't seem
to make any logical sense to others but what am I left to do?
It makes perfect logical sense. It is only those here that are trying to relate real world device with ideal devices,and the transition just dose not exist .
PW mentioned the real world superconductors we use today,like in MRI scanners. The problem with that is,they are not charged by an ideal voltage source,and so we only have half the circuit MH has proposed.
Current may flow through a shorted ideal inductor,but like you said--how is it measured?,and how can a voltage placed across an ideal shorted inductor induce a current flow through a shorted ideal inductor?. :o !!Hopefully Poynt will stand back,and look at the circuit MH poses,as MH seems to refuse to do that)
I told MH in the JT thread,that i did not know the answer to the question,in the hope that he would move on,and the JT thread would return back to it's original discussion. But no-MH insist that i continue on with the question,and says the first part has been answered. Truth is,it has not been answered-non of it.
So i stand by my answer due to MHs insistence.
You cannot place an ideal voltage from an ideal voltage source across an ideal inductor.
Brad
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Some things to consider.
An ideal voltage source is a voltage source that supplies constant voltage to a circuit despite the current which the circuit draws.
This means that despite the resistance which a load may be in a circuit, the source will still provide constant and steady voltage.
An ideal voltage source has the following characterstic that allows it to act as a 100% efficient source of voltage: it has zero internal resistance.
An "ideal inductor" has inductance, but no resistance or capacitance, and does not dissipate or radiate energy.
Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0
The polarity of the voltage across an inductor is determined by-the positive being the terminal the current is flowing into,and negative being the terminal the current is flowing out from. With a shorted ideal inductor,there are no terminals to measure the voltage across,and the current flowing through that ideal inductor is the same at any two points of that inductor.
Brad
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I think use of the term "shorted" when referring to an ideal inductor is not good nor accurate nomenclature.
An ideal inductor simply has zero series resistance. It is not "shorted" in any way, and will not present itself as a "short" if/when a voltage source (ideal or not) is connected across it.
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I think use of the term "shorted" when referring to an ideal inductor is not good nor accurate nomenclature.
An ideal inductor simply has zero series resistance. It is not "shorted" in any way, and will not present itself as a "short" if/when a voltage source (ideal or not) is connected across it.
You need to think a little beyond what you are Poynt,and draw the circuit as MH said i should,
I have provided the definitions of the ideal voltage from an ideal voltage source,and an ideal inductor.
If an ideal inductor is shorted,so as it becomes an endless loop,can a voltage be measured anywhere across any two points of that(now looped) ideal inductor while a current is flowing through it?.
Brad
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author=webby1 link=topic=16589.msg484135#msg484135 date=1463187555]
There could be voltage that you can not measure or interact with because all the way around the loop the voltage would be uniform,, so current flow but no way to measure the voltage.
It is good to see some one is thinking here.
Part of what I am thinking over is that there is a nexus event that can and is described from several views of the same event.
A paradox ;)
No voltage can be measured across a shorted(looped) ideal inductor,even though current may be flowing through that inductor,as V=IxR stands,and the very reason that current can continue to flow through an ideal inductor is because there is no resistance,and hence the fact that an ideal inductor dose not dissipate any power.
The ideal voltage source that supplies our ideal voltage,by true definition has no internal resistance. As it has no internal resistance,then it too will not dissipate any power by way of an internal resistance. Having no internal resistance,the current flow is in no way impeded ,an so that is what makes it an !ideal! voltage source.
At T=0,the ideal voltage source is connected to the ideal inductor-->what have you just done?
Brad
Brad
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You need to think a little beyond what you are Poynt,and draw the circuit as MH said i should,
I have provided the definitions of the ideal voltage from an ideal voltage source,and an ideal inductor.
If an ideal inductor is shorted,so as it becomes an endless loop,can a voltage be measured anywhere across any two points of that(now looped) ideal inductor while a current is flowing through it?.
Brad
What is there that is beyond a voltage source and an inductor in series/parallel? I can draw it out in my head, what am I missing?
Let's throw in an ideal switch as well. What happens when the switch closes?
The second part of your question sounds like Faraday induction with the coil shorted.
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What is there that is beyond a voltage source and an inductor in series/parallel? I can draw it out in my head, what am I missing?
Let's throw in an ideal switch as well. What happens when the switch closes?
The second part of your question sounds like Faraday induction with the coil shorted.
I would like to ask you the question again Poynt.
1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
Brad
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I would like to ask you the question again Poynt.
1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
Brad
As long as the current flowing is increasing or decreasing over time, the answer to both is yes.
It is an inductor...
PW
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As long as the current flowing is increasing or decreasing over time, the answer to both is yes.
It is an inductor...
PW
1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
As long as the current flowing is increasing or decreasing over time, the answer to both is yes.
It is an inductor...
I would like to see you do that PW.
Th inductor is a continual loop,and so the current would flow in both directions from the positive connection,to the negative.
the magnetic field produced by one half of the windings would be equal and opposite to that of the field produced by the other half of the windings. So there would be no inductive effect. Than now leaves you with only the resistance in which a voltage can be seen across,and the resistance value is 0.
Brad
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I think this is an example of the root cause of one of Brad's problems:
<<< Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0 >>>
He keeps on going back to Ohm's law for an inductor. He hears "an inductor has no resistance when DC current is flowing through it" then he says "R=0" and then he says the current must be infinity. At least sometimes he says that.
So I don't think he can make a distinction between the special condition where an inductor manifests zero resistance and Ohm's law and zero ohmic resistance.
Assuming that I am correct perhaps someone can lead him out of that quagmire.
MileHigh
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I think this is an example of the root cause of one of Brad's problems:
<<< Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0 >>>
He keeps on going back to Ohm's law for an inductor. He hears "an inductor has no resistance when DC current is flowing through it" then he says "R=0" and then he says the current must be infinity. At least sometimes he says that.
So I don't think he can make a distinction between the special condition where an inductor manifests zero resistance and Ohm's law and zero ohmic resistance.
Assuming that I am correct perhaps someone can lead him out of that quagmire.
MileHigh
The question for you MH
1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
Brad
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I think this is an example of the root cause of one of Brad's problems:
<<< Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0 >>>
He keeps on going back to Ohm's law for an inductor. He hears "an inductor has no resistance when DC current is flowing through it" then he says "R=0" and then he says the current must be infinity. At least sometimes he says that.
So I don't think he can make a distinction between the special condition where an inductor manifests zero resistance and Ohm's law and zero ohmic resistance.
Assuming that I am correct perhaps someone can lead him out of that quagmire.
MileHigh
Well, that depends. Is it an ideal Quagmire? If so, it will be bottomless and have infinity adhesion qualities. By definition, no one can ever escape an ideal quagmire...if they could, then it would have not be an ideal one.
Bill
PS Hopefully it is obvious that I am just attempting a bit of humor. It is, of course, not ideal humor, otherwise everyone would be laughing which I am sure they are not. It is Friday and it has been a long, hard week and I am just blowing off a bit of steam over here.
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You are making me think of the Flintstones and the moaning dinosaurs trapped in the tar pits.
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I would like to see you do that PW.
Th inductor is a continual loop,and so the current would flow in both directions from the positive connection,to the negative.
the magnetic field produced by one half of the windings would be equal and opposite to that of the field produced by the other half of the windings. So there would be no inductive effect. Than now leaves you with only the resistance in which a voltage can be seen across,and the resistance value is 0.
Brad
Do you believe you can you induce a current flow in an "ordinary" inductor with its ends shorted together?
PW
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Brad, the short answer is that you can always place a voltage source across an ideal inductor even if it has "zero resistance." The moment you place a voltage source across an inductor it acts as an impedance and the voltage really exists, and the current starts to change.
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The question for you MH
1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
Brad
I have made the question very simple MH--see diagram below.
Brad
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I have made the question very simple MH--see diagram below.
Brad
Is this loop current steady, or is it continuously-varying with time?
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I have made the question very simple MH--see diagram below.
Brad
When the supply is first connected or turned on (T=0) the voltage measured across the inductor will essentially be whatever the V supply voltage is.
It is still an inductor with reactance, and it will take time for the current flow to build.
PW
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When the supply is first connected or turned on (T=0) the voltage measured across the inductor will essentially be whatever the V supply voltage is.
It is still an inductor with reactance, and it will take time for the current flow to build.
PW
You have not answered the question asked in the diagram below.
Brad
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You have not answered the question asked in the diagram below.
Brad
I believe I did answer the question.
However, if you are referring to DC conditions, the answer would be no. But under time varying conditions, as in when you first connect the supply, the answer is yes.
As this relates to MH's original question, at T=0 there is a measurable voltage across the inductor.
PW
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Tinman,
I did not notice the short circuit you drew into your diagram. I mistook those arrows for measurement points (only glanced, time is short right now).
Surely you do not believe that is the equivalent circuit for an ideal inductor with zero resistance.
PW
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Tinman,
I did not notice the short circuit you drew into your diagram. I mistook those arrows for measurement points (only glanced, time is short right now).
PW
Surely you do not believe that is the equivalent circuit for an ideal inductor with zero resistance.
You forgot to take notice of the rest of the circuit described in MHs question.
This is what i have been trying to explain all along.
That will come soon enough.
Question 2--see diagram below.
Brad
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You forgot to take notice of the rest of the circuit described in MHs question.
This is what i have been trying to explain all along.
That will come soon enough.
Question 2--see diagram below.
Brad
Why do you indicate a wire shorting your coil? You do know that does not represent an ideal inductor don't you?
As you did not specify an ideal wire, just one with no resistance, shall we assume the wire still has inductance (like any wire)?
PW
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You forgot to take notice of the rest of the circuit described in MHs question.
This is what i have been trying to explain all along.
That will come soon enough.
Question 2--see diagram below.
Brad
My short answer to question number two as stated in the diagram is yes.
PW
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@tinman
For your last question, my answer is yes there will always be some form of impulse voltage but nothing that could be considered as gain since the short is bleeding it right away. This would somewhat equal your Lewan test.
@all
OK, then let me ask you guys this crazy question if possible. We will call it a Bizarre Four Stage Coil (BFSC). It is not an ideal coil, just a regular coil with regular copper wire of let's say 16 awg. You can give it the resistance value you want, it should not change the question.
You apply a DC voltage on the BFSC where in the first quarter of the coil the voltage can exist as applied, in the second quarter the voltage cannot exist, in the third quarter the voltage can exist again as applied and in the final quarter the voltage cannot exist again. What is meant by cannot exist just means the voltage will be zero on those quarters of the coil but will not hinder the voltage from continuing to the next quarter as if the previous quarter was not there. This would infer that the voltage would be as applied through the first and third quarters as if the second quarter was not there although the second and third quarters are there but at zero volts. Zero here should not infer infinity.
The inductance of the total coil is 1H. You apply a DC voltage of 10 volts at 5 amps.
The question is what will the current be in each quarter?
Also, to prevent any "that's impossible" drama you can modify this question any way you want as long as you keep the four quarters and their voltage handling attributes.
I will tell you in advance that this is not a trap question but it will lead to a second question that you may not like. This is an example of puzzles I make for myself to verify EE logic. Let's see how objective you guys really are. You can't get more basic the this while still providing a spread that can actually be discussed.
wattsup
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Why do you indicate a wire shorting your coil? You do know that does not represent an ideal inductor don't you?
As you did not specify an ideal wire, just one with no resistance,
PW
As we are talking about ideal inductors,i thought you would have nutted that out for your self.\If we are talking about an ideal coil,would it not be wound with ideal wire?--that has no resistance?.
shall we assume the wire still has inductance (like any wire)?
Makes no difference to the answer to the question.
This is a simple test that can be carried out on the bench using a real coil,and provide the correct result.
Brad
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Is this loop current steady, or is it continuously-varying with time?
.
Brad
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As we are talking about ideal inductors,i thought you would have nutted that out for your self.\If we are talking about an ideal coil,would it not be wound with ideal wire?--that has no resistance?.
The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
You do know that don't you?
PW
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The poor tinman is obviously very,very lost here.
I really like him all the same.
One needs to go right back to the basic concept and start from there.
John.
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The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
You do know that don't you?
PW
Of course you're right, the wire is ... ?
------------
Why not a small EE-Built-Off:
Copper pipe, with water flowing in, 2 cell's of a lead battery with SuperCaps, ......??
Just with all the ideas from, WITH respect our EE's, to make / compensate almost ideaal components from what we have on material, is that maybe and hopefully possible?
That would make lovers / rosa glasses from ................ yep, also me!!
Please, 5 min, YT?
Regards, Johan
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Tinman,
I did not notice the short circuit you drew into your diagram. I mistook those arrows for measurement points (only glanced, time is short right now).
PW
Surely you do not believe that is the equivalent circuit for an ideal inductor with zero resistance.
I believe that is an ideal inductor that a voltage cannot be measured across at any two points when current is flowing through it.
Brad
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As you did not specify an ideal wire, just one with no resistance, shall we assume the wire still has inductance (like any wire)?
PW
Why do you indicate a wire shorting your coil? You do know that does not represent an ideal inductor don't you?
Indeed i do PW--something for you to remember stating when the end result is presented.
Brad
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My short answer to question number two as stated in the diagram is yes.
PW
As i said,this i would like to see.
Brad
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The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
You do know that don't you?
PW
Yes i do.
Remember you stated that PW. ;)
Brad
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The poor tinman is obviously very,very lost here.
I really like him all the same.
One needs to go right back to the basic concept and start from there.
John.
What one needs to do,is look at MHs circuit as described,and understand what it is.
As soon as you do the MH paradox conversion,where you simply dismiss things like infinite and no resistance,because you !think! they have no meaning due to there value,then you will never arrive at a correct conclusion as to what will happen at T=0
The fact that there is no resistance,is the very reason you do not just dismiss it,just because you think inductance is going to make it obsolete-->big error.
Are you going to have a go at answering MHs question John,or are you just going to continue to say i am wrong,even though you can answer the question your self.
Much like telling some one that they dont know what the magnetic force is,even though you have no clue of your own as to what it is.
One can only conclude that your statements and remarks toward me ,are nothing more than you riding on the back of MH--and others here as well.
Agree with those you think are correct--not because you have an opinion of your own.
Brad
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What is the diagram with a shorted inductor?
John.
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tinman, did you study Lewin, Kirchoff for the birds, striped shirt about
16 mins YouTube?
John.
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.
Brad
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Is this loop current steady, or is it continuously-varying with time?
To be more accurate,lets say the current is increasing at 800mA a second.
Brad
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tinman, did you study Lewin, Kirchoff for the birds, striped shirt about
16 mins YouTube?
John.
I guess you missed the whole thread dedicated to this very subject that Poynt started.
The total sum of the voltage around that loop = 0,and Kirchoffs law hold's.
So now you have to decide whether you believe Lewin or Poynt?
If lewin is correct,and Kirchoffs law dose not hold,then im screwed.
If Poynt is correct,then my statement also remains correct,in that there is no potential difference that can be measured at any two points across that looped ideal coil. Also remember there is no resistance value in the wire,and so the two resistors in Lewins experiment are omitted.
Below is a circuit showing a real world inductor.
Using this circuit,turn it into an ideal inductor that is looped(shorted)
Lets see if you can do that John.
Brad
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When you think about that hard you realize that one Henry is one Volt-Second per Amp.
That is true, too. This is a very useful relation for building electronic circuits. But note, that it involves 4 variables.
For this reason, I do not consider the above relation to be most basic, like the relation of one Henry being one Weber per Amp.
Note that it involves 3 variables. It is also less useful for building electronic circuits - albeit not so for building motors.
Also, notice that it is impossible to have Amps without Webers but it is possible to have Volts without Amps.
This lack of difference makes the 3 variable relation more basic and coherent than the 4 variable relation.
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An "ideal inductor" has inductance, but no resistance or capacitance, and does not dissipate or radiate energy.
But it stores energy in the form of magnetic flux. Because of this an inductor can have reactance even of it does not have resistance
An ideal voltage source is a voltage source that supplies constant voltage to a circuit despite the current which the circuit draws.
This means that despite the resistance which a load may be in a circuit, the source will still provide constant and steady voltage.
An ideal voltage source has the following characterstic that allows it to act as a 100% efficient source of voltage: it has zero internal resistance.
That's quite true
It is impossible to connect such voltage source across a shorted ideal inductor, because in such case this voltage source would see a load, which does not have any resistance nor reactance
However it is possible to connect such voltage source in series with an ideal inductor. In this case the inductor becomes shorted by the zero internal resistance of the ideal voltage source and this voltage source sees a load, that does not have any resistance but has reactance.
Why a voltage cannot exist across a shorted ideal inductor that has current flowing through it>
Because there is no place to place the voltmeter probes on a shorted ideal inductor ...in practice as well as in theory.
...and the current flowing through that ideal inductor is the same at any two points of that inductor.
And there is no voltage drop anywhere along the ideal shorted inductor even if there is current flowing through it.
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There could be voltage that you can not measure or interact with because all the way around the loop the voltage would be uniform, so current flow but no way to measure the voltage.
And in such case voltage becomes just a postulate ...since you think it's there but cannot measure it.
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Having no internal resistance,the current flow is in no way impeded ,an so that is what makes it an !ideal! voltage source.
At T=0,the ideal voltage source is connected to the ideal inductor-->what have you just done?
Indeed the ideal voltage source has no internal resistance nor reactance.
However an ideal inductor has reactance even if it does not have resistance.
Impedance = Resistance + Reactance
That's why if an ideal voltage source is connected in series with an ideal inductor, then the current will be impeded by its reactance despite not being impeded by its resistance.
This is the reason why a simple Ohm's law i=V/R is not applicable to calculating current in an L circuit, as it totally disregards the reactance (half of the complex impedance).
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What is there that is beyond a voltage source and an inductor in series/parallel?
It seems that you are conflating the series connection of the voltage source with an inductor, with a parallel connection (across a shorted inductor) stipulated by Tinman.
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As long as the current flowing is increasing or decreasing over time, the answer to both is yes.
I disagree.
Current can vary in an ideal shorted* inductor only when the flux penetrating it is varied externally somehow.
But despite that variance, there is no place to connect a voltmeter and measure the voltage or voltage drop.
...and presto!, you have a voltageless current - finite current flowing in zero resistance outside of the confines of the Ohm's law.
* (shorted by an ideal wire, not by an ideal voltage source)
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Brad,
I am curious as to why you wish to apply an ideal voltage to a shorted ideal coil in reference to MH's original question? IMO, it really has no bearing. Perhaps this idea stems from the second condition of the question where zero volts is applied for 2 secs!?
In regards to an ideal voltage source not changing, we must qualify the change. Assume for a moment that I am the creator of an ideal voltage source. I am free from all known laws to set the voltage level at any magnitude I choose. The magnitude I choose however will not change with any attached load but I am still free to change the magnitude at any given time I wish. The output is still unable to change with any load variation. This is the ideal voltage source MH used in his question.
partzman
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I disagree.
Current can vary in an ideal shorted* inductor only when the flux penetrating it is varied externally
Which is what I stipulated, that the current flowing had to vary over time to be able to measure a voltage as per the question.
But despite that variance, there is no place to connect a voltmeter and measure the voltage or voltage drop.
* (shorted by an ideal wire, not by an ideal voltage source)
Consider a series string of ideal inductors connected into a loop with a shorting wire. If you induce a time varying current into the loop, would there not be a measurable voltage drop between the inductors due to the reactance of those inductors?
PW
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I think this is an example of the root cause of one of Brad's problems:
<<< Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0 >>>
He keeps on going back to Ohm's law for an inductor.
Yes, the Ohm's law is not applicable to inductors because it totally disregards the reactance of the inductor.
Resistance is only one half of the total Impedance. It actually is the reason why we have all these words to describe it.
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To be more accurate,lets say the current is increasing at 800mA a second.
Brad
It doesn't matter really. All inductors, whether ideal or real will have a voltage across them when there is current through them, regardless if the current is changing or not.
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It seems that you are conflating the series connection of the voltage source with an inductor, with a parallel connection (across a shorted inductor) stipulated by Tinman.
I'm not referring to tinman's circuit, but the original one stipulated by MH.
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Consider a series string of ideal inductors connected into a loop with a shorting wire.
With or without mutual inductance?
If you induce a time varying current into the loop, would there not be a measurable voltage drop between the inductors due to the reactance of those inductors?
If k<1 and the time varying current was caused asymmetrically, e.g. by varying the flux through only one of the inductors, then there would be a measurable voltage across that inductor as it would act as a voltage source in series with the other inductors.
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1-If we have an inductor that has no resistance,and the two ends of that inductor are joined,so as the inductor is now just a continual loop of wire(shorted),can we place a voltage across that inductor that has no resistance.
2-If there is now a current flowing in that shorted ideal inductor,is there any two points across that ideal inductor where a voltage can be measured?
No to 1 & 2.
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Do you believe you can you induce a current flow in an "ordinary" inductor with its ends shorted together?
Yes, by varying the flux penetrating that inductor.
And since that inductor has resistance now, then the current flow will cause a voltage drop across any two points on it.
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Brad, Mags,
Please see the attached.
This is the ideal varying voltage source MH poses in his question. It is an arbitrary wave form really, constructed of a number of voltage levels and times. That's all, nothing mysterious, other than it can source infinite current, being ideal and all.
Does this make sense now? I trust this is clearly understood.
The question is, what happens to the circuit current?, i.e. draw out the circuit current on this same graph.
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Brad, the short answer is that you can always place a voltage source across an ideal inductor even if it has "zero resistance."
I think you are conflating the series connection of the voltage source and the inductor with the parallel connection of the voltage source to a shorted inductor, as stipulated by Tinman,
Picowatt wrote that you had a different connection in mind earlier in the thread (which I did not read) so the meaning of the word "across" might be at the root of your disagreement with Tinman.
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I did not notice the short circuit you drew into your diagram. I mistook those arrows for measurement points (only glanced, time is short right now).
That could be the root of the misunderstanding with Tinman. When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".
Surely you do not believe that is the equivalent circuit for an ideal inductor with zero resistance.
I think he does and he is correct.
Why do you indicate a wire shorting your coil? You do know that does not represent an ideal inductor don't you?
The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all. This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.
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Question 2--see diagram below.
No.
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Indeed the ideal voltage source has no internal resistance nor reactance.
However an ideal inductor has reactance even if it does not have resistance.
Impedance = Resistance + Reactance
This is the reason why a simple Ohm's law i=V/R is not applicable to calculating current in an L circuit, as it totally disregards the reactance (half of the complex impedance).
That's why if an ideal voltage source is connected in series with an ideal inductor, then the current will be impeded by its reactance despite not being impeded by its resistance.
The connection is not just a series connection when there is only two components.
The connection is both series and parallel.
The fact that the ideal voltage source has no internal resistance,and is connected across the ideal inductor,means the inductor is now a loop connection with no resistance to current flow through that now looped inductor. And as we know,a voltage cannot be measured across any two points of a looped(shorted) ideal inductor.
Regardless of the fact that the ideal voltage source can produce a voltage,the fact that the ideal voltage source is now connected across that ideal inductor,means that the current flowing through it is in no way impeded,nor is there any loss to resistance,as the resistance value is 0--and so no power is dissipated.
So now you have a situation where we cannot measure a voltage across any two points of the circuit,and yet at the same time,we are trying to place the very same thing across that circuit that cannot be measured.
Brad
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That could be the root of the misunderstanding with Tinman. When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".
I think he does and he is correct.
The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all. This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.
What are you saying exactly?
That an ideal inductor is one that has a short across its terminals? Please clarify your point.
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That could be the root of the misunderstanding with Tinman. When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".
I think he does and he is correct.
The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all. This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.
Verpies,
I disagree here. The coil resistance should be in series with the inductance not in parallel. If this were a multiple winding arrangement, then the reflected resistance/impedance would be in parallel with the referenced winding.
partzman
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Brad,
I am curious as to why you wish to apply an ideal voltage to a shorted ideal coil in reference to MH's original question? IMO, it really has no bearing. Perhaps this idea stems from the second condition of the question where zero volts is applied for 2 secs!?
In regards to an ideal voltage source not changing, we must qualify the change. Assume for a moment that I am the creator of an ideal voltage source. I am free from all known laws to set the voltage level at any magnitude I choose. The magnitude I choose however will not change with any attached load but I am still free to change the magnitude at any given time I wish. The output is still unable to change with any load variation. This is the ideal voltage source MH used in his question.
partzman
Because an ideal voltage source has no internal resistance,and that is what makes it ideal.
The ideal voltage source is a series/parallel connection,as there is only two components in the circuit. As that ideal voltage source provides the very same link across the inductor as the piece of non resistant wire dose,then as soon as you hook the ideal voltage source across that ideal inductor,you have just shorted(looped) that ideal inductor.
If the voltage was reduced to 0 volts on the ideal voltage source,the current flow would continue through the loop that now exist in the ideal coil.=,as the voltage source has no internal resistance to impede the current flow.
Ask your self this.
When MH turns his voltage source down to a value of 0 volts,will the current flow continue on?
If not,then explain as to why not--what will impede that current flow,when the complete loop from the ideal inductor across the ideal voltage supply has no resistance ?
Who here can draw the complete circuit,along with the resistance values of that circuit?.
Brad
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I think he does and he is correct.
Are you stating that you believe the equivalent circuit for an ideal inductor is an inductor in parallel with (shorted) by an ideal wire?
Do you also believe that the equivalent circuit for a normal inductor has its wire resistance in parallel with the inductor?
PW
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The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
Just because most of the world does it wrong does not mean that we have to.
An energized capacitor can be correctly modeled in an open state, the inductor - just the opposite.
Are you stating that you believe the equivalent circuit for an ideal inductor is an inductor in parallel with (shorted) by an ideal wire?
Yes, with an addendum that it can also be shorted by an ideal voltage source.
I know that SPICE does not draw an inductor this way, but internally it calculates it that way.
Do you also believe that the equivalent circuit for a normal inductor has its wire resistance in parallel with the inductor?
No, I believe that when the parasitic capacitance is disregarded then the real inductor's equivalent circuit has its wire resistance in series with its inductance and that entire circuit is closed by an ideal wire just like with an ideal inductor devoid of resistance.
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Which is what I stipulated, that the current flowing had to vary over time to be able to measure a voltage as per the question.
PW
Consider a series string of ideal inductors connected into a loop with a shorting wire. If you induce a time varying current into the loop, would there not be a measurable voltage drop between the inductors due to the reactance of those inductors?
A MH paradox added?
There is only one inductor--not a series of them.
My question was very clear.
Brad
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Yes, the Ohm's law is not applicable to inductors because it totally disregards the reactance of the inductor.
Resistance is only one half of the total Impedance. It actually is the reason why we have all these words to describe it.
But it is applicable when that ideal inductor is shorted(becomes a continual loop)
Even when a current is flowing through that looped ideal inductor,ohms law states that V=IxR,and as there is no R,then there is no voltage across that looped inductor--as we know.
Brad
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I'm not referring to tinman's circuit, but the original one stipulated by MH.
You were answering my question posted on my circuit diagram Poynt.
How can you say that you were referring to MHs question?
Brad
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No to 1 & 2.
Thank you verpies
As we know,you are correct.
Brad
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A MH paradox added?
There is only one inductor--not a series of them.
My question was very clear.
Brad
Not a paradox, a model/tool for visualization purposes.
Every inductor can be thought of as being equivalent to a series string of inductors.
Would not measuring between several turns of your single inductor be equivalent to measuring between several series connected inductors?
PW
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What are you saying exactly?
That an ideal inductor is one that has a short across its terminals? Please clarify your point.
No
An ideal inductor that is looped(has a short placed across it by an ideal wire)is a shorted ideal inductor. If there is no wire across the ideal inductor terminals,then it is just an open circuit.
Brad
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The connection is not just a series connection when there is only two components.
The connection is both series and parallel.
Seemingly yes, if you do not count the ideal wire that shorts the inductor.
Pay attention to this issue and the associated terminology because in my opinion this is the reason why you and MH cannot agree.
The fact that the ideal voltage source has no internal resistance,and is connected across the ideal inductor,means the inductor is now a loop connection with no resistance to current flow through that now looped inductor.
Yes, there is no resistance to current flow but there is impedance to current flow. That is why the current does not become infinite immediately.
Impedance has two components. Please consider both of them.
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Because an ideal voltage source has no internal resistance,and that is what makes it ideal.
The ideal voltage source is a series/parallel connection,as there is only two components in the circuit. As that ideal voltage source provides the very same link across the inductor as the piece of non resistant wire dose,then as soon as you hook the ideal voltage source across that ideal inductor,you have just shorted(looped) that ideal inductor.
If the voltage was reduced to 0 volts on the ideal voltage source,the current flow would continue through the loop that now exist in the ideal coil.=,as the voltage source has no internal resistance to impede the current flow.
Ask your self this.
When MH turns his voltage source down to a value of 0 volts,will the current flow continue on?
If not,then explain as to why not--what will impede that current flow,when the complete loop from the ideal inductor across the ideal voltage supply has no resistance ?
Who here can draw the complete circuit,along with the resistance values of that circuit?.
Brad
Let me first answer your question. When the ideal voltage source goes to zero volts, the current in the ideal coil will remain at the level it reached with the previous condition and will stay that way until the ideal voltage source is changed to a different magnitude.
What was confusing is that it appeared you wished to apply an ideal voltage across an ideal coil with an ideal short. This is not equivalent to the circuit as MH proposed.
The circuit diagram is simply an ideal source in parallel with an ideal inductor with no resistance.
partzman
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No, I believe that when the parasitic capacitance is disregarded then the inductors equivalent circuit has it wire resistance in series with its inductance and that entire circuit is closed by an ideal wire just like with an ideal inductor devoid of resistance.
I was agreeing with this as far as the wire resistance of a normal inductor being in series with the inductor, but when you got to the point where you stated "that entire circuit is closed by an ideal wire just like with an ideal inductor devoid of resistance" you lost me.
Are you referring to some circuit in particular or are you stating that the equivalent model for every inductor includes a short circuit across its terminals?
The model for a normal inductor has the wire resistance in series with the inductor. The model for an ideal inductor removes that series resistor (or places its value at zero). There is no short circuit across either inductor.
PW
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You were answering my question posted on my circuit diagram Poynt.
How can you say that you were referring to MHs question?
Brad
Well, actually I wasn't. What I was doing which led to my response was the following:
I think use of the term "shorted" when referring to an ideal inductor is not good nor accurate nomenclature.
An ideal inductor simply has zero series resistance. It is not "shorted" in any way, and will not present itself as a "short" if/when a voltage source (ideal or not) is connected across it.
Here I was responding to a post from verpies. Referring to an ideal inductor as being "shorted" brings no practical utility to the discussion other than to add confusion.
You need to think a little beyond what you are Poynt,and draw the circuit as MH said i should,
I have provided the definitions of the ideal voltage from an ideal voltage source,and an ideal inductor.
If an ideal inductor is shorted,so as it becomes an endless loop,can a voltage be measured anywhere across any two points of that(now looped) ideal inductor while a current is flowing through it?.
Brad
What is there that is beyond a voltage source and an inductor in series/parallel? I can draw it out in my head, what am I missing?
Let's throw in an ideal switch as well. What happens when the switch closes?
The second part of your question sounds like Faraday induction with the coil shorted.
Here I was responding to your response. Clearly I am referring to the original circuit, an ideal inductor with an ideal voltage source connected across it. Then I introduce an ideal switch. You said it yourself, "draw the circuit as MH asked you to", to paraphrase. There is nothing more to the circuit, specifically, no short across the inductor.
It seems that you are conflating the series connection of the voltage source with an inductor, with a parallel connection (across a shorted inductor) stipulated by Tinman.
Here verpies misinterprets my post as referring to your circuit diagram with the short. As I explained, that is not what I was referring to.
I would strongly suggest that all focus on the original question and purpose of this thread. I have now given you a clear illustration of the voltage source contained within the question, and reworded it to get directly to the point of the question.
So Brad, or Mags, will you give it a go? That is, plot out the current trace right over top of the voltage trace I posted?
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What was confusing is that it appeared you wished to apply an ideal voltage across an ideal coil with an ideal short. This is not equivalent to the circuit as MH proposed.
That's classic Brad. From what I can gather the schematic that he posted did not match his written description from a few posts earlier, creating confusion.
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Seemingly yes, if you do not count the ideal wire that shorts the inductor.
Pay attention to this issue and the associated terminology because in my opinion this is the reason why you and MH cannot agree.
Yes, there is no resistance to current flow but there is impedance to current flow. That is why the current does not become infinite immediately.
Impedance has two components. Please consider both of them.
Quote
Ideal inductors and capacitors have a purely imaginary reactive impedance:
Verpies
Can you define what they mean by !imaginary!,as this seems to only be associated with ideal inductors,where as non ideal(real world)inductors are always stated as having impedance,without the use of the word !imaginary! .
2nd-
If the ideal voltage source is reduced to a value of 0 volts instantly,but the non resistive link of the ideal voltage source is still across the ideal inductor,will the current continue to flow through the circuit,as there is nothing to impede this current flow.
Brad
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Seemingly yes, if you do not count the ideal wire that shorts the inductor.
Pay attention to this issue and the associated terminology because in my opinion this is the reason why you and MH cannot agree.
That is why the current does not become infinite immediately.
Impedance has two components. Please consider both of them.
Yes, there is no resistance to current flow but there is impedance to current flow.
But that current flow must still be the same throughout the circuit/loop,regardless of the impedance created by the inductor.
As we have both stated,a voltage cannot be measured at any two points across a shorted ideal inductor. Adding the ideal voltage source to the open inductor,also shorts that inductor,due to the fact that the ideal voltage source also has no internal resistance--the loop is complete ,void of any resistance to current flow,regardless of the value of that current flow.
Brad
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That's classic Brad. From what I can gather the schematic that he posted did not match his written description from a few posts earlier, creating confusion.
The schematic i posted represents your circuit MH
Would it be easier if i placed a + and - sign in there for you ?
Brad
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That's classic Brad. From what I can gather the schematic that he posted did not match his written description from a few posts earlier, creating confusion.
Here is your circuit MH
Make it any easier to understand now?
The MH paradox?
Brad
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But that current flow must still be the same throughout the circuit/loop,regardless of the impedance created by the inductor.
As we have both stated,a voltage cannot be measured at any two points across a shorted ideal inductor. Adding the ideal voltage source to the open inductor,also shorts that inductor,due to the fact that the ideal voltage source also has no internal resistance--the loop is complete ,void of any resistance to current flow,regardless of the value of that current flow.
Brad
As the circuit is prescribed, there is always a voltage measured across the terminals of the inductor, and that voltage precisely follows what the voltage source is set to at any point in time.
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Most of you lot are very like lavatory brushes, clean round the bend!!
Luckily we've got poynt to point us in the right direction.
It's really good entertainment though.
John.
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Here is your circuit MH
Make it any easier to understand now?
The MH paradox?
Brad
Brad,
An ideal voltage source is not properly illustrated as a short circuit.
You need to draw in a voltage source, or function generator there.
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Here verpies misinterprets my post as referring to your circuit diagram with the short. As I explained, that is not what I was referring to.
Yes, and I stand corrected. I thought that you were referring to the circuit stipulated by Tinman and depicted in Fig.3.
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Yes, and I stand corrected. I thought that you were referring to the circuit stipulated by Tinman and depicted in Fig.3.
Please draw out the current trace of your figure no. 3 then if V=1V and L=1H (both ideal).
If it is anything but an infinite amplitude, what is the point of illustrating it with a short circuit, other than to add confusion?
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Brad,
An ideal voltage source is not properly illustrated as a short circuit.
You need to draw in a voltage source, or function generator there.
If it has no internal resistance through that ideal voltage source,how can it not be a short circuit?
Please post a diagram you !your! ideal voltage source.
This is the paradox i am referring to,and why an ideal voltage source cannot exist,and/or be placed across an ideal inductor.
What would happen if we reduced the internal series resistance of a charged cap(say 1000uF with 10 volts across it) to a value of 0(added),and then used that as our ideal voltage source,and placed the ideal inductor across it ?.
Brad
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Please draw out the current trace of your figure no. 3 then if V=1V and L=1H (both ideal).
If it is anything but an infinite amplitude, what is the point of illustrating it with a short circuit, other than to add confusion?
Figure 3 represents MHs circuit.
Brad
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Figure 2 represents my circuit.
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Figure 2 represents my circuit.
No
figure 3 represents your circuit.
Replace your ideal voltage source with an ideal capacitor,and you have the same.
an ideal capacitor is your voltage source,where that ideal capacitor has no series resistance.
You charge your capacitor to 4 volts,and you place it across your ideal coil.
Can you now measure a voltage anywhere around that circuit,even though current is now flowing through it?.
Brad
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Please draw out the current trace of your figure no. 3 then if V=1V and L=1H (both ideal).
If it is anything but an infinite amplitude, what is the point of illustrating it with a short circuit, other than to add confusion?
It is to show you that you cannot place a voltage across a shorted(looped) ideal inductor.
Brad
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Yes, and I stand corrected. I thought that you were referring to the circuit stipulated by Tinman and depicted in Fig.3.
Verpies, this is mass confusion day. I find your figure 3 confusing. If we view a shorted ideal coil like a classic toroidal inductor, then aren't we talking about putting a voltage source across the toroid such that it ends up looking like two separate coils in parallel?
If that is the case, I fail to see any utility in that.
(sorry for the chicken scratchings drawing.)
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Please draw out the current trace of your figure no. 3 then if V=1V and L=1H (both ideal).
In that case:
Current (i) flowing through the inductor equals i=ΔΦ/1H and the current flowing trough the voltage source is infinite.
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No
figure 3 represents your circuit.
Replace your ideal voltage source with an ideal capacitor,and you have the same.
an ideal capacitor is your voltage source,where that ideal capacitor has no series resistance.
You charge your capacitor to 4 volts,and you place it across your ideal coil.
Can you now measure a voltage anywhere around that circuit,even though current is now flowing through it?.
Brad
No I assure you that figure 2 represents my circuit.
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If it has no internal resistance through that ideal voltage source,how can it not be a short circuit?
If it has 0V across it, then yes it is equivalent to a short circuit. However, this is a voltage source that starts out with +4V across it, therefore it must be drawn as an ideal voltage source or function generator.
Please post a diagram you !your! ideal voltage source.
It is a voltage source (set to voltage X) with a series resistor equaling 0 Ohms.
This is the paradox i am referring to,and why an ideal voltage source cannot exist,and/or be placed across an ideal inductor.
There is no paradox. You are misinterpreting an ideal voltage source as a zero Ohm wire. That is not the case unless as I said, the voltage is set to 0V.
What would happen if we reduced the internal resistance of a charged cap(say 1000uF with 10 volts across it) to a value of 0 ?.
You would have a good quality capacitor. What would happen? Nothing if it wasn't connected to anything. If connected to some load it would happily discharge.
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Verpies, this is mass confusion day. I find your figure 3 confusing. If we view a shorted ideal coil like a classic toroidal inductor, then aren't we talking about putting a voltage source across the toroid such that it ends up looking like two separate coils in parallel?
If that is the case, I fail to see any utility in that.
(sorry for the chicken scratchings drawing.)
Well they wont be two seperate coils in parallel MH,because one winding will be CW and the other CCW.
So they will be in series,not parallel
Brad
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Verpies, this is mass confusion day.
I kind of like it because it stimulates us to think.
I think this discussion is beneficial to all involved as long as Ad Hominem remarks are absent.
I find your figure 3 confusing. If we view a shorted ideal coil like a classic toroidal inductor, then aren't we talking about putting a voltage source across the toroid such that it ends up looking like two separate coils in parallel?
The confusion will disappear immediately when you consider the coupling coefficient (k) between these two "separate coils" connected "in parallel".
In an ideal toroid the flux is completly shared and k=-1, thus in fact these coils are connected in anti-parallel when flux direction is considered. Thus they do not posses any inductance collectively. Consequently their anti-parallel combination possesses zero reactance and zero resistance, leading to zero impedance and the current flowing through the voltage source rises immediately to infinity.
If that is the case, I fail to see any utility in that.
It is pretty useless from an engineering standpoint, but it has a great educational value.
Anyway, it is what Tinman was referring to all along while you were apparently analyzing Fig.2.
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In that case:
Current (i) flowing through the inductor equals i=ΔΦ/1H and the current flowing trough the voltage source is infinite.
Now there is your paradox Brad.
When you place an ideal voltage source across an ideal short, who wins? The voltage source or the ideal wire? verpies seems to indicate that the voltage source wins, as the voltage holds and the inductor still gets some current.
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Well they wont be two seperate coils in parallel MH,because one winding will be CW and the other CCW.
So they will be in series,not parallel
Brad
If it really was a toroid, then there will be two junction points where the voltage source makes contact with the toroid as shown in the diagram. Current will flow say from top to bottom in each half coil.
There will be some flux cancellation at the two junction points. But excluding that, for all practical intents and purposes each half of the toroid will be a separate and independent coil. Because they are separate and independent, the winding direction is meaningless.
The two half-toroid coils will look like two separate coils in parallel across the voltage source.
MileHigh
.....................................................
This is an addendum.....
Okay so Verpies is talking about an ideal toroidal inductor where there is total flux coupling from coil turn to coil turn no matter what the physical configuration. It's almost like there is a "magic ideal core" to the toroid directing the flux.
In this case if you connect up the voltage source as per my diagram, the CW and the CCW turns due to the current splitting up in different directions will cause total flux cancellation and it will look like a direct short.
Note as per the toroidal inductor diagram, if the connections are not 180 degrees apart, you get a kind of "dial up an ideal inductor value" configuration.
I can get this but Verpies I think it had to be described better. I hope I am right, and please correct me if I am wrong.
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author=poynt99 link=topic=16589.msg484272#msg484272 date=1463239770]
If it has 0V across it, then yes it is equivalent to a short circuit. However, this is a voltage source that starts out with +4V across it, therefore it must be drawn as an ideal voltage source or function generator.
And who states that this is the case?
Regardless of whether there is a voltage or not,the fact that there is no internal series resistance means that the current can still flow through that voltage source unimpeded.
When we drop down to 0 volts (as stated in MHs question),the current will continue to flow,and at a steady state. As verpies stated,you cannot measure a voltage across a shorted(looped) ideal inductor.
It is a voltage source (set to voltage X) with a series resistor equaling 0 Ohms.
There is no paradox. You are misinterpreting an ideal voltage source as a zero Ohm wire. That is not the case unless as I said, the voltage is set to 0V.
And MHs question requires a o voltage at one point in the test. At that point,the current still flow's,as there is no resistance that impedes that current flow through the now looped(shorted )circuit. Now,as virpies stated,you cannot place a voltage across a shorted ideal inductor,and you have just stated that at 0 volts,then yes,the ideal voltage source is like a 0 ohm wire. So now how do you once again increase the voltage after 0 volt's,as you are now trying to place a voltage across an ideal shorted(looped) inductor?
See the paradox now?.
Brad
You would have a good quality capacitor. What would happen? Nothing if it wasn't connected to anything. If connected to some load it would happily discharge.
Now we place that ideal inductor across that ideal capacitor--what happens?
Can you measure a voltage across any part of that circuit?.
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Figure 3 represents MHs circuit.
Brad
Figure 2 represents MH's question, and is an accurate representation of an ideal voltage source and inductor.
An ideal inductor is "theoretically" made from ideal wire having no resistance or capacitance. It is not "shorted" by a wire having no resistance.
A straight length of ideal wire still has inductance and behaves accordingly. Coiled up, that same length of ideal wire has increased inductance. At no time is there any resistance in the ideal wire and at no time is there a requirement to short the inductor with another ideal wire to model it.
PW
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An ideal voltage source is not properly illustrated as a short circuit.
So what is the resistance of a 0V voltage source?
....or if you connect an ideal capacitor, charged to 11V, to an ideal 1V voltage source, then what current will flow through the capacitor at t0?
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What would happen if we reduced the internal series resistance of a charged cap(say 1000uF with 10 volts across it) to a value of 0(added),and then used that as our ideal voltage source,and placed the ideal inductor across it ?.
An ideal LC circuit will be formed and sinusoidal current will appear.
An infinite current will not flow because the ideal inductor will still possess non-zero reactance and impedance despite having zero resistance.
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If it really was a toroid, then there will be two junction points where the voltage source makes contact with the toroid as shown in the diagram. Current will flow say from top to bottom in each half coil.
There will be some flux cancellation at the two junction points. But excluding that, for all practical intents and purposes each half of the toroid will be a separate and independent coil. Because they are separate and independent, the winding direction is meaningless.
The two half-toroid coils will look like two separate coils in parallel across the voltage source.
MileHigh
And here we have another MH paradox added,so as he is not found to be wrong again.
Correct answer.
The two coils will be in series-not parallel.
The top of one coil (coil A) will produce say a north field,and the top of the other coil(coil B) will produce a south field. The opposite end of each coil will of course produce the opposite field. As it is a toroid,we can follow a circular path. We will have a field configuration that represents a series connection-North to south to north to south. If it were parallel,then we would have north/north at one end,and south /south at the other.
You only have to replace the two coils with batteries,where north may represent positive,and south represent negative,to see that it is a series arrangement ,and not a parallel arrangement.
Brad
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And here we have another MH paradox added,so as he is not found to be wrong again.
Correct answer.
The two coils will be in series-not parallel.
The top of one coil (coil A) will produce say a north field,and the top of the other coil(coil B) will produce a south field. The opposite end of each coil will of course produce the opposite field. As it is a toroid,we can follow a circular path. We will have a field configuration that represents a series connection-North to south to north to south. If it were parallel,then we would have north/north at one end,and south /south at the other.
You only have to replace the two coils with batteries,where north may represent positive,and south represent negative,to see that it is a series arrangement ,and not a parallel arrangement.
Brad
I did an addendum to my posting #382 to account for Verpies' explanation of his configuration.
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And who states that this is the case?
That an ideal 0V source is equivalent to an ideal conductor? By deduction, that is what it is. It is common sense. It is impractical of course (except in simulators where it can be used to measure current), but it is a precise equivalent. Doesn't an ideal non-inductive conductor always have 0V across it? Well, so does an ideal voltage source set to 0V.
Regardless of whether there is a voltage or not,the fact that there is no internal series resistance means that the current can still flow through that voltage source unimpeded.
When we drop down to 0 volts (as stated in MHs question),the current will continue to flow,and at a steady state.
Yep, I'm not arguing against that.
As verpies stated,you cannot measure a voltage across a shorted(looped) ideal inductor.
And MHs question requires a o voltage at one point in the test. At that point,the current still flow's,as there is no resistance that impedes that current flow through the now looped(shorted )circuit. Now,as virpies stated,you cannot place a voltage across a shorted ideal inductor,and you have just stated that at 0 volts,then yes,the ideal voltage source is like a 0 ohm wire. So now how do you once again increase the voltage after 0 volt's,as you are now trying to place a voltage across an ideal shorted(looped) inductor?
I'm not sure what verpies is saying, but the fact is that when the voltage drops to 0V (even after it was at some non-zero level), you will measure 0V across the inductor.
See the paradox now?.
No.
Now we place that ideal inductor across that ideal capacitor--what happens?
Can you measure a voltage across any part of that circuit?.
Of course you can.
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So what is the resistance of a 0V voltage source?
It is whatever the internal resistance of that source is.
....or if you connect an ideal capacitor, charged to 11V, to an ideal 1V voltage source, then what current will flow through the capacitor at t0?
Infinite current of course.
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author=poynt99 link=topic=16589.msg484272#msg484272 date=1463239770]
And MHs question requires a o voltage at one point in the test. At that point,the current still flow's,as there is no resistance that impedes that current flow through the now looped(shorted )circuit. Now,as virpies stated,you cannot place a voltage across a shorted ideal inductor,and you have just stated that at 0 volts,then yes,the ideal voltage source is like a 0 ohm wire. So now how do you once again increase the voltage after 0 volt's,as you are now trying to place a voltage across an ideal shorted(looped) inductor?
See the paradox now?.
Brad
If a voltage source has resistance, this resistance is equivalent to being in series with an ideal voltage generating means. The voltage generating means is free to vary while still maintaining the same series resistance. The same exists in an ideal voltage source except the series resistance is zero. So, you are correct that if we short the ideal voltage source, infinite current will flow. You are also correct that if the voltage source is zero when connected to an ideal inductor, any previous current flowing will continue without change.
However, we are allowed to vary the voltage generating means with a zero series resistance connected to an ideal coil which also has a zero series resistance and due to the nature of the self inductance of the coil, we will experience a change in current depending on the circuit values.
partzman
Edit-Changed to "connected to"
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<<< Now,as virpies stated,you cannot place a voltage across a shorted ideal inductor, >>>
Again, I believe I understand what Verpies meant because he responded to my questions about this.
A "shorted ideal inductor" just becomes a dead short circuit by his definition. Half of the ideal turns cancel out the flux of the other half of the ideal turns and you end up with a "ideal zero ohm resistor with no inductance."
By his definition a "shorted ideal inductor" simply disappears from the circuit and looks like an ideal wire with zero inductance.
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It is not "shorted" by a wire having no resistance.
An open inductor makes no more sense than a shorted capacitor and these components are complete conjugates of each other.
Open conductor cannot:
- store energy,
- maintain the level of flux that penetrates it,
- obey the Lenz law,
- generate magnetic flux density gradient that can do mechanical work.
In fact an open inductor loses all of the properties of inductors except an empty voltage potential under varying flux conditions, that cannot even be measured without completing the inductor's circuit.
A straight length of ideal wire still has inductance and behaves accordingly.
Yes, but what does it matter if k (https://en.wikipedia.org/wiki/Inductance#Coupled_inductors_and_mutual_inductance)=1 ?
At no time is there any resistance in the ideal wire and at no time is there a requirement to short the inductor with another ideal wire to model it.
The requirement to close the inductor's circuit is there every time you want an inductor to act as an inductor and do more than nothing.
That's why some good simulators will not even allow you to have an open inductor in a simulation and out of those they don't have problems with open capacitors.
I remind you that inductors and capacitors are complete conjugates (col: opposites) of each other.
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That an ideal 0V source is equivalent to an ideal conductor? By deduction, that is what it is. It is common sense. It is impractical of course (except in simulators where it can be used to measure current), but it is a precise equivalent. Doesn't an ideal non-inductive conductor always have 0V across it? Well, so does an ideal voltage source set to 0V.
No.
Of course you can.
Regardless of whether there is a voltage or not,the fact that there is no internal series resistance means that the current can still flow through that voltage source unimpeded.
When we drop down to 0 volts (as stated in MHs question),the current will continue to flow,and at a steady state.
Yep, I'm not arguing against that.
I'm not sure what verpies is saying, but the fact is that when the voltage drops to 0V (even after it was at some non-zero level), you will measure 0V across the inductor.
But we agree that the inductor is now a shorted loop,and current is flowing through this circuit loop that includes the ideal voltage source(not to be confused with the ideal voltage,which now has a value of 0 volts)
To quote verpies
It is impossible to connect such voltage source across a shorted ideal inductor, because in such case this voltage source would see a load, which does not have any resistance nor reactance
So now i ask--
At 0 volts we both agree that we are in a shorted(looped) condition,and a steady current is flowing through this shorted ideal inductor loop,and due to the 0 resistance value,it will continue to flow infinitely. How is this short removed just by turning up the voltage on the ideal voltage source?
If it is not removed,then how are you placing a voltage across this !now shorted! ideal inductor?
The paradox being-quote verpies-->It is impossible to connect such voltage source across a shorted ideal inductor.
Is there some sort of two kinds of !shorted!?.
A short is a short-is it not?.
Brad
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I wonder if MH would have said that the current continued to flow through his circuit during the 0 volt time of his question?
I think not,as it would have been something he would never have seen,due to not understanding the meaning of Ideal.
But we will never know,as he never would answer his own question ::)
Brad
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I wonder if MH would have said that the current continued to flow through his circuit during the 0 volt time of his question?
I think not,as it would have been something he would never have seen,due to not understanding the meaning of Ideal.
But we will never know,as he never would answer his own question ::)
Brad
You think wrong. I intentionally stated that the voltage becomes zero volts to see if you guys would get that.
You're just being ridiculous when you say I do not understand the meaning of "ideal."
You guys apparently are slowly but surely getting up the learning curve.
Do you now accept the fact that an ideal voltage source can output a voltage waveform that changes in time?
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I kind of like it because it stimulates us to think.
I think this discussion is beneficial to all involved as long as Ad Hominem remarks are absent.
The confusion will disappear immediately when you consider the coupling coefficient (k) between these two "separate coils" connected "in parallel".
In an ideal toroid the flux is completly shared and k=-1, thus in fact these coils are connected in anti-parallel when flux direction is considered. Thus they do not posses any inductance collectively. Consequently their anti-parallel combination possesses zero reactance and zero resistance, leading to zero impedance and the current flowing through the voltage source rises immediately to infinity.
It is pretty useless from an engineering standpoint, but it has a great educational value.
Anyway, it is what Tinman was referring to all along while you were apparently analyzing Fig.2.
Great thinking. ;) It is the reverse of the ideal inductor idea of no current can flow, where in your point here is there is no reactance, and the single inductor has 100% reactance. ;) In an ideal world.
Mags
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Attached is an equivalent circuit of MH's question using ideal components. The questions are, can we vary Vg and can we use delta I = E*t/L to analyze this circuit? If not, why? The main objection has been the short circuited this and that. I don't see any short circuits. What an I missing here?
partzman
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But we will never know,as he never would answer his own question ::)
And isn't it a good thing that I refused to answer the easy question and only answered the hard question, because slowly but surely you are actually learning something now.
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But we agree that the inductor is now a shorted loop,and current is flowing through this circuit loop that includes the ideal voltage source(not to be confused with the ideal voltage,which now has a value of 0 volts)
To quote verpies
So now i ask--
At 0 volts we both agree that we are in a shorted(looped) condition,and a steady current is flowing through this shorted ideal inductor loop,and due to the 0 resistance value,it will continue to flow infinitely.
As I said, I am not arguing against that.
How is this short removed just by turning up the voltage on the ideal voltage source?
If it is not removed,then how are you placing a voltage across this !now shorted! ideal inductor?
The short is not removed. The voltage source itself is the short (if you will), but it doesn't short itself out!
The paradox being-quote verpies-->It is impossible to connect such voltage source across a shorted ideal inductor.
There is no paradox, and verpies is wrong because the inductor does not represent a short the moment it is connected to something, even an ideal voltage source. The only true paradox I've seen so far is verpies' application of an ideal voltage source across an ideal short. Which one wins? That is your paradox Brad.
As I said, talk of such abstract theories as being posed is not helping the understanding here in any way, it is only hindering it.
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As I said, talk of such abstract theories as being posed is not helping the understanding here in any way, it is only hindering it.
I agree, Verpies is too far out sometimes. His comments on the thread from a couple of days ago were barely comprehensible.
Verpies: I suggest that you step it down a notch and add some more description at times so your message is more readily understood by both the "ordinaries" and the "gurus."
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Attached is an equivalent circuit of MH's question using ideal components. The questions are, can we vary Vg and can we use delta I = E*t/L to analyze this circuit? If not, why? The main objection has been the short circuited this and that. I don't see any short circuits. What an I missing here?
partzman
You are absolutely 100% dead on. Will the train see the light at the end of the tunnel and actually emerge from the tunnel in one piece? That is the question of the hour.
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As I said, I am not arguing against that.
The short is not removed. The voltage source itself is the short (if you will), but it doesn't short itself out!
There is no paradox, and verpies is wrong because the inductor does not represent a short the moment it is connected to something, even an ideal voltage source. The only true paradox I've seen so far is verpies' application of an ideal voltage source across an ideal short. Which one wins? That is your paradox Brad.
As I said, talk of such abstract theories as being posed is not helping the understanding here in any way, it is only hindering it.
I agree with you on the no current flow at t/0 of an ideal inductor.
But I dont think that if we're to study the ideals if an ideal inductor that we should ignore the mechanism that makes it do what it does. If resistance is zero, and no losses, then that underlying ideal inductor mechanism should be lossless and 100% efficient also. And if that mechanism is lossless then the the inductor should continuously impede an emf presented at the input. ;) PW says that a straight wire has inductance, and I agree, no matter how tiny the inductance is. So it may be that the ideal straight wire may not be able to pass current if the inductance mechanism is 100% efficient. Does that make any sense at all? If not then where might we find reference that tells us otherwise so we can examine that if possible?
In the real world we have resistance mostly no matter what. So all those losses, voltage drops no matter how tiny would definitely affect the efficiency of that mechanism to be less than 100% efficient, thus there could not be a 100% impediment to the input and the inductor would now work as we know them.
Mags
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I agree with you on the no current flow at t/0 of an ideal inductor.
But I dont think that if we're to study the ideals if an ideal inductor that we should ignore the mechanism that makes it do what it does. If resistance is zero, and no losses, then that underlying ideal inductor mechanism should be lossless and 100% efficient also. And if that mechanism is lossless then the the inductor should continuously impede an emf presented at the input. ;) PW says that a straight wire has inductance, and I agree, no matter how tiny the inductance is. So it may be that the ideal straight wire may not be able to pass current if the inductance mechanism is 100% efficient. Does that make any sense at all? If not then where might we find reference that tells us otherwise so we can examine that if possible?
In the real world we have resistance mostly no mater what. So all those losses, voltage drops no matter how tiny would definitely affect the efficiency of that mechanism to be less than 100% efficient, thus there could not be a 100% impediment to the input and the inductor would now work as we know them.
Mags
See, something MH said bothered me a bit. He said that a resistance of .000001ohm, 1uohm was virtually seemless to being an ideal inductor. Would you agree with that statement? Not trying to pit you against him. But it would be nice if that statement were to be considered true by you or not and give us your understanding as to why your answer is what it is.
I say it is very far from seamless, pretend world or not. It was said by Carl Segan that if we cut an apple pie in half, then cut 1 half in half, then cut 1/4 in half, and keep going, I think the number was about 70 or 90 cuts to get to a single atom. It was less than 100 cuts. But we could go further and further, somehow. When does it end? So the '1uohm is seamless with an ideal component' is not an accurate statement and we cannot accept that as fact here. .5uohm has half the resistance of his idealized 1uohm. What about .001uohm? .001 pico ohm? .000000001pico ohm? So I think that should be resolved on that seamless bit. It is not a good representation, of which happens quite often.
Mags
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See, something MH said bothered me a bit. He said that a resistance of .000001ohm, 1uohm was virtually seemless to being an ideal inductor. Would you agree with that statement? Not trying to pit you against him. But it would be nice if that statement were to be considered true by you or not and give us your understanding as to why your answer is what it is.
I say it is very far from seamless, pretend world or not. It was said by Carl Segan that if we cut an apple pie in half, then cut 1 half in half, then cut 1/4 in half, and keep going, I think the number was about 70 or 90 cuts to get to a single atom. It was less than 100 cuts. But we could go further and further, somehow. When does it end? So the '1uohm is seamless with an ideal component' is not an accurate statement and we cannot accept that as fact here. .5uohm has half the resistance of his idealized 1uohm. What about .001uohm? .001 pico ohm? .000000001pico ohm? So I think that should be resolved on that seamless bit. It is not a good representation, of which happens quite often.
Mags
Cut that 1uohm in half, 90 times. Are we done yet? Are we on the verge of an ideal component with zero losses yet?
Mags
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I agree with you on the no current flow at t/0 of an ideal inductor.
But I dont think that if we're to study the ideals if an ideal inductor that we should ignore the mechanism that makes it do what it does. If resistance is zero, and no losses, then that underlying ideal inductor mechanism should be lossless and 100% efficient also. And if that mechanism is lossless then the the inductor should continuously impede an emf presented at the input. ;) PW says that a straight wire has inductance, and I agree, no matter how tiny the inductance is. So it may be that the ideal straight wire may not be able to pass current if the inductance mechanism is 100% efficient. Does that make any sense at all? If not then where might we find reference that tells us otherwise so we can examine that if possible?
In the real world we have resistance mostly no matter what. So all those losses, voltage drops no matter how tiny would definitely affect the efficiency of that mechanism to be less than 100% efficient, thus there could not be a 100% impediment to the input and the inductor would now work as we know them.
Mags
Mags,
I am not the one you asked for an answer on this but I will go ahead and offer my opinion. It appears from your comment highlighted above, you assume that if an inductance is 100% efficient, it will not allow any current to flow. At 100% efficiency, the emf is totally cancelled by the cemf thus resulting in zero current flow or infinite inductance. It must have even the smallest amount of resistance to perform like a real inductor.
When we apply the formula delta I = E*t/L or rearrange the formula to solve for inductance of emf, we assume ideal conditions such as an ideal inductance. The answer we get from using this formula on an inductance with resistance is very close to what we would measure on the bench. The less dc resistance the coil has, the closer the answer is. From this we can deduce that an ideal 5h inductance is just that, 5h with no impediment from any resistance.
partzman
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Mags,
I am not the one you asked for an answer on this but I will go ahead and offer my opinion. It appears from your comment highlighted above, you assume that if an inductance is 100% efficient, it will not allow any current to flow. At 100% efficiency, the emf is totally cancelled by the cemf thus resulting in zero current flow or infinite inductance. It must have even the smallest amount of resistance to perform like a real inductor.
When we apply the formula delta I = E*t/L or rearrange the formula to solve for inductance of emf, we assume ideal conditions such as an ideal inductance. The answer we get from using this formula on an inductance with resistance is very close to what we would measure on the bench. The less dc resistance the coil has, the closer the answer is. From this we can deduce that an ideal 5h inductance is just that, 5h with no impediment from any resistance.
partzman
Yes you do understand my point. Thanks.
As for the rest of it, how can we deduce that the CEMF that counters the input isnt equal to the input? Maybe there is something a miss here. Why isnt the cemf ideal also when it comes to the ideal inductor? Where is the calculation of some loss that keeps the cemf lower than the input?
Again, the sim says what the sim says. Look at the graph again and expand that time out for hours or even days. There will always be a curve in the real world no matter the level of resistance. Who is to say that with absolute zero resistance that the mechanism that is at work in the inductor that impedes the input still has some sort of loss in order for it to be that the cemf is not equaled to the input applied, all of the time? How does that formula account for that? This is the question. ;) Maybe that possibility is ignored some how? Like how would we know for sure without actual hands on testing of such a device? Yet we talk about it as if it is just standard thinking without going any deeper. Just think a little deeper. How deep can we see beyond just some formula dropped on us and think thats all we need to know?
Mags
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You are dealing with the same problems in understanding, and the same "rules" that are seemingly made up on the fly using incorrect logic, and the same lack of understanding in how an inductor actually works.
When you connect a real or ideal voltage source to a real or an ideal inductor, or to a resistor, then the EMF imposed on any of those three devices results in a CEMF in the device that is always equal and opposite to the EMF.
The idea that the CEMF must be a bit lower than the EMF for current to flow is 100% wrong, it's a "rule" that has been made up because it "sounds right."
The resistor responds to the EMF with a resultant current flow and that power is burnt off as heat.
The real or ideal inductor responds to the EMF with a resultant current flow and that power is stored in the magnetic field and if there is a resistance then a small amount of that power is burned off as heat.
Why does the inductor do what it does? Why does the shopping cart move when you push on it? Read about an inductor and understand its dynamic response to changing voltage conditions. This is a device whose response is determined by differential and integral equations. Learn intuitively how an inductor responds and learn and understand the equations that back up the intuitive understanding of how the inductor responds. A shopping cart's response is intuitive, you have to get to the point where the inductor's response is intuitive.
I will repeat that this notion that "if the CEMF is the same as the EMF then current will not flow" is a fallacy. It does not apply to a resistor, and it does not apply to an inductor.
What about a capacitor? If the CEMF from the capacitor is the same as the EMF applied to it, does any current flow? The answer is no, there is no current flow. The capacitor is simply not the same as the resistor or the inductor. That's just the way it is and if you want to understand electronics then you have to understand these things.
What about "ideal CEMF?"
You guys define "ideal CEMF" first, and then perhaps we can discuss it. What does that actually mean? Or is that just a meaningless term that has been made up on the fly? Lay your cards on the table about this "ideal CEMF" business.
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Who is to say that with absolute zero resistance that the mechanism that is at work in the inductor that impedes the input still has some sort of loss in order for it to be that the cemf is not equaled to the input applied, all of the time? How does that formula account for that? This is the question. ;)
Mags
That's a fair enough question. Let's see if we can logically work out an answer. Obviously the formula(s) don't seem to supply a suitable answer because they assume ideal components. So, maybe we can look at one factor that determines the inductance L of a real air coil for example. This would be the geometry of the coil such as turns, spacing, length of winding and diameter of windings. Apart from any outside influence, this geometry would determine the effect of the self induced emf or cemf produced by the time rate change of current or dI/dt on the applied emf which is basically the inductance of the coil. If we now reduce the resistance of the coil windings to zero, we still maintain the same geometry. So are we to say that the laws of induction due to this particular geometry are going to change because of zero resistance? Or will this example coil become an ideal inductor with pure inductance as determined by it's geometry?
Regarding simulation of an ideal inductor, our current limited versions only offer us the ability to compare a reasonable resistance to a very small resistance. I was able to get LtSpice to simulate the 5H inductor with a dcr of 1e-320 without blowing up. The point of this is, the current slope is straighter or has less droop over time with every decrease in dcr. So, could we assume that a trend is established that says if we continue to decrease the dcr to zero, we will experience an infinite straight current line with a perfect dI/dt representing the ideal inductance?
partzman
Edit
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MH, ;)
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Working on my bike. The quick release lever shaft broke and the nut to nut fasteners on one end of the axle came loose and tightened the axle solid. Couldnt even push it back as the threads of the axle were digging into the axle holder slots. Was on my way back from the beach to get a little sun and see the beautiful women in bikinis everywhere. Then tragedy. About 3 miles from my shop or home. Some guys in a truck offered me a ride. ;D So now I am in fix the bike mode.
The bike is electric. About 80lb. So walking it back was a hard option without the wheel working in any way that it should.
I looked over what both of you posted. Ill go over it again after. Thanks for the explanations. That is all Ive been asking for. Lets see if it all fits.
Back later.
Mags
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There is no paradox, and verpies is wrong because the inductor does not represent a short the moment it is connected to something, even an ideal voltage source.
Indeed I would be wrong if I wrote this about an inductor connected to a voltage source as in Fig.2 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157668/) , but I was writing about the circuit stipulated by Tinman, which is the circuit depicted in Fig.3 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157668/).
The latter circuit is equivalent to the diametrically connected (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157670/) toroidal inductor that MH invented as an example and was analyzing in collaboration with me.
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Verpies: I suggest that you step it down a notch and add some more description at times so your message is more readily understood by both the "ordinaries" and the "gurus."
I don't do it deliberately.
I even consider it my failing if I am not understood.
I need detailed feedback so I can adjust my wording. Without it I am blind to such problems.
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See, something MH said bothered me a bit. He said that a resistance of .000001ohm, 1uohm was virtually seemless to being an ideal inductor. Would you agree with that statement? Not trying to pit you against him. But it would be nice if that statement were to be considered true by you or not and give us your understanding as to why your answer is what it is.
You can not really go by the absolute resistance alone to intuit if that will make the inductor act close to "ideal" or not. It really comes down to the ratio of the inductance to resistance, i.e. tau.
Yes, I would agree that 1u Ohm with 5H is sufficient to get good results when compared to an ideal inductor.
Let's explore if tau could be a good indicator of what inductance to resistance ratio is acceptable as an "ideal" inductor for our particular application. So let's look at MH's example, and use 1u Ohm as the inductor's series resistance: 5H/1u = 5Ms. That's a little less than 3/4 of a year. That is a ratio of 5M. Maybe this is excessive? We can also do some tests to see what might be reasonable: With R=10m Ohm, the end current after 3s is 2.389A, which is pretty close to 2.4. The L/R ratio for this case is 500. So we could establish this as a minimum ratio to achieve near-ideal results. If your L/R ratio is 500 or greater, you will achieve very close to ideal results.
Another example: if your inductance is 100mH, then you can have a maximum of 200u Ohm before it won't be so close to ideal when using the previous ratio of 500:1.
For interest sake, let's see how far we would be off with a ratio of 100:1. So with L=5H, that would be 50m Ohm. That gives us an average current of 2.34A, so the error is 2.5% or so? What is your desired tolerance? If 5% is acceptable, then perhaps we could go to a ratio of 50:1. Let's see: L=5H, R=100m Ohm. This gives us an average current of 2.28A, which is about a 2.28, exactly 5% error. If that is close enough, then we need only ensure a 50:1 L/R ratio to get results within 5% of ideal.
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Indeed I would be wrong if I wrote this about an inductor connected to a voltage source as in Fig.2 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157668/) , but I was writing about the circuit stipulated by Tinman, which is the circuit depicted in Fig.3 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157668/).
The latter circuit is equivalent to the diametrically connected (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157670/) toroidal inductor that MH invented as an example and was analyzing in collaboration with me.
Figure 3 is essentially nonsense, and does not aid in the understanding of the problem at hand.
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I agree with you on the no current flow at t/0 of an ideal inductor.
So do I and I even came to the same conclusion in a step-by-step analysis of a resistive inductor here (http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692).
If resistance is zero, and no losses, then that underlying ideal inductor mechanism should be lossless and 100% efficient also. And if that mechanism is lossless then the the inductor should continuously impede an emf presented at the input. ;)
That's a reasonable thinking but note that constant and continuous impediment does not mean complete impediment. The lack of complete impediment means that the current is not frozen and can increase with time.
That's why when an ideal voltage source is suddenly inserted into an ideal but finite deenergized inductor (as in Fig.2 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/dlattach/attach/157668/)), the current through the inductor increases linearly from zero to infinite current in infinite time - not instantaneously.
PW says that a straight wire has inductance, and I agree, no matter how tiny the inductance is.
I agree with that too.
So it may be that the ideal straight wire may not be able to pass current if the inductance mechanism is 100% efficient.
but when this wire shares the inductor's flux and when the coupling coefficient (k) approaches unity, then this wire, and its inductance, becomes a part of the inductor and closes/completes it losslessly.
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It appears from your comment highlighted above, you assume that if an inductance is 100% efficient, it will not allow any current to flow.
His comment referred to current at t0 only.
He never wrote that the current will be zero at t1.
The current will be totally impeded at all times (including t1), only if the ideal inductor has infinite inductance.
An ideal inductor must have zero resistance but it does not need to have an infinite inductance (nor infinite reactance).
At 100% efficiency, the emf is totally cancelled by the cemf thus resulting in zero current flow or infinite inductance. It must have even the smallest amount of resistance to perform like a real inductor.
No, an inductor does not need any resistance to perform its magic. Ideal inductors impede current flow due to their reactance, not due to their resistance.
Also, efficiency is inversely proportional to the square of the resistance because only resistance irreversibly converts energy to heat. Inductive reactance does not irreversibly convert energy to heat - it converts it to magnetic field. That conversion is lossless and reversible.
When we apply the formula delta I = E*t/L
The proper formula for current in a series RL circuit stimulated by a positive voltage step is:
i(t)= (V/R)*( 1-e^(-t*R/L) )
If you take it to the limit R-->0. then you get a linear current increase. (from zero if the inductor was not already energized at t0)
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Why isnt the CEMF ideal also when it comes to the ideal inductor?
Because the CEMF is a function of reactance, not of resistance.
An ideal inductor must have zero resistance but it does not need to have an infinite inductance (nor infinite reactance).
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His comment referred to current at t0 only.
He never wrote that the current will be zero at t1.
Mags agreed that I was correct with my assumptions so he will have to confirm what he really meant.
[/quote]
The current will be totally impeded at all times (including t1), only if the ideal inductor has infinite inductance.
An ideal inductor must have zero resistance but it does not need to have an infinite inductance (nor infinite reactance).
No, an inductor does not need any resistance to perform its magic. Ideal inductors impede current flow due to their reactance, not due to their resistance.
[/quote]
Yes I am fully aware of this. Let me make it clear that all of my first paragraph is stating what I assume Mags believes at this point in time and is not what I hold to believe. I apologize for my wording being confusing.
[/quote]
Also, efficiency is inversely proportional to the square of the resistance because only resistance irreversibly converts energy to heat. Inductive reactance does not irreversibly convert energy to heat - it converts it to magnetic field. That conversion is lossless and reversible.
The proper formula for current in a series RL circuit stimulated by a positive voltage step is:
i(t)= (V/R)*( 1-e^(-t*R/L) )
[/quote]
Yes I agree but my reason for using the formula as stated is because no resistance is included so therefore it is assuming an ideal inductor which was my point.
[/quote]
If you take it to the limit R-->0. then you get a linear current increase. (from zero if the inductor was not already energized at t0)
[/quote]
Yes I again agree.
partzman
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I was agreeing with this as far as the wire resistance of a normal inductor being in series with the inductor, but when you got to the point where you stated "that entire circuit is closed by an ideal wire just like with an ideal inductor devoid of resistance" you lost me.
Are you referring to some circuit in particular or are you stating that the equivalent model for every inductor includes a short circuit across its terminals?
The model for a normal inductor has the wire resistance in series with the inductor. The model for an ideal inductor removes that series resistor (or places its value at zero). There is no short circuit across either inductor.
PW
Is this not the model below?
Regarding MHs question,will there not be an alternating current flow?
If we take into account that MH thinks DC means a steady state flow of current in one direction,then we would have to use the AC model to satisfy MH :D
Brad
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Now there is your paradox Brad.
When you place an ideal voltage source across an ideal short, who wins? The voltage source or the ideal wire? verpies seems to indicate that the voltage source wins, as the voltage holds and the inductor still gets some current.
What you would get is a big explosion -the unstoppable force meets the unmovable object.
If there is a dead short across the ideal voltage supply,the current would simply build in the ideal voltage supply until either the short exploded,or the ideal voltage supply exploded. This would depend on which one of the two could contain the most energy before it failed-->or they(the shorted ideal wire and ideal voltage source) would continue to store the energy for an infinite time.
Brad
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You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts. Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts. Then after that the voltage is zero volts.
What happens from T=0 when the ideal voltage is connected to the ideal coil?.
After reading all of what has been posted from everyone here-->
At T=5 seconds,MHs device explodes.
Brad
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If we take into account that MH thinks DC means a steady state flow of current in one direction,then we would have to use the AC model to satisfy MH :D
Brad
I don't really think that you want to act like a little imp with respect to me when it comes to this discussion. I assure you that people that understand inductors knew exactly what I meant by saying "there is no voltage across an ideal inductor inductor with DC current flowing through it." I did not have to say "constant DC." You are the person that shockingly mixed up "constant DC" and "changing DC" and you used that ignorance in a vain attempt to "set me up" and it totally backfired on you to an extreme level.
An ideal voltage source does not "contain energy" and likewise an ideal short does not "contain energy." You still need to work on that angle.
No "little imp" please. Try to answer the question, that's your real goal.
MileHigh
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Why is that Brad?
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I don't really think that you want to act like a little imp with respect to me when it comes to this discussion. I assure you that people that understand inductors knew exactly what I meant by saying "there is no voltage across an ideal inductor inductor with DC current flowing through it." I did not have to say "constant DC." You are the person that shockingly mixed up "constant DC" and "changing DC" and you used that ignorance in a vain attempt to "set me up" and it totally backfired on you to an extreme level.
No "little imp" please. Try to answer the question, that's your real goal.
MileHigh
An ideal voltage source does not "contain energy" and likewise an ideal short does not "contain energy." You still need to work on that angle.
When we are talking about your circuit MH,then while your voltage value from your ideal voltage source is 0v,then yes,the ideal inductor dose contain/store energy,and that energy can be recovered when the shorted(looped) ideal inductor becomes open.
Regarding the DC current flow thing,it was you that told me to be specific when defining terms,when those terms have multiple meanings--such as a DC current dose.
Get off your ass,and stop being lazy,and be specific as you have told me to be--for those less in the know,as you described.
Brad
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Why is that Brad?
Very simple Poynt.
As we have agreed on,while the ideal voltage source has a value of 0 volts,the current will continue to flow through this ideal inductor loop.
At T=5 seconds,the voltage source wants to instantly reverse that current flow direction.
So we have an ideal 5 Henry coil,with current flowing in say a CW direction around the loop.
At T= 5 seconds,the coil is instantly supplied negative 3 volts from an ideal voltage source.
At that instant,you have to infinite current values trying to flow in opposite directions.
Lets use MHs water flow in pipes analogy.
We have water flowing through a pipe at a set rate. We then try to change that flow of water to the opposite direction in an instant. The instantaneous pressure would be infinite if nothing gave out--but something will.
Here in this situation that is !ideal!,and no energy can be dissipated either by the ideal inductor,or the ideal voltage source,you have to wonder what will happen at the instant of the collision of the two meeting apposing current flows.
In order for the current to stop flowing,it must be dissipated into a load-one that can dissipate the energy of that current flow. Normally this can be done just through the resistance of the winding wire it self,but here we have ideal wire that cannot do this.
So at T=5 second's,something has got to give.
Brad
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At T=0,the ideal voltage source is placed across the ideal inductor.
At T=3s,the current flowing through that inductor/ideal voltage source loop will be 2.4 amps.
From T=3s to T=5s(the 0 volt phase),the current flowing through that ideal loop will remain at 2.4 amps.
At T=5s,the ideal voltage source(being one that will supply 3 volts across a load,no matter what the load)wants to supply a voltage that will cause a current that apposes that which is already flowing through the ideal inductor/voltage source loop.
Being that both the inductor and voltage source is ideal,the energy stored in the ideal loop from T=3s to T=5s cannot be dissipated in order for a current to start flowing in the opposite direction,and the ideal voltage source says that it will supply 3 volts in opposition to the present current flow no matter what .
At T=5s,MHs circuit explodes.
Brad
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@tinman
I did this one in 2013.
https://www.youtube.com/watch?v=iAeoktG6hkg
Could say more but.
wattsup
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At T=5s,MHs circuit explodes.
Well, the circuit doesn't explode. So think it through some more and try to come up with a better answer or perhaps someone else will chime in.
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Well, the circuit doesn't explode. So think it through some more and try to come up with a better answer or perhaps someone else will chime in.
Oh,of course MH.
The MH paradox kicks in,and the stored energy before T=5s,just disappears(it has to,as there is nothing in the circuit that can dissipate this energy),so as the ideal voltage source can now induce a reversed state of energy into the inductor loop.
This MH paradox is truly fantastic---it makes everything work just the way you want it to.
Throw out resistance,throw out time constant's,make DC mean what ever you want it to mean--who needs all that crap when you have the MH paradox-->you bloody ripper :D
Brad
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Oh,of course MH.
The MH paradox kicks in,and the stored energy before T=5s,just disappears(it has to,as there is nothing in the circuit that can dissipate this energy),so as the ideal voltage source can now induce a reversed state of energy into the inductor loop.
This MH paradox is truly fantastic---it makes everything work just the way you want it to.
Throw out resistance,throw out time constant's,make DC mean what ever you want it to mean--who needs all that crap when you have the MH paradox-->you bloody ripper :D
Brad
You have to think Plan B because Plan A is a no-go.
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You have to think Plan B because Plan A is a no-go.
Ok,i will give it some more thought.
Brad
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Ok,i will give it some more thought.
Brad
No
No matter how i try and find a way for the stored energy to be dissipated before the opposite potential of that stored energy is released into the system,there is just no where for it to go.
Even using your flywheel analogy MH,it would mean the the flywheel would have to be stopped instantly,and sent spinning in the opposite direction. If there is no where to burn off(dissipate)that stored energy in the spinning flywheel,then the flywheel cannot be stopped-but were going to do that anyway with the ideal voltage source.
The homopolar motor would be a very close representation of this situation.
You place a voltage across the round magnet,and the magnet starts spinning in one direction. You remove the voltage ,and the magnet will keep spinning due to inertia/energy stored within that spinning mass. We then swap the voltage polarity over,and apply it to that spinning magnet,and now the magnet wants to spin the other way. The spinning magnet now becomes a generator that is producing a current flow opposite to that of the now inverted voltage. As we know,at this point in time,we will now have a very high current value between the spinning magnet,and the voltage source,and a lot of heat will be produced because of this. In this case,the energy stored in the spinning magnet is dissipated as heat,and the magnet will slow to a stop,and start spinning the other way. But in the ideal case,there is no resistance,and there for no way to dissipate the stored energy as heat. One current source want to go one way,and the other current source want the current to start flowing the other way. The result is an extreme instant current between the stored energy and the ideal voltage source.
I can see no where in the ideal circuit,where the stored energy can be dissipated,and it cant be stored within the system,as it is the opposite to that of what the ideal voltage source wishes to place in the system.
Brad
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Hi Tinman, "I can see no where in the ideal circuit,where the stored energy can be dissipated,and it cant be stored within the system,as it is the opposite to that of what the ideal voltage source wishes to place in the system."
Maybe ,and is what I think is, that all systems do store opposites at the same time occupying the same space.
artv
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Hi Tinman, "I can see no where in the ideal circuit,where the stored energy can be dissipated,and it cant be stored within the system,as it is the opposite to that of what the ideal voltage source wishes to place in the system."
Maybe ,and is what I think is, that all systems do store opposites at the same time occupying the same space.
artv
To put it simple,the flywheel cannot spin CW and CCW at the same time.
The energy is stored as a magnetic field in this case,and the magnetic field must decline to a 0 value before the opposite field can be induced. The only way the original magnetic field can collapse,is if the energy stored in that field has some where to go,or can be dissipated. As it has no where to go,due to it being in a closed loop,and there is no way of dissipating it's stored energy,due to there being no resistance in the loop,then it must remain.
Brad
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Not trying to get into a debate, not trying to learn anything or teach anyone anything. These are my opinions, they do not require the approval anyone reading this.
A flywheel cannot spin in two directions at once, however, one can spin two in opposite directions at the same time and arrange them in a manner which will allow them to constructively or destructively influence one another.
In my opinion its not wise to compare flywheel energy storage with magnetic energy storage, there are many reasons for this, for the sake of this post I only refer to two or three. The speed at which a magnetic energy storage can be charged and discharged is orders of magnitude faster than a flywheel energy storage is able to charge and discharge. The reactive cross section of the magnetic energy storage can be manipulated on the fly where as the flywheel energy storage cannot. There's the issue with the magnetic field of a magnetic energy storage system inverting when the current responsible for its manifestation is removed.
I don't need anyone to tell me what I can and more than likely have read over and over again on my own. What I have read, what we've all read, cannot explain what I am seeing on the bench, so please save the lessons in electronics, and "accepted" component behavior I am not interested. Please don't take this the wrong way, I am simply growing tired of coming here and seeing nothing but this game of who has the biggest pair. It should be clear by now that the guy with the biggest pair is the one who was kicked the hardest.
Fact is....we are all looking for something, most are looking for the same thing, it's clear from a casual review of the various topics that no one here has it, all the more reason to work together and not waste time nit picking bullshit. Stop trying to teach and correct each other, it's not working, its counter productive. If we work together and find it, but don't know what we have because we don't know what we are looking at....BIG DEAL, we will loose it, let them loose it! We will be forced to retrace our steps, and this second, third or 100th time around we will be mindful, motivated in by the fact that we did it, but lost it, and also motivated by the whispers of "I told you so....I told you so..."
Regards
The potential which is induced by an expanding magnetic field (magnetic energy storage being charged) is not the same polarity as the potential which is induced by a collapsing magnetic field (magnetic energy storage being discharged). This latter bit is difficult pill for some to digest, I take comfort in Faraday's law, from it one is informed of the polarity of the inducing field via the polarity of the EMF it induces.
Well as we are not talking about an EMF,then i dont know what your post is about?.
We are talking current flow,and the direction of the current flow that created the magnetic field will continue to be the same when that field collapses. The circuit is a closed ideal loop,and so there is no open circuit for an EMF to be produced.
When we close the switch on the circuit which includes an inductor "something" is motivated to move in a very specific manner through and about that circuit. Whatever this "something" is, it tends to want to continue in this very same direction after the circuit is opened, whatever this "something" is, its crystal clear (to me) it's not magnetism, the magnetism inverted, that which remains nameless was motivated by the magnetism, it continues to move in the direction dictated by the conditions established when the magnetic energy storage was charging....
Once again,the circuit is never open--it remains a constant loop-an ideal constant loop.
Brad
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Very simple Poynt.
As we have agreed on,while the ideal voltage source has a value of 0 volts,the current will continue to flow through this ideal inductor loop.
At T=5 seconds,the voltage source wants to instantly reverse that current flow direction.
So we have an ideal 5 Henry coil,with current flowing in say a CW direction around the loop.
At T= 5 seconds,the coil is instantly supplied negative 3 volts from an ideal voltage source.
At that instant,you have to infinite current values trying to flow in opposite directions.
Why do you believe the current will be infinite? In your posts following this one, you seem to be on board with the idea that the current after the first 3s is 2.4A, correct?
You also mentioned that at T=5s, the circuit would explode. This is not the case. Does the circuit explode when the circuit connection is first made? I can tell you that the two scenarios are no different, and the inductor simply adjusts for a change in current. In other words, going from 0V to 4V, and the resulting final value of 2.4A, is no different than going from 0V to -3V with a starting current of 2.4A. The circuit current simply begins adjusting/changing as a result of the new voltage.
Have you drawn out the circuit current as I suggested? I suspect not. Here is a hint: at t=0s, the current ramps up linearly to the final value of 2.4A at t=3s. Between t=3 and t=5, the current remains at 2.4A. Now, what do you suppose happens to the current between t=5 and t=7? Between t=7 and t=13? From t=13 onward?
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Brad,
Here is an inverted color version of the graph in case you want to print it out and finish the current plot with a pen a ruler.
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Why do you believe the current will be infinite? In your posts following this one, you seem to be on board with the idea that the current after the first 3s is 2.4A, correct?
You also mentioned that at T=5s, the circuit would explode. This is not the case. Does the circuit explode when the circuit connection is first made? I can tell you that the two scenarios are no different, and the inductor simply adjusts for a change in current. In other words, going from 0V to 4V, and the resulting final value of 2.4A, is no different than going from 0V to -3V with a starting current of 2.4A. The circuit current simply begins adjusting/changing as a result of the new voltage.
Have you drawn out the circuit current as I suggested? I suspect not. Here is a hint: at t=0s, the current ramps up linearly to the final value of 2.4A at t=3s. Between t=3 and t=5, the current remains at 2.4A. Now, what do you suppose happens to the current between t=5 and t=7? Between t=7 and t=13? From t=13 onward?
I do not agree with this. The energy stored in the magnetic field cannot just disappear. That energy has to be dissipated before the opposite magnetic field can be induced--which is what the-3 volts is trying to do. The startup current is dampened by the induction process due to the CEMF. But there is now a steady current flow through the looped inductor,and a magnetic field that is storing energy. The -3 volts is applied,and the current being produced is trying to collapse that already built magnetic field,which cannot be collapsed due to the steady state current that is flowing that keeps it built. In a real world situation,that energy would be dissipated as heat,but as we have an ideal inductor loop,then the energy cannot be dissipated.
Brad.
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The energy in the inductor does not "disappear", some is returned to the source during that period.
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I honestly disagree with the hand-holding at this point. There are others that were interested in this and I suggested they brainstorm. Magluvin may also give it a shot when he comes back.
The big "breakthrough" is apparently Brad now accepts that the current ramps up to 2.4 amps after three seconds. What about the other people that disagreed vehemently about this, what do you have to say?
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I wasn't planning on going much further MH.
There are enough clues now to fully and correctly answer the question, as long as the "infinite current" and "shorted inductor" barriers are no longer in the way.
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I do not agree with this. The energy stored in the magnetic field cannot just disappear. That energy has to be dissipated before the opposite magnetic field can be induced
Yes the energy stored in the magnetic field cannot just disappear but it can be transferred elsewhere without dissipation.
P99's current graph is correct so far.
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Just got to sit and go over it all, and there is more I see.
Have to run out for a while. Life.
Just a quicky....
In an ideal world, Im sure that the windings of the coil would be made to perfection as would be the conductors themselves. Zero flaws. Made in a coil shape, not just bent into shape. Ill go further on that when I get back. Would a single ideal wire allow current to flow? Until I get a grip an all that has been posted since yesterday, Im still looking at the possibility that current wouldnt flow. Just thoughts, not saying you guys are wrong.
Mags
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The energy in the inductor does not "disappear", some is returned to the source during that period.
If the source is ideal,and the voltage is fixed at -3v,then the flow of energy is in opposition to that stored in the inductor loop/magnetic field.
So this energy that is stored cannot return to the source,as the energy from the source is flowing in the wrong direction. This would be like trying to force a water flow through a pump in opposition to the water already flowing out of the pump.
Brad
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There are others that were interested in this and I suggested they brainstorm. Magluvin may also give it a shot when he comes back.
I honestly disagree with the hand-holding at this point.
Lets all be honest here MH.
You would never have stated in your answer(if you gave one),that the current would have continued to flow during the 0 volt portion of your question. You would have depicted a sloped drop of current,and then onto the negative voltage protion of the question.
This is why you never answered your question--you needed others input.
But of course,we will never know,as you did not answer your own question.
The big "breakthrough" is apparently Brad now accepts that the current ramps up to 2.4 amps after three seconds. What about the other people that disagreed vehemently about this, what do you have to say?
No i do not.
I am going through the process using your understanding.
The coil is ideal,and so should be the CEMF.
I am yet to see any reason posted why the CEMF is also not ideal.
Brad
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Something that keeps coming to mind as i think....
When we see the demo of a magnet being suspended above a superconductor, It is said that as we put the magnet in place, I suspect a particular height above the super conductive object, that as the field of the magnet sets up lenz currents in the superconductor that are set in motion indefinitely and it sets up an opposing field against the mags field and it floats. So in that case the lenz field is even stronger than the mags field at float as to hold up the weight of the magnets mass, let alone just be equal to the field of the magnet. So is it not possible that this balancing act could be inherent in the ideal perfect inductor? Still thinking on it all. Which is good I suppose. Have some work to do tonight. Will see what I figure on it all
Mags
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Lets all be honest here MH.
You would never have stated in your answer(if you gave one),that the current would have continued to flow during the 0 volt portion of your question. You would have depicted a sloped drop of current,and then onto the negative voltage protion of the question.
This is why you never answered your question--you needed others input.
But of course,we will never know,as you did not answer your own question.
Brad, you really are being silly with what you said there. I know you and MH don't seem to be getting along well, but he deserves more benefit of doubt than you are affording him here on this electronics question. MH did know the answer to the question, and could easily have plotted out the current trace as I have encouraged you to do, but he wanted you and others to work it through yourselves.
MH's question is thought-provoking and well thought out, although the wording could have been geared more towards the experimenters here rather than the techies. At any rate, I can assure you that MH knew all along exactly how the circuit currents behave, given the input he specified. After all, he is the one that formulated the question.
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If the source is ideal,and the voltage is fixed at -3v,then the flow of energy is in opposition to that stored in the inductor loop/magnetic field.
So this energy that is stored cannot return to the source,as the energy from the source is flowing in the wrong direction.
Sounds to me like you are agreeing with me.
The source is trying to drive the opposite polarity energy into the inductor. When the source is at -3V, it offers up a place for the inductor to dump some of its stored energy. Given more time at -3V, the inductor would fully lose its "positive" energy, and begin to energize in the "negative" direction.
Since it isn't long enough for that to occur, the energy in the inductor simply decreases to a lower "positive" level, and there is only one place for that lost energy to go. You can even see it in the sim.
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Had a thought while drilling holes for this sub box that I wanted to bring up.
While thinking about a physical ideal inductor, I visualized current through the conductors. If the conductor were very small, very fine wire, would there be a limit to how much 'current' by definition could flow through that ideal wire? Make the wire half the dia. Any limits there? Cut the dia in half again. Any limits? Lets think that there may be limits in the superconductive ideal conductors. Like if we kept increasing current, would there end up being some of it in skin effect?
If we have enough current through a given short piece of wire that ALL the electrons of the conductor(the ones that can)are in motion(Bill says they move at the same speed when they move, and I agree) with the direction of current. All moving in sync. Can more electrons be packed in to consider having more current flow than full up flow?
Just something to think on. You guys may not find these things as interesting possibilities. Maybe some of you do. Along side of what you may think are crazy, loony thoughts, well we are talking artificial, pretend environments. Im just looking at possible details that may alter what we can think when it comes to the legitimacy of the ideal world components. because we are taking them pretty seriously here, sooo. Example. If the ideal cap follows every capacitor rule except for resistance and inductance, then we could not design a perfect inductor in that environment. And likewise the other way around..
Anyway.. back to making holes. Its a bass reflex box using 2 Kicker 15" for my boss's daughter. Tuned at 30hz.
Mags
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@tinman
I put that video here to show what happens when any factor goes above the physical limits of the wire.
The only thing about ideal voltage is that it will not sag like if an ideal car battery is shorted, the voltage will not drop for a few seconds, it will stay at 12 volts and in the case of my video and the copper wire would have popped immediately and not after a few seconds.
But I'll play the game in my OU logic terms....... the math I will leave to others.
Ideal voltage holds the voltage steady while the current CAN rise to infinity, but only if infinity is called for by the inductor. So for current infinity to happen, the inductor would also need to be infinite in either or both wire length or thickness and with or without the resistance the ideal voltage would not care.
But here you have a great disconnect in the logic because current from the ideal voltage that could rise to infinity is now countermanded by an ideal inductor that has no resistance but has an inductance limit to 5H. So the two limiting factors are 4 volts with as much current as required and 5H with no resistance. Figure also that coil impedance will be minimal because most wires have resistance and little reactance to start with so if there is no resistance then only the reactance = impedance = peanuts.
Since the ideal voltage is ideal, it cannot vary but like any DC source, you can add to it, in or out of phase will not matter, but again because its ideal you cannot subtract from it having any less on those two ideal power terminals. Given this is ideal DC, the positive terminal will always be 4 volts (p4) and the negative terminal will always be 0 volts (n0).
During the exercise when you get to the zero volts reading this does not mean there is zero across the inductor since the voltmeter is also a differential reading it just sees the same voltage on each side of the inductor as would a scope that would then produce a flat line. If it shows zero with an ideal voltage, then you have to have a combination present at the two terminals like p4/n4 or add 1 from the inductor to p4 to get p5 the inductor would then have to add 5 to the n0 would mean you have p5/n5 which is still zero. At the -3 volts reading the p4 and n0 still cannot change but the inductor can add a -7 to the n side so you can have p4/-n7 and show -3 on the voltmeter. This does not mean the ideal voltage is dropping in voltage but that since it is DC, you can add to it with a positive or a negative value and your volt meter will see this change at the terminals but again it does not imply the ideal voltage changed.
A debate could be had here in terms of can an ideal voltage which also has zero resistance can also receive return voltage from the inductor as I had read here someone implying that at the -3 mark, power is being returned to the voltage source. If that's just another "acceptance" to be able to play the game then OK but I would think not since the ideal part of the voltage should prohibit this. Besides, take a 9 volt and 12 volts battery and connect them in parallel and what do you get. This does not mean the 12 volt battery is feeding anything to the 9 volts battery. This just means you will see 21 volts on your volt meter.
What all parties, especially @MH and company need to understand is that when you ask a question literally, it is taken literally. When you say ideal voltage, then indicate 4 volts, there is no turning back from that. Regardless if the voltage has zero resistance or 300% resistance or any other other factor you wish to equate, that ideal voltage is ideal for only one reason, to stay stable, unchanging, otherwise you just need to call it a standard DC power supply (PS) and then we could have all gone home a long time ago. If it was a regular PS we all know we can adjust the voltage where we want and the current will fix itself as per the inductive requirement. A regular PS is not an ideal voltage because depending on what you run with such a PS, yes you can see on the instrument voltage and current meters that voltage and current will vary with the pulsing or relaxation or inductive kick back that the DUT provides. But as an ideal voltage source that is not the case. Being ideal, one should consider there is a little Jennie inside the power source that magically holds the applied voltage steady under all circumstances. Come hell or high water she shall not flinch.
So to start you need to calculate the first 3 seconds of 4 volts hitting a 5H inductor that measures 4 volts after three seconds. These guys already calculated it to arrive at 2.4 amps of current in the coil. What voltage will that produce in the inductor? Take that apply it to your p4/n0 and go from there.
Anyways I am sure if I asked 1000 students who just graduated from university how they perceived the ideal voltage ideal inductor question, the grand majority will answer "Don't really know, I just faked it and passed". hahahahahaha
But let me make at least one thing very clear with all of you. Regardless of what each holds as truth to a fictitious ideal question, do not have the slightest presumption that this explains how a coil works. This will not tell you how a coil works, it only gives you a presently accepted and measured depiction of how a coil responds. This is far from knowing how it works and for me as an OUer looking to develop a better understanding of the logic behind how a coil actually WORKs, all EE discourse becomes purely presumptive. Now once you have all eaten all this ideal stuff and have washed the dishes and cleaned up the kitchen and then if you really want hard questions of logic, let me know. I have a case full that could keep you busy for a few years. One of them was the last question I asked here but again, better you wait till the kitchen is cleaned.
Went on long enough. As usual, sorry for long post. I even cut it down to half. hahaha
wattsup
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Besides, take a 9 volt and 12 volts battery and connect them in parallel and what do you get.
Very high current. Equivalent to a 3V shorted battery.
However the same does not apply to a 9V battery inserted into an ideal inductor, because the inductor is not a voltage source - it is a current source.
The internal impedance of an ideal current source is infinite, while the internal impedance of an ideal voltage source is zero.
That's why a current source connected to a voltage source does not result in any infinities.
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MH did know the answer to the question, and could easily have plotted out the current trace as I have encouraged you to do, but he wanted you and others to work it through yourselves.
MH's question is thought-provoking and well thought out, although the wording could have been geared more towards the experimenters here rather than the techies. At any rate, I can assure you that MH knew all along exactly how the circuit currents behave, given the input he specified. After all, he is the one that formulated the question.
Brad, you really are being silly with what you said there. I know you and MH don't seem to be getting along well, but he deserves more benefit of doubt than you are affording him here on this electronics question.
You mean like the benefit of doubt that he gave me regarding the ICE having resonant systems?. Guessed you missed all that. This is the very same situation. He told me i had no idea what i was talking about,when Internal combustion engines are my forte--my area of expertise.
The difference is,i backed up my knowledge with provided fact's,and this is something no one here can do with an actual test,as we are talking about ideals we do not have. What we are doing is placing a theory based around !best guesses!.
So i have given MH no more than he has given me,and in fact,i have never used the foul language he has toward me.
Not once did i see you,or any other EE guy here tell MH to calm it down when the roll was reversed,but i see you are quick to jump on me when i do the same that has been done to me.
I have seen this very same thing with other members that disagree with MHs analogy.
It's an !agree with me! or your wrong attitude MH has--plane and simple.
As i said in the other thread,i will now treat him as he treats me.
As i said,there is a pattern that is followed on this forum,and that is the EE guys stick together--bar one,that being (as i have always said) verpies. I would also put vortex1 in there with verpies,but he dosnt frequent this forum much-sadly.
As verpies said in reply to this question,Quote : The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
verpies-Just because most of the world does it wrong does not mean that we have to.
Brad
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Sounds to me like you are agreeing with me.
The source is trying to drive the opposite polarity energy into the inductor. When the source is at -3V, it offers up a place for the inductor to dump some of its stored energy. Given more time at -3V, the inductor would fully lose its "positive" energy, and begin to energize in the "negative" direction.
Since it isn't long enough for that to occur, the energy in the inductor simply decreases to a lower "positive" level, and there is only one place for that lost energy to go. You can even see it in the sim.
Well this is how i see it Poynt.
We have a loop of water pipe that represents our ideal inductor loop. In that loop of water pipe we have a pump. Our pump is our voltage source,and the water in that pipe is our current. We start the pump,and this puts pressure(our voltage) on the water(our current) the water starts to flow around our loop. We have a bypass valve in the pump,so as when we switch the pump off(0 volts),the water can still flow in the direction it was(our current is now flowing with the pump off). While the water is flowing,we start the pump up so as it spins in the opposite direction. The pump(our now reversed voltage) wants to now push the water in the opposite direction to that of which it is already flowing. The energy in the moving water is not added to,or stored in the pump--it is working against the pump,and the pump will draw more current to stop the flow of water that is flowing in the wrong direction, before it can start to move the water(current) in the right direction to that of what the pump wants to move it in.
That is how i see it.
Brad
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@Tinman
That's a mechanical/hydraulic analogy. This type of mechanical thinking is a long lost skill among physicists and will lead you to the correct results but the analogy must be precise. Unfortunately yours is not precise enough.
We have a loop of water pipe that represents our ideal inductor loop. In that loop of water pipe we have a pump.
Let's make it a positive displacement pump- like a Lobe Pump.
I chose the Lobe Pump for this analogy because in such pump, the direction and speed of the impeller has 1:1 correspondence to the direction and speed of the water current.
Our pump is our voltage source and the water in that pipe is our current.
Corrections:
The water in the pipe symbolizes electric charge. The motion of this charge symbolizes electric current.
BTW: The mass/inertia of the water symbolizes inductance.
The force/torque applied to the pump's impeller symbolizes the voltage.
It is important not to conflate the pump with the voltage, because the pump itself is not the force - it is only a mechanism to transfer the force to the water/charge.
We start the pump,and this puts pressure(our voltage) on the water(our current) the water starts to flow around our loop.
Generaly, I agree.
I would write: "...this puts force/pressure on the water causing its acceleration and motion (current)"
We have a bypass valve in the pump,so as when we switch the pump off (0 volts), the water can still flow in the direction it was (our current is now flowing with the pump off).
Yes, the water can flow even when the force (torque) applied to the impeller is zero, but a bypass valve is not necessary for this flow to continue, as e.g. the impeller of a lobe pump will continue to rotate under the current of water already flowing through this pump.
This "bypass valve" is an extraneous component that should have tipped you off, that the analogy is not precise enough.
While the water is flowing,we start the pump up so as it spins in the opposite direction. The pump(our now reversed voltage) wants to now push the water in the opposite direction to that of which it is already flowing.
Here is where you reap the bad fruit of your analogy ;(
Precisely the cause of the conceptual error is in the phrase: "we start the pump up so as it spins in the opposite direction".
The correct phrase should have been: "we apply a torque to the pump's impeller in the opposite direction".
Note, that the application of opposite force/torque to the impeller, does not immediately result in the reversal of the impeller's direction (nor water's direction). I remind you of the 1:1 correspondence between the direction of the impeller and the direction of the water, (their speed also).
I am sure that now you have the tools to complete the rest of the analogy by yourself.
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@Tinman
That's a mechanical/hydraulic analogy. This type of mechanical thinking is a long lost skill among physicists and will lead you to the correct results but the analogy must be precise. Unfortunately yours is not precise enough.
Let's make it a positive displacement pump- like a Lobe Pump.
I chose the Lobe Pump for this analogy because in such pump, the direction and speed of the impeller has 1:1 correspondence to the direction and speed of the water current.
Corrections:
The water in the pipe symbolizes electric charge. The motion of this charge symbolizes electric current.
BTW: The mass/inertia of the water symbolizes inductance.
The force/torque applied to the pump's impeller symbolizes the voltage.
It is important not to conflate the pump with the voltage, because the pump itself is not the force - it is only a mechanism to transfer the force to the water/charge.
Generaly, I agree.
I would write: "...this puts force/pressure on the water causing its acceleration and motion (current)"
This "bypass valve" is an extraneous component that should have tipped you off, that the analogy is not precise enough.
Note that the application of opposite force/torque to the impeller does not immediately result in the reversal of the impeller's direction (nor water's direction). I remind you of the 1:1 correspondence between the direction of the impeller and the direction of the water, (their speed also).
I am sure now you have the tools to complete the rest of the analogy by yourself.
Here is where you reap the bad fruit of your analogy ;)
Precisely the cause of the error is in the phrase "we start the pump up so as it spins in the opposite direction".
The correct phrase should have been: "we apply a torque to the pump's impeller in the opposite direction".
I see no difference in what i said,and what you have stated above.
The motor that drives the positive displacement pump you have used,will still encounter the force of the water moving in the opposite direction to that of the applied torque to the pump.
You have simply separated the pump from the motor. But any force placed upon the pump will be transferred to the motor.
Yes, the water can flow even when the force (torque) applied to the impeller is zero, but a bypass valve is not necessary for this flow to continue, as e.g. the impeller of a lobe pump will continue to rotate under the current of water already flowing through this pump.
As the motion of the pump/motor combo i was using to represent the voltage(our force),then i included the bypass valve to represent no motion of the motor/pump--the equivalent of the 0 volt level in the question. Having the impeller still moving,would be seen as a resistance against the flow of water,and in our ideal loop,we have no resistance to the flow of the current,and so the bypass valve was included for that reason also.
I believe that this is a close representation to what we have,than having the impeller being rotated by the water,resulting in a resistance to that flow of water.
Brad
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Have you had a gander at the Waterloo induction analogy?
J.
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Something that keeps coming to mind as i think....
When we see the demo of a magnet being suspended above a superconductor, It is said that as we put the magnet in place, I suspect a particular height above the super conductive object, that as the field of the magnet sets up lenz currents in the superconductor that are set in motion indefinitely and it sets up an opposing field against the mags field and it floats. So in that case the lenz field is even stronger than the mags field at float as to hold up the weight of the magnets mass, let alone just be equal to the field of the magnet. So is it not possible that this balancing act could be inherent in the ideal perfect inductor? Still thinking on it all. Which is good I suppose. Have some work to do tonight. Will see what I figure on it all
Mags
Mags,
Let me say again that I'm no expert on superconductivity however, I would like to comment on your thoughts above.
In a type I superconductor, all the magnetic flux is outside the superconducting material. If you approach the type I with a magnet, the magnet will be repelled into space because the magnetic field can not penetrate the type I superconductor.
In a type II superconductor however, the levitating magnet is held in place via flux pinning. In a type II superconductor, magnetic flux penetration is possible and it produces quantum current vortexes or tubes. These penetrating flux tubes loop around the magnet and hold it in fixed position above the superconductor. Wikipedia shows a good representation of this plus a good explanation.
partzman
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You mean like the benefit of doubt that he gave me regarding the ICE having resonant systems?. Guessed you missed all that. This is the very same situation. He told me i had no idea what i was talking about,when Internal combustion engines are my forte--my area of expertise.
The difference is,i backed up my knowledge with provided fact's,and this is something no one here can do with an actual test,as we are talking about ideals we do not have. What we are doing is placing a theory based around !best guesses!.
So i have given MH no more than he has given me,and in fact,i have never used the foul language he has toward me.
Not once did i see you,or any other EE guy here tell MH to calm it down when the roll was reversed,but i see you are quick to jump on me when i do the same that has been done to me.
I have seen this very same thing with other members that disagree with MHs analogy.
It's an !agree with me! or your wrong attitude MH has--plane and simple.
As i said in the other thread,i will now treat him as he treats me.
As i said,there is a pattern that is followed on this forum,and that is the EE guys stick together--bar one,that being (as i have always said) verpies. I would also put vortex1 in there with verpies,but he dosnt frequent this forum much-sadly.
As verpies said in reply to this question,Quote : The equivalent circuit model for an ideal inductor is not an inductor with a wire shorting across its ends.
verpies-Just because most of the world does it wrong does not mean that we have to.
Brad
All I will say Brad is that posts like you made inferring that MH did not know the answer to his question are just not good, for you, nor the forum, especially since it is a question having to do with electrical fundamentals.
And you are right, MH is not infallible, nor am I, TK, nor anyone I know on this forum. But you are wrong about the techies always sticking together. We do sometimes disagree, and that is ok. Like you, if I see something that I feel is incorrect or nonsense, I will point it out, regardless of who posted it. And I expect the same of others too, in regards to what I post.
Brad, if anyone can build a 50:1 L/R ratio inductor, I feel it is you. I would encourage you to try to get one together and give this thing a go so you can see for yourself what the circuit current does. For the supply voltages, you could build a 4V and -3V, and 0.5V supply with reasonable ease, and just use a rotary switch to change the voltages manually while monitoring a stop watch. It won't be exactly precise, but close enough to get the gist of what will happen at each transition.
Going with 5H and a 50:1 ratio however would be difficult to achieve without liquid nitrogen cooling I would think, so perhaps the ratio could be reduced and the resulting error taken into account?
What do you say?
Guitar pickups are on the order of 5H, but their R is on the order of 8k Ohms :(
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All I will say Brad is that posts like you made inferring that MH did not know the answer to his question are just not good, for you, nor the forum, especially since it is a question having to do with electrical fundamentals.
The first thing i will say is--have you said the same thing to MH,when he said i did not know what i was talking about and was wrong,when it came to the ICE,which is my speaciality ?
Secondly-can you say without doubt tha MH would have been able to answer the question correctly,without having proof to back it up.
Thirdly- Regardless of any answer being considered to be correct,it is just theory based around real world examples. As we cannot make such an ideal voltage source to test the theory,then it remains just that-a theory. Lust as verpies said--just because th erest of the world dose it wrong,dose not mean we have to.
Brad, if anyone can build a 50:1 L/R ratio inductor, I feel it is you. I would encourage you to try to get one together and give this thing a go so you can see for yourself what the circuit current does. For the supply voltages, you could build a 4V and -3V, and 0.5V supply with reasonable ease, and just use a rotary switch to change the voltages manually while monitoring a stop watch. It won't be exactly precise, but close enough to get the gist of what will happen at each transition.
And there in lies a problem. What about that ideal voltage source,where the current is free to flow during the 0 volt cycle. A rotary switch would mean an open circuit in between contacts,and there go's your current flow.
Why not simulate it Poynt,using the lowest value resistance you can.
We have to remember,it is going to be -3 volt's,not a build up of voltage as the current drop's from 2.8 amp's down to the lower value,the ideal voltage source will place -3 volts across that ideal loop regardless of the current. So lets see if you can get your sim to do that.
Going with 5H and a 50:1 ratio however would be difficult to achieve without liquid nitrogen cooling I would think, so perhaps the ratio could be reduced and the resulting error taken into account?
What do you say?
Guitar pickups are on the order of 5H, but their R is on the order of 8k Ohms :(
Why would it have to be a set value of inductance. Could we not see the effect with any decent inductor?.
Brad
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Have you had a gander at the Waterloo induction analogy?
J.
And as you can see from that very example minnie,that my prediction is correct. The water wheel being the inductor will keep pumping the water against the pump when the direction of the pump is reversed. This works against the pump,it dose not store it's energy in the pump at Poynt said.
Brad
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still reading this but have been wrapped up tinkering hardcore with some stuff someone sent me.
just wanted to leave this here for Mags and Bill. interesting stuff regarding electron movement.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html
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And there in lies a problem. What about that ideal voltage source,where the current is free to flow during the 0 volt cycle. A rotary switch would mean an open circuit in between contacts,and there go's your current flow.
Why not simulate it Poynt,using the lowest value resistance you can.
We have to remember,it is going to be -3 volt's,not a build up of voltage as the current drop's from 2.8 amp's down to the lower value,the ideal voltage source will place -3 volts across that ideal loop regardless of the current. So lets see if you can get your sim to do that.
Why would it have to be a set value of inductance. Could we not see the effect with any decent inductor?.
Brad
Brad,
Trust me when I say that a sim using an ideal voltage source and an inductor with a really, really small resistance will properly demonstrate the point that MH and others are trying to get across. The question is, would you believe it and accept it? To understand this may open up new horizons for you in your quest for OU.
I am not a 'EE' or an 'E' or even an 'e', but I have studied greatly to show myself approved. This is a difficult way to go but one can get an education either formally or informally but we all must be willing to learn. For example, I could raise a rucus here by stating that Distinti's magnetic theory says Maxwell's equations for electromagnetic waves are incomplete. I would guess that the EEs here would/will take issue with this. The point is, we must all be willing to learn.
Poynt or myself could post a sim showing the answer to the question but I chose not to do so out of respect to MH because he asked me not to.
partzman
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As I understand it in the analogy the torque of the pump is the voltage.
Am I correct?
Having a bad day "at the office".
J.
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The first thing i will say is--have you said the same thing to MH,when he said i did not know what i was talking about and was wrong,when it came to the ICE,which is my speaciality ?
Yes, in private I have talked to MH about keeping his tone in check, and yes I would agree that he still goes a little too far sometimes.
Secondly-can you say without doubt tha MH would have been able to answer the question correctly,without having proof to back it up.
Absolutely. It perplexes me why you would even question this.
Thirdly- Regardless of any answer being considered to be correct,it is just theory based around real world examples. As we cannot make such an ideal voltage source to test the theory,then it remains just that-a theory. Lust as verpies said--just because th erest of the world dose it wrong,dose not mean we have to.
Not sure what you mean by "theory based around real world examples", but as I've already explained, and MH did also a while back, we don't need a perfectly ideal source nor inductor to prove out the equation that MH posted, which determines the final value of current in the inductor, based on the L and t, and initial current Io.
And there in lies a problem. What about that ideal voltage source,where the current is free to flow during the 0 volt cycle. A rotary switch would mean an open circuit in between contacts,and there go's your current flow.
Most voltage sources are close enough to ideal for this test. Yes, a rotary switch may cause some loss due to an imperfect transition.
Why not simulate it Poynt,using the lowest value resistance you can.
I have already done so. A number of posts back I gave a recommendation as to the L/R ratio that would still provide results "close to ideal", at least close enough for our purposes. I established this level (50:1) by using the sim with various values of R to get 5% error on the final current. Did you miss that post? It was done with the simulation. I have already posted a partial plot of the current, did you miss that also?
We have to remember,it is going to be -3 volt's,not a build up of voltage as the current drop's from 2.8 amp's down to the lower value,the ideal voltage source will place -3 volts across that ideal loop regardless of the current. So lets see if you can get your sim to do that.
As I said above, I have already fully simulated the circuit, as has Partzman. I am sure our results are identical.
Why would it have to be a set value of inductance. Could we not see the effect with any decent inductor?.
If you followed my posts on establishing the L/R ratio for a "close to ideal" inductor, you would know that any value of inductance can work, as long as we are aware that a 50:1 L/R ratio will present a 5% error in the current values. The current will be 5% (or thereabouts) less than the value predicted by MH's equation.
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I already discussed simulating this in the real world on another thread. Say you had a 2x1000-watt car audio amp. I am pretty sure they have huge voltage inverters in them so the run off a bipolar supply. They are giant ideal voltage sources within certain bandwidth and IV limits. If you could hack into one so that you insert a current viewing resistor at the output such that the voltage sense is on the far side of the current viewing resistor then you should be good to go. You just need a scope channel for the CVR and I am assuming that the car audio amp is being powered by a car battery. You connect up your arbitrary waveform generator (or iPhone) to the amplifier.
Then perhaps go to the hardware store and buy a bunch of looped hollow copper pipe for your inductor. There is probably a better way of doing the coil but that's the one that comes to my mind.
All that you have to do is shorten the timing and lower the voltages and you should be able to do a setup that is a very good facsimile of what we are discussing here. As long as you don't exceed the IV capabilities of the beefy car audio amplifier you should be fine.
But of course, measurements like these were probably made thousands of times already. What's of more value is the intellectual understanding and solving the problem on paper. That's what we are trying to do here.
MileHigh
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As I understand it in the analogy the torque of the pump is the voltage.
Am I correct?
Yes.
It is interesting to consider, which way the energy flows when the pump rotates against that torque.
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If the question in this thread is ever answered properly or not, I strongly advise anybody interested to go back and read it again from the beginning. You can decide for yourselves.
As an example, I somehow doubt we are going to get any more challenges about the concept of a time-variable ideal voltage source. Nor will we get any admissions that this was all just silliness and a useless and nonsensical waste of time and energy from the main players.
I will also repeat the main goals for this thread:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands the concepts and understands what he is doing.
2. Brad admits that he was wrong when he stated that my response to the harder question was wrong.
I would really hope that Brad successfully achieves those two goals.
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I see no difference in what i said,and what you have stated above.
The motor that drives the positive displacement pump you have used,will still encounter the force of the water moving in the opposite direction to that of the applied torque to the pump.
You have simply separated the pump from the motor. But any force placed upon the pump will be transferred to the motor.
The difference is huge because now the torque is not synonymous with the rotational direction of the impeller and the pump can rotate with or against the torque.
Thus, we can have a typical 4-quadrant operation:
1) The pump moving CW with a CW torque.
2) The pump moving CW against a CCW torque.
3) The pump moving CCW with a CCW torque.
4) The pump moving CCW against a CW torque.
In two of these cases, the energy is transferred to the pump, and in two other cases, the energy is transferred from the pump.
Can you assign the direction of energy flow in these four cases?
As the motion of the pump/motor combo i was using to represent the voltage(our force),then i included the bypass valve to represent no motion of the motor/pump--the equivalent of the 0 volt level in the question. Having the impeller still moving,would be seen as a resistance against the flow of water,and in our ideal loop,we have no resistance to the flow of the current,and so the bypass valve was included for that reason also.
In an ideal pump, as well as in an ideal pipe, there is no resistance to the water's motion and lately we've been considering an analogy of an ideal L circuit here, so all the analogical hydraulic components must be ideal, too.
Thus, the water can move the impeller without any friction ...and the impeller can move the water without any friction, too.
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Yes.
It is interesting to consider, which way the energy flows when the pump rotates against that torque.
I am just going to offer up simplified analogies and perhaps they will help.
The water pump in this case never impedes the water flow, but what it does do is create an increase in pressure in that water itself. So you don't necessarily have to think about a tangible water pump, just what it does. So if the pressure is 10 psi on one side of the pump, then the pressure is 14 psi on the other side of the pump. Or perhaps the pump drives the pressure the other way: the pressure is 10 psi on one side of the pump, and 7 psi on the other side of the pump.
That's the type of water pump we are talking about in this example, a constant-pressure pump. You don't care about the water flow rate or even the direction of the flow, the only thing that counts is that the pump establishes a difference in water pressure from one side to the other side. You can even block the water flow, and the pump still does the same thing.
However there is another type of water pump you can also imagine, a constant-flow pump. It's easy to imagine perhaps a large diesel engine with a transmission that lowers the shaft output speed that drives some small pistons that pump water at a certain flow rate.
In this pump, you don't care at all what the water pressure is on either side of the pump. The only thing you care about is that the pump pumps say six gallons of water per minute. The pressure at the output side of the pump could be 100 psi or 1000 psi, it doesn't matter and the pump will pump at a constant water flow rate.
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If the question in this thread is ever answered properly or not, I strongly advise anybody interested to go back and read it again from the beginning. You can decide for yourselves.
As an example, I somehow doubt we are going to get any more challenges about the concept of a time-variable ideal voltage source. Nor will we get any admissions that this was all just silliness and a useless and nonsensical waste of time and energy from the main players.
I will also repeat the main goals for this thread:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands the concepts and understands what he is doing.
2. Brad admits that he was wrong when he stated that my response to the harder question was wrong.
I would really hope that Brad successfully achieves those two goals.
Where did the bold words in your post come from? Seems this is the first time this is used in front of the words "ideal voltage source" since this was not in your initial question of ideal voltage on an ideal inductor. If so then why is that graph showing a straight line at 4 volts for 3 seconds? Why would you equate a time variable with ideal voltage, when ideal voltages do not change?
Hmmmmmmmmm (with my wet index finger pointing upwards) did the wind change directions? Or do I sense a hurricane is about to form.
wattsup
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Here we go again. Who said that ideal voltages have to be fixed and can't change in time? It's an ideal voltage, I can say it does whatever I want it to do. In my second example I state that the ideal voltage v = 20*t^2. So the ideal voltage increases in value proportional to the square of the time. There is nothing stopping me from saying that.
What about your function generator when you set it to a triangle wave and you connect it to your circuit? Supposing that the triangle wave is somewhat attenuated especially at the peaks because of the load on it from the circuit. Well, what if I said that my "ideal voltage source" had an identical waveform to the somewhat attenuated triangle wave output from your function generator? Under those static load conditions then the ideal voltage source that clones your function generator output and the function generator output are indistinguishable. That means you can look at the output from your function generator as being a time-variable ideal voltage source as long as the load condition remains static and unchanging.
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Why would you equate a time variable with ideal voltage, when ideal voltages do not change?
I don't know what an "ideal voltage" is and I think that MH does not know either.
Perhaps you had an "ideal voltage source" in mind.
If "yes, then consider these questions:
Does an "ideal voltage source" need to output a constant voltage all the time?
Can a voltage source still be ideal if it outputs an alternating voltage ?
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@MH - @verpies
Common guys. We have been through this how many times.
Here is a common definition.
"An ideal voltage source is a voltage source that supplies constant voltage to a circuit despite the current which the circuit draws."
In this definition, one can summarize that there is no variability in the voltage source. If you adjust your voltage at 4 volts, it stays at 4 volts regardless of any current draw.
In the video I posted on my shorting a wire over a battery, the battery is not an ideal voltage source so the voltage will drop as I short it with that wire. But in that case it is still backed up with 100 amps so that wire went zap in a few seconds. This for @tinman and myself and many others was the complete basis of why the question of ideal voltage on an ideal inductor was more then moot, it approached ludicrous because for us, like I said in my post, come hell or high water, that voltage should never change. This for us signifies a DC voltage holding a fixed straight line as in @partzman's graph showing the first three seconds as a straight 4 volts. Where is the variable in time there for the voltage. None. Yes it will show a variable current rise from t0 onward.
This is why I was stating that for any voltage to change across the terminals of the ideal voltage, it has to come from the inductor.
This was the whole basis of my prior post and of most posts from @tinman and the root of all this commotion that started with an innocent JT circuit.
A time variable ideal voltage source, for me, is not a DC fixed ideal source but either an AC ideal source or a DC ramped ideal source. Totally different animal. But in either of these three, using the term IDEAL will still signify that once they are set, they are set for life. No change possible and thus they become the fixed anchor to other variables that one can experiment with.
Hmmmmmmm.
wattsup
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I don't know what an "ideal voltage" is and I think that MH does not know either.
Perhaps you had an "ideal voltage source" in mind.
This is what MH actually said:
As an example, I somehow doubt we are going to get any more challenges about the concept of a time-variable ideal voltage source.
It's quite clear to me what he is referring to.
If "yes, then consider these questions:
Does an "ideal voltage source" need to output a constant voltage all the time?
Can a voltage source still be ideal if it outputs an alternating voltage ?
It is perplexing to me to see these questions ???
To clarify for all interested, one simple answer to cover all questions as to what an ideal voltage source is:
An ideal voltage source is a source that outputs a voltage according to what it is set to, no matter what load is connected to it. This does not preclude ideal function generators.
I trust you can now answer both of your questions.
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@MH - @verpies
This for us signifies a DC voltage holding a fixed straight line as in @partzman's graph showing the first three seconds as a straight 4 volts. Where is the variable in time there for the voltage. None. Yes it will show a variable current rise from t0 onward.
wattsup
Wattsup,
Yes, I created that ideal voltage source and applied it to the ideal inductor for three seconds and that voltage source was faithful to it's duty and it did not change for that duration. I could however, create a new ideal voltage source of 0 volts in magnitude and replace the original 4 volt ideal voltage source and it too will do it's job. In a sim, I can do this in few ns of time and maintain a duration of my choosing.
I can continue to replace each ideal voltage source with another as I choose since there is no law I am aware of which prevents me from doing so. Each ideal voltage source I create has the ability to maintain it's magnitude no matter the load. Proceeding in this manner allows us to be able to solve MH's problem.
partzman
Edit
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wattsup was just having an "off day". That's all that was up!
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@partzman
I know that. Your are on a sim and that sim is not simulating an ideal voltage as per the definition otherwise it would not change. Don't you get it. If your sim could simulate an ideal voltage it would have stayed at 4 volts all the time according to the definition. There is no ideal voltage in your sim. It is just simulating an applied voltage given the other parameters and it will change in time.
Actually there is no point in using a sim with an ideal voltage because you will always have the same voltage straight line.
The idea of the ideal voltage is to maintain a fixed voltage source while you can vary other parameters that cannot vary the ideal voltage but will provide you with how the circuit works when you, let's say, vary the resistance, or inductance, or impedance or capacitance while that ideal voltage always stays the same. The require gain or reduction in current will be automatic but the voltage will never change. You can then measure across different components in the circuit to see those changing values but the ideal voltage will never change. Otherwise what is the point in having an ideal voltage when it is just simple voltage.
@all
Common guys. There is process, there is teachings but there is also logic and logic has to win every time. At least this is what has been paying my great salaries for years. Nothing beats logic.
Either that or come forward and convene that this question does not require an ideal voltage source to propose the teaching you wish to promote, because it just does not click at all. It should at least send alarms bells ringing when other @members here cannot adjust to your line of thinking that maybe the teaching requires some "fine tuning".
wattsup
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Wattsup:
I would call that the classic ironic twist of the free energy forums. You are supposed to be "out of the box" experimenters. You are supposed to be "free thinkers not held back by the constraints of dogmatic science." You mock the scientists and the engineers and say they "only know what is in books" or, even worse, they "are programmed by the Powers That Be not to think."
And then the subject of a time-variable ideal voltage source comes up. And what do you do? You look for a definition in a book and you stick to it like glue. The definition says nothing at all about whether or not the voltage can vary in time but the concept is seemingly "too radical" and you can't process it so you make up a "new rule" to "fit in" to how you think things should be.
It is so ironic, it's almost surreal. For myself, and Poynt, Verpies, Partzman and countless others the concept of a time-variable ideal voltage source was presented to us, we processed it, and didn't flinch for a second. The simple fact is that it makes perfect sense. The logic that describes it is perfect.
It's almost shocking that so much time and energy has been wasted on this non-issue.
MileHigh
P.S.: I will just repeat that a very powerful car audio amplifier could make for a pretty beastly variable ideal voltage source.
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Surreal is right.
Your thought-experiment ideal voltage source has a virtual knob on it that says "Voltage output" right? And you can virtually reach out and turn that knob up and down, can't you? Thus making a simple time-varying ideal voltage source. Replace the "knob" with whatever virtual control system is needed to vary the output on whatever time schedule you like. What is so difficult to understand about that?
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Yep, you could even imagine my "wrist" had a bandwidth of about 30 kHz and could make a variable ideal voltage source that sounded like two lead guitars trading licks....
https://www.youtube.com/watch?v=oZUp1gUQLyg
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Absolutely. It perplexes me why you would even question this.
300 years ago,89% of the worlds population believed in God. Today only 26% of the worlds population believe in God---the rest have seen the light.
Not sure what you mean by "theory based around real world examples", but as I've already explained, and MH did also a while back, we don't need a perfectly ideal source nor inductor to prove out the equation that MH posted, which determines the final value of current in the inductor, based on the L and t, and initial current Io.
Your theory being based around real world applications,is based on the fact that there exist a resistance-no matter how small. In our ideal situation,that resistance is no existent,and no energy can be dissipated anywhere in that ideal circuit loop. The energy now stored in the ideal loop at the 0v phase ,must be dissipated before the ideal voltage can set a current flowing in the opposite direction.
Most voltage sources are close enough to ideal for this test. Yes, a rotary switch may cause some loss due to an imperfect transition.
I have already done so. A number of posts back I gave a recommendation as to the L/R ratio that would still provide results "close to ideal", at least close enough for our purposes. I established this level (50:1) by using the sim with various values of R to get 5% error on the final current. Did you miss that post? It was done with the simulation. I have already posted a partial plot of the current, did you miss that also?
No i did not miss the post.
First,i do not think you grasp the difference between a very low resistance value,and no resistance--the difference is infinite,and so the outcome has an infinite difference.
Second-the voltage in this ideal circuit is seen as being in series with the inductor,but as far as the current go's,the connection is both a series and parallel connection. So example 3 that verpies posted some time back,represents MHs circuit as far as the current flow go's,that being the inductor has a short across it's terminals as far as the current is concerned.
As I said above, I have already fully simulated the circuit, as has Partzman. I am sure our results are identical.
If you followed my posts on establishing the L/R ratio for a "close to ideal" inductor, you would know that any value of inductance can work, as long as we are aware that a 50:1 L/R ratio will present a 5% error in the current values. The current will be 5% (or thereabouts) less than the value predicted by MH's equation.
When that L/R =0,what is your ratio then?. 50:0 ?
As you can see,we went from a real world obtainable calculation,to one that dose not exist.
This is what i mean by trying to use real word values against values that just are not there,and expecting to arrive at an accurate outcome.
I have spent countless hours,and thousands of dollars on experiments--not to mention time.
I have helped those purchase equipment that they otherwise could never hope to obtain. I have spent time organizing fun competitions ,and donated prizes to those judged as being the most innovative at what they built. And yet here we have MH,sitting in his rocking chair,not lifting one finger(other than to type)to help the cause.
I will leave you with one thing to think about Poynt--->
Are the books ever going to explain the TPU?. Is what you know going to line up all perfect to that of the operation of the TPU.
Perhaps this is why it(the TPU) still alludes all those trying to replicate it's effect--your trying to place known real world values against values that are infinite--the energy being delivered by the TPU seems to have that value--infinite.
I love that saying by verpies-->just because the rest of the world got it wrong,dose not mean we have to.
Maybe we can learn something from that quote.
Brad
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I am pretty sure they have huge voltage inverters in them so the run off a bipolar supply. They are giant ideal voltage sources within certain bandwidth and IV limits. If you could hack into one so that you insert a current viewing resistor at the output such that the voltage sense is on the far side of the current viewing resistor then you should be good to go. You just need a scope channel for the CVR and I am assuming that the car audio amp is being powered by a car battery. You connect up your arbitrary waveform generator (or iPhone) to the amplifier.
Then perhaps go to the hardware store and buy a bunch of looped hollow copper pipe for your inductor. There is probably a better way of doing the coil but that's the one that comes to my mind.
All that you have to do is shorten the timing and lower the voltages and you should be able to do a setup that is a very good facsimile of what we are discussing here. As long as you don't exceed the IV capabilities of the beefy car audio amplifier you should be fine.
But of course, measurements like these were probably made thousands of times already. What's of more value is the intellectual understanding and solving the problem on paper. That's what we are trying to do here.
MileHigh
I already discussed simulating this in the real world on another thread. Say you had a 2x1000-watt car audio amp.
And that is where your ideal world all falls apart.
Please explain as to why you need 2000 watts of power to simulate a circuit that dose not dissipate any power?.
Answer that,and then you may begin to understand the difference between a small resistance value,and no resistance at all.
Your circuit MH,should use no power at all,as everything put into it,should be what you get back out of it--there are no losses in an ideal circuit such as your's.
This is based on the fact that what Poynt said is true,and that you can store the energy from the loop,back into the ideal source.
So your 2000 watts are for what?.
Brad
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It is perplexing to me to see these questions ???
Oh, C'mon! - these were rhetorical questions. I was not seeking answers to them. I was provoking some thinking.
To clarify for all interested, one simple answer to cover all questions as to what an ideal voltage source is:
An ideal voltage source is a source that outputs a voltage according to what it is set to, no matter what load is connected to it. This does not preclude ideal function generators.
Of course, but this needs to be stated explicitly, since apparently some people are under the impression, that an ideal voltage source is a constant voltage source :o
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Please explain as to why you need 2000 watts of power to simulate a circuit that dose not dissipate any power?.
The servo amp with high power output gives you the ability to output high currents (and sink high currents). The amp pumps real power into the coil. The longer you impose a constant voltage across the coil, the higher and higher the power demands get. A high-power car audio amp gives you more headroom and flexibility to carry out various experiments.
Your circuit MH,should use no power at all.
It would seem that only in your mind can things like that be stated in all seriousness.
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Oh, C'mon! - these were rhetorical questions. I was not seeking answers to them. I was provoking some thinking.
Of course, but this needs to be stated explicitly, since apparently some people are under the impression, that an ideal voltage source is a constant voltage source :o
C'mon yourself. Your question about whether MH knows what an ideal voltage source is, is absolute bunk.
After that it seemed you were the one that was lost. I encourage you to avoid the so-called rhetorical questions, and instead try to help Brad understand why his thinking on this affair is a little off the tracks.
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So, just to be clear here...
I can have an ideal voltage source that puts out 4 volts @ 1 amp but then, after 2 seconds, puts out 10 volts at .5 amps
and later, after 20 seconds puts out 2,000 volts @ 500 amps?
Do we need ideal circuit breakers that do not blow when working with this ideal voltage source?
Honestly, this just completely blows my mind that you (meaning anyone) can just make up some hypothetical device and then assign it ANY operational parameters that you want and then, do an "experiment" with this made up device and then claim that something real was learned?
This sounds like the same crap that Mythbusters might use. I just listened to an audio book that mentioned the Mythbuster's show where they "proved" that Archimedes did not have a death ray. They tried it, it did not work so this was PROOF!
Well, some boys over at MIT did a replication and....boom! It worked as it was supposed to. Those idiots at Mythbusters were ALWAYS changing parameters and then claiming devices to be "impossible". So, they could not find a mirror large enough so, they substituted a bar of soap instead...didn't work...see? Impossible! (Of course I exaggerate here a bit, but not too much)
I apologize...I just can not get my head around making crap up to fit your theory, and when your theory works claiming a victory.
I must be getting old.
Bill
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I don't know what an "ideal voltage" is and I think that MH does not know either.
Perhaps you had an "ideal voltage source" in mind.
If "yes, then consider these questions:
Does an "ideal voltage source" need to output a constant voltage all the time?
Can a voltage source still be ideal if it outputs an alternating voltage ?
I think that I can solve the mystery for this one. It took me a few hours to get it.
Verpies is splitting hairs on semantics. What does "ideal voltage" mean vs. "ideal voltage source?" i.e.; How do you define an "ideal beauty?" Is there an "ideal voltage?"
So Verpies was not suggesting that I did not know what an ideal voltage source is, even though I myself thought the same at first. His posting is driven by looking at Wattsup's prose.
Does an "ideal voltage source" need to output a constant voltage all the time?
Can a voltage source still be ideal if it outputs an alternating voltage ?
NO and YES. But how many ideal voltage sources can dance on the head of a pin? ;)
Coles Notes on this subject will be available in six weeks. I looked them up and if you are not Canadian you may have to look them up too. The Americanized version is now called CliffsNotes.
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Honestly, this just completely blows my mind that you (meaning anyone) can just make up some hypothetical device and then assign it ANY operational parameters that you want and then, do an "experiment" with this made up device and then claim that something real was learned?
But how did they get to the moon? Answer: Lunar orbit rendezvous.
There is a great documentary, I think it's a Nova. I did a quick check but I don't think I saw it on YouTube. It's all about how the NASA scientists in the late 1950s and early 1960s were struggling to design a system that would get men to the moon and back. Typically, the solutions relied on massive rockets that would go to the moon, land, and then blast off and then go back to Earth for a standard reentry. The launch system to do that had to be humongous, say five times the size of a Saturn V rocket.
There was a lower-level scientist that had the idea for lunar orbit rendezvous. He could not get anybody's attention and was ignored for a few years, nobody took his ideas seriously. Out of frustration he sent off a letter and bypassed three levels of management to make his case and get the attention his idea deserved. That's how they ended up choosing the system for getting to the moon.
What's the point? The point is the scientist conceived of the lunar orbit rendezvous plan all by himself, in his own head. He did an entire successful moon mission in his head based on hardware and software that didn't even exist. Then he took out his napkin and started doing some basic number crunching to confirm that what he had conceptualized all by himself was doable. It's a great story about a true unsung hero.
What is the escape velocity for Earth? You can figure that out on a blackboard by writing down a few equations. You don't have to build a rocket and find out by trial and error.
MileHigh
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C'mon yourself. Your question about whether MH knows what an ideal voltage source is, is absolute bunk.
I never posed a question whether MH knows "what an ideal voltage source is".
After that it seemed you were the one that was lost.
Just go back and read exactly what I wrote. Read every word, understand it and come back to me with an apology.
I still don't think that MH knows what an "ideal voltage" is. Do you?
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I never posed a question whether MH knows "what an ideal voltage source is".
Just go back and read exactly what I wrote. Read every word, understand it and come back to me with an apology.
I still don't think that MH knows what an "ideal voltage" is. Do you?
I certainly don't. But I do know why Mona Lisa is smiling. ;D
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@MH
You know what. Your only fall back is to attack me with something that is totally irrelevant to the discussion. You want to discuss constructs then open a new thread and i will be there in my corner of the boxing ring. No problem. If you want we can play knowledge court where you will defend EE and I will accuse it of fraud. That would make a good weekly. Hmmmmm
You had a chance to teach something and you failed. Not me. For me a teacher is like a brain farmer. The farmer knows exactly how to treat the crop, feed it at proper intervals, make sure its thirst is quenched and then if the crop is harvested, he gets paid. Teachers should follow the same modus. No crop no pay. You failed not me. The onus is always on the teacher to read the possible misunderstandings and quench them before they grow into weeds. You failed because you were to busy with your big mouth and fast action posts, not really thinking things through, never judging where and how to properly help the crop grow. You failed not me.
You presented a problem, gave it some parameters and "assumed" that your students will not take it literally. That is your fault and not ours. So you know what. You learned something today. You learned that you can be one hell of a jackass always relying on your hing legs to protect yourself should things go bad. So defer the real question on who's responsibility it is to make sure a question is asked in its proper context. Surely not mine. I only found the fault. I only had to read endless pages of crap to then realize the fault, point it out so you can then chastise me instead of congratulating me for seeing it. Man, just great. So no need to thank me man. Maybe excuse yourself to @tinman for stringing him along while you whipped him good.
I even tried to make your bumble up work but no, not even one comment on that. Not even a "nice try wattsup, interesting way of analyzing the problem". Just your usual self-centered boy worrying about how the world will see him. Tell me what take more guts, pointing out the problem or following the pack. You should all be ashamed of yourselves. One stupid little question that could have been answered in one page and none of you saw the flaw. Oh, but I did, didn't I and I am the sureal. hahaha
I'll put my logic against anything you want to throw at me boy. You muster up any EE concept you wish, throw it at me and I will cut it down to flea grass. That's because now that I know how and why electricity conveys in our wires and coils, I know which questions to ask you that will prove it to yourself. That's what I am now good at. And actually I have you to that thank for being the typical pompous ass scientist that needs no more outlook on nature then a worm needs more earth. I asked you guys a question a few pages back and no answer, not even a remark because I now know the EE modus. Ignore whatever can eat away at your present comfort zone. Funny thing is it is not out-of-the-box. It is just normal logic taking its logical course like water eventually taming the stone.
wattsup
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But how did they get to the moon? Answer: Lunar orbit rendezvous.
There is a great documentary, I think it's a Nova. I did a quick check but I don't think I saw it on YouTube. It's all about how the NASA scientists in the late 1950s and early 1960s were struggling to design a system that would get men to the moon and back. Typically, the solutions relied on massive rockets that would go to the moon, land, and then blast off and then go back to Earth for a standard reentry. The launch system to do that had to be humongous, say five times the size of a Saturn V rocket.
There was a lower-level scientist that had the idea for lunar orbit rendezvous. He could not get anybody's attention and was ignored for a few years, nobody took his ideas seriously. Out of frustration he sent off a letter and bypassed three levels of management to make his case and get the attention his idea deserved. That's how they ended up choosing the system for getting to the moon.
What's the point? The point is the scientist conceived of the lunar orbit rendezvous plan all by himself, in his own head. He did an entire successful moon mission in his head based on hardware and software that didn't even exist. Then he took out his napkin and started doing some basic number crunching to confirm that what he had conceptualized all by himself was doable. It's a great story about a true unsung hero.
What is the escape velocity for Earth? You can figure that out on a blackboard by writing down a few equations. You don't have to build a rocket and find out by trial and error.
MileHigh
I believe you are speaking of Max Fagat...he is the guy that favored not only lunar orbit rendezvous, but came up with the ridiculous idea of throwing away the used portions of the spacecraft. Main booster tanks empty? Throw it away. 2nd stage burned out? Throw it away. Landed on the moon with the lander? Throw away the base. Back in the command module? throw away the lander...and etc., etc. He was a true genius.
Von Braun favored earth orbit rendezvous. He said that if we did not do that, the moon would be the last place we went...and he was right.
But, MH, I am not talking about criticizing brainstorming or creative thinking and analysis here. What if old Max used an ideal booster in his thinking? One that required no fuel and weighed nothing? How far would his thought experiments have gone then? Reality must overrule in any thought experiment with any components of any kind in my opinion. What if Max considered a rocket that would accelerate to 1.5 lightspeed? He would have then designed a spacecraft needing only 3 minutes of oxygen for the crew to get to the moon. Yes, he could have pictured a booster doing this but what good would it do?
I know were are on different wavelengths here and I mean no animosity by it. I have said this before, and I will say it again...you, and the other trained EE guys here have forgotten more about electronics than I will ever learn. But, this is not my field, but a hobby I have picked up in order to learn. I appreciate everyone's input...I just am missing something here with the made up "ideal" component business.
Bill
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I never posed a question whether MH knows "what an ideal voltage source is".
Just go back and read exactly what I wrote. Read every word, understand it and come back to me with an apology.
I still don't think that MH knows what an "ideal voltage" is. Do you?
I read every word. How was that post helpful to anyone?
I encourage you to avoid the so-called rhetorical questions, and instead try to help Brad understand why his thinking on this affair is a little off the tracks.
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So, just to be clear here...
I can have an ideal voltage source that puts out 4 volts @ 1 amp but then, after 2 seconds, puts out 10 volts at .5 amps
and later, after 20 seconds puts out 2,000 volts @ 500 amps?
You almost got it Bill.
The problem with your guess is that the currents probably aren't going to track that way. The assumption is and always has been that the ideal voltage source is always connected to the same load, regardless of what it is.
Did you see my post on arbitrary wave form generators? Did you see my post of the wave form MH prescribed for the experiment? I don't get what is so difficult to understand about this. Think of it as a special function generator that has zero output impedance and can be programmed to produce any imaginable wave form. Make sense? These aren't imaginary, at least the wave form generator part. The "ideal" part is of course not achievable, but we can get so close that it makes not a bit of difference in the final analysis. This is a hurdle that Brad also seems to be having trouble getting over.
Now I'm beginning to feel like I'm in an episode of the Twilight Zone :P
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You almost got it Bill.
The problem with your guess is that the currents probably aren't going to track that way. The assumption is and always has been that the ideal voltage source is always connected to the same load, regardless of what it is.
Did you see my post on arbitrary wave form generators? Did you see my post of the wave form MH prescribed for the experiment? I don't get what is so difficult to understand about this. Think of it as a special function generator that has zero output impedance and can be programmed to produce any imaginable wave form. Make sense? These aren't imaginary, at least the wave form generator part. The "ideal" part is of course not achievable, but we can get so close that it makes not a bit of difference in the final analysis. This is a hurdle that Brad also seems to be having trouble getting over.
Now I'm beginning to feel like I'm in an episode of the Twilight Zone :P
Thanks Darren.
So, is it OK to have more than one "ideal" component in an exercise? Or is it? Or, is it more to have an imaginary component (ideal) replace something you already know in the circuit and are wanting to find out about something else in the circuit? Is this it? Like solving for X when you already know Y?
Picture a place and time when you go to a roadside dinner at 3:00 a.m. and all of the waitresses have one large eye in the center of their head. You have entered...the Twilight Zone.
Bill
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@MH
You know what. Your only fall back is to attack me with something that is totally irrelevant to the discussion. You want to discuss constructs then open a new thread and i will be there in my corner of the boxing ring. No problem. If you want we can play knowledge court where you will defend EE and I will accuse it of fraud. That would make a good weekly. Hmmmmm
wattsup
I am not attacking you. In fact the "you" in my posting refers to all those that "don't believe" that an ideal voltage source can vary with respect to time. Like it or not, many people would find just arguing the issue to be strange. It's kind of a mom and apple pie issue and you are of the group saying that you are not allowed to put ice cream on your apple pie. It just makes no sense.
I am not going to address all of the drama in your posting about me nor all of the drama you raise about the question itself. There is no need for all of this, truly. Brad and others are supposed to be trying to answer a simple question and understand all of concepts and the related issues. As far as I am concerned this whole thing should have happened six years ago.
You made reference to a question of yours that was ignored. I don't see a question in post #454. That posting is really hard to digest, BTW. I went back a few more pages and did not see anything so I suppose you are taking about your post #454. If you can tell me what the question is I will try to answer it.
MileHigh
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Thanks Darren.
So, is it OK to have more than one "ideal" component in an exercise? Or is it? Or, is it more to have an imaginary component (ideal) replace something you already know in the circuit and are wanting to find out about something else in the circuit? Is this it? Like solving for X when you already know Y?
It is ok to have more than one ideal component in a circuit, yes.
In the sim we can get real close to ideal components (voltage sources are), in real life that is more of a challenge. MH keeps mentioning big audio power amplifiers, well that is to get the output impedance down. Use lots of negative feedback and big hefty transistor outputs, and you will have a nice low Z buffer for your arbitrary wave form generator (assuming it is DC coupled). The inductor is a far greater challenge, but still not insurmountable to get reasonably close, i.e. L/R=50.
Picture a place and time when you go to a roadside dinner at 3:00 a.m. and all of the waitresses have one large eye in the center of their head. You have entered...the Twilight Zone.
Bill
;D
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@MH
Maybe you need to understand how an OUer sees the question or anyone else that reads a question and responds to it literally. So just to clarify this without any chance of further misunderstandings, you need to clarify this yourself and I am spelling it out clearly for you to make it easy.
Method #1
1) the voltage stays at 4 volts for 3 seconds
2) then is falls on its own to 0 volts for 2 seconds
3) then it falls on its own to -3 volts for 2 seconds
4) then is rises on its own to 0.5 volts for 7 seconds
5) then it falls on its own to 0 seconds for infinity.
All these events are occurring in succession on their own with only that first 4V setting on a 5H inductor resulting from the actions occurring in the inductor itself. For us, that's how your question was asked and never was there any mention of time-variable anything.
Now with your sudden inclusion of those two words that I knew in advance would generate a hurricane you are saying this.
Method #2
1) the voltage is set manually or programmed to automatically go to 4 volts for 3 seconds
2) the voltage is set manually or programmed to automatically go to 0 volts for 2 seconds
3) the voltage is set manually or programmed to automatically go to -3 volts for 2 seconds
4) the voltage is set manually or programmed to automatically go to 0.5 volts for 7 seconds
5) the voltage is set manually or programmed to automatically go to 0 seconds for infinity.
Are you saying your question was as per Method #2, hence each is a separate event?
Or is there something different besides these two choices that you need to add.
wattsup
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Wattsup:
Is there really any difference between the two ways of wording it and the way I worded it? I don't think it is unreasonable to expect people to know what a voltage source is, or what an ideal voltage source is.
How about we go back to TK's metaphor? You are turning a dial to change the voltage on an ideal power supply. You can turn the dial very fast and the resultant voltage output looks like the plot that Poynt posted. The voltage source is active, it's driving the show.
All these events are occurring in succession on their own with only that first 4V setting on a 5H inductor resulting from the actions occurring in the inductor itself.
In my example, the inductor simply is a slave to the actions of the voltage source. That's it, the inductor has no say whatsoever in what voltage exists across its two terminals.
Does this make sense now?
MileHigh
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@MH
No. I just need an answer.
I thought spelling it out clearly is better then reading between the lines.
I thrive on precision and not on suppositions. I investigate things until they become clear.
Method #1 or Method #2
And the difference is enormous. 200 pages enormous.
Now do you understand why all this crap has been going on.
I know now just by your sidetracking that your answer is Method #2 and it should not have been asked as it was. It should have been 6 different questions each starting at t0 for their set duration and each starting at their identified voltage setting and each produces one effect.
Instead you led the question to be understood as one voltage setting "transmuting" to the others on their own direct from that one first 4V input. So do you realize the problem. Or now maybe I should ask you to respond to Method #1 and see how you like it while I badger you ever step of the way, telling you, "no no it's a perfectly sound question that I can answer in a jiffy".
Our total argumentation was based on Method #1 and you cannot say they are the same. They are not.
wattsup
-
I'll pick method number #2 of you want me to pick something.
I don't know what you really mean by "falls on its own" in method #1. You seem to be suggesting that it is a passive action by the voltage source. How could that be? How could the voltage source "know" to fall to -3 volts?
I don't why you focus on things like this. If you have a basic understanding of electronics then the question as originally posed is straightforward, self-evident, and not ambiguous. You are reading into something that is not there.
Instead you led the question to be understood as one voltage setting "transmuting" to the others on their own direct from that one first 4V input. So do you realize the problem.
No, there is no problem at all.
Our total argumentation was based on Method #1 and you cannot say they are the same. They are not.
You are in "how many angels can dance on the head of a pin" territory. People that understand basic electronics don't see any rhyme or reason in what you are saying.
-
wattsup,tinman and me, what I've learned is if you want to do electronics
you've got to go to college and start from DAY ONE and really pay attention.
I'm managing to get a bit but only by constantly referring to very basic
tutorials.
John.
We must thank the likes of MH. poynt etc. for their patience in inching us along.
-
Language...
A big part of this problem here is language ,The "taught ", hear and read things thru their learned Language ,which are indeed self evident to _Them_.
that is why one "Taught Man" can send a PDF to build a 747 to another "Taught man" on the other side of the world .
and a 747 can be built with no further contact.
here we try to talk outside the "taught Box" and not only outside of _that _ box but also with many here trying to contribute in tongues and cultures which they are not familiar with.
its a big mish mosh ,and I'm surprised there are not more fights.
And then we throw in Ego's insults and personal "agendas" [never good to do]
and.... Boom
Do we keep rinsing and repeating ??
we can self loop this in perpetuity .....
OR ???
we have a lot of very good men here , dedicated Men !
and plenty of Napkins...
-
I read every word. How was that post helpful to anyone?
It helped Wattsup to notice that he needs to be more careful with his words.
These are technical posts and every word matters. Making mental shortcuts is sometimes funny but most often it requires "secret decoder rings" from the reader. Those are not good habits for technical communication.
So now we have established that an ideal voltage source merely needs to have:
- zero internal resistance
- zero internal reactance
- an output voltage that is not affected by the load
...but it does not need to output a constant output voltage all the time, and it can be even an ideal alternating voltage source.
We can consider the direction of the current flowing through this ideal voltage source.
Brad will like this:
The current can flow in two directions through the voltage source and the voltage presented by this voltage source can have two polarities, too. So we have 2 variables and each one can have 2 states. This gives us 4 combinations.
Of course this is again the 4-quadrant operation, where:
- 2 combinations result in energy flowing from the voltage source to the load
- 2 other combinations result in energy flowing from the load to the voltage source
Can you enumerate which ones?
-
If the question in this thread is ever answered properly or not, I strongly advise anybody interested to go back and read it again from the beginning. You can decide for yourselves.
As an example, I somehow doubt we are going to get any more challenges about the concept of a time-variable ideal voltage source. Nor will we get any admissions that this was all just silliness and a useless and nonsensical waste of time and energy from the main players.
I will also repeat the main goals for this thread:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands the concepts and understands what he is doing.
2. Brad admits that he was wrong when he stated that my response to the harder question was wrong.
I would really hope that Brad successfully achieves those two goals.
MH-you are a true idiot.
Do not come to this thread i started,and belittle me like you have above.
You are no wizz kid,and that much was proven in the JT thread.
To come here nad have the arrogance to think i am the one that needs to climb the ladder,is you just grasping for air,and trying to make me look bad
Well bad new's MH--your question has not yet been answered correctly,and those that think they have,and it's game,set,and match ,are free to post there real world results using the two components of your question -an ideal inductor(no resistance),and an ideal voltage source(no internal resistance)--and no means none at all.
How good are you MH,well i now know that (as i suspected) you would not have answered your own question correctly. What i should have done,was to get you to post your answer to Poynt before this thread started,as Poynt (even though we disagree some times)would have posted your answer as you presented it at the end of this discussion.
But there is no need for that,as i have the proof i need--saved and screen shot-just in case you decide to go change things on said post when you realize your mistake.
So take your idiotic remark's,and place them in the waste bin.
Brad
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Yes.
It is interesting to consider, which way the energy flows when the pump rotates against that torque.
In the real world,the motor driving the pump would see a higher than startup load,and the energy contained in the flow of water would be converted into heat,by way of the motor now working harder to slow and stop that flow of water,which also is being pushed by the inertia of the water wheel(our inductor).
Brad
-
Here we go again. Who said that ideal voltages have to be fixed and can't change in time? It's an ideal voltage, I can say it does whatever I want it to do. In my second example I state that the ideal voltage v = 20*t^2. So the ideal voltage increases in value proportional to the square of the time. There is nothing stopping me from saying that.
What about your function generator when you set it to a triangle wave and you connect it to your circuit? Supposing that the triangle wave is somewhat attenuated especially at the peaks because of the load on it from the circuit. Well, what if I said that my "ideal voltage source" had an identical waveform to the somewhat attenuated triangle wave output from your function generator? Under those static load conditions then the ideal voltage source that clones your function generator output and the function generator output are indistinguishable. That means you can look at the output from your function generator as being a time-variable ideal voltage source as long as the load condition remains static and unchanging.
Oh here we go.
The MH paradox is kicking in again.
An ideal voltage source dose not change in time--how many times to you have to be told this?.
You have an ideal voltage source that !you! change in steps over time. Each time period in your question has a set voltage value that dose not change in time. Poynt also is in agreement with this.
Here we once again have MH doing the old !side step!,and adding more confusion to the discussion.
Brad
-
Oh, C'mon! - these were rhetorical questions. I was not seeking answers to them. I was provoking some thinking.
And dont ever stop doing that verpies,as it would seem that there needs to be more of it.
Of course, but this needs to be stated explicitly, since apparently some people are under the impression, that an ideal voltage source is a constant voltage source :o
An ideal voltage source will deliver the voltage selected by the user,for as long as the user decides to change the voltage value. It will deliver the selected value over any load,and will not dissipate energy,due to the non existence of an internal resistance.
An ideal voltage source dose not,and never will exist.
It is an !oxy moron!.
If an ideal voltage source can deliver an ideal voltage across any load,what happens when it is placed across an ideal short as the load?--this would be the same as clipping the two output leads from your ideal voltage source together.
Brad
-
C'mon yourself. Your question about whether MH knows what an ideal voltage source is, is absolute bunk.
Well he dosnt know what a shorted ideal inductor is,so is verpies remark that far off?
MH adds confusion to this thread ,by instating his later test mixed in with the original question.
After that it seemed you were the one that was lost. I encourage you to avoid the so-called rhetorical questions, and instead try to help Brad understand why his thinking on this affair is a little off the tracks.
And who is it that has tested this very circuit,that can say that !i! am lost ?.
Brad
-
So, just to be clear here...
I can have an ideal voltage source that puts out 4 volts @ 1 amp but then, after 2 seconds, puts out 10 volts at .5 amps
and later, after 20 seconds puts out 2,000 volts @ 500 amps?
Do we need ideal circuit breakers that do not blow when working with this ideal voltage source?
Honestly, this just completely blows my mind that you (meaning anyone) can just make up some hypothetical device and then assign it ANY operational parameters that you want and then, do an "experiment" with this made up device and then claim that something real was learned?
This sounds like the same crap that Mythbusters might use. I just listened to an audio book that mentioned the Mythbuster's show where they "proved" that Archimedes did not have a death ray. They tried it, it did not work so this was PROOF!
Well, some boys over at MIT did a replication and....boom! It worked as it was supposed to. Those idiots at Mythbusters were ALWAYS changing parameters and then claiming devices to be "impossible". So, they could not find a mirror large enough so, they substituted a bar of soap instead...didn't work...see? Impossible! (Of course I exaggerate here a bit, but not too much)
I apologize...I just can not get my head around making crap up to fit your theory, and when your theory works claiming a victory.
I must be getting old.
Bill
Your not getting old Bill--you are spot on,and we see this many times.
The biggest problem with !!some!! of the EE guy's,is they are programmed to make everything fit the way it should,as they have learned.
Myth busters indeed lol,did you see there attempt at the Bedini SSG lol. Now im no bedini fan,but these guys completely bungled that one up--and these guy's(the myth busters)get paid a fortune for there idiotic tests.
You will very often(in fact ,im sure you have many times already) see this sort of thing happen,where accurate descriptions are taken,and re arranged to fit in with what should happen,and how something is needed to work.
The fact is,an ideal voltage dose not !!vary!! over time. An ideal voltage will produce a steady voltage value across any load presented to it,until such time as that value is changed by the user. No load will cause a variance in the voltage from the ideal voltage source--only the user can change the voltage value.
For MH to state that the voltage can vary in time is incorrect,as we would see that as being like the current value varying in time with a steady slope. An ideal voltage can increase or decrease over time in step's selected by the user,not by the load varying the voltage as it can in a real world voltage source.
Brad
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I am not attacking you. In fact the "you" in my posting refers to all those that "don't believe" that an ideal voltage source can vary with respect to time. Like it or not, many people would find just arguing the issue to be strange. It's kind of a mom and apple pie issue and you are of the group saying that you are not allowed to put ice cream on your apple pie. It just makes no sense.
I am not going to address all of the drama in your posting about me nor all of the drama you raise about the question itself. There is no need for all of this, truly. Brad and others are supposed to be trying to answer a simple question and understand all of concepts and the related issues. As far as I am concerned this whole thing should have happened six years ago.
You made reference to a question of yours that was ignored. I don't see a question in post #454. That posting is really hard to digest, BTW. I went back a few more pages and did not see anything so I suppose you are taking about your post #454. If you can tell me what the question is I will try to answer it.
MileHigh
The only reason you are saying !Brad! and others are !!trying!! to answer the question,is because we dont agree with you,and this is something you do all the time.
If you think you are correct beyond being able to be incorrect,then that is nothing more than your own arrogance shining through--and this go's for any of the EE guys that think they have all the answers.
You are dealing with ideal that have not,and cannot be delt with. But you feel that you have all the answers sitting in your hand,and they are correct beyond doubt-->bullshit.
Here is one big flaw between the EE guys that think they all agree with one another,and the answer is nailed down solid.
Quote MH-->An ideal voltage source does not "contain energy" and likewise an ideal short does not "contain energy.
Im not sure what planet MH is on there?.
Quote Poynt-->The energy in the inductor does not "disappear", some is returned to the source during that period.
So we know that the source is the ideal voltage source,and being that Poynt says that the energy in the inductor is returned to the source,that must mean that the ideal voltage source is what contains that returned energy--but MH says that the ideal voltage source dose not conatin energy???
So we see here that the two guys that say that each other agree with each others theory ,dont seem to agree on what one of the two components in this circuit can do.
And as far as MHs comment about the ideal short not containing energy,well when it is taken !in! context as it should be,and that being the discussion of the ideal coil having an ideal short across it,then it dose indeed contain energy.
An ideal short is a short with no resistance,and our ideal coil has no resistance,and so when that ideal coil is a continual loop(shorted across it's terminal's),then it is an ideal short--as verpies showed it to be.
So you can see here that there is a discrepancy between the two that think they have the answer nailed down,and also the fact that MH is not the guru that he claims to be here.
How he ever came up with--an ideal voltage source dose not contain energy,is beyond me. :o
Brad
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@ Poynt
As you believe that MH could answer his question correctly,and following his statement-An ideal voltage source does not "contain energy"
I ask you once again--how is the energy dissipated in the ideal inductor loop during the 0 volt period,so as the negative 3 volt period can start inducing a current flow in the opposite direction to that of the current already flowing?. The energy stored in the inductor loop during the 0 volt period is in opposition to that of what the ideal voltage source wants to induce,and so it must be removed before the next phase can start.
So either you are incorrect,and the energy in the inductor is not returned to the source,or MH is incorrect,and the ideal voltage source can contain this returned energy.
If you are incorrect,then we have not yet derived at a correct conclusion to this question of MHs.
If MH is incorrect,then how is it possible that he could have answered his question correctly?--how would he have explained as to where the stored energy in the inductor went before the next part of the cycle started?.
Brad
-
John.
We must thank the likes of MH. poynt etc. for their patience in inching us along.
wattsup,tinman and me, what I've learned is if you want to do electronics
you've got to go to college and start from DAY ONE and really pay attention.
I'm managing to get a bit but only by constantly referring to very basic
tutorials.
You mean go for your Indoctrination.
You seen a perfect example of how !wrong! you can be taught--even at the best of the best of them--MIT.
One of the best physics teachers of all time's-Walter Lewin,got it wrong.
The best of the best teach them selves--Nikola Tesla.
Brad
-
It helped Wattsup to notice that he needs to be more careful with his words.
These are technical posts and every word matters. Making mental shortcuts is sometimes funny but most often it requires "secret decoder rings" from the reader. Those are not good habits for technical communication.
So now we have established that an ideal voltage source merely needs to have:
- zero internal resistance
- zero internal reactance
- an output voltage that is not affected by the load
...but it does not need to output a constant output voltage all the time, and it can be even an ideal alternating voltage source.
We can consider the direction of the current flowing through this ideal voltage source.
So we have 2 variables and each one can have 2 states. This gives us 4 combinations.
Of course this is again the 4-quadrant operation, where:
- 2 combinations result in energy flowing from the voltage source to the load
- 2 other combinations result in energy flowing from the load to the voltage source
Can you enumerate which ones?
Brad will like this:
The current can flow in two directions through the voltage source and the voltage presented by this voltage source can have two polarities, too
.
Well of course it can,but it cant have both at the same time.
Current cant flow in both directions at the same time,and the two voltage polarities cannot exist across the terminals at the same time.
But it would seem that the current can flow out and into this ideal voltage source at the same time???--well as far as Poynt is concerned. And MH--well ,he states that the ideal voltage source cannot contain energy at all. So,in MHs case, i have no idea as to where the energy comes from to induce the current flow MH calculated through his ideal circuit ::)
Brad
-
Brad:
The simple fact is that you have trouble with abstract concepts. An example is an ideal voltage source varying in time, you still refuse to believe that. In the more difficult version of the question the ideal voltage source varies in time. You need to move on with respect to the ideal voltage source business and just accept it.
An inductor can store energy. A capacitor can store energy. A battery can store energy. But an ideal voltage source does not "store energy." "How many Joules are in that ideal voltage source?" is a question that makes no sense. An ideal voltage source is a potentially unlimited source of power. It is simply "power on tap" and it doesn't make sense to think about it storing energy.
If an inductor returns a finite amount of energy back to an ideal voltage source then that energy is not to be "found inside" the ideal voltage source. The concept of an ideal short "containing energy" is simply ridiculous.
It's like a jigsaw puzzle were you want to force pieces of the jigsaw puzzle together that don't fit because you said something and the only way to backup your statement is to force some concepts together that don't fit. It's related to your issue about refusing to accept that you are wrong.
It's time for the discussion to move forward. What is the complete current waveform and more importantly what are the concepts that explain the current waveform? The only part of the question that you have answered so far is the fact that the current doesn't change when the ideal voltage source outputs zero volts. The clues to answering the full question are in this thread.
You have to understand what is taking place in the circuit and why it does what it does if you are going to understand and appreciate the harder version of the question that has already been answered.
MileHigh
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This is for those who hold to the misinterpretation of an ideal voltage source as "not being allowed" to vary. First the question, how do we solve a problem involving an ideal AC voltage source? Do we ignore such problems or do we "not allow" them to exist?
In an effort to help resolve this issue, I pose a new problem which is most relative to MH's original.
We have an ideal voltage source that starts at T0 with zero volts and ramps linearly to 4 volts at t1 = 1 second. In parallel with this ideal voltage source is an ideal inductor of 5h. What is the inductor current at T1?
partzman
edit
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tinman if you aren't prepared to learn and accept the basics you're a
waste of time.
Ideal voltage source zero internal resistance, able to supply or absorb any amount
of current.
Either independent or dependent as required.
Some things aren't for debate, for example I wouldn't put milk in the fuel tank
of my Honda or I wouldn't try to put petrol in our Tesla p85d.
John.
-
I'll pick method number #2 of you want me to pick something.
I don't know what you really mean by "falls on its own" in method #1. You seem to be suggesting that it is a passive action by the voltage source. How could that be? How could the voltage source "know" to fall to -3 volts?
I don't why you focus on things like this. If you have a basic understanding of electronics then the question as originally posed is straightforward, self-evident, and not ambiguous. You are reading into something that is not there.
No, there is no problem at all.
You are in "how many angels can dance on the head of a pin" territory. People that understand basic electronics don't see any rhyme or reason in what you are saying.
@MH
Let me just clarify this for the last time.
The question, in the way it is asked implies that with one application of an ideal voltage of 4V to an ideal inductor of 5H will produce in that one action the following effects in a continuous sequence. Consider the effect is a resulting single sine wave from that one first single action of applying that one instance of 4V for a duration of 14 seconds then to infinity.
Method #1
1) the sine wave starts at 4 volts for 3 seconds
2) the same sine wave then drops to 0 volts for 2 seconds
3) the same sine wave then drops to -3 volts for 2 seconds
4) the same sine wave then rises to 0.5 volts for 7 seconds
5) the same sine wave then drops to 0 seconds for infinity.
All this happens with only that first application of 4V at t0 and from there with only that 4V applied to the inductor, the voltage measurements across the inductor would indicate those voltage values from 2 to 6 in those time intervals, but always with that first 4V applied to the inductor. No stopping, manually changing voltage levels. Those voltage levels shift down and up on their own because of the action of that first 4V introduced into that inductor.
That's how your question was asked. That's why I was against your question. But again this is your lack of precision, not mine. You should have seen that something was not understood by the way your question was asked. IT WAS YOUR QUESTION. You should have known that after 2-3 pages of heated rebuttal that you needed to ask us to first explain what the question means. PRECISELY. Instead you kept pushing this bad question and chastised us for what?
The question the way I understood it was impossible to answer or maybe you would like to take a crack at it as I have explained above. I even tried to make heads or tales of it working out a logic base. Now that I know these are 6 independent events of ideal voltages applied to a 5H inductor, this question just went from 1000% difficulty to 2% difficulty. I was actually impressed that your Method #1 could have been a real scenario and I just could not figure it out. But now I know it was a Method #2 question which is just more rudimentary EE. Basically a false flag event.
Actually I should be commended for trying to at least work some logic into Method #1. hahahahaha
So again, this does not show how a coil works. It only shows how a coil responds. There is nothing in EE that shows how a coil works. That falls into the realm of physics where my Spin Conveyance will shed the light. From there it will migrate to EE and other disciplines.
I have 35 years as a water treatment professional. I have worked with ions and ions don't lie. When you realize how your coil works you will have to start over with your EE. You will have to create new math, new formulas (hehehe), new models. Or, the present math will have new correlations to cause and effect. This is not a bad thing. It will open up a whole new Renaissance of knowledge that Faraday was to chickenshit to realize because his balls were tied tight with his bosses fields. So it was a good stoop.
So here is a question for you. Why does the current never rise above the applied voltage? Why does it always ride at a certain percentage below? Why have I been talking about Half Coil Syndrome?
Now if this has been closed maybe I can go back to the JT thread when I get back from work I can post some new effects patterns that none of you have ever seen before and we can really talk about how a coil responds (not works) instead of this water in a pipe business.
@tinman
OK, here is a close analogy to how a coil responds (not works) with water in a pipe under the DC model.
You have two pumps, one on each end of a length of pipe both pumping into the pipe. Each pump is first connected to a tee connection where the pump is one end, a valve that opens and closes on one end and the pipe length is on the third end. One pump is your positive connection, the other is your negative connection. As your coils are plugged usually one connection is always connected and the other is always pulsed. Each pump has a rheostat. The positive side pump it set at 60%, the negative side pump is set at 40% of available voltage. So if you are pulsing the negative side, only that side pump turns on and off while the other polarity pump is "always on". When the pulsed pump is on, the valve on that same side is closed. When that same pump turns off, the valve on that same side opens. The valve on the always pumping side is always closed. Both pumps draw from the same tank. Each side also has a higher cracking pressure check valve that returns to the tank plus those two valves also return to the tank. By this you will realize that pulsing a coil on the negative will always cost 60% for rebias for 40% change, while if you pulse the positive side of the coil it will cost 40% rebias for 60% change. This analogy is still wrong because we are using water that can only flow. This automatically is not the right way to see it. A close physical way would be if there was a way to introduce a colored die into the water at pulse on and then retract that die at pulse off. The water never really moves. Actually even the die analogy is not right because it is much simpler then that but for physical means they come close enough. Maybe 40% close. hahahahahaha
wattsup
-
tinman if you aren't prepared to learn and accept the basics you're a
waste of time.
Dont call me a waste of time,you potty mouthed little weasel.
What have you got to show for your self?--yes,nothing.
Ideal voltage source zero internal resistance, able to supply or absorb any amount
of current.
MHs response to that is--an ideal voltage source dose not contain energy--> so go argue with him.
Either independent or dependent as required.
Some things aren't for debate, for example I wouldn't put milk in the fuel tank
of my Honda or I wouldn't try to put petrol in our Tesla p85d.
And you wouldnt try to claim victory when dealing with unknowns and ideals without proof.
You fall under the same spell as MH,and that is not being able to define between a small resistance and no resistance. I have shown you on a number of occasions that the difference is infinite.
Can you accurately calculate the top speed of a Chevy Camaro by measuring the top speed of a mini moke?. No ,i did not think so. But this is what is trying to be done here,using real world applications and devices to conclude how an ideal inductor and an ideal voltage source would react in a circuit,under the conditions that MH has set out.
-
@ Poynt
The best i can do as far as an inductor i have in the work shop,is a 1 Henry coil with 1.6 ohms of resistance.
This is a very large inductor out of a 300 amp HF mig welder.
Nothing else comes even close to the 5 Henry coil needed,with a low resistance value.
I do have a large MOT,and that is .71 Henry,and a resistance of 1.2 ohms.
I still think we could see the desired effect i am talking about with one of these inductors.
All you need to do,is work out how to switch at the rate needed for either of these two inductors,and maintain an unimpeded current flow through the inductor during the 0 volt portion of the test.----You have to design the !ideal! voltage supply ;)
I do have some 6 amp diodes that have only a .3 volt drop across them.
Maybe we could just use one of these as a free wheeling diode across the inductor,to allow for the continuation of the current flow--but how to remove the dead short when the voltage is applied inverted?.
I do have plenty of 20 amp double throw relays,but i think they will be too slow in switching for the job,and large arcs will be formed across the contacts.
I'll leave you i think.
Brad
-
@MH
Let me just clarify this for the last time.
The question, in the way it is asked implies that with one application of an ideal voltage of 4V to an ideal inductor of 5H will produce in that one action the following effects in a continuous sequence. Consider the effect is a resulting single sine wave from that one first single action of applying that one instance of 4V for a duration of 14 seconds then to infinity.
All this happens with only that first application of 4V at t0 and from there with only that 4V applied to the inductor, the voltage measurements across the inductor would indicate those voltage values from 2 to 6 in those time intervals, but always with that first 4V applied to the inductor. No stopping, manually changing voltage levels. Those voltage levels shift down and up on their own because of the action of that first 4V introduced into that inductor.
That's how your question was asked. That's why I was against your question. But again this is your lack of precision, not mine. You should have seen that something was not understood by the way your question was asked. IT WAS YOUR QUESTION. You should have known that after 2-3 pages of heated rebuttal that you needed to ask us to first explain what the question means. PRECISELY. Instead you kept pushing this bad question and chastised us for what?
The question the way I understood it was impossible to answer or maybe you would like to take a crack at it as I have explained above. I even tried to make heads or tales of it working out a logic base. Now that I know these are 6 independent events of ideal voltages applied to a 5H inductor, this question just went from 1000% difficulty to 2% difficulty. I was actually impressed that your Method #1 could have been a real scenario and I just could not figure it out. But now I know it was a Method #2 question which is just more rudimentary EE. Basically a false flag event.
Actually I should be commended for trying to at least work some logic into Method #1. hahahahaha
So again, this does not show how a coil works. It only shows how a coil responds. There is nothing in EE that shows how a coil works. That falls into the realm of physics where my Spin Conveyance will shed the light. From there it will migrate to EE and other disciplines.
I have 35 years as a water treatment professional. I have worked with ions and ions don't lie. When you realize how your coil works you will have to start over with your EE. You will have to create new math, new formulas (hehehe), new models. Or, the present math will have new correlations to cause and effect. This is not a bad thing. It will open up a whole new Renaissance of knowledge that Faraday was to chickenshit to realize because his balls were tied tight with his bosses fields. So it was a good stoop.
So here is a question for you. Why does the current never rise above the applied voltage? Why does it always ride at a certain percentage below? Why have I been talking about Half Coil Syndrome?
Now if this has been closed maybe I can go back to the JT thread when I get back from work I can post some new effects patterns that none of you have ever seen before and we can really talk about how a coil responds (not works) instead of this water in a pipe business.
@tinman
OK, here is a close analogy to how a coil responds (not works) with water in a pipe under the DC model.
You have two pumps, one on each end of a length of pipe both pumping into the pipe. Each pump is first connected to a tee connection where the pump is one end, a valve that opens and closes on one end and the pipe length is on the third end. One pump is your positive connection, the other is your negative connection. As your coils are plugged usually one connection is always connected and the other is always pulsed. Each pump has a rheostat. The positive side pump it set at 60%, the negative side pump is set at 40% of available voltage. So if you are pulsing the negative side, only that side pump turns on and off while the other polarity pump is "always on". When the pulsed pump is on, the valve on that same side is closed. When that same pump turns off, the valve on that same side opens. The valve on the always pumping side is always closed. Both pumps draw from the same tank. Each side also has a higher cracking pressure check valve that returns to the tank plus those two valves also return to the tank. By this you will realize that pulsing a coil on the negative will always cost 60% for rebias for 40% change, while if you pulse the positive side of the coil it will cost 40% rebias for 60% change. This analogy is still wrong because we are using water that can only flow. This automatically is not the right way to see it. A close physical way would be if there was a way to introduce a colored die into the water at pulse on and then retract that die at pulse off. The water never really moves. Actually even the die analogy is not right because it is much simpler then that but for physical means they come close enough. Maybe 40% close. hahahahahaha
wattsup
Method #1
1) the sine wave starts at 4 volts for 3 seconds
2) the same sine wave then drops to 0 volts for 2 seconds
3) the same sine wave then drops to -3 volts for 2 seconds
4) the same sine wave then rises to 0.5 volts for 7 seconds
5) the same sine wave then drops to 0 seconds for infinity.
Wattsup.
I dont see any confusion with the way MH has stated the question.
There are no sine waves in the voltage pattern.
MHs question describes a square wave pattern for the voltages--no sine waves.
I have always pictured the voltage pattern as being exactly what Poynt posted some pages back--see below.
The ideal voltage source,and the ideal coil has never been an issue. The confusion between what myself and MH,was in the words MH chose. When he said the voltage varies in time,i took it as meaning like the current varies in time through the inductor---just MHs bad choice of words that can have many meanings. The correct meaning as far as the question is stated,and the fact that a fixed voltage value is selected for a period of time(dose not vary),would have been to say--where the voltage value can be changed by the user at any point in time,but where the voltage value is not changed by the load-being the inductor.
The only way the voltage can vary from the ideal source at one point in time,is if the user (or timing device) makes that variation. As you can also see,more confusion has been added by talk of ideal AC voltage sources--which is not applicable to the question.
Brad
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It helped Wattsup to notice that he needs to be more careful with his words.
These are technical posts and every word matters. Making mental shortcuts is sometimes funny but most often it requires "secret decoder rings" from the reader. Those are not good habits for technical communication.
So now we have established that an ideal voltage source merely needs to have:
- zero internal resistance
- zero internal reactance
- an output voltage that is not affected by the load
...but it does not need to output a constant output voltage all the time, and it can be even an ideal alternating voltage source.
We can consider the direction of the current flowing through this ideal voltage source.
Brad will like this:
The current can flow in two directions through the voltage source and the voltage presented by this voltage source can have two polarities, too. So we have 2 variables and each one can have 2 states. This gives us 4 combinations.
Of course this is again the 4-quadrant operation, where:
- 2 combinations result in energy flowing from the voltage source to the load
- 2 other combinations result in energy flowing from the load to the voltage source
Can you enumerate which ones?
Good post verpies. ;)
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@ Poynt
The best i can do as far as an inductor i have in the work shop,is a 1 Henry coil with 1.6 ohms of resistance.
This is a very large inductor out of a 300 amp HF mig welder.
Nothing else comes even close to the 5 Henry coil needed,with a low resistance value.
I do have a large MOT,and that is .71 Henry,and a resistance of 1.2 ohms.
I still think we could see the desired effect i am talking about with one of these inductors.
The welder coil has the better L/R ratio of the two (0.625), but it is a far cry from 50, which is what we need to be close to ideal.
From the first plot below (red trace is MH's, violet trace Brad's coil), you can see that the lower value inductance and significantly higher series resistance (dissipating the inductor's energy) produces a result that is far from the ideal. So it seems this scheme as it stands won't work.
However, there is some hope. We can sort of "translate" our L/R ratio of 0.625 to 50 by significantly shortening the timing on the input source. We have little control over the real world L/R ratio, but we do have control over the input timing, which we can manipulate to utilize the "linear" portions of the circuit rise/fall transitions. We will shorten it by a factor of 1.6 x 50 = 80. So now our wave form timing becomes the following:
t0=0s
t1=37.5ms (was 3s)
t2=62.5ms (was 5s)
t3=87.5ms (was 7s)
t4=162.5ms (was 13s)
t5=250ms (was 20s)
From the second plot below you can see we've made a significant improvement in the "idealness" of our experiment, and will produce results good enough to compare to MH's original specs.
So the remaining challenge will be to design a source that can output this wave form.
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For comparison sake to see how far off we are from "ideal" using our shortened wave form timing and non-ideal inductor, see below for Brad's coil with an R=1m Ohm (close enough for ideal), the same as used for MH's inductor. The wave form timing is still the shortened version.
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@MH
Let me just clarify this for the last time.
The question, in the way it is asked implies that with one application of an ideal voltage of 4V to an ideal inductor of 5H will produce in that one action the following effects in a continuous sequence. Consider the effect is a resulting single sine wave from that one first single action of applying that one instance of 4V for a duration of 14 seconds then to infinity.
Method #1
1) the sine wave starts at 4 volts for 3 seconds
2) the same sine wave then drops to 0 volts for 2 seconds
3) the same sine wave then drops to -3 volts for 2 seconds
4) the same sine wave then rises to 0.5 volts for 7 seconds
5) the same sine wave then drops to 0 seconds for infinity.
All this happens with only that first application of 4V at t0 and from there with only that 4V applied to the inductor, the voltage measurements across the inductor would indicate those voltage values from 2 to 6 in those time intervals, but always with that first 4V applied to the inductor. No stopping, manually changing voltage levels. Those voltage levels shift down and up on their own because of the action of that first 4V introduced into that inductor.
That's how your question was asked. That's why I was against your question. But again this is your lack of precision, not mine. You should have seen that something was not understood by the way your question was asked. IT WAS YOUR QUESTION. You should have known that after 2-3 pages of heated rebuttal that you needed to ask us to first explain what the question means. PRECISELY. Instead you kept pushing this bad question and chastised us for what?
The question the way I understood it was impossible to answer or maybe you would like to take a crack at it as I have explained above. I even tried to make heads or tales of it working out a logic base. Now that I know these are 6 independent events of ideal voltages applied to a 5H inductor, this question just went from 1000% difficulty to 2% difficulty. I was actually impressed that your Method #1 could have been a real scenario and I just could not figure it out. But now I know it was a Method #2 question which is just more rudimentary EE. Basically a false flag event.
I think the question is clear enough. A voltage source is connected across an inductor. The voltage is a step waveform with various voltage levels, what happens?
Some people didn't even know where to begin. That is very telling. What happens? The only unknown is the current, solve for the current.
Honestly, all these words that you are throwing at my question itself are too much. The question is what it is.
MileHigh
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An ideal voltage source will deliver the voltage selected by the user,for as long as the user decides to change the voltage value.
Yes, an ideal voltage source will change the voltage across itself only when a user adjusts it.
An ideal voltage source will never alter its voltage when the load tries to change it.
In other words: An ideal voltage source obeys the user - not the load.
If an ideal voltage source can deliver an ideal voltage across any load,what happens when it is placed across an ideal short as the load?-
An infinite current flows and the universe explodes ;D
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An inductor can store energy.
Yes, unless it is open
A capacitor can store energy.
Yes, unless it is closed.
an ideal voltage source does not "store energy."
but it can absorb energy from a higher voltage source or from a current source.
Where does the absorbed energy go?
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Here again are the two versions of Brad's coil (ideal in red, non-ideal in violet) current traces on the same plot with the same vertical scaling.
There is obvious expected error with the non-ideal inductor (violet trace), but it is sufficiently accurate to allow us to understand how a perfectly ideal inductor would react to the same input.
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but it can absorb energy from a higher voltage source or from a current source.
Where does the absorbed energy go?
It gets sucked into the Dark Energy quantum foam vortex. Only to reappear later in the Jim Murray Dynaflux Alternator.
"It produces over 250% more electricity than it takes to run it."
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but it can absorb energy from a higher voltage source or from a current source.
Brad, verpies is agreeing that some of the energy stored in the inductor can be absorbed by the voltage source. Or at least I think he is.
What are your thoughts now?
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I think the question is clear enough. A voltage source is connected across an inductor. The voltage is a step waveform with various voltage levels, what happens?
Some people didn't even know where to begin. That is very telling. What happens? The only unknown is the current, solve for the current.
Honestly, all these words that you are throwing at my question itself are too much. The question is what it is.
MileHigh
@MH
Your question really involves 6 different experiments, so it should have been questioned as such. Each one would start at their own t0 mark at their respective voltage setting and duration. Each would have produce their individual result. Your question the way it was inferred is that all these events occurred with only one 4V application and nothing else. After the 4V you did not say stop, reset the voltage to 0, wait x seconds, stop reset the voltage to -3, wait x seconds, etc. You said all these events occurred because of the initial first application of 4V. Now do you get it. I don't see why this is so hard to understand.
If you were writing a technical report with such a question, you would have been fired the next day.
And please don't give this "If you were an EEer you would know what the question meant business". You were not asking this question to known EEers you were asking it to @tinman and others here. Wonder why no one else dared answer it? Because they were to smart to get involved in the first place. Dumb me all right.
@tinman
Sine wave, square wave, will not change that the question was just badly presented. Since these are 6 individual experiments with the same 5H, there is no point to answer it anymore because the first 2.4 amps gave out the rest of the answers. hehehe
It helped Wattsup to notice that he needs to be more careful with his words.
These are technical posts and every word matters. Making mental shortcuts is sometimes funny but most often it requires "secret decoder rings" from the reader. Those are not good habits for technical communication.
So now we have established that an ideal voltage source merely needs to have:
- zero internal resistance
- zero internal reactance
- an output voltage that is not affected by the load
...but it does not need to output a constant output voltage all the time, and it can be even an ideal alternating voltage source.
@verpies
I have always appreciated your input regardless of who you respond to it is always a pleasure. That includes @poynt99 and others who know who they are. But you all are not @MH and this is not your question.
So let me ask you this simple simple question.
You have an ideal voltage source of 4V and an ideal inductor of 5H. You apply the voltage at t0 for 5 hours. What will be the voltage read across the terminals at every hour? What will be the current measure at every hour?
You know why I made this easy. hahaha Here is my answer because it has already been said before. The voltage will remain at 4v throughout the 5 hours. The current will rise to 2.4 and remain there for 5 hours. Is this correct or not?
That's all we need to know to ascertain is @MH'S question was well presented of not.
wattsup
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Wattsup:
No, the question involves one experiment. A standard way to describe a process is chronologically, which is what I did. Many people have no problem at all with the question. I am attaching Poynt's graph that shows the voltage waveform that corresponds to the question. There is no more need to discuss the question.
What we need is progress towards answering the question.
MileHigh
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You have an ideal voltage source of 4V and an ideal inductor of 5H. You apply the voltage at t0 for 5 hours. What will be the voltage read across the terminals at every hour? What will be the current measure at every hour?
You know why I made this easy. hahaha Here is my answer because it has already been said before. The voltage will remain at 4v throughout the 5 hours.
Yes.
No load is incapable of altering the voltage at the output of an ideal voltage source.
The current will rise to 2.4 and remain there for 5 hours. Is this correct or not?
No, at t0 the current will be zero.
at 1h it will be 2.88kA
at 2h it will be 5.76kA
at 3h it will be 8.64kA
at 4h it will be 11.52kA
at 5h it will be 14.4A
...and it will keep increasing like that at the rate of 2880A per hour, ad infinitum.
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Brad, verpies is agreeing that some of the energy stored in the inductor can be absorbed by the voltage source. Or at least I think he is.
What are your thoughts now?
My toughts are,because of MHs statement that an ideal voltage source contains no energy,is a clear indication that he would not have been able to answer his question correctly.
You may wish to rethink your stance on MH being able to do so.
Brad
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@MH
If you cannot first concede your question was loaded the way it was asked, then you can play with yourself
wattsup
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Brad:
My toughts are,because of MHs statement that an ideal voltage source contains no energy,is a clear indication that he would not have been able to answer his question correctly.
You may wish to rethink your stance on MH being able to do so.
This is just useless spinning. You read how I described what an ideal voltage source is. An ideal voltage source can output or absorb an unlimited amount of power, and by extension, an unlimited amount of energy. But it does not "contain energy." It's just a concept, an important tool used all the time in electronics.
Wattsup:
If you cannot first concede your question was loaded the way it was asked, then you can play with yourself
Sorry, but you failed to make an impression. Reading you discussing electronics is difficult and stressful.
Let's focus on moving forward.
MileHigh
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My toughts are,because of MHs statement that an ideal voltage source contains no energy,is a clear indication that he would not have been able to answer his question correctly.
You may wish to rethink your stance on MH being able to do so.
Brad
I don't wish to change my stance. I know he could.
But that wasn't what my question was about. I said at one point that some of the inductor's energy would be returned to the source, and you disagreed and said it was not possible. And that had nothing to do with MH's statement, this was your own stance. verpies seems to agree with me on this and I'd like to know if this has caused you to reconsider perhaps?
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Brad:
This is just useless spinning. You read how I described what an ideal voltage source is. An ideal voltage source can output or absorb an unlimited amount of power, and by extension, an unlimited amount of energy. But it does not "contain energy." It's just a concept, an important tool used all the time in electronics.
Wattsup:
Sorry, but you failed to make an impression. Reading you discussing electronics is difficult and stressful.
Let's focus on moving forward.
MileHigh
The fact that you dont understand what a !source! Of power is, only means you cannot understand your own question .
Show me any source that can deliver power without that source containing enery.
I await the next MH paradox.
Brad.
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Brad, verpies is agreeing that some of the energy stored in the inductor can be absorbed by the voltage source. Or at least I think he is.
What are your thoughts now?
He also stated -but what happens to it?.
Then we look at MHs idiotic reply after that-shows how serious he is about the whole thing.
Verpies said-but what happens to it once it is absorbed?--MH says it cannot be contained within the ideal device that verpies and yourself just stated absorbed it.
Im wondering if you are seeing how stupid this sounds.
A source that can provide power, must contain the energy within it, in order to provide that power.
I remain firm on my position that MH could not possibly answer his own question,as he dose not even know what a power source is.
Brad
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Brad:
Well, if you are going to push it then we will get to the root of the matter, and it's a use of language issue. It makes sense to say that a capacitor or an inductor can "contain energy." It implies that there is a finite and measurable amount of energy in the device. In contrast, a voltage source has no finite and measurable amount of energy. It doesn't make sense to say that "A voltage source contains some energy." An ideal voltage source is not even a tangible device, it's a theoretical device.
In the world of electronics, nobody uses the language construct of an ideal voltage source "containing energy." That's the way it is, and sometimes you have to go with the flow. Just because you strung those words together does not mean that it is a valid thing to say. In fact it is an invalid thing to say and you should just absorb that fact and move on. When you used the argument that since an inductor can return energy to the ideal voltage source therefore the voltage source "must contain energy," it was simply wrong. You have to think and choose your words better than that. An ideal voltage source supplies energy, it does not contain energy.
Most importantly, we are certainly all in agreement on this fact: The ideal voltage source can supply power to the device it's connected to, and it can even absorb power from the device it's connected to. There is no disputing this fact by anyone in this debate, and that is the critical factor for advancing this debate.
So don't give us your trash talk that I "dont understand what a !source! of power is." You are not fooling anybody by a long shot. It's time for you to move forward in the technical discussion and talk about what we are really here for.
MileHigh
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Brad:
The simple fact is that you have trouble with abstract concepts. An example is an ideal voltage source varying in time, you still refuse to believe that. In the more difficult version of the question the ideal voltage source varies in time. You need to move on with respect to the ideal voltage source business and just accept it.
An inductor can store energy. A capacitor can store energy. A battery can store energy. But an ideal voltage source does not "store energy." "How many Joules are in that ideal voltage source?" is a question that makes no sense. An ideal voltage source is a potentially unlimited source of power. It is simply "power on tap" and it doesn't make sense to think about it storing energy.
If an inductor returns a finite amount of energy back to an ideal voltage source then that energy is not to be "found inside" the ideal voltage source. The concept of an ideal short "containing energy" is simply ridiculous.
It's like a jigsaw puzzle were you want to force pieces of the jigsaw puzzle together that don't fit because you said something and the only way to backup your statement is to force some concepts together that don't fit. It's related to your issue about refusing to accept that you are wrong.
It's time for the discussion to move forward. What is the complete current waveform and more importantly what are the concepts that explain the current waveform? The only part of the question that you have answered so far is the fact that the current doesn't change when the ideal voltage source outputs zero volts. The clues to answering the full question are in this thread.
You have to understand what is taking place in the circuit and why it does what it does if you are going to understand and appreciate the harder version of the question that has already been answered.
MileHigh
No need for any more of you babble MH.
My description of an ideal voltage source is correct,and backed up by verpies. So now your just making your self look stupid.
The fact that you think a source that can deliver power ,dose not contain energy,just go's to show how little you know.
That also means that you could not have answered your question correctly.
You would be trying to explain how a car is able to be powered by an engine,without knowing how that engine works.
Good show MH.
Brad
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Brad:
Well, if you are going to push it then we will get to the root of the matter, and it's a use of language issue. It makes sense to say that a capacitor or an inductor can "contain energy." It implies that there is a finite and measurable amount of energy in the device. In contrast, a voltage source has no finite and measurable amount of energy. It doesn't make sense to say that "A voltage source contains some energy." An ideal voltage source is not even a tangible device, it's a theoretical device.
In the world of electronics, nobody uses the language construct of an ideal voltage source "containing energy." That's the way it is, and sometimes you have to go with the flow. Just because you strung those words together does not mean that it is a valid thing to say. In fact it is an invalid thing to say and you should just absorb that fact and move on. When you used the argument that since an inductor can return energy to the ideal voltage source therefore the voltage source "must contain energy," it was simply wrong. You have to think and choose your words better than that. An ideal voltage source supplies energy, it does not contain energy.
Most importantly, we are certainly all in agreement on this fact: The ideal voltage source can supply power to the device it's connected to, and it can even absorb power from the device it's connected to. There is no disputing this fact by anyone in this debate, and that is the critical factor for advancing this debate.
So don't give us your trash talk that I "dont understand what a !source! of power is." You are not fooling anybody by a long shot. It's time for you to move forward in the technical discussion and talk about what we are really here for.
MileHigh
We are dealing with facts MH,not some deluded MH version of what an ideal voltage source is.
You are now trying to throw in one of your deluded paradoxes that dose not exist.
In one post you say ideal voltage sources exist,and now you say it's a device that dose not exist in reality.
First you argue with me when i state that an ideal voltage source dosnt exist,and now you agree with me--just to try and bail yourself out of your mistake.
Any voltage source contains energy-show me one that dose not.
If that source could supply an infinite amount of power,then it would contain an infinite amount of energy.
So just provide one example of a voltage source that can supply power,but has no stored energy within that soufce.
Brad
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it's a use of language issue. It makes sense to say that a capacitor or an inductor can "contain energy." It implies that there is a finite and measurable amount of energy in the device.
Agreed. The Inductor or Capacitor which is storing
energy is said to be "Charged."
In contrast, a voltage source has no finite and measurable amount of energy. It doesn't make sense to say that "A voltage source contains some energy." An ideal voltage source is not even a tangible device, it's a theoretical device.
Surprisingly, your language and your theory is rather
imprecise Miles. Is there some Wobble here? ???
In the world of electronics, nobody uses the language construct of an ideal voltage source "containing energy." That's the way it is, and sometimes you have to go with the flow.
...
When you used the argument that since an inductor can return energy to the ideal voltage source therefore the voltage source "must contain energy," it was simply wrong. You have to think and choose your words better than that. An ideal voltage source supplies energy, it does not contain energy.
Now that is definitely Wobbly! So you're actually saying that
you believe a Voltage Source contains no Charge? That it is
not a repository of Stored Energy? That it has no Capacity? :o
Miles, that is a Most Unusual Conclusion! ;)
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He also stated -but what happens to it?.
Then we look at MHs idiotic reply after that-shows how serious he is about the whole thing.
Verpies said-but what happens to it once it is absorbed?--MH says it cannot be contained within the ideal device that verpies and yourself just stated absorbed it.
Im wondering if you are seeing how stupid this sounds.
Brad
Well, in this posting I am going to assume that you are not properly conceptualizing what an ideal voltage source does when you pump power into it.
I cracked a joke because Verpies was just asking a silly question for fun. Any power that is pumped into an ideal voltage source doesn't go anywhere. It's simply gone, you can forget about it. The ideal voltage source is still the same ideal voltage source, nothing has changed.
A source that can provide power, must contain the energy within it, in order to provide that power.
Yeah, it contains an infinite amount of energy. So where does that get you? If a coil pumps more energy into a "container" that stores an infinite amount of energy then voila!, you still have a container filled with an infinite amount of energy.
Or, if you want to be "more sophisticated" you can forget about the container altogether and just call it an ideal voltage source.
So it's time to stop spinning your wheels and stop the trash talk.
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So just provide one example of a voltage source that can supply power,but has no stored energy within that soufce.
Brad
This is a ridiculous discussion and you are just wasting time.
Here is the answer to your question: I take a paper napkin and a pen, and I mark a few lines on the napkin, and there is your ideal voltage source and there is no stored energy in sight. The _idea_ that it can supply energy is in your mind only, and that's all that counts.
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tinman, forget about concepts and abstractions- you obviously can't handle them.
They're no use in the "real world" anyhow.
Forget about 5 Henry inductors- they're too big.
Make yourself a Maxwell bridge and have a bit of fun learning what that can do.
John.
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They're no use in the "real world" anyhow.
Forget about 5 Henry inductors- they're too big.
Make yourself a Maxwell bridge and have a bit of fun learning what that can do.
John.
tinman, forget about concepts and abstractions- you obviously can't handle them.
Dont give me that crap John,it's not me here thats talking double dutch.
Concepts and abstractions dont cut it,and if i have to be precise ,then so dose everyone else.
Perhaps take some time,and look up the definition of precision. ;)
Keep on reading,and see who is making no sense in this thread.
You continue on with your wollowing's,and yet know no better yourself.
Brad
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Well, in this posting I am going to assume that you are not properly conceptualizing what an ideal voltage source does when you pump power into it.
And here we go--MHs paradox that is needed so as he thinks he is not wrong in his statement-but falls apart with another of his own statement's.
So now we have an ideal voltage !source!,that has power pumped into it(a missing component of MHs 2 component circuit),even though it cannot store it ::)
So the ideal voltage source is now just some part that the incoming power passes through(as it cannot store it),and just flows straight into the inductor :o.
A capacitor(a voltage source)that has a voltage across it,contains stored energy.
A battery that has a voltage across it ,contains stored energy.
A sponge that absorb's water,contains that water.
I cracked a joke because Verpies was just asking a silly question for fun. Any power that is pumped into an ideal voltage source doesn't go anywhere. It's simply gone, you can forget about it. The ideal voltage source is still the same ideal voltage source, nothing has changed.
And this is the best yet.Any power that is pumped into an ideal voltage source doesn't go anywhere. It's simply gone
You have excelled your self there MH.You have just defied the laws of physics,and now it has to be rewritten. Energy can be transformed from one form to another-and also be destroyed by MHs voltage source ;)
A recap on what you said above in the previous paragraph-->So now we have an ideal voltage !source!,that has power pumped into it
Then in the next paragraph-->Any power that is pumped into an ideal voltage source doesn't go anywhere
So this power that is feeding the voltage source dose not make it to the inductor???,as you have stated it dose not go anywhere--just disappears.
I dont even have to go to any other of your post to put all this together--you have it all in one post MH :D
Yeah, it contains an infinite amount of energy. So where does that get you? If a coil pumps more energy into a "container" that stores an infinite amount of energy then voila!, you still have a container filled with an infinite amount of energy.
So now your ideal voltage source dose contain energy?,or is this just the supply of energy that go's into the voltage source that just disappears?.
Or, if you want to be "more sophisticated" you can forget about the container altogether and just call it an ideal voltage source.
So it's time to stop spinning your wheels and stop the trash talk.
Have a good look at your own statements above MH,and then ask your self--who is talking trash.
You are so lost it's not funny anymore,and your buddy minnie is not that far behind you.
Brad
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This is a ridiculous discussion and you are just wasting time.
Here is the answer to your question: I take a paper napkin and a pen, and I mark a few lines on the napkin, and there is your ideal voltage source and there is no stored energy in sight. The _idea_ that it can supply energy is in your mind only, and that's all that counts.
Another idiotic statement.
Lets see your paper napkin induce a current into an inductor--see how stupid that sounds MH.
You asked a specific question base around two components.
We know we can get very very close to an ideal inductor in the real world,and !you! have stated many times that we can build an ideal voltage source(which of course we cannot). And now we are going into the land of MHs make believe,by way of lines on a paper napkin to solve MHs question.
And you wonder why i say you are the laughing stock of the forum.
Well we only have to look at the last few of your posts to see why.
Im not interested in following you up the garden path of MH wonder land,where reality give way to paper napkins.
Brad
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I read every word. How was that post helpful to anyone?
I encourage you to avoid the so-called rhetorical questions, and instead try to help Brad understand why his thinking on this affair is a little off the tracks
.
My thinking is off track???
It is not me that thinks this ideal voltage source can absorb energy but not contain it.
Did you guys really think about this statement,and how it go's with other agreed upon definitions that have been made about the ideal voltage source?.
Sometime's you EE guys make no sense at all,and it's no wonder people get confused.
We have all agreed that an ideal voltage source dose not dissipate any power,as it's ideal.
If the ideal voltage source can absorb power,but cannot dissipate power-->where is this absorbed power if it is not contained within the ideal voltage source?.
Is it just like MH said,and it just vanishes without a trace--it's just gone--the energy is destroyed?
Do you see how ridiculous this sound's,and how far away from the fundamentals of science this is.
Here you are Poynt,saying that i should agree with what is being presented by the EE guy's here,but there is no way in hell i am going to settle on anything when statements such as above are being asked to be accepted,as statements such as MHs contradict them selves,and the others make no sense at all.
So my question remains--what happens to the stored energy (during the 0 volt part of the cycle),when the negative 3 volt part of the cycle start's?
1-MHs theory-->it just disappears--energy is destroyed.
2-it is stored in the ideal voltage source?
3-it is absorbed by the ideal voltage source that cannot dissipate power=stored in the ideal voltage source.
Unlike MHs mockery of this thread,i wish to solve this question correctly. But while there are nonsensical comments like-energy can be absorbed but not stored in a device that cannot dissipate that absorbed energy,then i will simply not be agreeing to anything.
So maybe you can try and make sense of that ,and let me know what it is,as i know of no other device that can have a voltage across it,but not have stored energy within it. And this rubbish about energy just disappearing by MH,is nothing but a joke.
So to put it simple,how can a component that absorbs energy,but cant dissipate energy,not store that energy?.
Brad
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@MH
You really are either willfully ignorant or willfully deceptive.
Give me one reason why for endless pages and pages i would disagree with your question continuously stating to you that ideal voltages do not change in time. @verpies again just confirmed this. You knew all along that we did not "understand" your question because there was no other reason for anyone to object to the question unless they understood the whole process to be one event.
You willfully, and, I have to add with the aid of others who were in the know but decided to just shut up and let the commotion continue endlessly, decided to not clarify the question and leave it as the ambiguous piece of shit it was. You had the choice but you decided to just play along, you fed the fire, you were implicit in this and played us for fools for two weeks.
You knew that one little clarification that would not have given out any of the answers to your question but would have brought more fluency to the question would have solved the whole matter, but you decided to both play your, "I am an EE king and you need to learn boy attitude". So now I know how much of a prick you are and will leave you to play with yourself.
You are an insult to EE teaching and I have to say now that those who knew were the small discrepancy was in this question and did not step forward to provide a correction are no better. But the onus was fully on @MH as he played the teacher fiddle and he knew the question was not in tune but he kept on whipping away enjoying ever minute.
So now, no more trust. You burned that one to hell this time. You played us for fools. You are now off my list. If I ever see you on any of my threads, you will be deleted so don't bother. I have no more trust in your opinions since I know now you are only on this forum to up your own ego. So enjoy it.
@tinman
Listen. I am only going to say this once. If you knew @MH's question involved 6 separate events combined in one sequence, then you had no damn reason to object to his question. So don't pretend you fully understood his question because that would be adding to the pile of bull already on the floor.
@all
All you guys do is play games. Every thread starts holy molly and ends in bullshit. And what did you learn about the coil, F all, but keep on plastering those games all over the placed and wish and wish and wish some more.
wattsup
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@MH
@tinman
Listen. I am only going to say this once. If you knew @MH's question involved 6 separate events combined in one sequence, then you had no damn reason to object to his question. So don't pretend you fully understood his question because that would be adding to the pile of bull already on the floor.
wattsup
And when did i object to his question?
I started this thread to answer his question,not object to it--so i dont know what page you are on,but it's the wrong one.
I fully understood his question from the day i read it,and did not object to the question at all.
I object to the fact that the EE guys think the answer is simple and straight forward,as when you use ideal components,it is never straight forward.
So i really do not know why you have said what you have said,as i do not object to the question,nor have i ever done so--other than the use of ideal components that dont exist being used in the question.
If real world components were used in place of the ideal components,then the answer is pretty straight forward,and that answer would depend on how much information MH required for the answer. Would he want to know things like magnetic field strengths during each part of the cycle?. Would he want to know coil temperatures at the start middle and end of the cycle?.
When you ask--what happens from T=0,leaves a very big list to choose from,and this was unspecified in the question.
Brad
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Wattsup:
You are truly baffling, and even Brad says you are baffling. From your comments it's like you are on another planet.
Brad:
The only thing you need to know about the ideal voltage source for this question is that it puts out the waveform as described.
So can you move forward now and try to answer the question?
MileHigh
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And when did i object to his question?
I started this thread to answer his question,not object to it--so i dont know what page you are on,but it's the wrong one.
I fully understood his question from the day i read it,and did not object to the question at all.
I object to the fact that the EE guys think the answer is simple and straight forward,as when you use ideal components,it is never straight forward.
So i really do not know why you have said what you have said,as i do not object to the question,nor have i ever done so--other than the use of ideal components that dont exist being used in the question.
If real world components were used in place of the ideal components,then the answer is pretty straight forward,and that answer would depend on how much information MH required for the answer. Would he want to know things like magnetic field strengths during each part of the cycle?. Would he want to know coil temperatures at the start middle and end of the cycle?.
When you ask--what happens from T=0,leaves a very big list to choose from,and this was unspecified in the question.
Brad
@tinman
Wow, this is playing out to be one hell of drama here.
I cannot believe if you knew what the actual question meant, you would have had a problem answering it then. The only reason I backed you up in this is because I saw this question as to ambiguous and did not openly imply 6 separate MANUAL settings of voltage. In my book there was no other VALID reason to object to it since we all new it was under ideal conditions. We know ideal conditions do not exist but the way the question was asked was in my book, deceptive in the process, not in the substance.
So good luck then.
Added: When did you object to the question? Just look at the JT thread which is the origin.
@MH
When you ask a question, you know, if your life depended on that question, you would be toast by now. Everyone should just go back and read the question from the stand point of an outsider, not your EE brainiacs perspective. Questions are not for those that are in the know. They are for those that want to understand your viewpoint. It's your view you want to bring across and you did a shitty job of it. I don't know where @tinamn is coming from to say he understood it. If he did, then bads on him.
Enough of this.
wattsup
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Brad:
If real world components were used in place of the ideal components,then the answer is pretty straight forward,and that answer would depend on how much information MH required for the answer. Would he want to know things like magnetic field strengths during each part of the cycle?. Would he want to know coil temperatures at the start middle and end of the cycle?.
We already discussed a variation on the question. How about you answer it where you add an 0.00001 ohm resistance to the 5 Henry coil? That's the only thing that needs to be added. The answer will be almost identical, you are free to go that route if you want.
There is no need to know the magnetic field strength, and no need to know the coil temperature.
MileHigh
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@tinman
Wow, this is playing out to be one hell of drama here.
I cannot believe if you knew what the actual question meant, you would have had a problem answering it then. The only reason I backed you up in this is because I saw this question as to ambiguous and did not openly imply 6 separate MANUAL settings of voltage. In my book there was no other VALID reason to object to it since we all new it was under ideal conditions. We know ideal conditions do not exist but the way the question was asked was in my book, deceptive in the process, not in the substance.
So good luck then.
wattsup
Here is the problem with being able to answer the question using ideal components.
1- if the coil is ideal,then why would not the CEMF be ideal to the EMF that created it?
If the CEMF is ideal,and equal to the EMF,would current ever flow through the coil?.
2- If the voltage source is ideal,it cannot dissipate power. If it absorbs power,and cannot dissipate power,why dose it not store that power as MH says?.
MH says an ideal voltage source can deliver energy,but dose not contain any energy.
He then says that an ideal voltage source can absorb power,and that power just is gone-disappears,no longer exist.
To many holes in the question when ideals are included.
To many holes in MHs explanation.
To many other EE guys agreeing with some of these MH paradoxes that are nonsense.
If we are to come to some sort of correct answer,then these nonsense's need sorting.
To look at the question again
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts. Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts. Then after that the voltage is zero volts.
What happens from T=0 when the ideal voltage is connected to the ideal coil?.
It is clear that an ideal voltage source delivers a volatge selected by the user,and will maintain that voltage no matter what the load. The voltage value can only be determined and change by the user--not the load.
The user(MH) has selected a voltage of 4 volts to be placed across the ideal coil,for a period of 3 seconds. After the first 3 seconds, he then changes that voltage value to 0 volts,for a period of 2 seconds. After that two seconds is up,he inverts the polarity,and selects a voltage value of 3 volts,for a time period of 2 seconds. After that period of 2 seconds is up,he then selects a voltage value of 500mV for 6 second's. As he dose not mention !negative! at this point,we can assume that the voltage polarity at this point in time,is now back to the original polarity-being the positive polarity. After this 6 second time period,the voltage value is then selected to be 0 volt's.
I do not see the problem in understanding the voltage wave form that would be associated with this question. What i do question is would that actually be the case,and would this ideal circuit follow the same rules as real world components?.
Brad
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He also stated -but what happens to it?.
Yes, that is a good question too.
But I'd like your answer on the concept that the source can and will absorb energy from the inductor.
Do you agree or disagree?
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What's the problem?
I.V.S. able to supply/absorb any amount of current.
The current through I.V.S. Completely under the control of the external circuit.
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I know some here and perhaps many that have followed this thread think that this is some kind of futile exercise that has no bearing on our OU efforts so let's get back to work!
Well, consider this- If I should see some kind of odd result in my prospective OU creation, how do I determine if the anomaly I see is the result of some newly discovered function or simply the result of conventional functions that slipped past me because of my lack of understanding. This has happened to me more times than I would like to admit and it is the reason I strive to understand the basics so I will be able to recognize a true anomaly if and when it occurs.
I believe that this was/is the intention of MH when he proposed the original problem as well as others who have contributed along the way. Whether the problem uses ideal components as originally stated or real world components as later stated, the resulting differences are insignificant. The point is, do I understand how to solve this problem or not?
partzman
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Yes, that is a good question too.
But I'd like your answer on the concept that the source can and will absorb energy from the inductor.
Do you agree or disagree?
I cannot agree to the ideal voltage source being able to absorb energy if it cannot contain it.
If any energy is absorbed by the ideal voltage source,and that ideal voltage source dose not dissipate energy,then the energy must now be contained in it(the ideal voltage source).
I cannot agree with MHs statement that the energy is just gone-disappears.
MHs question consists of two components only--the ideal voltage source,and the ideal inductor. He has made this apparent many times when he has stated that EMJ and Wattsup could not answer a simple question that involved on two components.
MH also states that the ideal voltage source can deliver energy,but dose not contain energy.
At T=5s, what would the solution below read?
And then again at T=7s,what would the solution below read?.
Brad
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MHs question on the JT thread
What happens to the energy if you pump 100 watts of power into an ideal voltage source for 10 seconds
Poynt
Am i correct in saying-->as an ideal voltage source dose not dissipate any energy,the energy is contained in that ideal voltage source.
Brad
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My assumption would be that since the Ideal Voltage Source has no means to dissipate nor store energy that the current flow would continue from the inductor through the Source, and at the time of the reversal of the polarity that the source would initiate a stream of charge carriers moving in the opposite direction.
Considering that at the time of a drop in voltage from the source the conductors self-inductance turns the conductor into a source, but not an ideal source, the 5h rating, it has a limit on stored energy and with no input from the source that energy would dissipate.
To hold against a change in current flow the self-inductance would need to be infinite but since it is not then the induced magnetic field would be less and resultant CEMF would be less.
So then,, at the moment the polarity is reversed from the source there would be no impedance to current flow from the source until the prior stored energy is dissipated.
And the value of that unimpeded current flow at this time would be?
Brad
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When T=7s,would the below be correct?.\
Brad
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Try looking at "abstraction" in Wiki and then it might make more sense.
John.
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tinman,
Seems there's just too many floating variables to nail down any of the 'weird' properties that show up at the extremes of an inductor.
In retrospect, you should have asked about an ideal capacitor, and the paradoxical properties of 'displacement current' ;D
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How John?
Perhaps like this:
http://www.oxforddictionaries.com/definition/english/abstraction
The process of considering something independently of its associations or attributes.
"The question cannot be considered in abstraction from the historical context in which it was raised."
"When, for instance, we claim that water can freeze, we consider water simply as such, in abstraction from the conditions in which any given amount of water finds itself."
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Brad:
Your postings #543, 544, 546, 547, 552, 553, 554 and 555 are all just useless trash talk. Poor Brad is having difficulty understanding what an ideal voltage source is and how it works and he can't wrap his mind around a few concepts that are associated with the abstract concept of an ideal voltage source.
So we have to endure yet another ridiculous push-back and a whole litany of what are basically nonsensical statements from you. You are trying to attach real and tangible properties to what is just an abstraction. You are back trying to force pieces of a jigsaw puzzle together that don't fit because apparently that's the only way your brain can process it, or, it's an obstinate refusal to learn.
A discussion about a simple circuit that has an ideal voltage source in it should be about the operation of the circuit, not about how an ideal voltage source works. You are just causing problems where there are no problems and in that sense your behaviour is the same as Wattsup's behaviour where he is freaking out about the very simple and straightforward question.
So that's eight postings that should never have even been made because they are all useless and don't deal with the question, as well as mostly being useless trash talk.
From the very start, there should have been no disagreement at all about what an ideal voltage source is, and how it works. You have to do better than that, and it's time to move on.
MileHigh
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I cannot agree to the ideal voltage source being able to absorb energy if it cannot contain it.
If any energy is absorbed by the ideal voltage source,and that ideal voltage source dose not dissipate energy,then the energy must now be contained in it(the ideal voltage source).
I cannot agree with MHs statement that the energy is just gone-disappears.
MHs question consists of two components only--the ideal voltage source,and the ideal inductor. He has made this apparent many times when he has stated that EMJ and Wattsup could not answer a simple question that involved on two components.
MH also states that the ideal voltage source can deliver energy,but dose not contain energy.
At T=5s, what would the solution below read?
And then again at T=7s,what would the solution below read?.
Brad
No Brad, we are asking you for what would be happening in the circuit at t=5 seconds and t=7 seconds. And if you can't put numbers to it yet, we are asking you to tell us what you think should be happening and why it should be happening. That is the whole point of this exercise, to learn how the circuit works and to understand the concepts and to demonstrate competency.
For example, let's back up for a second. Look at the first three seconds where you have been given the answer. Please explain why there is a linear ramp of increasing current up to 2.4 amps. Why is that? How do you explain it? This is what this thread is all about, and I don't think you have even explained the answer to the first part of the question that has been given to you. Can you explain the ramp up in current to us in your own words? Why is it 2.4 amps at the end? Why isn't it two amps or three amps?
It's too bad your peers have dropped out, I guess they don't know themselves and aren't comfortable trying to brainstorm with you. The only brainstorming I can recall was the usual pie-in-the-sky brainstorming talk about electrons and electron drift and all that jazz that had nothing to do with the question.
It would be great if you met those two goals that I have posted several times.
MileHigh
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At T=5s, what would the solution below read?
And then again at T=7s,what would the solution below read?.
I did not follow the discussion and I am not sure what the values for the inductance (L), exciting voltage(V) or resistance (R) are supposed to be in this case. Without these values I cannot make the calculation.
Anyway, whatever these values are, I would use the first formula if R>0 and the second formula if R=0 to calculate the evolution of the current in time i(t) flowing through the inductor. This is because the first formula degenerates into the second formula when R approaches 0 Ohms.
P.S.
These formulas are accurate only when the inductance (L), exciting voltage (V) and resistance (R) do not vary in time. If they do, than much more complicated formulas would need to be used.
But if there is only an initial current I0 already flowing at the time t0, then its value should be simply added to the result.
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Verpies:
Thanks for the two formulas. Way back earlier in this thread I told Brad you use the appropriate formula for the appropriate circuit. If there is no resistor in the circuit then you don't work with a formula that includes an undefined L/R (or V/R) of infinity. Of course with Brad that was another battle.
The formulas are fine but of course, and just to repeat myself, the purpose of this thread is for Brad and his peers to actually understand the how and the why, and demonstrate full competency with respect to this subject matter. As we know, there is a potential downside in providing formulas because then you rely on the formulas only without thinking.
MileHigh
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As we know, there is a potential downside in providing formulas because then you rely on the formulas only without thinking.
Of course. Conceptual understanding should always precede mathematical analysis.
Sadly, often this is not the case.
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So my question remains--what happens to the stored energy (during the 0 volt part of the cycle),when the negative 3 volt part of the cycle start's?
1-MHs theory-->it just disappears--energy is destroyed.
2-it is stored in the ideal voltage source?
3-it is absorbed by the ideal voltage source that cannot dissipate power=stored in the ideal voltage source.
Yes, 3 would be the answer. And you reaffirmed that you can't agree with that.
So to put it simple,how can a component that absorbs energy,but cant dissipate energy,not store that energy?.
You agree that during the period when the voltage source is 0V, it looks essentially like a short across the inductor? Why does the current flatline during this period?
You agree that during the period the voltage source is 4V, the current ramps up? Why does it do that? What would happen if the startng voltage was -4V rather than +4V?
From this you may be able to deduce, at least in concept, what the current does when the voltage source reverses polarity from the initial voltage.
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Miles, your conceptualization of an Ideal Voltage Source
reminds one of the demonstrations of Daniel Pomerleau. ???
The Sources of electrical energy in his demonstrations
are simply coils of wire; yet, when Daniel is in communion
with the True Source electrical energy mysteriously appears
and it actually powers whatever devices are connected to
Daniel's coils of wire. ???
In his (Daniel's) case the Source isn't really a Source but more
akin to a Conduit. A conduit which conveys the energy from a
real source somewhere outside our physical dimension. :o
Apparently something has changed in how Ideal Voltage Sources
are taught in today's World. If, that is, your conceptualization is
characteristic of what is taught these days. ::)
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Yes, 3 would be the answer.
3-it is absorbed by the ideal voltage source that cannot dissipate power=stored in the ideal voltage source.
Thank you.So it is stored in the voltage source,and not just disappears as MH say's. But of course,we knew that was a ridiculous statement anyway.
And you reaffirmed that you can't agree with that.
That is correct,and i draw your attention to verpies comment below.
These formulas are accurate only when the inductance (L), exciting voltage (V) and resistance (R) do not vary in time. If they do, than much more complicated formulas would need to be used.
As at T=5s,the ideal coil loop has a steady DC current flowing through it. At this point in time,there is no induction taking place. At T=5s,a negative 3 volts is placed across the coil. How is the L value of that coil changed when the now negative EMF first has to pull down the existing current flow to a value of 0,before the opposite current flow starts to flow?.
You agree that during the period when the voltage source is 0V, it looks essentially like a short across the inductor? Why does the current flatline during this period?
It flat lines at 2.3 amps because there is no impedance to the current flow during the 0 volt time period,and so it retains that 2.4 amp current flow reached at T=3 seconds. Since both the coil and voltage source are ideal,then no power is dissipated,and so the current flow remains a constant until T=5s.
You agree that during the period the voltage source is 4V, the current ramps up? Why does it do that? What would happen if the startng voltage was -4V rather than +4V?
The current ramps up because the CEMF is reducing,due to the magnetic fields change in time decreasing. If the applied voltage was inverted(negative),then the current would flow in the opposite direction through the current loop.
From this you may be able to deduce, at least in concept, what the current does when the voltage source reverses polarity from the initial voltage.
Yes. It would first have to stop the current flow that already exist in the loop,before it could start to flow in the opposite direction. Being an ideal voltage from an ideal source,it would want to instantly collapse the existing magnetic field around the coil to a non existent state to stop the existing current flow,so as it can start to induce the reversed current flow into that coil.
So what effect dose this have on how the EMF sees the L value of the inductor?.
Brad
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If we are to take things as being !normal!,and the inductance value seen by the EMF is not changed due to the existing current flow at T=5 seconds,then i have plotted my current trace below for the entire cycle.
I would first ask that MH say whether it is correct or not,before anyone else says whether or not it is correct.
Brad
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Brad:
The request is that you explain how you arrived at that curve and that you demonstrate that you understand the principles at play and you know what you are talking about.
I am getting too much of a Jiffy Pop popcorn vibe due to the seemingly instant magical appearance of that waveform. Please explain the whole waveform.
MileHigh
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Brad:
The request is that you explain how you arrived at that curve and that you demonstrate that you understand the principles at play and you know what you are talking about.
I am getting too much of a Jiffy Pop popcorn vibe due to the seemingly instant magical appearance of that waveform. Please explain the whole waveform.
MileHigh
MH:
If they don't have Kool-aid in OZ then I doubt they have Jiffy Pop either. Man, what a great product that was. I think you can still buy it in some places. What ever happened to Fizzies? Remember them? Except for a ref. to them in the movie Animal House in 1976, I have never seen nor heard of them. I used to love those things.
Bill
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I had no idea that Jiffy Pop was not really available anymore. I am devastated. I don't know what Fizzies are.
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I had no idea that Jiffy Pop was not really available anymore. I am devastated. I don't know what Fizzies are.
https://en.wikipedia.org/wiki/Fizzies (https://en.wikipedia.org/wiki/Fizzies)
They were like little tablets in a foil pouch that you dropped into a glass of water and, it carbonated and flavored it to make soda! My favorite was root beer. They sort of worked like an Alka-Seltzer tablet, except with flavoring. Very big in the US in the mid 1960's. The above link says they sold twice as much as Kool-Aid...I didn't know that.
Bill
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Brad:
The request is that you explain how you arrived at that curve and that you demonstrate that you understand the principles at play and you know what you are talking about.
I am getting too much of a Jiffy Pop popcorn vibe due to the seemingly instant magical appearance of that waveform. Please explain the whole waveform.
MileHigh
I have posted that waveform going on what i believe Poynt and your self are asking me to believe will happen.
Now i ask you if you believe that wave form is correct.
Once you have stated a yes or no,i will tell you how i derived at that waveform for the current.
Once that is done,we will discuss the issues i believe may change the outcome of the waveform posted.
So it is a simple yes or no MH.
Brad
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The waveform is correct.
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I might remind you MH,that your question asks 'what happens from T=0!
I have answered that question in way of the current trace graph,as that is about all that happens-rising and falling current flows. You have already stated that i need not worry about the magnetic fields'although there value would just rise and fall with the current. As we are dealing with ideal components,then no heat or power is dissipated from the closed loop.
You question dose not ask as to how i calculated the answer,only what happens through the entire cycle at each time period.
So you have my answer,and im asking you if it is correct.
Yes or no is all thats needed.
Brad
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We must thank the likes of MH. poynt etc. for their patience in inching us along.
Yep, you''''re right, present is prepared out of thank, a fan-site is now running, 682 members, also including:
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The waveform is correct.
I am getting too much of a Jiffy Pop popcorn vibe due to the seemingly instant magical appearance of that waveform. Please explain the whole waveform.
There wasnt any Jiffy Pop (what ever that is) popcorn moment MH. As i stated to you some time back,a generic calculated answer was quite simple--refer to post 569,where i posted the formula used from T=5 seconds to T-7 second's,as also posted below.We just subtract or add the calculated value to that of the previous value--depending on what polarity you stated in your question. Then it's just a matter of playing-join the dots. But my argument was and still is,that is not the correct answer/current trace when using ideal's.
The 2.4 amps flowing through the loop at T=5 seconds,will be an impedance against the current that is induced at T=5 seconds,that is of the opposite polarity. The calculated current peak value at T=7 seconds,is calculated based around the inductance value,time and a starting current of 0-->I=Io. As the polarity is now reversed,that current value is actually I=I-2.4amps.
So i am not sure that simply subtracting(due to it being the negative voltage part of the cycle) the calculated peak current value at T=7 seconds from the value at T=5(2.4 amps) seconds is correct,as the impedance value of the coil at T=5 seconds is higher than would normally be seen by the current flow,should the current start with a value of 0.
Brad
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Well, you are seemingly making progress, and I am going to ignore the various errors in what you posted because what you are saying is more important in the "error glitches" in your posting.
But I have a question for you: Way back very early in the thread I posted that formula and told you that it was basically the short answer to the question. When I did that you went into a small frenzy and you insulted me like a drunk sailor. So what gives, how do you explain using the formula now when before when I showed you the very same formula you insulted me repeatedly like a drunk sailor?
Don't even bother saying that you don't drink, it's just an expression.
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Well, you are seemingly making progress,
But I have a question for you: Way back very early in the thread I posted that formula and told you that it was basically the short answer to the question. When I did that you went into a small frenzy and you insulted me like a drunk sailor. So what gives, how do you explain using the formula now when before when I showed you the very same formula you insulted me repeatedly like a drunk sailor?
Im not sure if you read everything i write or post,but you seem to keep missing the fact that i do not agree with the results of your formula,and believe the values are wrong.
I told you right from the start,that using your generic formula would be an easy way out,but the results would not be that that your formula would show.
and I am going to ignore the various errors in what you posted because what you are saying is more important in the "error glitches" in your posting.
How is it i made errors,when the result is correct-as far as your concerned ?.
The method i used seemed to be correct,as the result was what you were looking for.
I do not believe the current value reached at T=7 seconds is correct.
I am not sure that it should be I=I 2.4 - 1/5 integral V dt.
I believe as verpies said,there is a higher order of math required here.
The 2.4 amps that is flowing opposite to that of the current to be induced by the negative value between T=5 and T=7,will be seen as a high impedance to that current to be induced during the negative portion of the cycle. This impedance value is greater than that which would be encountered by the current flow during the negative voltage part of the cycle to that of if the existing current of 2.4 amps was not there.
Our calculated current for T=7 seconds is 3/5 x 2=1.2 amps. This is calculated on the assumption that I=0 at the time of the calculation. But we have an I value of 2.4 amps of the opposite polarity,not a value of I=0.
As i said,i do not believe that subtracting that 1.2 amps from the negative voltage phase,from the previous 2.4 amp value is the correct way to do this,and gives a wrong answer when done like this.
The inductance value seen by the EMF during the negative phase,must be much lower due to the existing steady state current flow that is apposing the current to be induced during the negative voltage part of the cycle. The other problem is,there is no give in the voltage being applied across that coil loop,in that no matter what the load,the ideal voltage source will apply that full selected voltage across the coil. To me,this would be like trying to stop a spinning flywheel instantly.
Perhaps verpies and/or Poynt might think about that a bit,and see if it is as straight forward as some think it is.
And MH--->we need to call a truce here,as all this bickering is doing no one any good.
At the end of the day,we should all be here for the same reason,and that being they very name and nature of the forum.
I am not blaming it all on you ,as i know i have given as good as i have gotten.
Perhaps when we disagree ,we can just agree to disagree.
Don't even bother saying that you don't drink, it's just an expression.
I gathered that. The truth is,i am having a bourbon and coke right now--just one,for a mate(we call friends mates over here-just in case you take the word !mate! the wrong way) that passed away early this morning.
Brad
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Perhaps verpies and/or Poynt might think about that a bit,and see if it is as straight forward as some think it is.
My question to you Brad is what do you think will happen? In other words, please draw out the current wave form according to your theory of how the voltage source and inductor would interact.
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Brad:
I am going to ask you the question again:
Way back very early in the thread I posted that formula and told you that it was basically the short answer to the question. When I did that you went into a small frenzy and you insulted me like a drunk sailor. So what gives, how do you explain using the formula now when before when I showed you the very same formula you insulted me repeatedly like a drunk sailor?
MileHigh
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My question to you Brad is what do you think will happen? In other words, please draw out the current wave form according to your theory of how the voltage source and inductor would interact.
As i said,it's not so easy to work out when dealing with a voltage source and coil that form a loop that current can flow through unimpeded.
What happens when two 12 volt batteries are looped in series?.
We now have two voltage sources where a voltage cannot be measured at the terminal's,but we have lot's of current flowing through them. How do you measure that current flow if the series loop resistance is 0 ohms?.
i dont think there is much point in posting my thought's,as it seems you and MH have made up your mind's,and anything i say will just be dismissed anyway.
As MH has said that my current values and the trace i have drawn out are correct,and that you have agreed with MH most of the way through this topic,then it is safe to say that you also agree that my provided values,times and current trace are also correct,as far as your concerned.
So is there any real need to go on?.
Perhaps you could show us how you would calculate the peak current at T=7 second's?.
What is the formula and values you would use?.
Brad
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i dont think there is much point in posting my thought's,as it seems you and MH have made up your mind's,and anything i say will just be dismissed anyway.
As MH has said that my current values and the trace i have drawn out are correct,and that you have agreed with MH most of the way through this topic,then it is safe to say that you also agree that my provided values,times and current trace are also correct,as far as your concerned.
So is there any real need to go on?.
The point of asking you to draw out the wave form not so we can just dismiss it, it is to see how your thinking has caused you to arrive at your theory, and to see how to steer you toward the correct understanding. Yes of course your wave form trace is correct. It is not MH's way btw, it is just how it is, it is physics and it is reality (even with an ideal or near-ideal inductor).
Perhaps you could show us how you would calculate the peak current at T=7 second's?.
What is the formula and values you would use?.
Brad
I would use the formula MH posted. But I prefer to use the sim, which btw, fully supports the formula and the graph you have drawn out.
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TinMan extends a Kind hand in a peaceful gesture to move forward!
MileHigh wants more Blood ,and curls The Lip?
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Brad:
I am going to ask you the question again:
Way back very early in the thread I posted that formula and told you that it was basically the short answer to the question. When I did that you went into a small frenzy and you insulted me like a drunk sailor. So what gives, how do you explain using the formula now when before when I showed you the very same formula you insulted me repeatedly like a drunk sailor?
MileHigh
OK MH
I will try and explain this one more time.
1st-As i said,i was giving back as good as i was getting,as far as your insulting go's.
I would like to point you toward post two,the very second post on this thread,and your very first post on this thread-->quote: You are one strange egg Brad because you think you are "running the show" now but in fact the show is running you.
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he is wrong when he stated that my response to the harder question is wrong.
You will see my first post said--Please keep the insults down,and the language clean.
And my last line in that post was-->For the record,could you please post your answer to your question above?
As you can see,i asked for insults to be kept down,and also asked you very politely to post your answer. So i think you can see from just the first two posts on this thread,who wanted it to run smooth without insults,and who was the first to cast the first insult--and it just escalated from there.
Perhaps you should go and read the first page of the thread,and see who was demeaning to who.
2nd- As i have already tried to explain to you,i do not agree that the formula being used is correct from T=5 seconds to T=7 seconds. I only used your formula to show you that i am quite capable of dealing with generic formulas,and calculating generic results. I told you i could do this very early in the thread--perhaps you thought i could not. All the information to do so is on the net,and i can learn very quickly.
But once again,i only gave you what you wanted to see,and i gave it correctly.
But as i have said on more than one occasion now,this dose not mean that i believe them to be correct in this situation. In a non ideal situation,this collision of energy would be burnt of as heat,via the internal resistance of the voltage source and the coil it self. But being that we are in an ideal situation,this collision energy cannot be dissipated as heat,as there is no series resistance in the circuit.
Brad
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The point of asking you to draw out the wave form not so we can just dismiss it, it is to see how your thinking has caused you to arrive at your theory, and to see how to steer you toward the correct understanding. Yes of course your wave form trace is correct. It is not MH's way btw, it is just how it is, it is physics and it is reality (even with an ideal or near-ideal inductor).
I would use the formula MH posted. But I prefer to use the sim, which btw, fully supports the formula and the graph you have drawn out.
As i said,you are not interested in what i have to say,as you have stated that you wish to !!steer!! me in the right direction.
I have already stated my concerns,and why--several times now,but maybe you missed them all.
How will the steady state current flow of 2.4 amps effect the seen inductance value by the EMF that wishes to induce a current flow in the opposite direction at T=5 second's?. The reason i ask this,is because that current flow of 2.4 amps,will be seen as a high value impedance to the current trying to be induced during the negative voltage part of the cycle. At the moment,the current value for T=7 seconds, is being calculated on the assumption that the inductance value seen by the now negative EMF is still 5H. I am only asking if this higher impedance value,due to the !already flowing! 2.4 amps of current acting against the current that the negative EMF is trying to induce,will alter the inductance value seen by that negative EMF.
To me it seems that the EMF will see a different inductance value,and there for a different impedance value,when the coil has no current flowing through it at T=0, to that when the current flowing through it is 2.4 amps,but of opposite polarity.
To make this clear,please see diagrams below to see the difference that i am trying to explain.
Brad
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@tinman
At least I agree with you the the wave form should not be like that but maybe for another reason.
For me, ideal voltage has zero resistance, ideal inductor has zero resistance so at 4 seconds when the voltage suddenly drops to 0 volts, what is 0 - 0 - at 0 is just like an inductor being disconnected and what happens when an inductor is disconnected especially at 5H, should create a good discharge of the 2.4 * 4 = 8.8 watts. Some will hit back into the ideal voltage but most will just dissipate. At least in real life if you had a 5H coil in your hand changed at 4 volts and 2.4 amps and if you just turned off the power supply, good luck.
So each zero point for me is like an inductive discharge.
Again what is missing is data is the question. We have to suppose to many things. Is it DC ideal voltage. If so then the applied negative is always at zero volts and the positive is the one changing voltage at t0 and at t4 and t6, but then at t6 to t8 both polarities are switched for the applied -3 while the volt meter stays were it is, so you have a different effect because both ends of the ideal voltage are changed.
Anyways, I guess the answer has to be as lazy as the question.
Or, you have to do like 1000 EE students probably have to do when they are confronted with this question is to just play the game, don't break your head, say yes yes yes and just pass. hahahaha
wattsup
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As i said,you are not interested in what i have to say,as you have stated that you wish to !!steer!! me in the right direction.
I have already stated my concerns,and why--several times now,but maybe you missed them all.
How will the steady state current flow of 2.4 amps effect the seen inductance value by the EMF that wishes to induce a current flow in the opposite direction at T=5 second's?. The reason i ask this,is because that current flow of 2.4 amps,will be seen as a high value impedance to the current trying to be induced during the negative voltage part of the cycle. At the moment,the current value for T=7 seconds, is being calculated on the assumption that the inductance value seen by the now negative EMF is still 5H. I am only asking if this higher impedance value,due to the !already flowing! 2.4 amps of current acting against the current that the negative EMF is trying to induce,will alter the inductance value seen by that negative EMF.
To me it seems that the EMF will see a different inductance value,and there for a different impedance value,when the coil has no current flowing through it at T=0, to that when the current flowing through it is 2.4 amps,but of opposite polarity.
To make this clear,please see diagrams below to see the difference that i am trying to explain.
Brad
Brad, the honest truth is that I don't understand your explanation nor your questions. I can't make sense of them. So rather than spending my time trying to understand your theory, I asked you to plot out your current trace according to your understanding, which gives me instant insight into your thinking. Then I might have a chance of steering you in the right direction. But you state that you can not plot out the current according to your theory, while at the same time, rejecting the present accepted theory which is not only predicted by equation and simulation, but makes sense from the conceptual point of view. I think if you are going to reject a theory, you should have one the you feel is the correct one, and be able to explain it and prove that the existing one is incorrect. So far I have not seen this from you.
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...like a drunk[en] sailor?
Aye, to you Land-Lubbers it is just an expression. ;)
To those of us who crewed the "haze gray and underway"
men o' war it was a way of life. Extended periods at sea
develop quite a thirst in the Sailor and when finally in
port to enjoy some "Liberty" sipping the brew was a joyous
relief. ;D
Naturally, too much of the brew leads to some really
odd behaviors which the Sailor is naturally inclined to
indulge in. Hence, the expression of the Land-Lubbers. 8)
Sailors are not offended by the expression. :)
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2nd- As i have already tried to explain to you,i do not agree that the formula being used is correct from T=5 seconds to T=7 seconds.
Brad
Please tell us in your own words what the formula means.
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I have taken the liberty of changing MH's original problem sightly so there is now a period following T3 to T5 from T5 to T8 with -4 volts applied to the 5H inductor. This is equal to but opposite the initial T0 to T3 so we can now see what happens to the inductor current.
One might find it easier to visualize the magnetic field around the inductor and how it varies in relation to the current. I've included an algebraic proof of this relationship.
𝑬𝒎𝒇 = - 𝑵 × 𝚫𝚽/𝚫𝒕 (Faraday’s Law)
𝑬𝒎𝒇 = - 𝑳 × 𝚫𝑰∕𝚫𝒕 (Inductance defined in terms of Emf)
∴ 𝑵 × 𝚫𝚽/𝚫𝒕 = 𝑳 × 𝚫𝑰∕𝚫𝒕 (Substitution)
∴ 𝑵 × 𝚫𝚽 = 𝑳 × 𝚫𝑰 (Reduce)
∴ 𝑳 = 𝑵 × 𝚫𝚽∕𝚫𝑰 (Inductance in terms of flux)
∴ 𝚫𝚽 = 𝑳 × 𝚫𝑰 (Flux over time verses inductance and current over time with 1 turn)
partzman
edit
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Thank you Partzman,
So the input to spin up the flywheel is the same as is required to stop it.
Yes, in that analogy you are correct.
partzman
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In spirit of the thread lets consider an ideal ferromagnetic as a break from the ideal voltage sources.
What properties would such material have?
For sure it wold not exhibit any hysteresis loss and it would not heat up at all when immersed in a changing magnetic flux.
It would not conduct electric current at all so Eddy currents could not form in it.
Would it have infinite permeability? - I don't think so, anymore than an ideal inductor needs to have an infinite inductance.
What are your thoughts?
What other properties would an ideal ferromagnetic have?
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Brad, the honest truth is that I don't understand your explanation nor your questions. I can't make sense of them. So rather than spending my time trying to understand your theory, I asked you to plot out your current trace according to your understanding, which gives me instant insight into your thinking. Then I might have a chance of steering you in the right direction. But you state that you can not plot out the current according to your theory, while at the same time, rejecting the present accepted theory which is not only predicted by equation and simulation, but makes sense from the conceptual point of view. I think if you are going to reject a theory, you should have one the you feel is the correct one, and be able to explain it and prove that the existing one is incorrect. So far I have not seen this from you.
The inductance value is being used to calculate the peak current at T=7 seconds,but the induction process to make this calculation is not correct between the time period T=5 seconds to T=7 seconds. The inductance value being used to make this calculation is not correct. We have started at T=5 seconds,and ended at T=7 seconds to calculate the peak current reached at T=7 seconds. This is on the understanding that the induction process taking place at this time will start with no current flowing through the coil,and no existing magnetic field. We apply our voltage,and current starts to flow,and a magnetic field begins to build(induction). We calculate that using a 5H coil,the peak current value reached at T= 7 seconds will be 1.2 amp's. But as i said,this assumes that there is no current flowing through the coil. This assumes that a current will begin to flow,a magnetic field will begin to form,and the CEMF value will fall as the magnetic fields change in time reduces.
But what we actually have happening here is the opposite.
A current flow and magnetic field already exist .
The current dose the exact opposite to what the calculations we are using say it should.
The current dose not start from 0 and rise to 1.2 amps,it starts from 2.4 amps and falls.
The CEMF produced from this !once again! magnetic field that is changing in time,is now the same as the EMF that created it,and dose not appose it as it should the way we have made the calculation for the time period of T=5 seconds to T=7 seconds.
So we have used a calculation to gain a peak current value at T=7 seconds, that go's on the premise that there will be a Counter EMF--this give us our current rise over time value.
But what we actually have is a current value drop over time,not a rise,and no CEMF,but an EMF working with the induced EMF.
So it would seem to me,that the formula used to calculate the peak current value at T-7 seconds,is not the correct formula to use.
If we have no CEMF but an EMF that is not apposing the inducing EMF,then there is no impedance/resistance to to the induced current flow.
So it makes sense that the current flow would sky rocket instantly,as there is no resistance/impedance to slow or stop it.
Brad
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Brad:
Let's back up and discuss the inductor impedance over the first three seconds. We all know the drill now, the five Henry inductor makes contact with the ideal voltage source, and for the first three seconds the voltage is four volts.
What is the impedance of the inductor over the fist three seconds?
MileHigh
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I have taken the liberty of changing MH's original problem sightly so there is now a period following T3 to T5 from T5 to T8 with -4 volts applied to the 5H inductor. This is equal to but opposite the initial T0 to T3 so we can now see what happens to the inductor current.
One might find it easier to visualize the magnetic field around the inductor and how it varies in relation to the current. I've included an algebraic proof of this relationship.
𝑬𝒎𝒇 = - 𝑵 × 𝚫𝚽/𝚫𝒕 (Faraday’s Law)
𝑬𝒎𝒇 = - 𝑳 × 𝚫𝑰∕𝚫𝒕 (Inductance defined in terms of Emf)
∴ 𝑵 × 𝚫𝚽/𝚫𝒕 = 𝑳 × 𝚫𝑰∕𝚫𝒕 (Substitution)
∴ 𝑵 × 𝚫𝚽 = 𝑳 × 𝚫𝑰 (Reduce)
∴ 𝑳 = 𝑵 × 𝚫𝚽∕𝚫𝑰 (Inductance in terms of flux)
∴ 𝚫𝚽 = 𝑳 × 𝚫𝑰 (Flux over time verses inductance and current over time with 1 turn)
partzman
Thank you, excellent and very informative and enlightening post, especially the new voltage and current vs. time graph.
MileHigh
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In spirit of the thread lets consider an ideal ferromagnetic as a break from the ideal voltage sources.
What properties would such material have?
For sure it wold not exhibit any hysteresis loss and it would not heat up at all when immersed in a changing magnetic flux.
It would not conduct electric current at all so Eddy currents could not form in it.
Would it have infinite permeability? - I don't think so, anymore than an ideal inductor needs to have an infinite inductance.
What are your thoughts?
What other properties would an ideal ferromagnetic have?
I understand fully. But its just pretend world. Anything can be whatever one may want it to be.
Ive been delving back into the resonance projects. Its not pretend. As Ive read over things here, Ive lost interest. Was thinking, as you just did above, of all the hows and whys of it all and it just plain isnt required as the rules are set. So pretty much all the ideal components and equipment are virtually limitless. Pioneer used to make a set of 6x9 speakers back in the early 80s. The magnets were bigger than any other that have been made. The max power handling was labeled 'Unlimited'. It wasnt that they were not telling the truth really. There just wasnt any car amplifiers in those days that exceeded or even came close to the real power handling of the speakers. So in that world back then, they were unlimited in power handling. ;) They were ideal in that world. ;D
Mags
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Brad:
Let's back up and discuss the inductor impedance over the first three seconds. We all know the drill now, the five Henry inductor makes contact with the ideal voltage source, and for the first three seconds the voltage is four volts.
What is the impedance of the inductor over the fist three seconds?
MileHigh
Well,as the impedance is just a resistance to the current that wants to flow,is it correct to say that the impedance is a result of the CEMF?,--as we know,there is no ohmic resistance.
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Methinks a perfect inductor has reactance without resistance. Thus the REAL component
of its impedance would be ZERO.
Has anyone else any trouble with this?
John.
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Has anyone else any trouble with this?
Not me.
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I understand fully. But its just pretend world. Anything can be whatever one may want it to be.
Not fully because the ideal components that we've been taking about here lately, still have restrictions placed on them even if they do not exist in reality. Thus an ideal voltage source must have zero impedance and an ideal inductor must have zero resistance and capacitance. So it is not anything whatever one may want it to be.
Considering ideal components unburdens the thinker from analyzing their imperfections and allows for clarity of their modeling. Thus such components have great conceptual utility.
I think that an ideal ferromagnetic will still have the S shaped BH curve, albeit without hysteresis and coercivity.
However its permeability would be user-adjustable just like the voltage of an ideal voltage source.
What do you think?
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Not me.
Are you saying that an ideal inductor has no impedance in reference to MHs question?.
I would think that anything that acts against a current flow,could be seen as an impedance to that current flow. Impedance is just a form of resistance -is it not?.
Brad
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Are you saying that an ideal inductor has no impedance in reference to MHs question?.
I would think that anything that acts against a current flow,could be seen as an impedance to that current flow. Impedance is just a form of resistance -is it not?.
Brad
verpies was responding to minnie's statement about an ideal inductor having reactance, but 0 resistance.
Reactance is the imaginary part of the impedance equation, so no, verpies is not saying that the inductor has no impedance. The impedance however in this case is purely reactive.
MH's question is a good one; what is the inductor's impedance over the first 3 seconds?
Yes, impedance is a form of resistance to current flow. That should give you a hint how to answer the above question.
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The inductance value is being used to calculate the peak current at T=7 seconds,but the induction process to make this calculation is not correct between the time period T=5 seconds to T=7 seconds. The inductance value being used to make this calculation is not correct. We have started at T=5 seconds,and ended at T=7 seconds to calculate the peak current reached at T=7 seconds. This is on the understanding that the induction process taking place at this time will start with no current flowing through the coil,and no existing magnetic field. We apply our voltage,and current starts to flow,and a magnetic field begins to build(induction). We calculate that using a 5H coil,the peak current value reached at T= 7 seconds will be 1.2 amp's. But as i said,this assumes that there is no current flowing through the coil. This assumes that a current will begin to flow,a magnetic field will begin to form,and the CEMF value will fall as the magnetic fields change in time reduces.
Where and how did you arrive at the notion that at T=5s or T=7s, that no current is flowing?
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Where and how did you arrive at the notion that at T=5s or T=7s, that no current is flowing?
Ok,i give up.
I thought i had explained it quite clearly,but apparently not.
Im not saying that there was no current flowing at T=5 second's--im saying the exact opposite.
Because there is a current flowing at T=5 second's,the inductance value that the EMF see's at T=5 seconds is not correct,due to this already flowing current.
See if this help's.
Lets say there is no current flowing through the inductor.
We apply our negative 3 volts for 2 seconds. That gives us a peak current at the end of the 2 seconds of 1.2 amps.
Now we do the same,only this time there is 2.4 amps flowing through the coil loop.
We once again place our negative 3 volts across the coil for 2 second's. We now have the very same answer as far as current value go's ,of 1.2 amps peak at the end of the 2 seconds.
How can it be the same value,when in one case there is no current flowing through the coil,and in the other case there is 2.4 amps flowing through the coil?.
In one case ,we have a rising magnetic field that will produce a counter EMF,and in the other case,we have a falling magnetic field that will produce an EMF that is not !counter! against the applied EMF.
How is it that the same formula can be used for two very different situations?.
Brad
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See if this help's.
Lets say there is no current flowing through the inductor.
We apply our negative 3 volts for 2 seconds. That gives us a peak current at the end of the 2 seconds of 1.2 amps.
Now we do the same,only this time there is 2.4 amps flowing through the coil loop.
We once again place our negative 3 volts across the coil for 2 second's. We now have the very same answer as far as current value go's ,of 1.2 amps peak at the end of the 2 seconds.
How can it be the same value,when in one case there is no current flowing through the coil,and in the other case there is 2.4 amps flowing through the coil?.
Brad,
First, understand this; the equation tells us what the final value of current will be, not the "peak" current as you have been calling it. That may be part of your confusion.
Ok, with no current flowing (the beginning of the test) if we apply a -3V supply for 2s, the final current will be -1.2A, not +1.2A as you have stated. The current will ramp down from 0A to -1.2A over 2s.
Now, if we do the same and apply our -3V for 2s but this time there is already +2.4A of current flowing, then the current will ramp down from +2.4A to +1.2A, again a change of current (of 1.2A) in the negative direction.
You will note that the final current in these two cases is not nearly the same; one is -1.2A, and the other is +1.2A.
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Are you saying that an ideal inductor has no impedance in reference to MHs question?.
No. I think that an ideal inductor has nonzero reactance and nonzero impedance but it has zero resistance.
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Brad,
Ok, with no current flowing (the beginning of the test) if we apply a -3V supply for 2s, the final current will be -1.2A, not +1.2A as you have stated. The current will ramp down from 0A to -1.2A over 2s.
You will note that the final current in these two cases is not nearly the same; one is -1.2A, and the other is +1.2A.
First, understand this; the equation tells us what the final value of current will be, not the "peak" current as you have been calling it. That may be part of your confusion.
No,it's not my confusion at all. As i have stated a time period,then the peak current reached at the end of that time period is the final current value.
Now, if we do the same and apply our -3V for 2s but this time there is already +2.4A of current flowing, then the current will ramp down from +2.4A to +1.2A, again a change of current (of 1.2A) in the negative direction.
And that there is what i think is the problem.
Is it correct to use the same equation when the coil has a positive current already running through it,to make a calculation of the negative current value at the end of the 2 seconds,as to when that same equation is used when the coil has no current flowing through it,to make a calculation of the negative current at the end of the two seconds.
The coil is in a different state when it has current already flowing through it to that if it has no current flowing through it,but yet we use the equation to calculate the negative current value as if there is no current flowing through the coil.
Example 1.
The coil is open.
We apply a voltage of -3 volts(negative to keep in line with MH question only,and keep things clear)across the 5H coil for 2 seconds. At the end of the 2 seconds,the peak(final) current value will be 1.2 amps. That is 3/5 x 2=1.2. At T=0,the voltage is connected across the coil. First a voltage appears across the coil,and then a short time after,a current starts to flow,and a magnetic field starts to build. This increasing magnetic field causes a CEMF to be developed,and this CEMF is what slows the rise time of the induced current. As the magnetic fields change in time is reduced in value,the CEMF is also reduced,and so the current continues to increase over time. If there was no CEMF,then the current would go straight to it's maximum value. So this CEMF can be seen as the impedance to the current flow.
Example 2.
We are now going through the phases of MHs question.
At T=5 seconds,we apply -3 volts across the 5H coil for 2 seconds.
We once again use the same math(equation) 3/5 x 2=1.2 amps.
The difference this time being that there is already a positive current flowing through the coil,with a value of 2.4 amps. This time a magnetic field already exist,that is opposite to that of what the applied EMF wants to create. This time there will be no CEMF as the current value increases,as the current value in the coil is decreasing from T=5 seconds to T=7 seconds,not increasing. As the current is decreasing in value,the EMF across the coil during this decrease is the same as the applied EMF-->no counter EMF during this 2 second time period.
If there is no CEMF,then what stops the current going straight to it's maximum value when the -3 volt EMF is applied across that coil?.
Brad
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I suggest that you try again Brad because there are several mistakes in each of your examples. Perhaps if you read more about inductors and how they respond to voltage step functions you will be able to put the pieces of the puzzle together and give it another try.
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Brad,
You now have everything at hand required to arrive at the full and correct understanding of the circuit current in MH's question. It has been explained, illustrated, simulated, and elaborated upon. It's now up to you.
I know you can do better and that you can "get it", if you give it a fair and persistent go.
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Brad,
You now have everything at hand required to arrive at the full and correct understanding of the circuit current in MH's question. It has been explained, illustrated, simulated, and elaborated upon. It's now up to you.
I know you can do better and that you can "get it", if you give it a fair and persistent go.
I have already got it,the way you guys are seeing it--as i said to MH,that is not a problem,and the question was never a problem-->when dealing with generic equation's.
But i question those equation's,and the situation they are being used in.
In that we are using an ideal voltage source,and that voltage is retained under any load,then i would expect to see a large reverse(negative) current spike at T-5 second's-the instant the -3 volts is placed across the coil.
This slow drop in current from T=5 seconds to T=7 seconds,is not what i think should be the case.
We already know that if the coil became open,then we would see a polarity change in voltage,and this polarity change would then be the same as the EMF applied at T=5 seconds.
The CEMF is no different to that induced by an electric motor,only it is ass about,where the CEMF will increase with motor speed,resulting in a drop in current draw,and with the coil,the CEMF will decrease over time,resulting in a higher current draw. So an increase in CEMF is seen as an impedance to the current flow,by way of reducing the potential voltage difference between the applied EMF,and the CEMF. In the case of the inductor,the CEMF reduces over time,meaning a larger potential difference between applied EMF and CEMF,resulting in a higher current flow value.
We have no CEMF when the -3 volts is applied,due to a collapsing magnetic field that is of the opposite polarity to that of which the applied-3v EMF wishes to build.
We now have an EMF+ an EMF-->CEMF is gone.
Remove the CEMF from an electric motor while it's running,and what will happen to the current draw?.
Brad
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I have already got it,the way you guys are seeing it--as i said to MH,that is not a problem,and the question was never a problem-->when dealing with generic equation's.
But i question those equation's,and the situation they are being used in.
In that we are using an ideal voltage source,and that voltage is retained under any load,then i would expect to see a large reverse(negative) current spike at T-5 second's-the instant the -3 volts is placed across the coil.
This slow drop in current from T=5 seconds to T=7 seconds,is not what i think should be the case.
We already know that if the coil became open,then we would see a polarity change in voltage,and this polarity change would then be the same as the EMF applied at T=5 seconds.
I can't see how you are "getting it" if you don't see how the equation, and sim works for all cases. So I have to disagree that you get it.
If you are expecting there to be a large reverse current spike, then you're forgetting that the current can't and won't do that in an inductor. By their very nature, inductors don't work that way, and in fact they resist any change in current. As I said, when the -3V step occurs, the inductor current will ramp in a negative direction, no matter what the starting current is. There is no "spike", and the current doesn't instantly go from +2.4A to some negative current value.
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The difference this time being that there is already a positive current flowing through the coil,with a value of 2.4 amps. This time a magnetic field already exist,that is opposite to that of what the applied EMF wants to create. This time there will be no CEMF as the current value increases...
But the value of the CEMF does not depend on the level of magnetic flux and current flowing through an ideal coil.
The CEMF depends on the rate of change of the flux and current.
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Kinetic energy. Flywheel.
If you've got a decent sized flywheel it's not easy to get a spike.
Forget about infinite energy in infinite time, just deal with the
relatively short term.
I have struggled because the whole thing isn't intuitive with the
limited knowledge of inductors which I had.
MH's. question was a hell of a good one, very thought provoking.
John.
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Could well do.
I think the speed of light would put a limit on infinity.
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picture spinning the flywheel up using compressed air
That would be an accurate analogy of an ideal voltage source and inductor, if the flywheel could also push the compressed air back in.
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Yes John,,
Now picture spinning the flywheel up using compressed air,, now picture slowing it back down using compressed air,, just reverse the direction of the air flow right?
The flywheel analogy makes it pretty damn easy to answer the question. However, I have mentioned the flywheel analogy perhaps 30 times in the past, and I wasn't going to mention it again. This time I switched to a shopping cart analogy, which is just as easy, but it did not hit home and apparently did not register.
Yes reversing the direction of the air flow is perfectly valid. But you did not mention an important thing. As the flywheel spins up in either direction, the speed of the air flow has to keep on increasing proportional to the speed of the flywheel.
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Kinetic energy. Flywheel.
If you've got a decent sized flywheel it's not easy to get a spike.
Forget about infinite energy in infinite time, just deal with the
relatively short term.
I have struggled because the whole thing isn't intuitive with the
limited knowledge of inductors which I had.
MH's. question was a hell of a good one, very thought provoking.
John.
Thanks John, but from my perspective this has still not reached a conclusion, and Brad still has not met the two milestones that I stated for him. There is an intermediate question proposed by Partzman to consider which is very educational. Then there is the issue of the second question that I answered right away that was "summarily dismissed" by Brad earlier in the thread as being wrong.
So does the thread die a miserable death, or does Brad try to see it through?
This thread has had the usual "barrel of monkeys" craziness. Just look at the issue of the variable ideal voltage source. We had Brad, Magluvin, Magneticitist, and Wattsup all insisting that it was "not permitted" because they read a definition online or in a book and couldn't think beyond what they read and use their noggins and show some creative thought. Will any of them simply post and admit that they were wrong?
Anybody that cares to read this thread from the beginning will see how truly crazy and nonsensical it could get at times. Does it die, or does Brad see it through?
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You can do many things that bring things back into equal,, but that is adding in the mechanism that the formulas "as used" with these ideals do not have.
Say if you use pneumatic rams,, then the rams connect the air tank to the flywheel and you have the mechanism,, same thing if you use springs,, or if you use charge separation within the ideal voltage supply <= but it does not have that since it is ideal.
Now what if you are using rams,, what would happen to the pressure inside the ram that is going to stop the flywheel?
Well that depends doesn't it,, an infinite size air tank would not see a pressure change and there you go,, however, there is the adding in of the rams and pipes. <= a mechanism
If you have a limited air tank size then there will be a decrease in pressure as you are spinning up the flywheel and an increase in pressure when slowing it back down.
So using the ideals then we need a mechanism in place that itself does not consume energy but makes the transfer of the potentials equal,, same quantity transferred as stored and then as returned.
Without it the ideal voltage source is only blowing air,, 14.4J worth to spin it up and then another 14.4J worth to stop it,, and like I have said,,, even in this ideal space that can not happen.
Webby1,
Do I understand you correctly that you are saying 14.4J is consumed from the positive 4v supply during T0 to T3 to produce 2.4 amps in the 5H inductor and then as we apply a negative 4v supply during T5 to T8 to reduce the 2.4amps in the 5h inductor to zero, we consume another 14.4J?
partzman
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High there
Can’t say it better. hope the attached helps.
Anybody that cares to read this thread from the beginning will see how truly crazy and nonsensical it could get at times.
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Sort of,
The system starts at zero stored
We add 14.4J and it is stored
We then use another 14.4J to extract the 14.4J we added
If you will
14.4+14.4-14.4=14.4
With a resistor you have
+14.4-14.4=0 dissipated as heat
This should be the outcome for either method but using the formulas and ideals it does not.
If you apply the formula to the negative part of the cycle to get the change in current, that cost is the same as what was stored,, so then you would need to reverse the current value from the source which would be a full stop of current instantly.
If you ramp up the change then it will slowly slow down and stop the current.
The energy differences would be moved into and out of the source, so a sink of ~10.15J from the inductor for a cost of ~4.25J then the last of the extraction of ~4.25J would cost ~10.15J
So it cost me nothing to kill the energy that was stored,, what was taken out equals what was put in to kill it,, but I had to put it in to start with.
This must be wrong,, or incomplete.
Worse is the flywheel analogy using air,, makes an easy think since you are reversing the direction of the input influence to stop the flywheel, so you now have to spend the energy to spin it up,, you also then have to spend the energy to stop it since the air is the brake.
OK, let's take a closer look at the symmetrically equal charge and discharge cycles of the 5H inductor with equal and opposite +4/-4 voltage sources over equal time periods. I've attached a schematic with Circuit A which is an equivalent to the previous sim, and Circuit B with a re-positioned ground connection but otherwise identical in operation to Circuit A.
I will attempt to point out that during the ramp down phase, the energy stored in the inductor is returned to the -4 supply so theoretically no energy is lost with ideal components.
Looking at Circuit B, when switch W1 is closed, L1 begins to receive a positive current flow out of V1 entering the dot end of the coil and exiting the non-dot end. When W1 opens and W2 closes, the current stored in L1 still flows in a positive direction out of the non-dot end of L1 into the positive terminal of V2 and by the time the current in L1 has reached zero, the energy taken from V1 is returned to V2 due to equal supply voltages and ideal components. The voltage across L1 changes polarity at the switching W1 and W2 but the current begins a gradual decline. These actions are able to be seen in the simulation.
The same energy action occurs in Circuit A but is harder to "see" because of the layout but may become apparent after careful study. The nomenclature below each circuit calls out the voltage polarities across L1 for the various switch positions. Note that they are identical.
partzman
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I will attempt to point out that during the ramp down phase, the energy stored in the inductor is returned to the -4 supply so theoretically no energy is lost with ideal components.
Yes but with the compressed air and flywheel analogy the air is not pushed back where it came from when the wheel is braked so the analogy fails.
With this analogy energy has to be actually expended to create the reverse torque and brake the flywheel, because the air leaks out after it hits the flywheel. In ideal electronic circuit there is no such leakage.
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Since there is no resistance within this circuit there is no loss from the stored energy,, so to MAKE it loose the stored energy you need to supply more energy.
No, it is enough introduce any series resistance into the L circuit in order to make that circuit perform work on that resistance and convert the stored energy into heat ...or introduce an empty capacitor into the L circuit in order to make that circuit perform work on that capacitance and charge it up.
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Yes and an empty capacitor, too.
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How about the Root's Blower (http://www.mekanizmalar.com/roots3.html) with flywheels attached to the impellers and voltage symbolized by the pressure difference between two air-tanks?
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You should say, "Okay, I will discuss it with my peers and go do more research and learn more and improve my skills so that I can answer the question successfully by myself."
After all the ground that has been covered in this thread, and for the innumerable crazy theories and misconceptions that have been addressed and dealt with, don't you feel a bit ridiculous for trolling me like that on the very first page?
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I have an issue with the pulses from that,,
Pulses are a minor imperfection that have no bearing on the overall energy balance.
The temperature difference due to air de/compression is a much larger flaw in this analogy.
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Since most of the technical discussion has already occurred, and other sims posted, here is my voltage and current trace in its complete form. R=1m Ohm.
Hopefully Brad will continue on the quest to discover the facts about this circuit, and perhaps use my proposed timing with his welding coil to prove it out on the bench. I would suggest that proving the entire wave form is not even necessary, as the main point hindering the understanding I believe has to do with the transition from a positive current to a negative source voltage. I am sure Brad could set up this single voltage transition on his bench without the need for an elaborate wave form.
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Since most of the technical discussion has already occurred, and other sims posted, here is my voltage and current trace in its complete form. R=1m Ohm.
Hopefully Brad will continue on the quest to discover the facts about this circuit, and perhaps use my proposed timing with his welding coil to prove it out on the bench. I would suggest that proving the entire wave form is not even necessary, as the main point hindering the understanding I believe has to do with the transition from a positive current to a negative source voltage. I am sure Brad could set up this single voltage transition on his bench without the need for an elaborate wave form.
Hopefully Brad will continue on the quest to discover the facts about this circuit,
Here are the facts about this circuit.
fact 1-i do not have an ideal coil
fact 2-i do not have an ideal voltage source.
fact 3-I tried a test using my 1H inductor,where i placed 12 vDC across it for 300ms,and then reversed the polarity of that 12 volts across the coil with no off time in between. This was done by way of 2x 100 amp solid state relays,and they were triggered by way of my FG.
There was no sign of any high current spike shown on the scope,and the current trace(over the .2ohm 60 watt CVR) shows a smooth transition as seen on the presented scope shots on this thread.
Brad
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Were you able to draw any conclusions from your test results?
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Were you able to draw any conclusions from your test results?
Was that not clear in my previous post?
As i stated--no high current spike was observed as i thought may have been seen-only a very thin(as in time frame) high voltage spike could be seen across the coil,but i expect that to be due to the switching period between relays,where there is a very slight off time for both of them during the polarity changeover.
Brad
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What you failed to achieve Brad was this:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he was wrong when he stated that my response to the harder question was wrong.
So one more time, you are hightailing it away now that you see that "your way" was completely wrong.
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What you failed to achieve Brad was this:
1. Brad gets up the learning curve and understands the original question and then answers it correctly all by himself and clearly demonstrates that he understands what he is doing.
2. Brad admits that he was wrong when he stated that my response to the harder question was wrong.
So one more time, you are hightailing it away now that you see that "your way" was completely wrong.
You are no saint pal,and that much has been proven many times now.
1--MH learns what resonance means
2--MH learns how ICEs function
3--MH learns what a J/FET is.
4--MH learns that he is not perfect.
5--MH understands what good could be had by using a VR on a JT
So how about you take a long walk off a short plank MH,and on your way down,take a good hard look at how !good! you really are.
When you come back with results of a test using an !ideal! voltage source,and an !ideal! inductor,just remember that your answer is just that--a theory-a best guess based around !non ideal! equipment and components.
I had no problem at all answering your question,using non ideal generic equations.
But you will have all sorts of trouble putting together the actual circuit in your question,and backing up your !generic! answer--thats a fact.
1-Brad will bow to no mans Theories.
2-Brad will most certainly not be taking MHs word for anything.
Brad
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Webby1,
I would encourage you to do some reading on Faraday Induction, or watch Lewin's lecture (https://www.youtube.com/watch?v=nGQbA2jwkWI) on YT.
That is after all what it seems you are asking about.
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You are no saint pal,and that much has been proven many times now.
1--MH learns what resonance means
2--MH learns how ICEs function
3--MH learns what a J/FET is.
4--MH learns that he is not perfect.
5--MH understands what good could be had by using a VR on a JT
So how about you take a long walk off a short plank MH,and on your way down,take a good hard look at how !good! you really are.
When you come back with results of a test using an !ideal! voltage source,and an !ideal! inductor,just remember that your answer is just that--a theory-a best guess based around !non ideal! equipment and components.
I had no problem at all answering your question,using non ideal generic equations.
But you will have all sorts of trouble putting together the actual circuit in your question,and backing up your !generic! answer--thats a fact.
1-Brad will bow to no mans Theories.
2-Brad will most certainly not be taking MHs word for anything.
Brad
The truth Brad is you're so weak that you wouldn't even have reported your latest test results and if Poynt didn't ask you would never have said anything at all.
1. You need to learn what resonance means because you are just BSing and you failed to answer the two wine glass questions. Your claim that a wine glass resonating after it has been struck is not actually resonating is a joke.
2. The good old ICE again. Would you like to see some selective quotes of yours from the first 10 pages of this thread?
3. Kiss my ass with the stupid JFET nonsense. Where is your circuit that uses a JFET to start up your Joule Thief oscillations at low voltages? Oh, you don't have one, do you?
4. I am not perfect and I have no problem with that. You are not perfect and this thread was a showcase for your serious imperfections that stunt your ability to learn.
5. The variable resistor for the Joule Thief was another insane argument put forth by you where you outright refused to try to understand what I was trying to tell you. Just like in this thread you outright refused to learn and understand until you caved in an the end. It didn't have to be like this at all and you have some serious problems to work on.
I had no problem at all answering your question,using non ideal generic equations.
Oops, you never answered it using non-ideal generic equations even though the offer for you to answer it that way was was made to you several times. Of course you had "no problem at all." Anything can be true when your brain is frying in a hot skillet.
The big question beyond the technical question that you failed to answer is this: Have you learned anything about yourself and where you could make improvements and corrective actions?
MileHigh
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Im not sure if you read everything i write or post,but you seem to keep missing the fact that i do not agree with the results of your formula,and believe the values are wrong.
I told you right from the start,that using your generic formula would be an easy way out,but the results would not be that that your formula would show.
Brad
Well you are flat-out WRONG, and the results of the formula are 100% correct.
I told you right from the start,that using your generic formula would be an easy way out
Yes, we are going to talk about the integral form of the formula for an inductor and the double-standard you showed with your jackass behaviour.
I posted the formula for an inductor and the image is attached to this posting.
That is a generic formula that anybody that is familiar with an inductor will recognize right away and you can find it in 1000 textbooks. The formula has nothing to do with me at all.
And what did you do?
You went nuts and made a complete ass of yourself over multiple postings. You said stuff like this:
You are the epic failure others claim you to be.
You are a total disaster.
Your (sic) a fraud.
You epic failure.
You are now the laughing stock of this forum.
If Poynt or Verpies or someone else had posted that standard formula would you have reacted like that? The answer is no, you would not have done that.
It shows a double-standard and how you shamelessly compromised your behaviour and made a fool of yourself.
I have no problem with debating, but double-standards like that are unacceptable.
And as far as this thread goes you can eat your own words. You are the epic failure that could not make progress and get up the learning curve and answer this simple question that consists of a power source and one single component. You are the laughing stock of the forum, just go read the first 10 pages of this thread and look at what you are saying.
I really doubt that I will debate much with you in the future, but if we do, do not try to pull off another idiotic stunt like you tried to pull off when I posted a standard formula used in electronics all the time. Pull yourself together and act like a responsible adult.
MileHigh
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Poynt99,
Let me explain a little further.
My assumption is that at t=3 and V=0 then all differentials are also 0 meaning that there is no current flow and no voltage and all the energy is stored within the flux field as a pure pressure.
I am trying to prove my assumption wrong.
In my opinion, your first assumption should be that the equation, the books and the simulation are all correct. If you feel they are not correct, you need to come up with a theory that proves them wrong.
Therefore, the assumption is that at t=3 the voltage goes to zero, but the current remains at +2.4A.
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At t=3 and I=2.4 because of L=5 then the 2.4 represents the flux potential equivalency.
Namely the flux (Φ) equals 12 Webers, because Φ=L*I
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Well, then you can't talk like a sexist pig in Engineeringese:
B4∝qru/18qtπ?
No secret decoder rings are available.
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So that 12 Webers then could be placed on any identical inductor and when "released" return the stored energy.
Almost, but it would depend how many Amperes were responsible for creating that flux, because Joule=Weber*Ampere.
E=½LI2 still holds.
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Well you are flat-out WRONG, and the results of the formula are 100% correct.
Yes, we are going to talk about the integral form of the formula for an inductor and the double-standard you showed with your jackass behaviour.
I posted the formula for an inductor and the image is attached to this posting.
That is a generic formula that anybody that is familiar with an inductor will recognize right away and you can find it in 1000 textbooks. The formula has nothing to do with me at all.
And what did you do?
You went nuts and made a complete ass of yourself over multiple postings. You said stuff like this:
You are the epic failure others claim you to be.
You are a total disaster.
Your (sic) a fraud.
You epic failure.
You are now the laughing stock of this forum.
I have no problem with debating, but double-standards like that are unacceptable.
MileHigh
Oh come now MH. We only need look at some of your idiotic idea's to see that you are not one to follow or listen to.
E.G-- an ideal voltage source dose not contain energy
Energy just disappears<--that one's a doozy :D
Just a couple in this thread alone that i can recall,but the JT thread--well,that one is loaded with your mistakes. You are free of course to put your actual circuit together,and confirm your theoretical answer ;)
If Poynt or Verpies or someone else had posted that standard formula would you have reacted like that? The answer is no, you would not have done that.It shows a double-standard and how you shamelessly compromised your behaviour and made a fool of yourself.
I noticed that you did not go off at Poynt like a half cocked chicken when he also answered your question incorrectly. You will also notice that Poynt made a public post here on this thread telling me to calm it down a bit,and yet he graced you with a personal!private! message to tell you to do the same-->how's them double standards looking now?.
So here is how it is cupcake.
I will not be a part of MHs lobotomy class,nor will i accept theory as fact.
I really doubt that I will debate much with you in the future, but if we do, do not try to pull off another idiotic stunt like you tried to pull off when I posted a standard formula used in electronics all the time. Pull yourself together and act like a responsible adult.
You seem to suffer from memory loss as well MH ::)
And as far as this thread goes you can eat your own words. You are the epic failure that could not make progress and get up the learning curve and answer this simple question that consists of a power source and one single component. You are the laughing stock of the forum, just go read the first 10 pages of this thread and look at what you are saying.
An ideal voltage source contains no energy
The energy just disappears.
Im sure some will have a good chuckle at those two statements,and because of them,i doubt very much you could make an accurate power calculation of how much energy your circuit will need for a continual run of the cycles you set.
I also doubt that you would have answered your question correctly,as you would have missed the bit about the current continuing to flow during the 0 volt phase of your question--but i guess we will never know,as you avoided answering your own question at all costs.
Perhaps i should have got you to email Poynt your answer before the thread got under way,and then he could have posted your answer here,after i posted the generic one. Hindsight is a wonderful thing,but it never seems to help much :(.
Brad
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I need to look over that post on the pulse motor on time :)
You can find it here (http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692). The break-even point when the energy dissipated in the resistance = energy stored in the magnetic flux, is 1.15 Tau.
You may also find another post of mine interesting, which is 3 post after the one linked above.
If the assumption I have made about the 0 constraints leaving the energy stored in the flux is reasonable then I need to find the mechanism that holds the flux when V=0
Indeed, an ideal inductor (shorted) will maintain the level of magnetic flux penetrating it ...no matter what happens.
You can see it in this animation (https://www.youtube.com/watch?v=uL4pfisCX14).
I call this mechanism the quantitative Lenz law.
This is to differentiate it from the qualitative Lenz law that only states the direction of the induced current and nothing about its magnitude.
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Brad:
No surprise, you would not account for your double-standard and your outrageous behaviour.
E.G-- an ideal voltage source dose not contain energy
Energy just disappears<--that one's a doozy
One more time, you are not playing the thread, the thread is playing you. All that you are doing is showing that you are incapable of understanding the secondary issues related to an ideal voltage source. Your imagination is not capable of going there and fully understanding this abstraction, it's beyond your powers of conception. Even though I made several attempts to explain this to you, it didn't register, it was like talking to a blank wall. I can assure you that many people feel dismay in seeing this limitation that you have. The only thing you can do is comical, and pretend that it is wrong. You are exposing your severe limitations.
Just a couple in this thread alone that i can recall,but the JT thread--well,that one is loaded with your mistakes. You are free of course to put your actual circuit together,and confirm your theoretical answer
I made mistakes in the JT thread, but you easily made 10X the number of mistakes. I just didn't parade them around the block 40 times like you did. I could spin circles around you on a bench.
I noticed that you did not go off at Poynt like a half cocked chicken when he also answered your question incorrectly.
I did not go after Poynt because I knew that he just temporarily tripped up. I knew that he knew the true answer just like he knew that I knew the true answer. There was no double-standard.
If you say that I suffer from memory loss, then you suffer way more memory loss. What about all of those technical points that just pass right through you like you aren't even there? Did you forget my multiple attempts to explain the secondary issues related to an ideal voltage source to you?
An ideal voltage source contains no energy
The energy just disappears.
Yes, and it's a shame that your brain is so stuck and so limited. Unfortunately, there is nothing to laugh about there.
I also doubt that you would have answered your question correctly,as you would have missed the bit about the current continuing to flow during the 0 volt phase of your question--but i guess we will never know,as you avoided answering your own question at all costs.
The above is just shameless bluffing in an attempt to save face but all that "bluffing" does is make you look even worse.
MileHigh
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Brad:
No surprise, you would not account for your double-standard and your outrageous behaviour.
One more time, you are not playing the thread, the thread is playing you. All that you are doing is showing that you are incapable of understanding the secondary issues related to an ideal voltage source. Your imagination is not capable of going there and fully understanding this abstraction, it's beyond your powers of conception. Even though I made several attempts to explain this to you, it didn't register, it was like talking to a blank wall. I can assure you that many people feel dismay in seeing this limitation that you have. The only thing you can do is comical, and pretend that it is wrong. You are exposing your severe limitations.
I made mistakes in the JT thread, but you easily made 10X the number of mistakes. I just didn't parade them around the block 40 times them like you did. I could spin circles around you on a bench.
I did not go after Poynt because I knew that he just temporarily tripped up. I knew that he knew the true answer just like he knew that I knew the true answer. There was no double-standard.
If you say that I suffer from memory loss, then you suffer way more memory loss. What about all of those technical points that just pass right through you like you aren't even there? Did you forget my multiple attempts to explain the secondary issues related to an ideal voltage source to you?
Yes, and it's a shame that your brain is so stuck and so limited. Unfortunately, there is nothing to laugh about there.
The above is just shameless bluffing in an attempt to save face but all that "bluffing" does is make you look even worse.
MileHigh
The facts are MH,you cannot back up your theory with a working modle--this is a truth that your words cannot deviate from.
As far as the JT thread go's,saying that i made 10 times the mistakes you did,is just an outright lie,and the proof of that is in the thread.
Another truth is that i accurately described an ideal voltage source long before you did-another fact that is on this thread. The fact that you think that energy is not stored in the ideal voltage source,is a clear indication that you are not full bottles on the meaning of an ideal source. Poynt and verpies agree with my description,so perhaps take it up with them,but i will tell you now ,the energy returned by the coil dose not just disappear as you stated.
I made you an offer to put your smarts to the test,in way of a friendly pulse motor challenge,but as usual,you declined the offer. Perhaps a JT challenge?,surely you could throw one of them togeter?,and back up your claimed knowledge there?.
Words are just that MH,and mean nothing until they are backed up with actions.
Brad
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Too much Tu Quoque (https://en.wikipedia.org/wiki/Two_wrongs_make_a_right)
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Brad:
I don't have to back up my theory with a working "modle," you are supposed to understand and appreciate this stuff in your head. The simulations are often better than real life. And I actually explained how to make a working model in quite a bit of detail unless you forgot that.
At the heart of every real coil you work with is an ideal inductor. The resistance of the real coil is just window dressing draped over the ideal inductor. And you have been playing with coils on the bench for six years without understanding how they actually work. You are still stuck.
Go onto a real science forum and start a new thread with the title "After you strike a bell it is not resonating," and watch yourself get eaten alive. You are still stuck there too.
A serious attempt was made to unstick you on these two important subjects and it failed and the reason is failed is mostly because you failed yourself.
Right now if I posted the nice graphic of the full solution that Poynt made and asked you to explain it in detail without using the formulas that you were given my assumption is that you would not be able to do that. Likewise, I doubt that you would be able to explain why the second example I gave the answer for is correct. So you did not get to the level that I was hoping for. It's a bloody shame. There are three more variations on the question that would also be very educational but it feels like it would be pointless since you are still stuck on the first one. Could you answer Partzman's mini question with the voltage ramp? I don't think you can.
I described an ideal voltage source about 40 years ago. You are lost on the subtleties of an ideal voltage source and my sense is that Poynt was just being nice to you to avoid any hassle.
I am not going to be building anything, period.
MileHigh
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...your double-standard and your outrageous behaviour.
Gadzooks! :o
Could this be the Pot calling the Kettle Black? ???
You are aware of the character trait which applies to the
Nom de Guerre who sanctimoniously accuses others of
the odd behaviors which he himself takes pleasure in? ::)
Miles! Are you losing your marbles? ;)
H _ p _ c _ i _ y
The assumption or postulation of moral standards to which
one's own behavior does not conform.
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Go foof Sea Monkey. I am not claiming I am perfect, and what I said is valid. Yes, getting into an argument with Brad can be very frustrating. Why don't you try it sometimes? After all, we all know that you are reasonably astute when it comes to electronics and you could have been raising objections to what Brad has been saying until you were blue in the face. But, no surprise, you said nothing at all. Backing me up technically would be unthinkable, right? You just couldn't do that because I have openly discussed my opinion of your little pet "issues" and you don't like what I have to say.
I take no pleasure in fighting, that's a lie. Brad took pleasure in attempting to do a farce of a technical setup on me where he fell flat on his face. Why don't you go after him for that? Why don't you go after Magluvin, because he takes pleasure in harassing me? He did it recently and he also did for a full year non-stop and you had nothing to say about that. Cat got your tongue?
You talk about losing marbles. Tell us, when is the new projected date for The End of the World? When are all the Dark Forces going to be revealed? What are you going to do? Do you have a remote cottage and three tons of spam in your cellar?
I am solid and not perfect and not nearly the hypocrite that you are.
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Tell us, when is the new projected date for The End of the World? When are all the Dark Forces going to be revealed? What are you going to do? Do you have a remote cottage and three tons of spam in your cellar?
Considering the direction our World is presently moving in
(or being pushed in) that is a really good question Miles.
The Prophecies do not reveal any particular date for "The
End" of the World as we know it, but rather, provide details
of significant events to occur which will indicate that it is
near. Certain of the events will prevail for a fairly short period
of time as a prelude to the Main Event to alert those who are
watching for it.
The Revealing of the "dark secrets" is already underway and
will intensify in the coming months and years. As you've no
doubt noticed, the investigation into 9/11 is still ongoing and
more and more people are paying attention to the discrepancies
in the "Official Story." In due time the complete Truth regarding
that event and numerous others, including names, will be made
public.
I am going to continue studying and watching. At a critical time
a path to safety will be revealed to all peoples of good will. No
other physical preparations are necessary beyond continuing to
embrace Truth and Goodness while eschewing badness.
Nope no cottage with tons of Spam, although I am a fan of home
cooked Spammus Alabamus with eggs over easy. Just taking it one
day at a time in anticipation of the very bad times yet to come soon.
May peace be with you.
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Gadzooks! :o
Could this be the Pot calling the Kettle Black? ???
You are aware of the character trait which applies to the
Nom de Guerre who sanctimoniously accuses others of
the odd behaviors which he himself takes pleasure in? ::)
Miles! Are you losing your marbles? ;)
H _ p _ c _ i _ y
Yes,that is MH.
The one thing that stands out most,is that he is here-on overunity.com
A forum dedicated to a subject his books do not allow for. He refutes every claim of any claimed OU device before he even takes the time to look and see if it has any merritt--the big''rubbish'' button is hit automatically.
One has to wonder why he is actually here-on a forum that researches something he dose not believe in.
It has become apparent that he strives on arguments,and he has found many here on this forum--and boy dose he have a tanty when he looses,and is proven wrong--all sorts of fowl language starts coming out then.
He will tell you straight up,that magnets can do no useful work,but has no idea as to what a magnetic field even is. Thank god there is one around the earth,keeping those nasty radiations away from us--I'd call that pretty useful.
Mh got quite the shock when i plotted his circuits current trace correctly-well as far as he is concerned. Guess he under estimated my skills again. But do you see how he comes after you-and keeps coming at you until you agree with him. Well he will be quite busy if he thinks i am going to say i agree with him ,just because he has an urge to be correct,and have everyone agree with him--not going to happen.
Anyway-he is best ignored,and dont take his insults to heart SeaMonkey.
He's just like a bad headache,and will go away soon enough.
Brad
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Sorry Brad, but that alternative BS strategy you are taking is not going to work.
I posted the integral version of the equation for a coil and said that it was the short answer to the first question and you went nuts and acted like a fool. It was a morally bankrupt double-standard because we know you would never do that for anybody else. And you won't even own up to it.
It has taken about 45 thread pages to try to help you help yourself and answer a very very simple electronics question and you still are not there and you still don't really understand what is going on. Instead you withdrew and fell silent.
You want to prove me wrong? I attached Poynt's graphic that answers the question. Go ahead and using that graphic answer the first question with a full written description in your own words of what is taking place on that graph without using any formulas at all. Then correct yourself and explain why my answer to the second question below is actually correct, and not wrong like you originally stated.
Here is the second question and the answer that I provided:
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
Are you at the point where you can fully explain Poynt's graph? Can you answer the first question on a conceptual level in your own words without using any of the formulas that were given to you?
Are you at the point where you can explain why the answer to the second question is correct?
I am calling your bluff, and I would be happy to be proven wrong.
MileHigh
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I bookmarked it a while ago :)
Unfortunately that posts refers to real coils (with series resistance) - not to ideal coils, where R=0 and i(t)=t*V/L in which Tau does not appear at all.
Reading the other post reminded me of Franken Motor,, unlike the air core solenoid I used a soft iron core solenoid and allowed the core\coil to move through a virtual magnetic pole,
To do that motor well, the duty cycle of the energizing and recovery pulses has to be very low in order to keep the working pulse widths well below 1 Tau where the efficiency is high. See the graph below:
Did you ever consider a force vs. displacement curve on a piece of a soft ferromagnetic material (not a magnet) attracted into an energized shorted air-core ideal inductor ? ... and how that curve differs when the same is attracted by a permanent magnet?
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Sorry Brad, but that alternative BS strategy you are taking is not going to work.
I posted the integral version of the equation for a coil and said that it was the short answer to the first question and you went nuts and acted like a fool. It was a morally bankrupt double-standard because we know you would never do that for anybody else. And you won't even own up to it.
It has taken about 45 thread pages to try to help you help yourself and answer a very very simple electronics question and you still are not there and you still don't really understand what is going on. Instead you withdrew and fell silent.
You want to prove me wrong? I attached Poynt's graphic that answers the question. Go ahead and using that graphic answer the first question with a full written description in your own words of what is taking place on that graph without using any formulas at all. Then correct yourself and explain why my answer to the second question below is actually correct, and not wrong like you originally stated.
Here is the second question and the answer that I provided:
Are you at the point where you can explain why the answer to the second question is correct?
I am calling your bluff, and I would be happy to be proven wrong.
MileHigh
Im calling your bluff--take me up on my challenge.
Take all that useful information you believe in,and put it to work in a real world device-->a simple pulse motor,or JT-->im even giving you the choice as to which one you would prefer.
How hard can it be for you to make just one experimental device--->just 1.
For years and years this forum have been enduring all of your insults toward others,and your relentless pursuit of other members,until they give in to you,and accept your answer as the only one.
Well time for you to put your hands to work,and show us all that your ramblings have some firm ground upon which you claim. Time for you to show us that the books have all the answers,and that you can outdo me any time you wish.
Are you at the point where you can fully explain Poynt's graph? Can you answer the first question on a conceptual level in your own words without using any of the formulas that were given to you
Im not sure if you are aware of this MH,but formula's are given to everyone--even you. Is that not how you learned?. So i must ask,what do you hope to gain when you say!! formulas given to you!!?,when it is the very same way you learned what you know.
Anything i need to know can be found on the net. Everything i need to confirm,can be confirmed on my bench--something you do not do.
What you see in book's,and what reality is,is two very different things.
You have much to learn,and you will not do that by looking in your book's.
Lets take your JT circuit,where you say the most efficient JT circuit is your generic circuit,where the LED is across the collector/emitter. I try and tell you that it is more efficient to have the LED across the coil directly,so as to eliminate the internal resistive losses of the battery,,and you say rubbish.
There is the bench winning over the book's right there MH,as i have tested both circuit's,and the one with the LED across the coil wins hands down. Even though i gave you a valid explanation as to why it is more efficient to have the LED across the coil it self,you still insist you are right,and myself(along with many others that tried to tell you the same thing)are wrong.
In post 600,i called a truce MH,and that we would have to agree to disagree.
But in post 570,you started your bullshit again---Brad must agree with me,or he is wrong.
You have serious issues you need to work out MH.
Brad never believes anyone that cannot (ever) back up what he says with experimental proof--thats you MH.
Brad
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Brad:
Yes, I used the term "formulas given to you" because in the beginning of this thread you were completely and utterly lost and the formulas had to be given to you.
So you are completely avoiding my challenge to you to show your knowledge and demonstrate that you understand the circuit and can explain it in your own words. That says it all right there. It means that you can't do it.
It's no surprise, look at a very recent quote from you from just three days ago:
The CEMF is no different to that induced by an electric motor,only it is ass about,where the CEMF will increase with motor speed,resulting in a drop in current draw,and with the coil,the CEMF will decrease over time,resulting in a higher current draw. So an increase in CEMF is seen as an impedance to the current flow,by way of reducing the potential voltage difference between the applied EMF,and the CEMF. In the case of the inductor,the CEMF reduces over time,meaning a larger potential difference between applied EMF and CEMF,resulting in a higher current flow value.
The CEMF does not reduce over time and there is no such thing as a difference between the applied EMF and the CEMF. I posted that the EMF and the CEMF are always equal and you either missed it, forgot about it, or simply did not understand it, or you "choose to go your own way" and you make up things in your mind that you believe "fit."
So, most unfortunately, you have backed yourself into a corner and you are feigning that you understand what is taking place in the circuit when clearly you still don't understand and you still have a long way to go. You started this thread with confidence and you were going to "show me." I didn't even want to get into this discussion. You simply can't be honest right now and that's a real shame.
If you study this thread carefully and do your own supplementary research then one day you will be able to explain how this simple circuit works. Then you need to try to answer Partzman's mini question. Then you need to try to explain how the second already answered question is correct.
Then, using the identical format for the question, replace the ideal 5 Henry inductor with an ideal 5 Farad capacitor and try to answer the same question again and fully explain it.
Then, take the original question and replace the ideal voltage source with an ideal current source and answer two more questions, one question where there is an ideal 5 Henry coil, and another where there is an ideal 5 Farad capacitor. Substitute when the voltage is four volts for a current of four amps, etc.
So, you take my first question, and you add the three questions described above, and you have a total of four questions that teach basic concepts related to an ideal voltage source, an ideal current source, an ideal inductor, and an ideal capacitor. Any person that plays with electronics and wants to be serious must be able to answer those four questions and fully understand all of the nuances associated with those questions. It is an absolute must.
If you can answer those four questions with a full understanding of what is going on and demonstrate complete competence with respect to these very basic electronics concepts, then you will have advanced your knowledge by a big jump. It's all up to you.
MileHigh
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Yes,that is MH.
The one thing that stands out most,is that he is here-on overunity.com
A forum dedicated to a subject his books do not allow for. He refutes every claim of any claimed OU device before he even takes the time to look and see if it has any merritt--the big''rubbish'' button is hit automatically.
One has to wonder why he is actually here-on a forum that researches something he dose not believe in.
Brad
I don't even argue that stuff anymore. I am just waiting for the next Naima Feagin of QEG infamy to come along. I am only interested in the big fish that want to steal money from people. Discussing circuits with you is just an attempt to get you to help yourself, and it has been a nightmare.
Yes Brad, it's time to eat your own words or have a good old fashioned brain fry.
http://overunity.com/16550/mechanical-resonance-projects-unlike-forums-hacks-tinman-and-magluvin/msg482002/#msg482002 (http://overunity.com/16550/mechanical-resonance-projects-unlike-forums-hacks-tinman-and-magluvin/msg482002/#msg482002)
You need to get this !!overunity!! bullshit out of your head-there is no such thing as !overunity! period.
As i said,those that may one day see an overunity device,are those that are blind to the source of energy.
Says a man that exists in a universe that is expanding at an increasing speed.
Overunity is only confusion,and misunderstanding--there is no such thing as !overunity!.
Brad
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author=MileHigh link=topic=16589.msg485082#msg485082 date=1464097150]
MileHigh
Yes, I used the term "formulas given to you" because in the beginning of this thread you were completely and utterly lost and the formulas had to be given to you.
Ah,so you must have taught me well MH. I am following your lead,where one makes bold rejections against those who know better--like !there is no resonance or resonant systems what so ever in or around an ICE. The proof had to be given to you,as you were completely and utterly lost.
If the shoe fit's MH :D
So you are completely avoiding my challenge to you to show your knowledge and demonstrate that you understand the circuit and can explain it in your own words. That says it all right there. It means that you can't do it.
As you are avoiding mine ;)
But the truth is MH,worst case scenario,i could spend 20 minutes on the net,and find the answers you require,where as you could not build a simple pulse motor or JT,because your attitude will not allow it.
So, most unfortunately, you have backed yourself into a corner and you are feigning that you understand what is taking place in the circuit when clearly you still don't understand and you still have a long way to go. You started this thread with confidence and you were going to "show me." I didn't even want to get into this discussion. You simply can't be honest right now and that's a real shame.
Oh please MH-->you were the very first to comment on the thread.
You were itching for this to happen.Taking into account the difference in times around the world,it only took you 2 hours,18 minutes to make your first comment--the first reply on the thread.
If you study this thread carefully and do your own supplementary research then one day you will be able to explain how this simple circuit works. Then you need to try to answer Partzman's mini question. Then you need to try to explain how the second already answered question is correct.
Sure,right after you take me up on my challenge.
Ever notice that it is always everyone else that answers the questions,while you avoid everything.
All those here have to do everything for you. Others have to build and test,others have to put up sim scope shot's,others have to do all the research,while you do nothing but talk.
Then, using the identical format for the question, replace the ideal 5 Henry inductor with an ideal 5 Farad capacitor and try to answer the same question again and fully explain it.
Oh,so now we have an ideal voltage source being fed from an ideal voltage source. :D
Imagine that connection,and ideal voltage source hooked across an ideal capacitor--that has no internal series resistance :o
Would this ideal capacitor,being an ideal voltage source,store the energy that is provided by the ideal voltage source that has no stored energy?
Maybe it just disappears MH? lol.
Maybe it is time for you to answer a question ::)
Then, take the original question and replace the ideal voltage source with an ideal current source and answer two more questions, one question where there is an ideal 5 Henry coil, and another where there is an ideal 5 Farad capacitor. Substitute when the voltage is four volts for a current of four amps, etc.
So, you take my first question, and you add the three questions described above, and you have a total of four questions that teach basic concepts related to an ideal voltage source, an ideal current source, an ideal inductor, and an ideal capacitor. Any person that plays with electronics and wants to be serious must be able to answer those four questions and fully understand all of the nuances associated with those questions. It is an absolute must.
Anyone that plays with electronics will know there is no such thing as an ideal voltage source,or an ideal capacitor.
If you can answer those four questions with a full understanding of what is going on and demonstrate complete competence with respect to these very basic electronics concepts, then you will have advanced your knowledge by a big jump. It's all up to you.
If you can build an actual device,say a pulse motor,or JT,that is more efficient at converting electrical energy into wanted energies than what i can,then you will know that your !!vast!! knowledge in electronics has some bases behind it. If not,then your word's of wisdom are just that--word's.
Brad
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I don't even argue that stuff anymore. I am just waiting for the next Naima Feagin of QEG infamy to come along. I am only interested in the big fish that want to steal money from people. Discussing circuits with you is just an attempt to get you to help yourself, and it has been a nightmare.
http://overunity.com/16550/mechanical-resonance-projects-unlike-forums-hacks-tinman-and-magluvin/msg482002/#msg482002 (http://overunity.com/16550/mechanical-resonance-projects-unlike-forums-hacks-tinman-and-magluvin/msg482002/#msg482002)
Ah,so you are here only to debunk peoples devices,while im here to find unknown ,untapped energy sources.
Yes Brad, it's time to eat your own words or have a good old fashioned brain fry.
The brain fry is actually on you MH,as some here call it OU,while i call it an unknown energy supply-->which of the two would be correct using your very own book's?
I bet you wont answer that one,as that would make your attempt to !once again! belittle me,look very foolish-->much like you saying that using a J/FET in a low voltage JT makes no sense :D
Brad
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much like you saying that using a J/FET in a low voltage JT makes no sense :D
Brad
Well, isn't that special Brad. I explained to you that the last time I thought about JFETs I was sitting in a class 35 years ago. I did not Google a JFET to check my statement before I posted, I was hedging my bets and I lost. Instead of accepting my explanation and moving on, here you are like some pimp, still pushing this nonsense.
You want to see some real incoherent and idiotic nonsense from someone that probably plays with electronics a few times a week and he does this right now in May 2016, and not in the early 1980s?
Try this:
My answer to this question is--you cannot place an ideal voltage across an ideal inductor.
when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity.
My skills are fine thank you MH.
So i stand by my answer-->you cannot place an ideal voltage across an ideal inductor.
If you did(theoretically),the current would rise instantly to an infinite value.
This results in an instant current rise to an infinite value.
I dont think MH gave much thought to his question,or the outcome of installing the !ideal! parts to this !so called! simple circuit.
If the time constant is infinite for maximum current through the ideal inductor,then that means that no current flows through the inductor--ever
The ideal inductor has no resistance,and so now our ideal voltage is placed across a dead short,and that means an infinite amount of current will flow instantly
I can claim my answer to be correct,and no one can disprove it,as the ideal inductor and ideal voltage source do not exist.
So an ideal inductor dose not exist for that very reason,and there for your question cannot be answered
As you ,nor anyone else has proven that i have made a mistake,then my answer stands-you cannot connect an ideal voltage across an ideal inductor.
No MH. You are making claims you cannot back up,as you do not have access to an ideal inductor.
These two values are far from your 99.99% close enough is near enough coil,as it is not even close.
Like i said,you should have thought about your question a little better.
No-the difference is !infinite!--you just dont get this,do you ?.
This is the very reason that MHs question cannot be answered,as i have stated before.
If R = 0,which id dose,as the inductor is ideal,then no current flows through the ideal inductor.
This means that it will also take an infinite amount of time before current start to flow
But there is also no resistance in an ideal coil,and so the ideal voltage is now across a dead short.
So,the current either rises instantly,or the current rise time is infinite,which means there is no current flowing through the ideal coil.
If we are going to be accurate and true to our selves in this discussion,then i think you are going to find that there is an infinite gap between real and ideal.
Your question cannot be answered,as it is a contradiction to it self.
At this point in time,i am sticking to my answers given-both the real world answer-->you cannot place an ideal voltage across an ideal inductor,and also my theoretical answer,being the current would rise instantly,to an infinite value.
And so my answer of an instant current rise of an infinite value.
Unfortunately partzman,it is no where near an ideal inductors outcome,as an ideal inductor never has any current passing through it.
My other answer is because there is no resistance with an ideal inductor,and there for it is a dead short.
My real world answer is(and has been throughout this thread)that you cannot place an ideal voltage across an ideal inductor,as an ideal inductor dose not -and never will exist.
If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
The rest of us are hoping that MH learns that when you add ideals into questions,it changes everything drastically,and the situation in no way represents real worl outcomes.
It has already been established that from T=0 to T=13 seconds,nothing will happen,as current will not flow through an ideal inductor.
I am no longer interested in proving you wrong
The ramifications of my theories being correct,change everything as far as what is believed to be an ideal inductor.
So unless you know some sort of math that allows a division of 5/0,and provides a value we can work with,then i will stick with my claim.
Regardless of whether it is L/0 or R/0,Tau is always infinite,meaning that the current will not rise in the case of an ideal inductor.
It is like my answer says it is--you cannot place an ideal voltage across an ideal inductor,as an ideal inductor dose not exist.
I have also shown that regardless of how little the resistance value may be,it will lead to a value that is infinitely different to that of an ideal inductor that has no R value.
The fact that you have dismissed the L/R time constant to answer your original question is troubling.
This method (Tau=L/R) is the correct method to use in regards to your question.
The only reason you do not wish to use this method of Tau=L/R,is because that then puts you in a position of being incorrect.
I am standing firm on my answers,and i hope Poynt(and others) takes the time to have another look at this,and not just accept your example as a reality.
Unfortunately MH is just not getting it,and he is trying to use a math function that dose not account for the voltage and inductor on being ideal.
As i said,and have all along--you cannot place an ideal voltage across an ideal inductor,because as you see,you are left with a paradox.
If an ideal voltage is placed across an ideal inductor(that has no resistance to control the flow of current),then the current would take an infinite amount of time to reach it's peak level.
So that is the paradox,but it is also correct,and once again backs up all my answers i have given in regards to the original question.
This all sounds crazy i know,and hence the reason i included the word conundrum and/or paradox with my answers.
This also shows that MHs question cannot be answered,as it cannot exist.
Changing values around,and changing from an ideal to a non ideal,and using math that is based around non ideal situations,is not going to make the original question answerable.
You have confirmed my real world answer--an ideal voltage cannot be applied to/placed across an ideal inductor.
Being an ideal inductor,means that it dose not dissipate power,and that also means the CEMF is also ideal,--> equal to that which creates it,and thus no current flows when a voltage is placed across that ideal inductor.
A non ideal inductor dose have an R value,and this means it dose dissipate power. This also means that the CEMF value is not as high as the EMF that created it,and so current will flow through a non ideal inductor--as we know.
And hence,once again,you cannot place a voltage across an ideal inductor,when current is flowing through that closed inductor loop.
Mh is using math that applies to an inductor on the understanding that that inductor will reach a maximum current value in a finite time.
I dont think it is clear Poynt,and your original thought (current will not flow)is correct.
This means that the CEMF is also ideal,and so is equal to the EMF ,and so an equal current will flow in the opposite direction to that of the current produced by the EMF.
Remember-it is only the resistance and parasitic capacitance that allows the EMF to be greater than the CEMF,and allow the flow of current,something that an ideal inductor is void of.
So that would mean a dead short when an ideal voltage from an ideal source is placed across the ideal inductor,as as much current would be trying to flow back into the ideal voltage source,as the ideal voltage source is trying to deliver.
What it means ,is that there can be no voltage across the ideal inductor
the current would be instant,and infinite--but no current flow
The result would be an instant and infinite current build up between the ideal voltage source,and the ideal inductor,but no current would flow.
And as there is no resistance throughout the circuit,no voltage would appear anywhere across that loop.
It is hard for some to understand what !ideal! mean's,but think about it long enough,and you begin to put all the pieces together.
Because the current produced by the inductor is equal and opposite to that being provided by the ideal voltage source,and so no current flows,but it dose rise to an infinite amount.
When dealing with ideals,we deal with absolutes,and there for the CEMF is ideal,meaning that it is equal and opposite to that of the EMF.
It's really not that simple MH. And the travesty is you have not taken the time to draw out your own circuit,or realize what you have described.
It is like i said,you cannot place an ideal voltage from an ideal voltage source across an ideal inductor.
The reason you dont understand this,is because you dont understand your own two component circuit.
Your circuit is an oxymoron-a paradox,and cannot work in reality,as one cancels out the other.
If you took the time to draw out your own circuit,and write down all the values of that circuit,and applied all that you have stated in this(and the JT)thread,then you would see the error of your ways.
But as you continue to try and relate ideal coils to non ideal coils,and ideal voltage sources with non ideal sources,you havnt a hope in hell in seeing what your circuit represents.
I can debunk your circuit in just 5 lines of text,but i will give you and the other EE guys here say-4 to 8 weeks lol,--just kidding,say 4 days to think about it.
It is only those here that are trying to relate real world device with ideal devices,and the transition just dose not exist .
how can a voltage placed across an ideal shorted inductor induce a current flow through a shorted ideal inductor?
So i stand by my answer due to MHs insistence.
You cannot place an ideal voltage from an ideal voltage source across an ideal inductor.
the fact that the ideal voltage source is now connected across that ideal inductor,means that the current flowing through it is in no way impeded
Even when a current is flowing through that looped ideal inductor,ohms law states that V=IxR,and as there is no R,then there is no voltage across that looped inductor--as we know.
If there is a dead short across the ideal voltage supply,the current would simply build in the ideal voltage supply until either the short exploded,or the ideal voltage supply exploded.
This would depend on which one of the two could contain the most energy before it failed-->or they(the shorted ideal wire and ideal voltage source) would continue to store the energy for an infinite time.
At T=5 seconds,MHs device explodes.
At that instant,you have to infinite current values trying to flow in opposite directions.
Being that both the inductor and voltage source is ideal,the energy stored in the ideal loop from T=3s to T=5s cannot be dissipated in order for a current to start flowing in the opposite direction
This MH paradox is truly fantastic---it makes everything work just the way you want it to.
No matter how i try and find a way for the stored energy to be dissipated before the opposite potential of that stored energy is released into the system,there is just no where for it to go.
As it has no where to go,due to it being in a closed loop,and there is no way of dissipating it's stored energy,due to there being no resistance in the loop,then it must remain.
The -3 volts is applied,and the current being produced is trying to collapse that already built magnetic field,which cannot be collapsed due to the steady state current that is flowing that keeps it built.
In a real world situation,that energy would be dissipated as heat,but as we have an ideal inductor loop,then the energy cannot be dissipated.
So this energy that is stored cannot return to the source,as the energy from the source is flowing in the wrong direction.
I am yet to see any reason posted why the CEMF is also not ideal.
So, shall I also act like a sleazy pimp and put all my Bradisms on display on a regular basis just like you?
MileHigh
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So if I take a superconducting coil, closed that is, and excite it with a voltage and wait for the current to ramp up
It would be impossible to apply a potential difference (voltage) to a closed superconducting coil, since there would be no place to insert a voltage source.
However it would be easy to insert a voltage source in series with an open superconducting coil.
Also, varying the flux that penetrates such closed coil would induce a current in it, but you still would not be able to measure any voltage because there would not be any place you could insert a voltmeter into.
and then open the coil through a low resistance device,,,
Any resistance would dissipate the current and energy stored in the coil through simple I2R losses sooner or later.
Is that not free electricity since voltage is free?
Why would it be?
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author=MileHigh link=topic=16589.msg485082#msg485082 date=1464097150]
MileHigh
Ah,so you must have taught me well MH. I am following your lead,where one makes bold rejections against those who know better--like !there is no resonance or resonant systems what so ever in or around an ICE. The proof had to be given to you,as you were completely and utterly lost.
If the shoe fit's MH :D
As you are avoiding mine ;)
But the truth is MH,worst case scenario,i could spend 20 minutes on the net,and find the answers you require,where as you could not build a simple pulse motor or JT,because your attitude will not allow it.
Oh please MH-->you were the very first to comment on the thread.
You were itching for this to happen.Taking into account the difference in times around the world,it only took you 2 hours,18 minutes to make your first comment--the first reply on the thread.
Sure,right after you take me up on my challenge.
Ever notice that it is always everyone else that answers the questions,while you avoid everything.
All those here have to do everything for you. Others have to build and test,others have to put up sim scope shot's,others have to do all the research,while you do nothing but talk.
Oh,so now we have an ideal voltage source being fed from an ideal voltage source. :D
Imagine that connection,and ideal voltage source hooked across an ideal capacitor--that has no internal series resistance :o
Would this ideal capacitor,being an ideal voltage source,store the energy that is provided by the ideal voltage source that has no stored energy?
Maybe it just disappears MH? lol.
Maybe it is time for you to answer a question ::)
Anyone that plays with electronics will know there is no such thing as an ideal voltage source,or an ideal capacitor.
If you can build an actual device,say a pulse motor,or JT,that is more efficient at converting electrical energy into wanted energies than what i can,then you will know that your !!vast!! knowledge in electronics has some bases behind it. If not,then your word's of wisdom are just that--word's.
Brad
No, I was not lost about an ICE, I was ignorant. You, on the other hand, where completely and utterly lost at the beginning of this thread about a power supply connected to one single component. And where you are right now is less lost, but still lost enough to shy away from my challenge to you to describe how this extremely simple circuit works in your own words. You tried to deflect away from the challenge. You are going to have to keep on researching and studying to get to the point were you can write out five paragraphs that present a coherent and sensible and correct explanation for how the circuit works. You are a long way away from being able to do that at this point in time.
But the truth is MH,worst case scenario,i could spend 20 minutes on the net,and find the answers you require
Good, you are admitting that you don't know what you are doing and have a lot to learn. With respect to a 20-minute Google search solving all of your problems, we have ample evidence that this is not the case. You are BSing. And running off and doing a bunch of copying and pasting will not cut it either.
And no, I did not want to get into this discussion. You badgered me for the question multiple times so I made up a new version of the question on the spot and you took that question and started this thread. And we now know the results: the stark realization that you have to put in a serious effort to finally understand how inductors work after playing with them for so many years and bluffing.
Imagine that connection,and ideal voltage source hooked across an ideal capacitor--that has no internal series resistance
Would this ideal capacitor,being an ideal voltage source,store the energy that is provided by the ideal voltage source that has no stored energy?
Maybe it just disappears MH? lol.
That's pure nonsensical sarcasm. If you are serious about electronics then you will go through the exercise of answering all four versions of the question. This is for your own benefit.
Anyone that plays with electronics will know there is no such thing as an ideal voltage source,or an ideal capacitor.
After all of the work done on this thread in a desperate attempt to get you up to speed on basic electronics, that's an idiotic counterproductive statement.
If you can build an actual device,say a pulse motor,or JT,that is more efficient at converting electrical energy into wanted energies than what i can,then you will know that your !!vast!! knowledge in electronics has some bases behind it. If not,then your word's of wisdom are just that--word's.
Right now, my words are way more powerful than any device you can build on your bench. Your goal is to get up to speed in electronics so you start to know what you are really doing on a more deeper and more serious level. For example, you could build an MHOP pulse motor and have precise control of the pulse width and angular timing. You could measure how much of a time constant you are energizing the coil for. You could set the pulse width to your own discretion. You could position the energizing pulse at the sweet spot of the magnetic repulsion if you wanted to maximize your RPM.
There is no "calling of my bluff" because I never made any kind of claim about building a pulse motor. When you say something Brad, it actually has to make logical sense, you can't just pluck things out of thin air. You seriously have to work on that very serious problem.
You, on the other hand, are claiming that you understand this very simple circuit when in fact it was readily apparent that you were completely lost at the beginning of the thread. Now you are less lost. Hence I called your bluff and challenged you to explain how the circuit works without using any formulas and you caved in right away and tried to use distraction to take the attention away from you. What you want to do is get yourself up the learning curve to the point where you can describe how the circuit operates and it all flows naturally and you use proper electronics terms and concepts.
MileHigh
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Ah,so you are here only to debunk peoples devices,while im here to find unknown ,untapped energy sources.
The brain fry is actually on you MH,as some here call it OU,while i call it an unknown energy supply-->which of the two would be correct using your very own book's?
I bet you wont answer that one,as that would make your attempt to !once again! belittle me,look very foolish-->much like you saying that using a J/FET in a low voltage JT makes no sense :D
Brad
That's pretty pathetic or should I say impressive Joe. Oh, so it's not "over unity," it's an "unknown energy supply."
So that fixes everything. You did not make yourself look like a complete fool by knocking me about over unity when just a few weeks ago you made a posting definitively stating that over unity dose not exist.
You are so impressive, you have all the angles covered. Say it ain't so, Joe?
https://www.youtube.com/watch?v=Oo_u4pMAlx0 (https://www.youtube.com/watch?v=Oo_u4pMAlx0)
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That's pretty pathetic or should I say impressive Joe. Oh, so it's not "over unity," it's an "unknown energy supply."
So that fixes everything. You did not make yourself look like a complete fool by knocking me about over unity when just a few weeks ago you made a posting definitively stating that over unity dose not exist.
You are so impressive, you have all the angles covered. Say it ain't so, Joe?
https://www.youtube.com/watch?v=Oo_u4pMAlx0 (https://www.youtube.com/watch?v=Oo_u4pMAlx0)
OK,i will try and give the baby explanation here,so as you understand MH.
Overunity is an incorrect term,and there is no such thing as OU.
What there is,is unknown sources of energy yet to be tapped.
So what some may see as being overunity,is nothing more than !a yet to be understood! energy source.
So the word !overunity! ,means nothing more than the word used until the energy source is understood.
So no,i do not believe in overunity,but i do believe in yet to be discovered energy sources.
Is that clear for you now?
Perhaps this unknown energy source,is that which contains all that energy of yours, that just disappears from your ideal voltage source? :D
Brad
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author=MileHigh link=topic=16589.msg485125#msg485125 date=1464141509]
MileHigh
No, I was not lost about an ICE, I was ignorant.
Well thats handy ;). Who'da ever thought ::)
You, on the other hand, where completely and utterly lost at the beginning of this thread about a power supply connected to one single component.
Are we talking about that power supply that contains no energy,and makes energy disappear?.
I thought it was an ideal voltage source that contained no energy,but now it is a power supply ???
How can you have a power supply that contains no energy?.
And where you are right now is less lost, but still lost enough to shy away from my challenge to you to describe how this extremely simple circuit works in your own words.
Im up for the challenge MH,but first you take me up on mine to you.
So you building a JT or a pulse motor?
You tried to deflect away from the challenge. You are going to have to keep on researching and studying to get to the point were you can write out five paragraphs that present a coherent and sensible and correct explanation for how the circuit works. You are a long way away from being able to do that at this point in time.
First we need to find out if all this study of yours is worth it.
As i presented my challenge to you first,it's only fair that we complete that one first.
We need to know if all your !!study!! is worth it,and you can put it all to work,and beat a bench hack at building a JT or pulse motor.
Good, you are admitting that you don't know what you are doing and have a lot to learn.
I am admitting no such thing.
As i said,take me up on my challenge,and we will see who can put there skills into making the most efficient device. Word's are just word's MH,but an actual device--now there is where the science is at--hands on building.
With respect to a 20-minute Google search solving all of your problems,we have ample evidence that this is not the case. You are BSing. And running off and doing a bunch of copying and pasting will not cut it either.
Ah,that brings back memories MH. I remember well when you told us all that you spent 20 minutes on google,and have the definitive answer to a wine glass resonating :D
That did not work out well for you,as you seem to be the only one in the world that has a self resonating wine glass ;)
And no, I did not want to get into this discussion. You badgered me for the question multiple times so I made up a new version of the question on the spot and you took that question and started this thread.
I made one post--the first post in this thread,before you had to throw your two bob's worth in.
Please go to that post,and show me where there was any badgering toward you.
And we now know the results: the stark realization that you have to put in a serious effort to finally understand how inductors work after playing with them for so many years and bluffing.
Says the man that is to chicken shit to take up my challenge.
To scared to find out who can make better use of an inductor--who can make a more efficient JT or pulse motor.
Maybe you pick the electrical device to be made MH,,maybe a boost converter,or a 12vDC to 240AC inverter--maybe a 20 amp 24 volt PWM/speed controller?. Im up for anything you got ;)
You say i have no idea as to how things work--you say i am at a basic level when it come's to electronics-->well lets put it to the test MH,lets see who can deliver the good's :D
MileHigh V Tinman-->the books V the bench ;D
That's pure nonsensical sarcasm. If you are serious about electronics then you will go through the exercise of answering all four versions of the question. This is for your own benefit.
First up MH,i am not serious about electronics--where did you ever come up with that?
It is nothing more than a hobby--thats it--nothing more.
If you are serious about how good you are,and you have learned so much from your book's,then take up my challenge ,and prove that all that learning from the books, actually pays off--you can actually put it to some sort of real world use.
After all of the work done on this thread in a desperate attempt to get you up to speed on basic electronics, that's an idiotic counterproductive statement.
No it's not MH,it's the truth,unless you have an ideal voltage source,or an ideal capacitor?
If we placed an ideal voltage source across an ideal capacitor,do you think something would go bang?. ;D
Right now, my words are way more powerful than any device you can build on your bench.
Oh yes MH,your words are going to solve the worlds energy crisis lol.
Words are just words MH--nothing more. All that claimed knowledge,and you cant do a thing with it.
I am happy with what i do MH--i love to build.
Your goal is to get up to speed in electronics so you start to know what you are really doing on a more deeper and more serious level.
As i said,show us all where your !deeper! level of understaning and learnings have got you. Take me up on my challenge :D
For example, you could build an MHOP pulse motor and have precise control of the pulse width and angular timing.
I can already do that MH,and more. What about a governing system,where more power is supplied to maintain a set RPM when mechanical energy is drawn from the pulse motor.
How about one that has a generator,where the pulse motor will draw less power when a load is placed on the generator?.
How about a pulse motor where you can pulse the coil at any time,and the motor will run just fine,and there is no such thing as pulse timing at all?
As i said,you under estimate my skills MH.
You could measure how much of a time constant you are energizing the coil for. You could set the pulse width to your own discretion. You could position the energizing pulse at the sweet spot of the magnetic repulsion if you wanted to maximize your RPM.
As i said,i can do all that now.
There is no "calling of my bluff" because I never made any kind of claim about building a pulse motor. When you say something Brad, it actually has to make logical sense, you can't just pluck things out of thin air. You seriously have to work on that very serious problem.
What good are words and skills MH,if you cannot put them to use?.
You, on the other hand, are claiming that you understand this very simple circuit when in fact it was readily apparent that you were completely lost at the beginning of the thread. Now you are less lost.
As i said MH,anything i need to know--when i need to know it,can be found on the web. Is this not what you preach?,is this not how we learn?. The web is just one giant book MH,that has most of what we need to know in it. But when it comes to real world devices MH,then things dont always add up as the books say they should.
Hence I called your bluff and challenged you to explain how the circuit works without using any formulas and you caved in right away and tried to use distraction to take the attention away from you.
No i did not MH. I placed my challenge upon you,and then you gave me another.
So,to keep things fair MH,i think it is your turn to take up a challenge for a change,instead of just dishing them out all the time. ;)
What you want to do is get yourself up the learning curve to the point where you can describe how the circuit operates and it all flows naturally and you use proper electronics terms and concepts.
First,we find out if all this knowledge you insist i have,is worth the time,and we do this by using the skills we already have,and build an actual device--any one you like MH.
Second--as i said,i have no intention of becoming an electronics guru,nor will i be spending my time learning all the jargon that makes sense to only a hand full of people on this forum.
EE guys are only a minority on this(and most other) forums,so no need to waste time on silly language that will make things no better for me.
Brad
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If a capacitor is charged, it took a certain amount of energy to charge it, and the capacitor is left with X Joules of energy in it. It is safe to say that the capacitor is a source of energy, potential energy. The same for a storage battery.
What about an ideal voltage source? It is conjured up from the theoretical realms of discussions on electrical engineering and does not require a precharge before it can function as a voltage source with unlimited current. How much power and energy can it deliver? In theory those quantities are infinite, if it is a true ideal voltage source. "Power" is basically VxI, and "Energy" is essentially how long it can maintain that power output. Again being an ideal source, both are potentially infinite.
Can we say then that an ideal voltage source is an energy source? I think it's more an issue of philosophical debate than a technical one.
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Brad:
You are not exactly a Rhodes scholar, are you?
I thought it was an ideal voltage source that contained no energy,but now it is a power supply
From Wikipedia: A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn (σύν) ("with") and onoma (ὄνομα) ("name").
All that you did in your posting was degenerate into a sad clown. You could not understand this simple circuit consisting of a power supply and one single component so you ended up withdrawing and you wouldn't even share your test result because the result refuted your latest crazy pet theory. You had to be asked to share your result.
And in that last posting you do a sad clown silly chicken dance and basically admit that you give up. It's really sad.
you seem to be the only one in the world that has a self resonating wine glass
So says the dancing chicken.
MileHigh
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If a capacitor is charged, it took a certain amount of energy to charge it, and the capacitor is left with X Joules of energy in it. It is safe to say that the capacitor is a source of energy, potential energy. The same for a storage battery.
What about an ideal voltage source? It is conjured up from the theoretical realms of discussions on electrical engineering and does not require a precharge before it can function as a voltage source with unlimited current. How much power and energy can it deliver? In theory those quantities are infinite, if it is a true ideal voltage source. "Power" is basically VxI, and "Energy" is essentially how long it can maintain that power output. Again being an ideal source, both are potentially infinite.
Can we say then that an ideal voltage source is an energy source? I think it's more an issue of philosophical debate than a technical one.
In relation to the question that this thread is about,then the answer is very clear. As there is onlt the two components described in the question,one being the ideal coil,and the other the ideal voltage source,then for any current to pass through the coil,we need to supply it with power,and to provide power we need energy. The only other component in the question is the ideal voltage source,and since it is this ideal voltage source that is providing the power to the coil,it must contain the energy that can provide that power.
Any energy absorbed by the ideal voltage source by way of the coil,must also be contained within that ideal voltage source,as it cannot dissipate any power,as it's ideal.
Why these questions are so hard to answer in relation to the question being debated here,is beyond me :o. Energy just dose not disappear,nor is it just absorbed without being contained--as it cannot be dissipated by either of the two components in the circuit.
Brad
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Brad:
MileHigh
You are not exactly a Rhodes scholar, are you?
Not at all.
But i bet your ass i have a larger skill set than you do MH.
All that you did in your posting was degenerate into a sad clown.
Here we go again with the insults.
You always revert to this when you know you are falling behind MH.
You need to find another hobby.
You could not understand this simple circuit consisting of a power supply and one single component so you ended up withdrawing and you wouldn't even share your test result because the result refuted your latest crazy pet theory. You had to be asked to share your result.
Well thats pretty funny coming from some one that thinks energy just disappears,and an ideal voltage source dose not contain any energy.
But you also failed to provide just one type of voltage source that dose not contain energy--not one.
And in that last posting you do a sad clown silly chicken dance and basically admit that you give up. It's really sad.
So says the dancing chicken.
You see the bit highlighted in red MH-->that is another lie from you-->yes ,thats right,a LIE,plain and simple.
You need to stop bullshitting MH,you really do.
From Wikipedia: A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn (σύν) ("with") and onoma (ὄνομα) ("name").
I'll keep that in mind,next time you insist that the rest of us be accurate with our descriptions of components ;)
So MH,you going to take up my challenge,or is this just a !!MH only gives out challenges!! forum,where everyone must take up MHs challenges,but MH will do what ever it takes to avoid being challenged.
Brad
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Brad, you can't even understand what the implications are when you work with the concept of an ideal voltage source. There is no hope for you.
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The old tinman's dug himself into such a deep hole I'm
expecting him to emerge in the U.K.
John.
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The electric field is a force,,
Strictly speaking it is not a force.
Electric field is a region of space where an electric charge experiences a parallel force.
However in a mechanical analogy the voltage can be symbolized by an unbalanced force, or torque, or pressure...
voltage is a differential within that field, current responds to that differential.
It would be more correct to write that electric charges respond to that differential.
Electric current is not electric charges. It is the motion of these charges ...not necessarily electrons.
The magnetic field is a force,
Again, strictly speaking it is not a force.
Magnetic field is a region of space where a moving electric charge experiences a perpendicular force.
A "field" is an abbreviation for a "force filed" ...or in other words: "field of forces".
is a reaction to current being excited by voltage.
It would be more correct to write, that magnetic flux is proportional to electric current.
It is possible to create electric current in an inductor without inserting a voltage source into it.
For example as in your example cited below:
If I place an open superconductor next to a source of controllable magnetic field,, I turn up that field as to envelope the superconductor,, then I close the super conductor and try to turn down the source of the magnetic field.
Then you will create an electric current in the superconducting coil without inserting a voltage source into it.
The moment you close that superconducting coil, the level of magnetic flux penetrating that coil will became frozen. It will not change no matter what you do with the external "source of controllable magnetic field". If you remove that source altogether, the closed superconducting coil will maintain the level of flux, which existed at the moment the coil was closed.
This means that the closed S.C. coil will become a sort of a "permanent magnet" ...which will attract iron chunks and repel or attract other permanent magnets (depending whether their N or S poles are facing the closed S.C. coil).
So if I supply the differential and the current responds but it does so with no resistance except to build the magnetic field,
...which is called the inductive reactance.
and at some point that field stalls in growth,
Why would it stall?
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Bad choice of words,, is there not a curve to the change in flux density?
Coils do not care about the flux density (B) but they do care about the magnitude of flux (Φ).
There is no limit to the flux magnitude in an ideal inductor energized by an ideal voltage source inserted in it.
However, for resistive coils there is a flux limit. Namely ΦMAX=LV/R
For resistive coils there is also a current limit. Namely iMAX=V/R
I am assuming that the differential will have some cost,, so choosing the better bang for the buck on the curve is what I was getting at.
Choosing the best point on the i vs. t curve makes a lot of sense with resistive coils. However with ideal or S.C. coils it does not make much sense below the superconductor's breakdown limit.
I would think that "if" the S.C. could be opened across a low resistance device and then if it were a coil that created the magnetic field,
Do you mean that the "low resistance device" is a 2nd coil that is resistive and in series with the previously energized S.C. coil?
If "yes", then you have one coil transferring electric current to a second coil. This is known as one of the most inefficient energy transfers in existence, because the energized S.C. coil behaves as an almost ideal current source, feeding a 2nd coil whose reactance is opposing a current change.
A coil is the worst device to receive current from another coil (while a capacitor is the best).
The result of a coil-to-coil transfer is a huge voltage spike at the beginning and a lot of the energy radiated away as EM wave. This is very, very bad for the efficiency of the energy transfer.
I also refer to the local area effect,, as in turning off the local area field effect, not meaning turning off the field but just the effect,, the gradient is changed.
Coils don't care about the gradients of magnetic flux nor about the flux density. They care only about the total flux magnitude that penetrates them. Really!
However the force exerted on a magnet or another coil is very dependent on the magnetic flux density gradient.
But because a higher gradient also means a shorter distance, then the integral of force over distance (which is work or energy) is the same as with a lower gradient but over a larger distance, thus it is a no-win scenario.
But don't despair. There might be a light in the tunnel if you consider the closed coil in your example (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg485149/#msg485149) that attracts a soft iron chunk or better yet: a nonconductive soft ferrite.
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So the ideal source does not "need" to have a closed short.
The ideal voltage source cannot have a short. If it did, an infinite current would flow through it.
The ideal current source cannot have an open. If it did, an infinite voltage would develop across it.
A voltage source can be directly connected to a current source in parallel, without bad consequences (infinities).
An energized capacitor behaves like a voltage source.
An energized inductor behaves like a current source.
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I thought that coils cared abut the change in flux density,,
They don't.
so that would be the flux and the rate of change of that flux.
That's correct. Coils "care" about the total flux very much.
It is important to distinguish the flux (measured in Webers) from the flux density (measured in Webers/m2 or Teslas or Gauss).
I used that understanding to build my dual voltage generator. It provided 2 different voltages at the same time from the same coil,, just by using a different rate of change,, :)
It is not surprising.
It must have been a different rate of change of flux (dΦ/dt), not a different rate of change of flux density (dB/dt)
I look at voltage like pressure...
So do I.
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You know that you can wrap your ferromagnetic around a straight conductor and move the PM field in line with that conductor and make electricity
Of course.
It works in the other direction, too - threading a wire through a ferrite bead increases its inductance and reactance to high frequencies. That's how EMI filters are often made.
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The old tinman's dug himself into such a deep hole I'm
expecting him to emerge in the U.K.
John.
Oh there you are John.
I have been waiting for days for one of your idiotic comments.
Do you ever plan on doing something useful on this forum?.
Brad
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Brad, you can't even understand what the implications are when you work with the concept of an ideal voltage source. There is no hope for you.
More words MH--just word's.
Well i have some news for you-->you (and others) have missed/overlooked something regarding your !ideal! voltage source/ideal coil circuit. All to busy looking at what is happening with the coil,and totally missed what is happening with the ideal voltage source ::)
Wonder if your as smart as you say you are MH,and can work out what you missed?.
Brad
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My words are true Brad. The last couple of posts from you have been clown arguments. I say one thing, and you can't deal with it so your response is about a completely different thing.
There is nothing missed or overlooked regarding the ideal voltage source. Considering your past statements regarding ideal voltage sources, and considering that you could only answer about 10% of the question, I am not expecting a pearl of wisdom to come forth from you.
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So the output will be from both values,, the density and the rate in which that density changes,, or moves,, relative to the coil. I have measured this.
It is very difficult to change the flux density without changing the magnetic flux, but it is possible. That's why you conflate these two concepts and your experiments seem to confirm this.
If you make a drawing of the flux lines you can count how many of them penetrate the coil. That count is your flux level.
Flux density is represented by the closeness of these lines.
If you look closely at this video (https://www.youtube.com/watch?v=uL4pfisCX14) of a superconducting coil (ring), you will notice that the number of flux lines penetrating that ring is constant regardless of the position of the permanent magnet. It also works in reverse.
In the same video you can observe how the flux lines get closer to each other in some places, despite that the total number of flux lines penetrating the ring does not change.
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Squishing the lines closer raises the density but may not create an induction event,, adding more lines does and that changes the density and quantity,, adding more into the same volume.
Yes
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I say one thing, and you can't deal with it so your response is about a completely different thing.
There is nothing missed or overlooked regarding the ideal voltage source. Considering your past statements regarding ideal voltage sources, and considering that you could only answer about 10% of the question, I am not expecting a pearl of wisdom to come forth from you.
My words are true Brad. The last couple of posts from you have been clown arguments.
Your words are false. The only clown here,is you MH(Oh,and your son minnie)
You cower away from any challenge,and argue on circuits that cannot be built or tested.
You have missed something in relation to the ideal voltage source,as your to busy looking only at what the coil dose. A lack of vision has always been your undoing,as it was in the JT thread.
Anyway,you have declined my offer to show us how much better your skills are than mune,and yet you insist that i know so little.
The difference between us MH,is your all talk,and i actually build devices based around what i know.
So you enjoy your self-->perhaps you could take up posting farm animals like minnie :D.
Brad
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tinman, I've learned a heck of a lot in the last couple of weeks.
You have come out with copious amounts of rubbish.
What about that silly post 302?
Read through post 707, it's cringeworthy!
You're absolutely hopeless at concepts and abstractions.
For me the whole thing has been most enjoyable
Don't give up, go to college, start from day one
I guarantee you'll enjoy it.
John.
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Brad,
If you reveal what it is you believe we missed, then we will know. Perhaps it is something that we are aware of already but have not discussed?
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tinman, I've learned a heck of a lot in the last couple of weeks.
You have come out with copious amounts of rubbish.
What about that silly post 302?
Read through post 707, it's cringeworthy!
You're absolutely hopeless at concepts and abstractions.
For me the whole thing has been most enjoyable
Don't give up, go to college, start from day one
I guarantee you'll enjoy it.
John.
I am amazed that those who have only negative things to say about me,are the very same that have nothing to show,or anything of value to contribute to this forum.
You are one of these very people John,all so fast to open your mouth,but not one thing that shows any smarts what so every.
You continue to say how wrong i am,but you have no idea your self as to how things work. You ride on the back of MH and other's. You wait for there answers to question's,and then post your unwanted comment's that have no substance what so ever.
If you went to fight a war,you would be the one standing at the back of the troop's,waiting for them to clear the way.
Brad
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tinman, I've learned a heck of a lot in the last couple of weeks.
You have come out with copious amounts of rubbish.
?
You're absolutely hopeless at concepts and abstractions.
For me the whole thing has been most enjoyable
Don't give up, go to college, start from day one
I guarantee you'll enjoy it.
John.
Read through post 707, it's cringeworthy!
The part about not being able to place an ideal voltage from an ideal voltage source across an ideal inductor?
Well here is a little research project for you John-->go and find your self an ideal voltage source.
That should keep you busy for a while.
What about that silly post 302
And what is so silly about John.
Do you know the answer?
Brad
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Brad,
If you reveal what it is you believe we missed, then we will know. Perhaps it is something that we are aware of already but have not discussed?
What are the characteristics of an ideal voltage source Poynt ?.
No series resistance-no resistance to current flow
No inductance--very important
Capacitance?--according to MH-no,as it cannot contain energy,so has no capacity to do so ???
Do you know what water hammer is Poynt?
Brad
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What are the characteristics of an ideal voltage source Poynt ?.
No series resistance-no resistance to current flow
No inductance--very important
Capacitance?--according to MH-no,as it cannot contain energy,so has no capacity to do so ???
No capacitance, no.
Do you know what water hammer is Poynt?
Yes. How does that relate?
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Your words are false. The only clown here,is you MH(Oh,and your son minnie)
You cower away from any challenge,and argue on circuits that cannot be built or tested.
You have missed something in relation to the ideal voltage source,as your to busy looking only at what the coil dose. A lack of vision has always been your undoing,as it was in the JT thread.
Anyway,you have declined my offer to show us how much better your skills are than mune,and yet you insist that i know so little.
The difference between us MH,is your all talk,and i actually build devices based around what i know.
So you enjoy your self-->perhaps you could take up posting farm animals like minnie :D .
Brad
No in fact my words are absolutely true. You knew beforehand when you made the latest "build challenge" that I was going to say no because I already told you no multiple times before that. It was just a diversion for the umpteenth time to try to weasel yourself out of an uncomfortable situation - you still can't explain how the circuit works in your own words.
I have built stuff in the past and I am satisfied with that. I would feel silly building a pulse motor.
go and find your self an ideal voltage source.
Like you have already been told multiple times now, a good quality bench power supply is an ideal voltage source within certain IV and bandwidth limits. And we are going to ignore your idiotic comment about a bench power supply not being able to hold its voltage steady under load to 0.000001 volts. We already know that, and we already know that for the vast vast majority of experiments we do that we can ignore that.
Go ahead and do your big reveal about the ideal voltage source.
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No in fact my words are absolutely true. You knew beforehand when you made the latest "build challenge" that I was going to say no because I already told you no multiple times before that. It was just a diversion for the umpteenth time to try to weasel yourself out of an uncomfortable situation - you still can't explain how the circuit works in your own words.
I have built stuff in the past and I am satisfied with that. I would feel silly building a pulse motor.
Like you have already been told multiple times now, a good quality bench power supply is an ideal voltage source within certain IV and bandwidth limits. And we are going to ignore your idiotic comment about a bench power supply not being able to hold its voltage steady under load to 0.000001 volts. We already know that, and we already know that for the vast vast majority of experiments we do that we can ignore that.
Go ahead and do your big reveal about the ideal voltage source.
If only you could understand your own circuit.
It is also no surprise that you dare not take anyone up on a challenge.
Brad
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If only you could understand your own circuit.
It is also no surprise that you dare not take anyone up on a challenge.
Brad
Can you say "Dunning-Kruger Effect?"
All you have to do is read this thread to see how reality can be stranger than fiction.
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When the focus of the question is changed to the ideal voltage source and how it interacts with the ideal L5 inductor it becomes another question, or topic of discussion.
IMHO,, as you were to have known, understood or assumed the conditions for the first question, it should also of been known, understood or assumed that the focus of your question changed.
Those that were not aware of that shift have been responding with the answers that would be pertinent to the first question but not the second.
What in blazes are you talking about?
-
You are just building a straw man when you talk about "two conditions" and nearly everybody knows that an ideal voltage source is part of the standard model for a battery and if you don't know what it is you can look it up on Google. The question is straightforward and the conditions do not change and there is no shift in focus or whatever you are trying to allude to. There is no point in trying to muddy the waters. Look at how futile the "an ideal voltage source cannot change in time" argument was.
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and this is why I have been ignoring you MH.
You asked a reasonable question so I answered with a reasonable response.
Bottom line.
And your response has been challenged because it is a straightforward question with a straightforward answer. Instead of just alluding to something just lay your cards on the table and say what it is you have to say.
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Webby in reply 751 what are you on about?
John.
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...everybody knows that an ideal voltage source is part of the standard model for a battery...
There are, of course, (1) the Theoretical Ideal Voltage Source
and (2) the Practical Ideal Voltage Source.
The Practical Ideal Voltage Source is a design objective for
a target application. Circuitry within the application must
be optimized to tolerate whatever limitations/variations in
internal parameters are characteristic of the Practical Source.
Chemical Voltage Sources, although idealized, will exhibit
variations which deviate considerably from the Theoretical
Model over their lifetimes as they transition from reasonably
ideal to less than ideal.
Less than Ideal is always an important consideration since it
is typically how life goes.
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I really don't know what you are on about SeaMonkey because "practical ideal voltage source" is pretty much an oxymoron and a rather obtuse use of technical language when it comes to electronics. I think we should try to keep the discussion on track and focused on the now-answered question. Presumably Brad and Webby are also off the beaten track and are alluding to something or some effect that doesn't directly relate to the first question.
It's unfortunate that nobody that was trying to answer the first question wants to take a stab at Partzman's mini question or discuss the already-answered second question. I view that as very disappointing, and overall the whole exercise was a fail for those that wanted to answer the first question because it had to be answered for them. Not to mention the fact that it looks like many still don't truly understand what's going on.
What is the impedance of the five Henry inductor over the first three seconds? A very interesting question that was never answered.
I think that John offered the best advice about going to school and I will morph it into something similar: Go buy a good book on electronics that includes lab exercises and open it up on page one and start reading. You can do the lab exercises on your bench and start to really learn.
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I'll have a guess, something like open circuit a time O to 1.666 ohms at time 3.
John.
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Yes John, you are correct!
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No capacitance, no.
Wouldn't a charged ideal capacitor of infinite capacitance, be indistinguishable from an ideal voltage source ?
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I'll have a guess, something like open circuit a time O to 1.666 ohms at time 3.
John.
Good. In what form does the impedance make the transition from 0 to 1.67 Ohms over that 3 second time period?
-
Wouldn't a charged ideal capacitor of infinite capacitance, be indistinguishable from an ideal voltage source ?
Agreed.
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Wouldn't a charged ideal capacitor of infinite capacitance, be indistinguishable from an ideal voltage source ?
And what would happen if this charged ideal capacitor of infinite capacitance,has an inverted voltage placed across it,from an ideal voltage source?.
Brad
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And what would happen if this charged ideal capacitor of infinite capacitance,has an inverted voltage placed across it,from an ideal voltage source?.
Lovely question!
In the World of Theoretical Fantasy who is able to tell?
Would there be lots and lots of sparks?
A Black Hole?
There may be several "correct answers" to this riddle.
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Yeah, the ideal cap with infinite capacitance is a neat 'ideal' idea. But lets say it is at 0v. It would never charge to any particular voltage above 0v. It would be an infinite ideal load. It would be far from falling under a definition of a capacitor in any form.
So if we could buy one, it would need to be precharged. ;)
But I understand the comparison to an ideal voltage source. I also understand that if we have an ideal voltage source, we would be just considering it it at its face value of being a source and as to where its power comes from doesnt matter. ??? That would be another hangup for me being the screw ball that I am. ;D Its all sorta fun to think about for a bit, but I dont believe spending great amounts of time on the subject is necessary to 'advancing' any projects here. I just find it to be a huge distraction. How many pages on that alone here? Tires me to think about it any longer.
Im just perplexed as to any need to think of things 'ideally' and that it would help me with any of my projects. For me it doesnt help me understand inductance any better. It doesnt help me understand caps any better. Im just not getting it. Just like I dont get if we have 2 ideal caps, one at 10v and 1 at 0v, that the result of going cap to cap would be 7.07v per cap, ideally. I still stand by what I believe on that, until someone can physically show me that the results would be such. On paper only, and according to 'laws' just doesnt get me there in the least. And none of what has been posted here has shown me any different.
When I say we just lost 'pressure', basically that is what we lost. 50% doing the ideal cap to cap. I find that the 50% loss due to resistance(of any value above 0ohms) is a prick in the science as to conservation of energy and resistance was given as the culprit by way of heat loss. Especially when it is 'claimed here' that 1uohm is 'seamless' to being ideal, by Mh and backed up by Poynt, but also claiming that .000001 picoohm is still responsible for the 50% loss from cap to cap. ;) ;) Just doesnt work for me.... Like why wouldnt there be some ledge of very very slight resistance that would give us say 6v in each cap? Or 5.1v??? Or 7.06v????? ::)
Ideal. No resistance. No heat. So 100% of the 'ideal energy' used to charge the cap to 10v was 'converted' into 'pressure' of opposite charge in the caps plates measured in voltage. So if we decide to diversify or better yet divide that 10v pressure of that cap between 2 caps of the same value, then we have lost pressure, as Ive said, stupidly. Ideally or not.
Mags
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Yeah, the ideal cap with infinite capacitance is a neat 'ideal' idea. But lets say it is at 0v. It would never charge to any particular voltage above 0v. It would be an infinite ideal load. It would be far from falling under a definition of a capacitor in any form.
So if we could buy one, it would need to be precharged. ;)
But I understand the comparison to an ideal voltage source. I also understand that if we have an ideal voltage source, we would be just considering it it at its face value of being a source and as to where its power comes from doesnt matter. ??? That would be another hangup for me being the screw ball that I am. ;D Its all sorta fun to think about for a bit, but I dont believe spending great amounts of time on the subject is necessary to 'advancing' any projects here. I just find it to be a huge distraction. How many pages on that alone here? Tires me to think about it any longer.
Im just perplexed as to any need to think of things 'ideally' and that it would help me with any of my projects. For me it doesnt help me understand inductance any better. It doesnt help me understand caps any better. Im just not getting it. Just like I dont get if we have 2 ideal caps, one at 10v and 1 at 0v, that the result of going cap to cap would be 7.07v per cap, ideally. I still stand by what I believe on that, until someone can physically show me that the results would be such. On paper only, and according to 'laws' just doesnt get me there in the least. And none of what has been posted here has shown me any different.
When I say we just lost 'pressure', basically that is what we lost. 50% doing the ideal cap to cap. I find that the 50% loss due to resistance(of any value above 0ohms) is a prick in the science as to conservation of energy and resistance was given as the culprit by way of heat loss. Especially when it is 'claimed here' that 1uohm is 'seamless' to being ideal, by Mh and backed up by Poynt, but also claiming that .000001 picoohm is still responsible for the 50% loss from cap to cap. ;) ;) Just doesnt work for me.... Like why wouldnt there be some ledge of very very slight resistance that would give us say 6v in each cap? Or 5.1v??? Or 7.06v? ??? ? ::)
Ideal. No resistance. No heat. So 100% of the 'ideal energy' used to charge the cap to 10v was 'converted' into 'pressure' of opposite charge in the caps plates measured in voltage. So if we decide to diversify or better yet divide that 10v pressure of that cap between 2 caps of the same value, then we have lost pressure, as Ive said, stupidly. Ideally or not.
Mags
" I find that the 50% loss due to resistance(of any value above 0ohms) is a prick in the science as to conservation of energy and resistance was given as the culprit by way of heat loss."
We couldnt have anyone knowing that heat may be had for free in some way, could we. ???
Mags
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And what would happen if this charged ideal capacitor of infinite capacitance,has an inverted voltage placed across it,from an ideal voltage source?.
Infinite current would flow.
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Yeah, the ideal cap with infinite capacitance is a neat 'ideal' idea. But lets say it is at 0v. It would never charge to any particular voltage above 0v. It would be an infinite ideal load.
More like an ideal short.
Ideal. No resistance. No heat. So 100% of the 'ideal energy' used to charge the cap to 10v was 'converted' into 'pressure' of opposite charge in the caps plates measured in voltage.
Not 100% because of EM radiation.
So if we decide to diversify or better yet divide that 10v pressure of that cap between 2 caps of the same value, then we have lost pressure,
Yes, but neither pressure nor voltage alone are energy.
-
Just like I dont get if we have 2 ideal caps, one at 10v and 1 at 0v, that the result of going cap to cap would be 7.07v per cap, ideally. I still stand by what I believe on that, until someone can physically show me that the results would be such. On paper only, and according to 'laws' just doesnt get me there in the least. And none of what has been posted here has shown me any different.
Haven't you done your own test with this? What was your result?
When I say we just lost 'pressure', basically that is what we lost. 50% doing the ideal cap to cap. I find that the 50% loss due to resistance(of any value above 0ohms) is a prick in the science as to conservation of energy and resistance was given as the culprit by way of heat loss. Especially when it is 'claimed here' that 1uohm is 'seamless' to being ideal, by Mh and backed up by Poynt, but also claiming that .000001 picoohm is still responsible for the 50% loss from cap to cap. ;) ;) Just doesnt work for me.... Like why wouldnt there be some ledge of very very slight resistance that would give us say 6v in each cap? Or 5.1v??? Or 7.06v? ??? ? ::)
I need to correct you here. If you followed what I said, you would understand that the absolute value of resistance is not the deciding factor that establishes the resistance as "close to ideal" for an ideal inductor, it is the RATIO of inductance to resistance, and I established a baseline of 50:1 ratio for a 5% error (from ideal). If you want less error then the ratio must increase.
And yes, 50% of the energy in a transfer through pure resistance between two equal value caps is burned in that resistance, no matter how small the resistance is. Why does the value of resistance make no difference? It is a self-regulating process. We know the power burned in the resistor is P=I2R. We also know that as R decreases, so does tau (tau=RC), and I increases. And energy E is essentially the integral of power burned in the resistor over time. So let's look at two crudely-calculated examples:
1) Source cap voltage is 10V, and R=1 Ohm. C1,2=1uF (ideal). Ipeak=10A, Ppeak=100W, tau=1us.
2) Source cap voltage is 10V, and R=0.1 Ohm. C1,2=1uF (ideal). Ipeak=100A, Ppeak=1000W, tau=0.1us.
In case 1 we have 100W peak and the tau of the transfer process is 1us. In case 2 we have 1000W peak and the tau of the transfer process is 0.1us. In both cases, the total energy burned in the resistor is the same. Case two burns 10 times the power, but for 10 times less time.
This is really general and not exact by any means. The idea is to illustrate how and why the energy burned in the resistor is always the same, regardless of its value.
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The mechanical analogy for the two capacitor issue can be quite clear and revealing if you put in the effort in to think about it.
You have a 5 Kg mass going two meters per second on a frictionless surface that hits a stationary 5 Kg mass. The masses stick together and become a 10 Kg mass. So what are the energy dynamics?
I am pretty sure that most people know that momentum is conserved when these things happen.
The initial momentum is 10 Kg-meters-per-second.
The final mass is 10 Kg. Therefore the 10 Kg mass must be moving at one meter per second to give you a momentum of 10 Kg-meters-per-second.
Now, let's look at the energy.
Initial energy: 10 Joules
Final energy: 5 Joules.
Whoops, we lost half of the energy so where did it go? The answer is that the energy was lost in the hit itself. It was a perfectly inelastic collision. When the two 5 Kg masses hit you can imagine a thin layer of putty absorbs the shock and keeps the two masses stuck together. 5 Joules of energy are burnt off in the deforming putty as heat.
This is exactly the same as the two capacitors.
-
Infinite current would flow.
Interesting.
So we have a current flowing through an ideal voltage source,and in an instant,we try to reverse this current flow by inverting the voltage across that ideal source.
What would be the result?
Brad
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The mechanical analogy for the two capacitor issue can be quite clear and revealing if you put in the effort in to think about it.
You have a 5 Kg mass going two meters per second on a frictionless surface that hits a stationary 5 Kg mass. The masses stick together and become a 10 Kg mass. So what are the energy dynamics?
I am pretty sure that most people know that momentum is conserved when these things happen.
The initial momentum is 10 Kg-meters-per-second.
The final mass is 10 Kg. Therefore the 10 Kg mass must be moving at one meter per second to give you a momentum of 10 Kg-meters-per-second.
Now, let's look at the energy.
Initial energy: 10 Joules
Final energy: 5 Joules.
Whoops, we lost half of the energy so where did it go? The answer is that the energy was lost in the hit itself. It was a perfectly inelastic collision. When the two 5 Kg masses hit you can imagine a thin layer of putty absorbs the shock and keeps the two masses stuck together. 5 Joules of energy are burnt off in the deforming putty as heat.
This is exactly the same as the two capacitors.
Here is a good question for you MH.
Why can this transfer be made more efficiently between the two caps by way of induction?
I will state for the record that i have no idea as to why,as i have never looked into it.
Brad
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Here is a good question for you MH.
Why can this transfer be made more efficiently between the two caps by way of induction?
I will state for the record that i have no idea as to why,as i have never looked into it.
Brad
Sorry MH, but I'm somewhat shocked that Brad has never seen nor heard of my document on this very subject. Feel free to still answer Brad though.
Brad, here it is: http://overunity.com/downloads/sa/view/down/209/ (http://overunity.com/downloads/sa/view/down/209/)
First posted about 8 years ago. A bit of clarification is in order though:
My reference to the inductor slowing down the transfer process, while true, is not the whole picture. It does that by storing a large portion of the energy, then transferring it to the second cap. A charged ideal capacitor connected to an ideal inductor will oscillate forever because there are no losses, and the energy simply transfers back and forth from one to the other. It is a similar idea with the cap to cap energy transfer. If we insert a high Q inductor (i.e. the same idea as in MH's question where I established a L/R ratio of 50:1 approaches ideal) between the caps, the transfer becomes much more efficient when compared to a pure resistor.
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Haven't you done your own test with this? What was your result?
I need to correct you here. If you followed what I said, you would understand that the absolute value of resistance is not the deciding factor that establishes the resistance as "close to ideal" for an ideal inductor, it is the RATIO of inductance to resistance, and I established a baseline of 50:1 ratio for a 5% error (from ideal). If you want less error then the ratio must increase.
And yes, 50% of the energy in a transfer through pure resistance between two equal value caps is burned in that resistance, no matter how small the resistance is. Why does the value of resistance make no difference? It is a self-regulating process. We know the power burned in the resistor is P=I2R. We also know that as R decreases, so does tau (tau=RC), and I increases. And energy E is essentially the integral of power burned in the resistor over time. So let's look at two crudely-calculated examples:
1) Source cap voltage is 10V, and R=1 Ohm. C1,2=1uF (ideal). Ipeak=10A, Ppeak=100W, tau=1us.
2) Source cap voltage is 10V, and R=0.1 Ohm. C1,2=1uF (ideal). Ipeak=100A, Ppeak=1000W, tau=0.1us.
In case 1 we have 100W peak and the tau of the transfer process is 1us. In case 2 we have 1000W peak and the tau of the transfer process is 0.1us. In both cases, the total energy burned in the resistor is the same. Case two burns 10 times the power, but for 10 times less time.
This is really general and not exact by any means. The idea is to illustrate how and why the energy burned in the resistor is always the same, regardless of its value.
"Haven't you done your own test with this? What was your result?"
My results were that I get 5v per cap after cap to cap transfer. ??? And What Im saying is that I think that even if they were ideal caps, 10v cap to 0v cap, that we would still have 5v per cap.
Now Ive heard that term 'burn' before. Even before the internet was around. Id like a detailed explanation of that term here. What is 'it' that is consumed in the 'burn'? Energy? What form?
Here is a couple of questions for you....
We have 2 'Ideal' capacitors of the same value. One is charged at 10v and the other at 0v.
Lets say just for simplifying the example that the 10v cap has an imbalance of 2000 electrons (pos plate -1000 and neg plate +1000) between the pos and neg plates and the 0v cap has no imbalance.
So we do the cap to cap zap. When all is said and done, we disconnect the caps. What would the voltage be across those caps? And what would the electron imbalance count be for each cap?
Now we will do the same with real world caps..... Same values as described above.....
Cap to cap zap and disconnect. What will the voltages be across those caps? And what would the electron imbalance count be in this example?
Thats as simple as I can put it. So anyone here can understand it.
If you can answer those questions, then I will continue with my explanation. ;D
Mags
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As to my prev post, Id like to see anyone have a crack at those questions. ;D
Mags
-
Sorry,
I thought it was obvious that "burn" implied energy dissipated in the resistor as heat.
In terms of answering yet more of your questions, you've not yet acknowledged that you understand or agree (or not) with my explanation in that post as to why the resistor value does not matter when a pure resistance connects the two caps.
-
Sorry,
I thought it was obvious that "burn" implied energy dissipated in the resistor as heat.
In terms of answering yet more of your questions, you've not yet acknowledged that you understand or agree (or not) with my explanation in that post as to why the resistor value does not matter when a pure resistance connects the two caps.
Im thinking that the heat from the resistance only costs time. Time for the cap to fully distribute half of its electron count imbalance to the other cap. If it is ideal, then there is no time in the transfer according to what is said, and with resistance, the transfer takes longer the higher the resistance is.
So thats my answer, and my earlier questions deal with it specifically.
You said something much earlier on the electron count imbalances Im speaking of. Dont remember. It was more of a question about if Im sure about the counts meaning anything.
But maybe you dont believe the electron imbalance between cap plates determines its particular voltage level accurately for a particular cap value. Not sure. ??? If not, could you explain why?
Mags
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Im thinking that the heat from the resistance only costs time. Time for the cap to fully distribute half of its electron count imbalance to the other cap. If it is ideal, then there is no time in the transfer according to what is said, and with resistance, the transfer takes longer the higher the resistance is.
So thats my answer, and my earlier questions deal with it specifically.
You said something much earlier on the electron count imbalances Im speaking of. Dont remember. It was more of a question about if Im sure about the counts meaning anything.
But maybe you dont believe the electron imbalance between cap plates determines its particular voltage level accurately for a particular cap value. Not sure. ??? If not, could you explain why?
Mags
"Im thinking that the heat from the resistance only costs time. Time for the cap to fully distribute half of its electron count imbalance to the other cap."
Actually, not just a cost of time. We did waste the energy doing the ideal cap to cap by not using the action of the current flow. When there is resistance, I agree there is heat. Just to be clear....
My whole point is, I dont believe that resistance is responsible for the 50% loss in the cap to cap example. If we needed heat from the cap to cap device, then we get it. If we use a motor in series with the 2 caps till the caps at 5v each, then we got motor output during the transfer and we end up with 5v in each cap. We used the transfer. We used the missing energy. But Im still thinking that the ideal caps in these situations and cap to cap would still end up with 5v per cap when all is said and done. And Im putting my money on the electron count to prove so.
2000 Electron Count Imbalance of an ideal cap to a 0 imbalance cap should divide the imbalance to 1000 imbalance in each cap.
Now if we were to say that the ideal cap is 2000 ECI and we do the cap to cap, how could it be that we end up with 1400 ECI per cap? 10v to 7.07v each?
Now in your much earlier question I would have to think maybe you agree on the imbalance but think that 2000 ECI to 1000 ECI would equate to 10v to 7.07v each. Well if that is the case, then that would mean we lost some of the beginning ECI once the caps balance out in the real world cap to cap deal. If so, where did they go?
Mags
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Capacitor = potential .
Inductor = kinetic.
Sounds good to me.
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Mags, I'd be happy to answer your questions and respond to your answers, but I simply can't make much sense of them. Probably my failing.
As far as I'm concerned, I've given you the info you need to sort things out in regards to the cap to cap transfer problem.
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I don't know why this is being discussed again because I already discussed it with Magluvin on the other thread. If you can imagine a cap transfer where no energy is lost and the two caps are at 7.071 volts then you need more charge than is in the original cap sitting at 10 volts. An idealized arrangement with a coil and a switch can do this. Without the idealized arrangement the initial amount of charge in the original cap loses some energy through resistance when it spreads itself out between the two caps.
Conservation of charge equals conservation of momentum in the two colliding masses example.
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What you'll have to do is brush-up on yer polynomial integrals !
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Energy stored on a capacitor has counterintuitive elements.
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Trust the experts, constant current rules!!!
John.
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Why would that be John?
I think he wrote that, because two electrons can represent different energies depending on their separation distance and the work needed to move them closer together is a result of their repulsion force integrated over the distance of their approach.
Reminder: The instantaneous repulsion force of two electrons is inversely proportional to the square of the distance (1/d2) between them.
BTW: this is an example how the same amount of charge (here, the two electrons) can represent very different levels of energy.
In other words: Charge alone, is not energy.
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When people start going into stuff like charge carriers and whatnot, it's usually a sign that the discussion is going nowhere and people are just spinning their wheels and going through the same old motions.
Nobody was able to answer the first question, and that includes all you experimenters.
How about trying to tackle Partzman's question now that the first question has been answered for you?
It went something like this: You have an ideal five henry inductor. There is an ideal voltage source that is put across the inductor at t=0 and for two seconds the voltage applied across the inductor is a linear ramp that starts at zero volts and ends at two volts. After that the voltage is zero volts. What happens?
Now, is anybody going to say something about this?
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Capacitor = potential .
Sounds good to me.
Inductor = kinetic.
With the exception of MHs question,between T=3s and T=5s,where the magnetic field is stable,and so the stored energy is potential energy.
Brad
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When people start going into stuff like charge carriers and whatnot, it's usually a sign that the discussion is going nowhere and people are just spinning their wheels and going through the same old motions.
Nobody was able to answer the first question, and that includes all you experimenters.
How about trying to tackle Partzman's question now that the first question has been answered for you?
Now, is anybody going to say something about this?
It went something like this: You have an ideal five henry inductor. There is an ideal voltage source that is put across the inductor at t=0 and for two seconds the voltage applied across the inductor is a linear ramp that starts at zero volts and ends at two volts. After that the voltage is zero volts. What happens?
The current ramps up on a linear ramp,but 90* behind that of the voltage ramp,and ends with a value of 800mA,and maintains that value until interrupted.?
Brad
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That's not right but more importantly how did you arrive at that answer? That's the whole point for the brainstorming, to bounce ideas back and forth.
The other question is why are you talking about phase here and how do you define it?
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Question Mags,,
Are these electrons stacked up in a straight line or across in a straight line?
It takes more "energy" to put the last electron into place than it does the first one,, just like stacking bricks,, the low ones are easy,, the high ones are harder.
Hmm. How much simpler can I put it? Poynt is stumped also.
Ok. Here is another set of questions. We will start from the very beginning. These should be very basic knowledge questions. All refer to a 1000uf cap charged from 0v to 10v....
Does anyone here believe that when we charge a cap, that we are depleting the pos plate of electrons, and adding extra electrons to the neg plate?
If we have say a 1000uf cap and we charge it from 0v to 10v, are there electrons pulled from the positive plate and electrons pumped into the negative plate during the charge period?
Is the reason the positive plate becomes positively charged because it is stripped of electrons, and that the negative plate is becomes negatively charged is because it has taken on extra electrons?
If you do not agree that the answer to those 2 questions should be 'Yes', then I need an explanation as to why.
Mags
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I agree.
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"Haven't you done your own test with this? What was your result?"
My results were that I get 5v per cap after cap to cap transfer. ??? And What Im saying is that I think that even if they were ideal caps, 10v cap to 0v cap, that we would still have 5v per cap.
Well we can't have ideal conductors (when shorting an ideal cap or voltage source), so this scenario is unachievable/unsolvable to begin with. You would have infinite current as soon as the two caps are connected.
Here is a couple of questions for you....
We have 2 'Ideal' capacitors of the same value. One is charged at 10v and the other at 0v.
Lets say just for simplifying the example that the 10v cap has an imbalance of 2000 electrons (pos plate -1000 and neg plate +1000) between the pos and neg plates and the 0v cap has no imbalance.
So we do the cap to cap zap. When all is said and done, we disconnect the caps. What would the voltage be across those caps? And what would the electron imbalance count be for each cap?
Assuming the universe didn't blow up trying to source infinite current, the voltage would be 7.07V in each cap. The electron balance would be 707 on each plate, vs 1000 when it was 10V, assuming there is a valid linear relationship between the charge count and voltage of course.
Now we will do the same with real world caps..... Same values as described above.....
Cap to cap zap and disconnect. What will the voltages be across those caps? And what would the electron imbalance count be in this example?
Surely you know the answers? 5V and 500 electrons.
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I agree.
Ok.
When I was saying to simplify things by saying that the electron count was -1000 electrons for the Pos plate and +1000 electrons for the Neg plate when the cap is charged to 10v, the 1000 number is just to simplify things. The real numbers are probably so large, but the symmetry should be fairly close. Nearly as many electrons come out of the Pos cap lead as there is going in to the Neg cap lead.
Would you agree that if we charged the cap from 0v to 10v, and we 'could' count the numbers of the electron count offset between the Pos and Neg plates, then if we discharged the cap to 0v and recharged the cap to 10v, and we did another count of the electron offset between the two plates, would that number be the same as the offset count after the first charge? Im talking theoretically 0v and 10.00000000000000000000000000000000000v Not a 10.001v or 9.999999v. 0v to 10v.
Mags
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Agreed. I think you may want to skip ahead; see my last response to your questions.
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Agreed. I think you may want to skip ahead; see my last response to your questions.
"Well we can't have ideal conductors (when shorting an ideal cap or voltage source), so this scenario is unachievable/unsolvable to begin with. You would have infinite current as soon as the two caps are connected."
"Assuming the universe didn't blow up trying to source infinite current, the voltage would be 7.07V in each cap. The electron balance would be 707 on each plate, vs 1000 when it was 10V, assuming there is a valid linear relationship between the charge count and voltage of course."
Ok. Good.
1 cap at 10v - +1000 excess electrons on the Neg plate and -1000 electrons on the Pos plate.
1 cap at 0v - each plate has an equal amount of electrons and no imbalance.
If we let the cap discharge into a 0v cap and equalize, how do we get +707 offset count on both caps Neg plates and -707 on both caps Pos plates? If we divide 1000 by 2 we get 500 + and - for each cap. Where did we get the extra electrons to get the 207 count difference? Its like saying if we have 1 gal of water and we divide it equally between 2 containers that each container would have .707 gal of water at no loss, but if we ended up with .5 gal per container that we have lost half. In a way.
The total offset for the 2 ideal caps would be 1414 electron offset count. We started with 1000 offset in the source cap. Can you see the discrepancy? ;)
So how do we account for the extra electrons in the ideal cap to cap? I can see how we do it with the inductor, where we cut off the source cap at 7.07v, then let the inductor freewheel electrons from the Pos of the receiving cap to the Neg until it reaches 7.07v. All say done with super fast timed switching, no diodes..
But with the cap to cap, there isnt the option of gaining extra electrons in the offset to alter the original count. They can only be distributed equally between he 2 caps. 1000 + and - offset count of the source cap to 1000+ and - offset count for both caps total, 500 + and - offset each. The above explanation with the inductor, we stopped the flow from the source cap at 707 + and - offset count, and at that time the inductor pumps the receiving cap the rest of the way by way of taking from the Pos and giving to the neg.
Similar to the air tank with an air motor with fly wheel. 100lb air on source tank and 0lb in the receiving tank. Open the valve and the pressure gets the flywheel going while the receiving tank fills. We cut of the source tank at 70.7lb and switch over to letting the flywheel pump 'extra' air from the outside, till the receiving tank is at 70.7lb. If we simply did tank to tank, we would have 50 lb per. Heat losses or not, tank to tank could never be a result of 70.7lb per tank all said and done.
So if we can agree on the simple mathematics of the offset count, then we would have to agree that the ideal cap to cap would result in 5v per cap. So where did we lose the 50%energy with no resistance and or heat losses? Thats my point Poynt. ;D
Mags
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So how do we account for the extra electrons in the ideal cap to cap? I can see how we do it with the inductor, where we cut off the source cap at 7.07v, then let the inductor freewheel electrons from the Pos of the receiving cap to the Neg until it reaches 7.07v. All say done with super fast timed switching, no diodes..
Mags
Yes Mags, we had that very civil conversation on the the other thread about that and I went over the process in detail. I described it all to you.
Then subsequent to that your harassed me about some nonsensical foolishness over about a dozen postings. You made it very clear that you enjoyed doing it too.
I don't know what this sickness is that you have in your head and your heart but it's time for you to stop acting like a jackass harassing idiot towards me. I endured one full year of that despicable behaviour and I don't want to see any relapses of it any more.
Now, will you post here stating to everyone that this aberrant behaviour from you is going to stop right now?
MileHigh
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Yes Mags, we had that very civil conversation on the the other thread about that and I went over the process in detail. I described it all to you.
Then subsequent to that your harassed me about some nonsensical foolishness over about a dozen postings. You made it very clear that you enjoyed doing it too.
I don't know what this sickness is that you have in your head and your heart but it's time for you to stop acting like a jackass harassing idiot towards me. I endured one full year of that despicable behaviour and I don't want to see any relapses of it any more.
Now, will you post here stating to everyone that this aberrant behaviour from you is going to stop right now?
MileHigh
Im not here to harass anyone about this. Nor argue. Just talking. If any of what I wrote in the last couple days sounds like im yelling at anyone, or trying to insult anyone, or their intelligence, then turn down your internal volume level when you read my posts.
Can you please give me a link to that "process in detail" you referred to, or repost it? Just asking.
Mags
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Im not here to harass anyone about this. Nor argue. Just talking. If any of what I wrote in the last couple days sounds like im yelling at anyone, or trying to insult anyone, or their intelligence, then turn down your internal volume level when you read my posts.
Can you please give me a link to that "process in detail" you referred to, or repost it? Just asking.
Mags
The quote you posted from me in your last post refers to using an inductor. That was an example of I understand that result. Worked with that for some time. What Im interested in is the cap to cap electron counts when it comes to ideal and real cap to cap results. That should be consistent with the voltages we end up with in the cap to cap deal.
Mags
Mags
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Im not here to harass anyone about this. Nor argue. Just talking. If any of what I wrote in the last couple days sounds like im yelling at anyone, or trying to insult anyone, or their intelligence, then turn down your internal volume level when you read my posts.
Can you please give me a link to that "process in detail" you referred to, or repost it? Just asking.
Mags
The process was described on the Joule Thief 101 thread.
Before I try that, I made a mistake and your harassment was also on the Joule Thief 101 thread.
Here is the link for the start of the harassment:
http://overunity.com/8341/joule-thief-101/msg483976/#msg483976
You make two crazy nonsensical arguments and push me and mock me about them:
1) There is no such thing as an ideal voltage source that can vary in time.
2) "Prove to me that there is no such thing as an 'ideal' CEMF."
Don't you feel like a fool now in making those arguments?
I get fed up and in post #1262 I say, "That's twelve postings from you on the same subject. That's harassment."
In post #1263 you reply, "lol. So now you 'make up' a 12 post rule? lol. Please post a document that describes that rule exists.. Look at your most recent posts to me. They are just happy happy joy joy? (http://overunity.com/Smileys/default/huh.gif) ? Hypocrite."
You are clearly enjoying doing it.
I will ask you again:
Are you man enough to post here stating that you are not going to harass me any more?
MileHigh
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Magluvin:
I spent 10 minutes searching both threads but I could not find the original posts.
However, it is easy to restate and you already stated it: When Cap A is at 7.071 volts a "magic ideal switch" instantly moves the coil so that it is across Cap B only and there is also an ideal diode. It doesn't matter what value the coil is, the coil will charge Cap B to 7.071 volts and the coil pumps the "missing" electrons to bring Cap B up to 7.071 volts.
We had a very civil conversation about that.
And I am going to repeat to you again that I do not want to be harassed by you and I am requesting that you make a public posting stating that you will not harass me any more.
I do not want to endure another year of torture from you. Do you understand that?
MileHigh
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Magluvin:
I spent 10 minutes searching both threads but I could not find the original posts.
However, it is easy to restate and you already stated it: When Cap A is at 7.071 volts a "magic ideal switch" instantly moves the coil so that it is across Cap B only and there is also an ideal diode. It doesn't matter what value the coil is, the coil will charge Cap B to 7.071 volts and the coil pumps the "missing" electrons to bring Cap B up to 7.071 volts.
We had a very civil conversation about that.
And I am going to repeat to you again that I do not want to be harassed by you and I am requesting that you make a public posting stating that you will not harass me any more.
I do not want to endure another year of torture from you. Do you understand that?
MileHigh
Yes I understand that we can get 7.07v in each cap from a source cap of 10v using the inductor.
But when we consider the electron count, as Webby has put up that the electron count is directly related to the voltage of a particular cap value, then there is a problem with the ideal cap to cap supposed outcome.
Forget the inductor version. Just direct cap to cap, Ideal and Real world examples.
The electron count screws up the idea of an ideal cap with 10v connected to an ideal cap of 0v, ends in both caps having 7.07v each. This conclusion would need extra electrons added to the system. Or the addition of the inductor and switching to pull more electrons from the pos to the neg of the receiving cap.. So the ideal direct cap to cap will end with 5v each from a 10v source cap. We still lost 50%. If no heat loss or other loss in the ideal world, how did we still lose 50% with the ideal cap to cap gig? ;) And if Im correct, then resistance is 'not the cause' of the 50% loss. Also if Im correct, how will it change how we should think about heat losses in other areas of science?
I hope you dont read that as harassment, other than I seem to have to repeat this stuff many times with this to get the point across. Poynt seems to be close to understanding what Im getting at.
This could be a very important discovery. It could possibly show an example of losing energy without it being converted to another form, heat. If there is no induction in the ideal cap, then we cannot be losing it as magnetic radio radiation.
So for me, I would hope that someone can explain this if they know how and why, etc.
Mags
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Have a look at 795.
John.
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I think he wrote that, because two electrons can represent different energies depending on their separation distance and the work needed to move them closer together is a result of their repulsion force integrated over the distance of their approach.
Reminder: The instantaneous repulsion force of two electrons is inversely proportional to the square of the distance (1/d2) between them.
BTW: this is an example how the same amount of charge (here, the two electrons) can represent very different levels of energy.
In other words: Charge alone, is not energy.
This is post 795 above.
"BTW: this is an example how the same amount of charge (here, the two electrons) can represent very different levels of energy.
In other words: Charge alone, is not energy."
I can agree with that. But if we know the value of the capacitance, and the value of charge, then there is an energy value directly related to those values as to how much energy is held in the cap.
Anyway...
Mags
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Yes I understand that we can get 7.07v in each cap from a source cap of 10v using the inductor.
But when we consider the electron count, as Webby has put up that the electron count is directly related to the voltage of a particular cap value, then there is a problem with the ideal cap to cap supposed outcome.
Forget the inductor version. Just direct cap to cap, Ideal and Real world examples.
The electron count screws up the idea of an ideal cap with 10v connected to an ideal cap of 0v, ends in both caps having 7.07v each. This conclusion would need extra electrons added to the system. Or the addition of the inductor and switching to pull more electrons from the pos to the neg of the receiving cap.. So the ideal direct cap to cap will end with 5v each from a 10v source cap. We still lost 50%. If no heat loss or other loss in the ideal world, how did we still lose 50% with the ideal cap to cap gig? ;) And if Im correct, then resistance is 'not the cause' of the 50% loss. Also if Im correct, how will it change how we should think about heat losses in other areas of science?
I hope you dont read that as harassment, other than I seem to have to repeat this stuff many times with this to get the point across. Poynt seems to be close to understanding what Im getting at.
This could be a very important discovery. It could possibly show an example of losing energy without it being converted to another form, heat. If there is no induction in the ideal cap, then we cannot be losing it as magnetic radio radiation.
So for me, I would hope that someone can explain this if they know how and why, etc.
Mags
Well Mags, there you go. I asked you politely three times to post publicly that you will not harass me any more and you refuse to do it. You are not enough of a man to admit that you were wrong and simply post that you would not harass me anymore.
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With respect to the two ideal caps connecting to each other, that's like two temporary ideal voltage sources connecting to each other where infinite current wants to flow. It simply doesn't work and it gives you some insight into why the simulation programs have to sometimes have insignificant resistor values added to the sim to get them to run properly.
I already discussed a way of looking at this with Magluvin before using a very small inductor between the two caps. As the inductor value goes towards zero, the oscillation frequency goes towards infinity.
Connecting two ideal caps together with a different voltage simply doesn't work. That's the real answer.
That's why I groan when I see people post schematics with two car batteries connected in parallel. It doesn't make sense and could be a recipe for disaster.
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I will just make another posting about people failing to step up and account for things or admit that they were wrong and have learned something new.
Let's take the example of the "ideal voltage source 'not being allowed' to vary in time." That is a completely ridiculous idea that seemingly was plucked out of a hat, for lack of a better term.
Who here stuck to this false idea?
Her is my list:
Brad
Wattsup
Magluvin
Magneticitist
Webby may also be in that group, I can't remember.
How many of you have posted admitting that you were wrong and now acknowledge that an ideal voltage source can vary in time?
I think I know the answer to that: ZERO
And some of you guys put up a big fight about that. It was a lot of foolishness representing a lot of wasted time and wasted energy. Specifically because so much time and energy was wasted on this nonsense, you would think that some of you would at least want to acknowledge that you were wrong and now you know better. Instead you get nothing. Grown men that can't simply step up to the plate and acknowledge something.
I am shaking my head.
It's the same story for the "ideal CEMF" nonsense.
I am not saying that every single time you learn something new that you were previously stating incorrectly has to be acknowledged, but the ideal voltage source example is real. There was so much time and energy wasted with that nonsensical push-back and nobody wants to even admit it.
MileHigh
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You have an ideal five henry inductor. There is an ideal voltage source that is put across the inductor at t=0 and for two seconds the voltage applied across the inductor is a linear ramp that starts at zero volts and ends at two volts. After that the voltage is zero volts. What happens?
Now, is anybody going to say something about this?
During the first time period, the current increase is parabolic (a quadratic function of time) and during the second period, the current is constant, since a 0V ideal voltage source is equivalent to a perfect short.
The magnetic flux through an ideal shorted inductor is always constant*, and in the absence of a varying external magnetic flux, the current is constant, too.
* I like to call this the "Quantitative Lenz Law".
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Mags,
No electrons are ever added or deleted from the circuit.
It comes down to the electron imbalance as you call it. When the connection is made the source cap becomes less imbalanced, and the charge cap more imbalanced. In both the inductor and ideal wire cases, there is no voltage drop across the "transport medium", therefore no loss of voltage or energy in the transfer. Therefore the two caps settle at 7.07V. Conservation of energy also supports the end voltages to be 7.07V.
In the case when the conductor is a real resistance, there is a voltage drop due to the current through it and this is where the 2.07V is lost in each capacitor. This is also where half the energy is "burned".
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MH,
I'm not sure what the problem is; I haven't seen anything derogatory towards you from Mags in the last few pages or so.
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MH,
I'm not sure what the problem is; I haven't seen anything derogatory towards you from Mags in the last few pages or so.
The harassment is fully documented in post #809. It took place about two weeks ago. He was pushing a nonsensical technical agenda. If he wasn't aware then that it was technically nonsense then he is surely aware by now that it was pure nonsense. It is obvious that if the debate was with you or with someone else that he would not have behaved like he did. It's also obvious that he was enjoying it.
I don't know what this creepy ugly darkness is that exists in his heart and in his soul, but it is clearly there. In recent times I have warned him several times that there is never going to be a return to the full year of harassment and demeaning and degrading behaviour from him that he perpetrated on me, and he laughed it off and challenged me to prove that it even took place. Recently he posted to you that he has an "issue" with me. The man clearly has some problems with respect to me, and the sick borderline-psychotic continual harassment and demeaning and degrading behaviour is not going to start again.
Just now I asked him three times in a polite manner to state publicly that he will not harass me and he has refused to acknowledge the request and he has refused to state that he will not harass me.
The man has problems, and I am making it clear to him publicly that the sick behaviour that he displays is not going to start up again. There was a flare-up of it two weeks ago, and you could sense how he was licking his chops thinking about doing it some more.
Magluvin: This is the fourth request, will you publicly state that you will not harass me?
MileHigh
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MH,
I sense that you've become jumpy on this matter. I know there have been issues between you two in the past, and perhaps two weeks ago, but I was referring to just the last couple of days. Mags seems to be civil and peaceful so I'm having trouble understanding why you're feeling threatened by him now?
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I went and read a few posts on the thread from your link, and while it does appear Mags may have been knowingly taunting you (perhaps the reason for the plethora of ;) faces), I think he may have been trying to make a point, but I'm not certain. Do the guys understand things but pretend they don't just for the sake of argument? Again I don't know, but I sincerely hope that is not the case.
Some things are crystal clear to anyone with a formal electronics education, while it is always not so with those who are electronics hobbyists. I think both parties need to understand and make allowances for this difference in understanding.
Yes, Mags appears to have been going hard on you, but no harder than your criticisms of the tinman at times, and perhaps that is the point Mags was trying to make.
@Mags and MH, for now might I suggest we put that behind us best we can and give peace a chance? Focusing on the technical as much as possible might be a good game plan.
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Poynt:
Magluvin cannot seamlessly switch from a civil technical conversation where I was happy to help him understand a way of looking at the cap transfer business, to enjoying harassing me for "sport."
That is simply not going to happen. Let's see if he is man enough to step up to the plate and state that he is not going to harass me. Let's see if any of these guys are man enough to admit that they were wrong about the variable voltage source.
Brad got criticism from me and that ended up being a mutual two-way affair and he got disjointed because of it and went haywire. Brad has been coasting along for years and I made a conscious decision to be straight with him for his own benefit, even though that was a very distasteful thing for him. That was something that he was not used to. But Brad will not maliciously and intentionally harass me like Magluvin did for a very long time, and then there was that incident two weeks ago. I am making it very clear to Magluvin that he does not have license to talk tech in a civil manner and then switch over to being a harassing jackass whenever he pleases.
There is a distinct difference between my dust-up with Brad for his own benefit and being stalked and harassed by Magluvin. Magluvin's atrocious behaviour was unacceptable in the past and it still is unacceptable now.
MileHigh
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Poynt:
Magluvin cannot seamlessly switch from a civil technical conversation where I was happy to help him understand a way of looking at the cap transfer business, to enjoying harassing me for "sport."
How do you know this? Why not give him a chance and see what happens.
That is simply not going to happen. Let's see if he is man enough to step up to the plate and state that he is not going to harass me. Let's see if any of these guys are man enough to admit that they were wrong about the variable voltage source.
Why not just give him the benefit of doubt and see where it goes? He hasn't harassed you in the last couple of pages, so can we not start there? If he or you become unreasonable, then we'll all step in before it gets out of hand. I'm no fan of reading this stuff, and I doubt any others here are either.
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Yeah I am no fan of reading it either. But you know what you or any of the readers would be much less of a fan of? That would be to be relentlessly and viciously harassed and demeaned and degraded by Magluvin for months and months on end.
The man has a serious problem, let's see if he is man enough to post that he will stop harassing me.
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From my point of view, if he is already posting and interacting with you (and he has), and not harassing you, then that is statement enough.
For the record, I've had my own share of go-arounds with mags in the past.
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author=MileHigh link=topic=16589.msg485400#msg485400 date=1464593672]
MileHigh
I will just make another posting about people failing to step up and account for things or admit that they were wrong and have learned something new.
Let's take the example of the "ideal voltage source 'not being allowed' to vary in time." That is a completely ridiculous idea that seemingly was plucked out of a hat, for lack of a better term.
Who here stuck to this false idea?
More lies from you MH,and im fed up with them.
It was told very clearly that the ideal voltage from the ideal voltage source would not vary in time!!REGARDLESS OF LOAD!!-->when will that sink into your thick head?.
The only time the voltage will vary,is when determined to do so by the user.
So enough of your bullshit.
You think Mags is harassing you?,well i think you should look at the crap you continue to post--The lies such as above.
How many of you have posted admitting that you were wrong and now acknowledge that an ideal voltage source can vary in time?
When will you admit that you got your wires crossed again?.
And some of you guys put up a big fight about that. It was a lot of foolishness representing a lot of wasted time and wasted energy.
The only time wasted here,is on you,and trying to get you to read everything that is posted in threads.
Specifically because so much time and energy was wasted on this nonsense, you would think that some of you would at least want to acknowledge that you were wrong and now you know better. Instead you get nothing. Grown men that can't simply step up to the plate and acknowledge something.
I am shaking my head.
What you need to do MH,is give your head a good slap,and snap out of this !!poor me!! crap--it's getting beyond a joke.
No one ow's you anything,as you have given as good as you have gotten,and as could be seen in the JT thread,you gave to me far worse that i gave to you--did you see me asking for an apology ?--no,didnt think so,as i really dont care for your insults to much at all.
So give it a rest MH,as we can all see what your doing here,and that is !!once again!! taunting Mag's,and just itching to get him fired up--so as you can once again say--oh look,Mags is being nasty toward me again.
I am not saying that every single time you learn something new that you were previously stating incorrectly has to be acknowledged, but the ideal voltage source example is real. There was so much time and energy wasted with that nonsensical push-back and nobody wants to even admit it.
The only time wasted on the ideal voltage saga,was your time,as we all knew what an ideal voltage is/was long before you started your rant on the subject.
Brad
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Mags,
No electrons are ever added or deleted from the circuit.
It comes down to the electron imbalance as you call it. When the connection is made the source cap becomes less imbalanced, and the charge cap more imbalanced. In both the inductor and ideal wire cases, there is no voltage drop across the "transport medium", therefore no loss of voltage or energy in the transfer. Therefore the two caps settle at 7.07V. Conservation of energy also supports the end voltages to be 7.07V.
In the case when the conductor is a real resistance, there is a voltage drop due to the current through it and this is where the 2.07V is lost in each capacitor. This is also where half the energy is "burned".
Below is 3 pics.
1st depiction is of 2 caps at 0v.
2nd is of the left cap charged to 10v. So I depicted it as taking 10 electrons from the top plate and put them in the bottom plate, understanding the electron numbers are far greater in reality. ;)
3rd pic is of the 2 caps after cap to cap connection, where I took electrons from the top plate of the right cap to the top plate of the left cap to equalize the numbers, and took electrons from the left caps bottom plate to the right caps bottom plate to equalize their numbers also.
So in the real world cap to cap, this should be what has happened once the imbalance of electron numbers in the left cap equalize with the cap on the right.
So, 10v in source cap, do the cap to cap and we get 5v per cap.
But in the ideal example, when we charge the left cap and do the cap to cap with the right cap, the numbers of electron imbalance should balance out the same, thus still having 5v per cap. the only way to get 7.07v in each cap would be to start out with a 14.14v in the source cap where it had a greater imbalance of electrons to be divided between the 2 caps, of which would give us 7.07v per cap.
The only other way to get the electron number balance to come out where we end up with 7.07v per cap is if we pulled more electrons(using inductor during cap to cap, cut off source at 7.07v, letting inductor charge the right cap to 7.07v) from the top plates to the bottom plates. But cap to cap this cannot happen because the electrons cannot pass from the bottom plates to the top plates due to no electrical connection. Only in the initial charge of the cap on the left did that occur.
My saying earlier of adding electrons to the system was incorrect. What I meant was the imbalance between the Pos and Neg would have to be changed, taking from the top and adding to the bottom, as in the case of this post. Sorry for the confusion there.
Mags
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But in the ideal example, when we charge the left cap and do the cap to cap with the right cap, the numbers of electron imbalance should balance out the same,
And they do, at 7.07V each, not 5V each.
thus still having 5v per cap. the only way to get 7.07v in each cap would be to start out with a 14.14v in the source cap where it had a greater imbalance of electrons to be divided between the 2 caps, of which would give us 7.07v per cap.
Try stepping outside the box a little. The source cap can discharge to ANY voltage between 9.999V and 0V, depending on what it is connected to and how. The charge cap can charge to any voltage from 0V to 7.07V (max in this case). Can you not add a fig.4 to your drawing with an imbalance to create 7V on each cap?
I know you can ;) (hint, use fig.3 and drop 4 more electrons from the top plate to the bottom plate). See, now we have 7V on each cap, and we didn't have to add any electrons. ;)
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More lies from you MH,and im fed up with them.
It was told very clearly that the ideal voltage from the ideal voltage source would not vary in time!!REGARDLESS OF LOAD!!-->when will that sink into your thick head?.
The only time the voltage will vary,is when determined to do so by the user.
For Pete's sake Brad. This is simply a case of different terminologies used, by you and by MH, OK? Some folks do understand what it means, put the way MH put it, and some don't. Can we settle this now and never argue about it again? MH did not mean that the voltage would change after it was set, he meant that it can change at various times between t=0 and t=x. In other words, he meant that it would never deviate from its setting until the next setting. But the fact that it is being changed a number of times between t=0 and t=x, means it IS varying over that time period. OK? THAT is what he meant. Don't think that MH doesn't know what an ideal voltage source is, that would be ridiculous of you, and this silly argument is becoming extremely old. >:(
I'm not going to comment on the last part of your post as it is simply not worthy of comment. Same with MH's knee-jerk reaction to Mags' last few postings. I think you both need to take a pill. ;D
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And they do, at 7.07V each, not 5V each.
Try stepping outside the box a little. The source cap can discharge to ANY voltage between 9.999V and 0V, depending on what it is connected to and how. The charge cap can charge to any voltage from 0V to 7.07V (max in this case). Can you not add a fig.4 to your drawing with an imbalance to create 7V on each cap?
I know you can ;) (hint, use fig.3 and drop 4 more electrons from the top plate to the bottom plate). See, now we have 7V on each cap, and we didn't have to add any electrons. ;)
If we have an ideal 10uf cap and a real 10uf cap,when we charge each to 10v, the electron number imbalance for each should be the same. So that is what we start with considering the electron imbalance. From there on in, the Pos plate has no connection to the Neg plate for either cap.
So we only have a specific number for each cap imbalance. And when we do the cap to cap, that imbalance can only be divided by 2 when we let the two caps equalize. There is no chance in the 2 caps for there to be any more electrons taken from the top to the bottom, only from top to top and bottom to bottom(left to right, etc). All of the top electrons are trapped in the top side of the caps and the bottom side electrons are trapped in the bottom. Cap to cap that is.
For some odd reason(it seems) I see it clear as a bell. Im struggling to figure out better ways of explaining it.
Like as you said, take 4 more electrons from the top to the bottom, 2 electrons for each cap. Well after we are done charging the left cap, and then we do the cap to cap, when is it that those 4 electrons get a chance to move from the top to the bottom? ;) Where is the bridge that they cross? The dielectric? At what point does this happen?
Mags
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Sorry. Edited the first line and added the last question to my last post
Mags
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Like as you said, take 4 more electrons from the top to the bottom, 2 electrons for each cap. Well after we are done charging the left cap, and then we do the cap to cap, when is it that those 4 electrons get a chance to move from the top to the bottom? ;) Where is the bridge that they cross? The dielectric? At what pint does this happen?
Mags
Right, 2 electrons per cap from top to bottom to change it from 5V each (15T, 25B) to 7V each (13T, 27B), agreed?
I don't understand part two of your question; We still start out with 10V on the source cap, and the electrons distributed as drawn (10T, 30B). However, now that we have ideal caps and an ideal wire connecting them, there is no loss, so after the transfer takes place, each cap will be left with an electron distribution of 13T, 27B.
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Gotta git. Im not getting what you are getting at. ;D If we look at the 2 top plates after cap to cap, the electron imbalance can only be half in each top plate of the left caps total electron imbalance after it was charged. As would also be with the bottom plates. There can be no more imbalance changes between top and bottom after the initial charge of the left cap.
If we were to move more electrons from one top plate to the 'other' top plate so that the 'other' top plate has 7 electrons, for just say 7v,(do same for bottom plates) then they would not be equalized in electron count and the other top/bottom plate would only have 3 electrons. When we talk about equalization of the 2 caps, Im talking about equally divided by 2 distribution. I dont see any other way of the electron distribution other than divided by 2.
If you have a pic editor, could you show me how and when the electron changeover is done how you say? Im having a hard time getting it. I used Picpick. Free and fairly simple to use. Mostly use for screen grabs.
Mags
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For Pete's sake Brad. This is simply a case of different terminologies used, by you and by MH, OK? Some folks do understand what it means, put the way MH put it, and some don't. Can we settle this now and never argue about it again? MH did not mean that the voltage would change after it was set, he meant that it can change at various times between t=0 and t=x. In other words, he meant that it would never deviate from its setting until the next setting. But the fact that it is being changed a number of times between t=0 and t=x, means it IS varying over that time period. OK? THAT is what he meant. Don't think that MH doesn't know what an ideal voltage source is, that would be ridiculous of you, and this silly argument is becoming extremely old. >:(
I'm not going to comment on the last part of your post as it is simply not worthy of comment. Same with MH's knee-jerk reaction to Mags' last few postings. I think you both need to take a pill. ;D
No,MH wrongly accused myself and others that we do not know the definition of an ideal voltage source. He clearly stated that we say that the voltage cannot change with time-and that is crap. 300 posts ago,i posted my understanding of an ideal voltage ,and it is correct,and i will not have MH bullshitting about me being wrong-full stop.
The voltage can only change if determind to do so by the user-fact.
So for MH to say i am wrong,is just bullshit-plane and simple.
Why have you not told MH that he is incorrect,in stating that i do not know what an ideal voltage is?
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author=MileHigh link=topic=16589.msg485400#msg485400 date=1464593672]
MileHigh
More lies from you MH,and im fed up with them.
It was told very clearly that the ideal voltage from the ideal voltage source would not vary in time!!REGARDLESS OF LOAD!!-->when will that sink into your thick head?.
The only time the voltage will vary,is when determined to do so by the user.
So enough of your bullshit.
You think Mags is harassing you?,well i think you should look at the crap you continue to post--The lies such as above.
When will you admit that you got your wires crossed again?.
The only time wasted here,is on you,and trying to get you to read everything that is posted in threads.
What you need to do MH,is give your head a good slap,and snap out of this !!poor me!! crap--it's getting beyond a joke.
No one ow's you anything,as you have given as good as you have gotten,and as could be seen in the JT thread,you gave to me far worse that i gave to you--did you see me asking for an apology ?--no,didnt think so,as i really dont care for your insults to much at all.
So give it a rest MH,as we can all see what your doing here,and that is !!once again!! taunting Mag's,and just itching to get him fired up--so as you can once again say--oh look,Mags is being nasty toward me again.
The only time wasted on the ideal voltage saga,was your time,as we all knew what an ideal voltage is/was long before you started your rant on the subject.
Brad
For the ideal voltage source, that's your 150th bait and switch. You should get a trophy for that or something. You fought the idea that an ideal voltage source can vary in time repeatedly, and you pulled up the textbook definition as "proof" that an ideal voltage source cannot vary in time. The fact that you are denying that fact with a bait and switch based around the choice of words is laughable. We all know, your brain would sizzle and crackle and spit out hot embers if you simply said, "Sorry guys, I was way off on the ideal voltage source business and I wasted a lot of time." What a joke. Step up to the plate and be a man once in a while.
Do you remember perhaps about six or eight months ago some guy was on here for less than two weeks. He taunted you, he mocked you, he demeaned you repeatedly. He called you nasty names and insulted you. He did it every single day he was on the forum. Did you like it? How would you like it if he stuck around for a full year and did it to you every single day?
But within two weeks he was gone. And before he left he apologized to you and acknowledged what he did was wrong. He was a complete jackass, but in the end owned up to his behaviour and acted like a man. How about them apples?
And the reality for you on the technical side of things is we found out that you are not the equivalent of six months through an Electronics 001 course, it's more like you are 2 1/2 weeks through an Electronics 001 course and you have barely opened up your book. So you can do nothing about that because it's "just a hobby," it's your choice. But if I am involved with a thread that you are on you are not going to get special treatment from me and if you say daft nonsensical junk then you are going to be told that it's daft nonsensical junk. We have had truckloads of that from you and I hope you go up the learning curve and get more out of your hobby. "Ideal CEMF" is nonsensical junk, period. "An ideal voltage source cannot vary with time" is nonsensical junk.
MileHigh
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For the ideal voltage source, that's your 150th bait and switch. You should get a trophy for that or something. You fought the idea that an ideal voltage source can vary in time repeatedly, and you pulled up the textbook definition as "proof" that an ideal voltage source cannot vary in time. The fact that you are denying that fact with a bait and switch based around the choice of words is laughable. We all know, your brain would sizzle and crackle and spit out hot embers if you simply said, "Sorry guys, I was way off on the ideal voltage source business and I wasted a lot of time." What a joke. Step up to the plate and be a man once in a while.
Do you remember perhaps about six or eight months ago some guy was on here for less than two weeks. He taunted you, he mocked you, he demeaned you repeatedly. He called you nasty names and insulted you. He did it every single day he was on the forum. Did you like it? How would you like it if he stuck around for a full year and did it to you every single day?
But within two weeks he was gone. And before he left he apologized to you and acknowledged what he did was wrong. He was a complete jackass, but in the end owned up to his behaviour and acted like a man. How about them apples?
And the reality for you on the technical side of things is we found out that you are not the equivalent of six months through an Electronics 001 course, it's more like you are 2 1/2 weeks through an Electronics 001 course and you have barely opened up your book. So you can do nothing about that because it's "just a hobby," it's your choice. But if I am involved with a thread that you are on you are not going to get special treatment from me and if you say daft nonsensical junk then you are going to be told that it's daft nonsensical junk. We have had truckloads of that from you and I hope you go up the learning curve and get more out of your hobby. "Ideal CEMF" is nonsensical junk, period. "An ideal voltage source cannot vary with time" is nonsensical junk.
MileHigh
Your full of crap MH,and you know it.
As per usual,you leave half of everything out,because your to much of a coward to admit when your wrong.
As i stated,an ideal voltage dose not change over time-regardless of the load. It only changes when the user determines that change. 300 post ago i stated this,but apparently you missed it--how convenient.
As far as my skills go-being very limited according to you,then stop being a coward,and take me up on my challenge. Of course,you wont-some horse shit excuse about--oh i dont build.
You just keep on taunting people until they bite back,and then you have one of your little baby tantrums,and start demanding apologies,and garenties that they will leave you alone--just like your doing with Mags now.
The only skill you have,can be anyone's,as the net has all that you know.
My skills are hands on,and can only be obtained in that manner.
Any time you want to take me on in actually building a device,you let me know. Until you can do so,then your words of wisdom mean nothing.
How about we see who can convert a universal motor to be the most efficient?,where we measure P/in ,and mechanical and ''electrical'' P/out.
You want to tell everyone here my electrical skills are basic--then take me on.
You want to say that past power measurements on such a device were wrong or 'some how'fake--then take me on.
When were both finished our modified motors,we will ship them to Poynt,and let him do the power measurements.
Give it your best shot MH ,and we'll see who has just basic 001 skills when it comes to electromagnetic/mechanical devices.
Lets get this show on the road MH,as i am no longer bound by restrictions.
Time for you to prove that you know more than me.
But i will even give you the edge MH--you may team up with anyone you like,get them to build your converted universal motor,and help you out as much as you need.
Lets discuss terms MH.
Lets see who can build the most efficient Rotary Transfomer ;)
Brad
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Since it is possible to imagine, in the Fantasy World of
Theoreticals, (1) an Ideal Voltage Source which outputs a
constant DC ElectroMotive Force across any imagined
Load, then it must also be possible to imagine
(2) an Ideal AC Voltage Source
(3) an Ideal RF Voltage Source
(4) an Ideal Audio Signal Generator
(5) an Ideal Function Generator
(6) an Ideal Complex Wave Generator
etc., etc., etc... 8)
Therefore, within the context of Theoretical
Problem Solving, why not simply state within
each "problem" the type of Ideal Voltage Source
which is intended to be used in order to arrive at a
Theoretical Solution? :o
After all, isn't that consistent with the Scientific Method? ::)
Specifying clearly and unambiguously what the conditions
of the problem are? ::)
Unless of course, the alleged "problem" is really naught more
than a "head game" of trickery. ;)
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Specifying clearly and unambiguously what the conditions
of the problem are? ::)
Unless of course, the alleged "problem" is really naught more
than a "head game" of trickery. ;)
What a bunch of crap your posting is. I can't believe you would post nonsense like that. The question is straightforward and clearly expressed and unambiguous. There were never any head games or trickery intended.
Here you are supposedly the guy that is "fighting to warn us of the NWO and the End Times" and what is implicit in that is "we have all been deceived" and "the truth will come out" and "all will be resolved in the battle between the forces of truth and good and the evil deceptive forces of trickery and deceit" BLA BLA BLA....
Right?
And you have the bloody nerve to come on and make a posting that makes you into a force of deception and trickery by falsely trying to suggest that some "evil trickery" is going on here. Ironically, you are the purveyor of "deceit and evil trickery" by the totally disingenuous nonsensical posting that you just made. Not only are you "out there" with many strange views, arguably someone with their "head screwed on backwards" but you come here and make a posting where you act exactly like the "bad guys" that you despise. It's like you have your head "doubly screwed on backwards" with that posting. You are acting exactly like the "shadowy guys" that you "warn" us about and despise. Talk about "out of this world" irony.
Did I ruin your pulsations of pleasure? Perhaps you need to read some Trotsky to reestablish some equilibrium.
Here, I stumbled across a YouTube guy that you will love.
https://www.youtube.com/channel/UCX9977Q36-GvegkIt-3N5Ew/videos (https://www.youtube.com/channel/UCX9977Q36-GvegkIt-3N5Ew/videos)
I think you should "talk shop" with Rudolph of Germany, he comes from another galaxy. He is waiting for the End Times. The two of you will probably really hit it off.
MileHigh
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Your full of crap MH,and you know it.
As per usual,you leave half of everything out,because your to much of a coward to admit when your wrong.
As i stated,an ideal voltage dose not change over time-regardless of the load. It only changes when the user determines that change. 300 post ago i stated this,but apparently you missed it--how convenient.
Brad
No, I am not full of crap at all. One of the many ridiculous "problem student in the class" arguments that had to be made with you and others is that an ideal voltage source can do whatever you want it to do. You had this ridiculous notion that it must be fixed and so that had to be argued out with you. When you saw others agreeing with me you clammed right up and stopped forcing that nonsensical issue. Instead of having the guts to say that you realized that you were wrong you just "magically reappeared" on the right side of the argument much later.
Talking tech with you has been a near-endless stream of irrational arguments because of your ignorance. You hear something new and "make up your own rule" about that new thing and then it's another stupid battle with you to talk some sense into you. This thread from the very get-go was like that, an endless stream of battling basic electronics vs. the electronics nonsense that you made up in your head. This was all stuff that you should have been learning on your own starting six years ago, not to mention the six years worth of valuable and correct information that has been covered endless times on this forum that apparently made no impression on you at all and almost none of it sunk in. Next time hopefully you will do better and not make up nonsense in your head first, but rather you will undertake to do the research yourself and inform and educate yourself properly.
MileHigh
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MileHigh
No, I am not full of crap at all. One of the many ridiculous "problem student in the class" arguments that had to be made with you and others is that an ideal voltage source can do whatever you want it to do. You had this ridiculous notion that is must be fixed and so that had to be argued out with you. When you saw others agreeing with me you clammed right up and stopped forcing that nonsensical issue. Instead of having the guts to say that you realized that you were wrong you just "magically reappeared" on the right side of the argument much later.
The endless stream of garbage you post is unbelievable . We were talking about your question,where the voltages are fixed per time periods given,and the voltage dose !!not!!change within those time periods--regardless of the load. You know full well that this is what was meant by all those referring to your question,and now-still,you try your old !switcheroony! crap to try and make us look like we were wrong. The voltage dose not change over time-->unless you change it,as in your question. Once again-->the voltage will not change over time unless you change it.
You set the voltage at 4 volt's for 3 second's--that voltage will not change if it is an ideal voltage. You set the voltage at 0 volts for two seconds--that voltage will not change over time. You set the voltage to minus/negative 3 volt's-->that voltage will not change over time. You set the voltage to 500mV for 6 seconds-->that voltage will not change over time. You then set the voltage to 0 volts-->that voltage will not change over time.
The voltage dose not change over time-->unless you change it,and once you have done this,it once again will not change,until once again, you change it.
What part of this are you having trouble with?.
Talking tech with you has been a near-endless stream of irrational arguments because of your ignorance. You hear something new and "make up your own rule" about that new thing and then it's another stupid battle with you to talk some sense into you. This thread from the very get-go was like that, an endless stream of battling basic electronics vs. the electronics nonsense that you made up in your head. This was all stuff that you should have been learning on your own starting six years ago, not to mention the six years worth of valuable and correct information that has been covered endless times on this forum that apparently made no impression on you at all and almost none of it sunk in. Next time hopefully you will do better and not make up nonsense in your head first, but rather you will undertake to do the research yourself and inform and educate yourself properly.
You are no different MH,and you are the pot calling the kettle black.
How much did i have to do to show you that resonant systems exist in and around the ICE before you accepted that they do indeed exist?. And it was not just me that was trying to explain and show you this,but blindly you went on and on about how resonance had nothing to do with the ICE what so ever. Only after i posted proof ,you then come forward and say that the ICE was not your strong point.
You think i know nothing about electromagnetic machines,then take me up on my bloody challenge--show everyone here that you can put all your knowledge to use,and beat the bench hack.
It's all well and good to sit up there on your throne,and belittle people like myself,Mag's,EMJ,wattsup--the list go's on,but when it comes to the crunch,you have nothing--nothing but words that mean just as much in the real world. Your Indoctrination is your downfall,always has been,and always will be.
Surly you can find an old vacuum cleaner motor,or one from an old washing machine--any type of brushed universal motor,floating around some where?--it's not that hard.
The test is very simple--measure P/in,then measure electrical P/out,and mechanical P/out-->thats it,and you can modify the motor how ever you want.
So let's start a thread--lets get the show on the road.
I am offering to send my finished motor to Poynt,where there can be no !so called! fake ass shit going on that he wont find--no hidden wire's,no hidden batteries,no hidden radiant !what ever you like! power of any sort that i have been accused of in the past,by those i thought were friends--non of that bullshit.
You want to know the truth?,would you believe it if it came from Poynt?,well time to put up or shut up,and stop with your 001 basic crap until you can show us that your knowledge is far superior than mine,and there is only one way to find out--you have to build MH.
But i feel this all falls on deaf ears with you ,as you avoided all this in your last post.
You will be the man standing at ground zero,while the rest travel the stars,and you will be saying to your self-->nah,that shit is fake--it's not in the book's.
Those that are here,are not looking for what is in the books that you get to see MH,there looking for the stuff in the books you dont get to see.
Take me up on my challenge MH,instead of this endless garbage you post.
Brad
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Brad:
Quoting you:
Post #95: If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
Joule Thief 101, post #2434: Your voltage is ideal-an ideal voltage dose not change in value over time,and when talking ideal inductors,3 seconds is an extremely long time to have a fixed voltage across it of 4 volt's.
Joule Thief 101, post #2655: An ideal voltage dose not change with time-period. That is what makes it ideal.
Joule Thief 101, post #2657: An ideal voltage dose not vary in time-regardless of the load it is placed across.
Joule Thief 101, post #2410: 1-An ideal voltage is one that dose not change in selected value.
The voltage dose not change over time-->unless you change it,and once you have done this,it once again will not change,until once again, you change it.
What part of this are you having trouble with?
The part that you were having trouble with is someone saying, "There is an ideal voltage that changes in time by method 'x'." That blew your mind and caused needless foolishness, nonsense and trouble.
Read this thread from the beginning and look at how difficult you make it, and how crazy and irrational your statements are with respect to electronics. Get your act together next time.
I am not going to rip apart a bloody vacuum cleaner. And if you truly think about it, your silly challenge doesn't even make sense. But that simple exercise in rational thought escapes you, which is no surprise at all.
MileHigh
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Brad:
MileHigh
1-An ideal voltage is one that dose not change in selected value.Your voltage is ideal-an ideal voltage dose not change in value over time,and when talking ideal inductors,3 seconds is an extremely long time to have a fixed voltage across it of 4 volt's.
An ideal voltage dose not vary in time-regardless of the load it is placed across.
And there you go MH,as plain as day,it can be seen in your own quote's,that i was referring to the stipulated time frames per your question,and the fact that the voltage will not change.regardless of load. It only changes when the user sets it to change-period--so get off my back,as everything i said was correct.-->again MH-1-An ideal voltage is one that dose not change in selected value.
You do see that i clearly said !!selected value!! dont you?.And you do know your question clearly explains the changes in !!selected value!! dont you?
The part that you were having trouble with is someone saying, "There is an ideal voltage that changes in time by method 'x'." That blew your mind and caused needless foolishness, nonsense and trouble.
The only one that had problems understanding what i said MH,is you--no one else.
Read this thread from the beginning and look at how difficult you make it, and how crazy and irrational your statements are with respect to electronics. Get your act together next time.
It would be far easier if you took up some refresher courses on english.
I am not going to rip apart a bloody vacuum cleaner. And if you truly think about it, your silly challenge doesn't even make sense. But that simple exercise in rational thought escapes you, which is no surprise at all.
What part makes no sense to you MH?(should i ask ::))
It dose not come much simpler.
Modify the motor to deliver an electrical output as well as a mechanical output--the best your knowledge will allow for.
The input is simply a 12 or 24 volt battery.
P/in=VxI---P/out =VxI + mechanical HP or watts.
How hard is that?. What part do you find irrational ?.
Why will you not take up my challenge?--we all know why.
Brad
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Brad:
The simple fact is that the whole ruckus over the idea that an ideal voltage source could vary in time started with you refusing to agree that that simple idea was valid. It was just a stupid waste of time because you seemingly couldn't understand it and/or accept it because of what your search results showed. And here you are denying this fact because that would mean that you were wrong about something. It's almost unbelievable. You saying that I need some refresher courses in English is a joke. The fact is that you made dozens and dozens of crazy and irrational statements with respect to electronics and most of them where more time wasters because you kept insisting the crazy things you were saying were valid. Yes, we know why I am not going to open up a bloody vacuum cleaner. Modifying an electric motor to deliver an "electrical output" is a ridiculous thing to do. It's no surprise at all that you can't figure out why your challenge doesn't really make sense.
You are one special case Brad. I can only speculate that your "magic" ability to answer the question and post the proper current trace is because someone took sympathy on you and emailed you the answer. You were not making any progress at all towards answering the question, you were a blank slate. You were not showing any indication at all that you were picking up on what was going on, there was nothing. And then suddenly out of nowhere you had the answer. If my suspicions are indeed true then you are a fraud. Look at your one attempt to answer Partzman's question, you mention a phase shift of 90 degrees when phase in this example does not even make sense and does not apply. You were just blindly throwing something at the answer for the sake of saying something. If you want to get more out of your hobby then you need to get a good book.
MileHigh
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MH, why not take up the challenge?
On planet tinman you can make up the rules!
The books are no use.
You can have 90 degrees shift when and where you need it.
This reminds me of AC/DC,they were from Australia, and very
good they are too!
John.
You are not getting your hands on my Fisher and Paykel, I use it
for laundry and I love it!
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What a bunch of crap your posting is. I can't believe you would post nonsense like that. The question is straightforward and clearly expressed and unambiguous. There were never any head games or trickery intended.
Here you are supposedly the guy that is "fighting to warn us of the NWO and the End Times" and what is implicit in that is "we have all been deceived" and "the truth will come out" and "all will be resolved in the battle between the forces of truth and good and the evil deceptive forces of trickery and deceit" BLA BLA BLA....
Right?
And you have the bloody nerve to come on and make a posting that makes you into a force of deception and trickery by falsely trying to suggest that some "evil trickery" is going on here. Ironically, you are the purveyor of "deceit and evil trickery" by the totally disingenuous nonsensical posting that you just made. Not only are you "out there" with many strange views, arguably someone with their "head screwed on backwards" but you come here and make a posting where you act exactly like the "bad guys" that you despise. It's like you have your head "doubly screwed on backwards" with that posting. You are acting exactly like the "shadowy guys" that you "warn" us about and despise. Talk about "out of this world" irony.
Did I ruin your pulsations of pleasure? Perhaps you need to read some Trotsky to reestablish some equilibrium.
Here, I stumbled across a YouTube guy that you will love.
https://www.youtube.com/channel/UCX9977Q36-GvegkIt-3N5Ew/videos (https://www.youtube.com/channel/UCX9977Q36-GvegkIt-3N5Ew/videos)
I think you should "talk shop" with Rudolph of Germany, he comes from another galaxy. He is waiting for the End Times. The two of you will probably really hit it off.
You've outdone yourself Miles! :o
Oh well, a sterling example of what we've come to expect
from Miles when he gets agitated. ;)
I'd not heard of Rudolf of Germany, but thanks for the link.
I'll look into what he has to say - there may be something
of interest there. 8)
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So what SeaMonkey? You make a totally stupid posting that is supposedly to criticize me and my motivations, and for what? The posting remains totally stupid and untrue. So what, this is an exercise in "agitating me?"
You are left with nothing but a totally senseless posting. A useless piece of "performance art" from SeaMonkey that means nothing and says nothing. It was just you intentionally going through the motions as a "provocateur," a hollow vapid exercise in nothingness - an aimless pseudo provocateur that has run out of ideas. You can think that you did a little "social experiment" to "get a rise" out of me, but as far as I am concerned it backfired on you, and you yourself ended up being the "experiment."
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MH, why not take up the challenge?
On planet tinman you can make up the rules!
The books are no use.
You can have 90 degrees shift when and where you need it.
This reminds me of AC/DC,they were from Australia, and very
good they are too!
John.
You are not getting your hands on my Fisher and Paykel, I use it
for laundry and I love it!
I saw AC/DC once and they were great! Perhaps they play with motors...
My real fantasy is the "Pulse or Other Motor Destroy-Off." That's were you take a motor and let it spin with no load and over-voltage it until it burns up or flies apart or both. It's an opportunity to be sadistic and hang a poor little 12-volt DC motor by the wires and over-voltage it while you drop oil onto it to keep it going while it screams away in a death spiral. A mad scientist with protective goggles and a big mean bench power supply with his hand cranking up the voltage like some insane Frankenmotorstein. That's the ticket. There are winners for fastest RPM by weight class and also for the best burn up in a blaze of glory.
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So what SeaMonkey? You make a totally stupid posting that is supposedly to criticize me and my motivations, and for what? The posting remains totally stupid and untrue. So what, this is an exercise in "agitating me?"
You are left with nothing but a totally senseless posting. A useless piece of "performance art" from SeaMonkey that means nothing and says nothing. It was just you intentionally going through the motions as a "provocateur," a hollow vapid exercise in nothingness - an aimless pseudo provocateur that has run out of ideas. You can think that you did a little "social experiment" to "get a rise" out of me, but as far as I am concerned it backfired on you, and you yourself ended up being the "experiment."
It would seem that the "social experiment" goes on. ::)
It has gotten legs. :o
You never disappoint Miles - you devote much time and
effort to constructing your verbose responses. :)
It is always a pleasure to read your unorthodox views. 8)
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The SeaMonkey makes some Valid points.
Here Miles Became aware [or had prior Knowledge] of some Trade /Laymen terms which
would be a semantic focal point he could gleefully dance all around whilst attempting to embarrass
his opponent.
Then demean ...err demand his opponent go to school [and study the terms ] and come back when he knew what
he was talking about.
His opponent had plenty enuff understanding to engage ...But Miles ...Ever the opportunist repeatedly intimated the
inappropriate verbiage here or uncrossed T there etc etc etc showed him a winner by default and suggested many times
his opponent go and educate himself and come back when Worthy...[twas a Friendly and gentlemanly gesture ::)]
I think a contest or festavis would be a great idea here , there must be a way that Miles could mentor a Build ?
I will donate supplies or whatever towards this ?
my Dream team would have Tinsel as the builder ...however he would probably want to beat me with
a petrified Cheeseburger for even writing his handle in a sentence here.....
FestiVus for the restofus !!
just one mans opinion....
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It would seem that the "social experiment" goes on. ::)
It has gotten legs. :o
You never disappoint Miles - you devote much time and
effort to constructing your verbose responses. :)
It is always a pleasure to read your unorthodox views. 8)
Here is your answer SeaMonkey:
https://www.youtube.com/watch?v=GSruW2osLYY
It's not "mice" or "42," it's Black Goop.
I think Herr Rudolf has watched Raiders of the Lost Ark one time too many. The End Times are coming.
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Here is your answer SeaMonkey:
https://www.youtube.com/watch?v=GSruW2osLYY (https://www.youtube.com/watch?v=GSruW2osLYY)
It's not "mice" or "42," it's Black Goop.
I think Herr Rudolf has watched Raiders of the Lost Ark one time too many. The End Times are coming.
Rudolf is a humorous guy - the George Carlin of Germany
perhaps. He's clearly a comedian. :)
But, you are right about that. The End Times are upon us. :-*
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Here Miles Became aware...
Chet, can you weld?
I think you need to build a shrine to Brad in your backyard with junkyard dishwasher and washing machine motors.
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yes I can Weld ,built this out of junk around the shop a few weeks ago to raise some Bucs ,
I would rather wind a universal Chassis for Tinsel and you than build shrines....
???
Sincerely
Chet K
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yes I can Weld ,built this out of junk around the shop a few weeks ago to raise some Bucs ,
I would rather wind a universal Chassis for Tinsel and you than build shrines....
???
Sincerely
Chet K
Wow! Nice build Chet. With that open pipe, I'll bet it sounds pretty good...loud too, ha ha. Did you richen the carb jet a bit so you don't go lean with the open pipe? You should post a video of that running around...I'll bet it is fun to drive.
Nice work.
Bill
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author=MileHigh link=topic=16589.msg485476#msg485476 date=1464708746]
MileHigh
I can only speculate that your "magic" ability to answer the question and post the proper current trace is because someone took sympathy on you and emailed you the answer.
LOL--i have been waiting for this one to come MH--so predictable.
I gave the formula i used wayyy back in the thread,so your idiotic statement above is just some more rubbish for your pile you have built over this thread,and the JT thread.
Modifying an electric motor to deliver an "electrical output" is a ridiculous thing to do. It's no surprise at all that you can't figure out why your challenge doesn't really make sense.
You truly are blind MH.
I guess you have never heard of rotoverter's ?.
You were not making any progress at all towards answering the question, you were a blank slate.You were not showing any indication at all that you were picking up on what was going on, there was nothing.
The fact is MH,i had no trouble in working out the current trace--as you think it should be.
But that dose not change the fact that i believe that is wrong.
And then suddenly out of nowhere you had the answer.
Another lie,as i posted the formula i used long before i gave you !your! current trace.
If my suspicions are indeed true then you are a fraud.
The only fraud here is you--and now another attempt to discredit me by way of your lies.
Look at your one attempt to answer Partzman's question, you mention a phase shift of 90 degrees when phase in this example does not even make sense and does not apply.
And why not?
I dont expect we will see an answer from you--ever.
You were just blindly throwing something at the answer for the sake of saying something. If you want to get more out of your hobby then you need to get a good book.
And you need to take me up on my challenge--but we know why you will not--not even the one on a simple JT.
Brad
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yes I can Weld ,built this out of junk around the shop a few weeks ago to raise some Bucs ,
I would rather wind a universal Chassis for Tinsel and you than build shrines....
???
Sincerely
Chet K
Ah,my kind of guy :)
Very nice Chet--nice build indeed.
I'm guessing MH would be lost at the wheel nut's. ;D
Brad
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Brad:
LOL--i have been waiting for this one to come MH--so predictable.
I gave the formula i used wayyy back in the thread,so your idiotic statement above is just some more rubbish for your pile you have built over this thread,and the JT thread.
But the formula had to be given to you, you had no clue. I challenged you to make a posting explaining how this very simple circuit worked with no formulas allowed and you balked and tried another "build challenge first" as a diversionary tactic. The simple fact is that you can't explain how the circuit works in your own words. Suspecting that someone took sympathy on you and fed you the answer is a reasonable speculation.
Speaking of idiotic statements, this is an idiotic statement: "At T=5 seconds,MHs device explodes."
Rotoverters are just curiosities for hobbyists. You will not find rotorverters in real-world applications.
Look at your one attempt to answer Partzman's question, you mention a phase shift of 90 degrees when phase in this example does not even make sense and does not apply.
"Why not" a phase shift of 90 degrees? That's for you to explain. I asked you about that and you shied away and ignored the question. You are also ignoring the fact that I said that it doesn't even make any sense. Plus we can't forget that your attempt to answer the question was dead wrong yet again confirming that you have no idea what is truly taking place in the first question.
And you need to take me up on my challenge--but we know why you will not--not even the one on a simple JT.
No in fact I do not need to take you up on your challenge at all. This is a thread about a question that deals with very basic electronics concepts that any experimenter worth their salt should be able to understand and answer without any problems whatsoever. This is not a thread about hacking into motors or building Joule Thieves and all attempts by you to throw up that diversionary tactic are doomed to fail.
There is no real point in arguing this stuff any more Brad. The conclusion is that you need to start learning basic electronics and that's all up to you. You can pursue your hobby in a fog or with some understanding and clarity, it's your choice. The bottom line is you still can't describe what is happening in this very simple circuit in your own words. And then you scoffed at the other three variations of the circuit that I suggested that you try to answer which is not exactly confidence inspiring.
MileHigh
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Ah,my kind of guy :)
Very nice Chet--nice build indeed.
I'm guessing MH would be lost at the wheel nut's. ;D
Brad
You would guess wrong actually. I have excellent mechanical aptitude but never pursued it. I got the best mark in the class in my Industrial Arts course way back in high school and I absolutely loved working with a metal lathe.
Metaphorically speaking, you were lost at the "wheel nuts" of the first question and you still are lost in a fog.
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Here is the basic question for Brad:
When you apply a voltage across an inductor what does it do?
And no, don't trot out how a real-world coil will work with a time constant, bla bla bla. I am not interested in that. Don't trot out the formula that you learned for an ideal coil with a DC voltage across it. I am not interested in that.
Again, when you apply a voltage across an inductor what does it do?
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You would guess wrong actually. I have excellent mechanical aptitude but never pursued it. I got the best mark in the class in my Industrial Arts course way back in high school and I absolutely loved working with a metal lathe.
Metaphorically speaking, you were lost at the "wheel nuts" of the first question and you still are lost in a fog.
And yet totally lost it when it came to resonant system relationships with ICEs,which have existed for over 40 years with regards to the two stroke ICE.
And your comment about me having to be shown the formula for working out the current trace of your question,is really quite stupid. What i mean MH,is how else would you learn to do something-if not shown how to do it?.
How did you learn MH?--so that was really a silly comment.
What i am not,is limited to your understandings of reality or indoctrination. This allows me to try things that you would dismiss,and so i have the advantage over you.
As far as rotoverters and the likes go,not having any real world aplications,well thats just another of your limits shining through,as they are still used world wide today. Pollyphase converters are widely used throughout our country in the farm industry,and i have installed many of them.
So why will you not take me up on my challenge,if you think my level of understanding of electromagnetic devices is very basic?.
I think it's because you are scared of being outdone by a hobbyist.
You say your mechanical skills are good,and your electrical skill are excellent--and thats all thats needed to answer the challenge.
I will put a video up in the next few days,and we will see how good your knowledge really is on inductors,and the likes
Brad
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And your comment about me having to be shown the formula for working out the current trace of your question,is really quite stupid. What i mean MH,is how else would you learn to do something-if not shown how to do it?.
How did you learn MH?--so that was really a silly comment.
What i am not,is limited to your understandings of reality or indoctrination. This allows me to try things that you would dismiss,and so i have the advantage over you.
Because you have been doing this stuff for six years and you started this thread where I told you I was not going to answer the question for you, you were going to have to figure this stuff out by yourself and with your peers. Spoon feeding does not work for you, you have to figure things out for yourself. If you had demonstrated some progress and asked some intelligent questions then they would have been answered but none of that happened. All that you really had to do was focus your energies and do some good Internet searching and do some reading and some thinking and analyzing to answer the questions by yourself. Or buy a good book and study it. It's apparent that the thread has died with the first question being 90% answered for you, and the rest unanswered. It's also apparent that you want to avoid all of this and just move on and go back to building stuff.
Don't use the old "indoctrination" line. It's readily apparent that the most flexible and creative minds around here are from the people with education and experience. It's apparent that some of the "blank slate" experimenters that claim that they are "free of indoctrination" often turn out to be the ones that are less creative and stuck in a linear thinking mode. That has clearly been demonstrated on this thread. Or they might do the wrong things and just lead themselves down a whole network of garden paths.
Take a look at these two clips:
https://www.youtube.com/watch?v=aPvXnmBIO7o
https://www.youtube.com/watch?v=BhnoSREmWVY
Here is the Indiegogo crowd funding page:
https://www.indiegogo.com/projects/fontus-the-self-filling-water-bottles#/
$346,000 USD for a self-filling water bottle that DOES NOT WORK. The reason they raised all that money for bullshit is that there are a lot of people out there in the world that think like you. Yes, there is a connection between your giving up on trying to learn how inductors really work and the Fontus scam. There will be no surprise if somebody takes their fake marketing claims literally and goes off into the Outback on a cycling trip and dies three days later of dehydration.
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Because you have been doing this stuff for six years and you started this thread where I told you I was not going to answer the question for you, you were going to have to figure this stuff out by yourself and with your peers. Spoon feeding does not work for you, you have to figure things out for yourself. If you had demonstrated some progress and asked some intelligent questions then they would have been answered but none of that happened. All that you really had to do was focus your energies and do some good Internet searching and do some reading and some thinking and analyzing to answer the questions by yourself. Or buy a good book and study it. It's apparent that the thread has died with the first question being 90% answered for you, and the rest unanswered. It's also apparent that you want to avoid all of this and just move on and go back to building stuff.
Don't use the old "indoctrination" line. It's readily apparent that the most flexible and creative minds around here are from the people with education and experience. It's apparent that some of the "blank slate" experimenters that claim that they are "free of indoctrination" often turn out to be the ones that are less creative and stuck in a linear thinking mode. That has clearly been demonstrated on this thread. Or they might do the wrong things and just lead themselves down a whole network of garden paths.
Take a look at these two clips:
https://www.youtube.com/watch?v=aPvXnmBIO7o
https://www.youtube.com/watch?v=BhnoSREmWVY
Here is the Indiegogo crowd funding page:
https://www.indiegogo.com/projects/fontus-the-self-filling-water-bottles#/
$346,000 USD for a self-filling water bottle that DOES NOT WORK. The reason they raised all that money for bullshit is that there are a lot of people out there in the world that think like you. Yes, there is a connection between your giving up on trying to learn how inductors really work and the Fontus scam. There will be no surprise if somebody takes their fake marketing claims literally and goes off into the Outback on a cycling trip and dies three days later of dehydration.
Well then,if all that is true,and you think i need to read books,and search the net for real answers,then you should have no trouble taking me up on my challenge.
It is a good thing Tesla did not listen to the big guns in power supply, as if he did, we'd all be using DC.
As i said,you have much to say,but nothing to show.
You cower from any sort of a challenge that involves putting your words into action.
Your so good at making acusations toward those you think are beneath you,but never will you take on those very same people in way of putting your claimed knowledge into a working device-you can never back yourself up with real world devices.
I have seen the videos on the MHOP,and fail to see what is so good about it--perhaps you could tell us all why you think it's so great?.
I see lots of power being used to light a neon-thats about it
Is this the best you have MH?
Brad
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It's not about finding the answers and doing paint-by-numbers electronics. It's about learning the knowledge so you can then formulate the answers yourself.
We were never going to use DC for power distribution, it was not practical at the time.
I don't "cower" to any challenge from you. I am telling you straight to your face the answer is no. Making your pitch for a tenth time is not going to make any difference. You talk about all of your big "real world working devices." Is hacking into a perfectly good motor and turning it into some kind of pulse motor were you collect back-spike energy really such a big thing? Seriously, when you really think about it, is anything truly significant accomplished when you do something like that? I get the impression you do something akin to UFOPolitics. I think the general consensus is that he never did anything real, it was all just useless rewiring of a perfectly good AC motor to produce an inferior DC version of a motor. I just took a peek and I think his two huge threads have long since died out. If you are going to do something real, then you have to have some kind of design goal and then test for that goal. I don't really know what you do because I don't really watch your clips. But I can make a general statement and I don't even know if it applies to you: The days of hacking into some kind of motor or building a pulse motor from scratch and then watching it spin with no real mechanical load and then collecting back-spike energy has got to be getting pretty stale for lots of people. I don't see any point in doing that beyond it being a nice little educational exercise for someone that wants to play with a pulse motor just for the sake of doing the exercise. It has no real practical value.
Do you appreciate my perspective? Just building something for the sake of building something with no real design goal has got to get pretty lame after a certain point. Even the MHOP doesn't really do anything. It's no different than any other pulse motor in that sense. But what it does do is accomplish the pulse motor function in a superior way in just about any way you want to look at it compared to a conventional Bedini SSG.
Like it or not, I would actually feel foolish building a pulse motor because it doesn't really do anything. It just sits there and spins and charges a battery. There is typically no precision in the battery charging function, it's just a "what-you-see-is-what-you-get" train of spikes going into a charging battery. You don't even know if the battery is being over-charged.
MileHigh
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Brad:
For all your "big build talk" I can give you a really good design challenge that would be cool for a pulse motor build off but it will never ever get done. These things are always "too complicated" and "too difficult" for your typical forum "builder" and all that you get is blank stares. I find it sad in a way, people back away from a real challenge. The pulse motor build off is basically "build anything." It caters to the lowest common denominator and therefore is totally bland.
Everybody plays with supercapacitors these days. Most people have or can by a digital scale.
This is the challenge:
1. Everybody starts off with the same supercaps and they also measure them as accurately as possible. Say everybody has 2000 Farads for the energy supply so they all start with approximately the same amount of energy.
2. Build a pulse motor and pulley system so that the pulse motor runs off of the caps and lifts up a mass as efficiently as possible. You can design any pulley and transmission system you want and lift any amount of weight you want.
3. The winner is the person that makes the most efficient setup with respect to (Mgh)/(1/2*CV^2)
In other words, who can output the most mechanical energy (mass x lift height) assuming that they all start with approximately the same amount of energy in the supercaps. Plus you have to demonstrate your skills in making as precise a measurement as possible of the size of your supercaps. And of course you have to get creative and actually have the pulse motor do some mechanical work and lift up a mass through a certain height until the cap voltage gets too low. That also implies you may want to build a circuit to extract energy from the supercap when the voltage gets very low. And, horror of horrors, you can forget about the stupid back-spikes. Presumably you want to reduce them or even eliminate them because they are useless to you.
Now, that's a real engineering build challenge. It's 100 times more interesting than watching a bloody pulse motor just sit there and spin for the 250th time. I admit that it is a lot of work, and teams of people working together would be appropriate for this competition. It also gives people a creative outlet for using their 3D printers to perhaps make the transmission and pulley system.
You will never see anything even remotely as challenging as that around here.
And when you compare that to your build challenge to me, your challenge looks pretty bland and it's the same old crap. All that you want to do is hack into a motor and collect back-spike energy. When you talk about "mechanical output" I take that with a huge grain of salt. I don't know what you mean and you didn't try to define it. If you are going to say it's the classic "attach a propeller to the shaft of the motor to push air" then I am going to laugh. I am never ever going to do a futile exercise like that, and I wouldn't do it if I actually was a builder.
MileHigh
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So Miles
You think Brads challenge is to be the Pulsiest? or prettiest? or Nicest?
No Miles... its to do the Most with the least.
Power in ...Power Out, Not a beauty contest at all .
It would require a work performed measurement to be a viable competition.
---------------------------
so far so good ,
would you mentor a team to compete against Brad in this competition?
We have a saying around these parts ...when fellows get to the higher skill levels in a field and the really skilled stand out as exemplary
those that can't [compete successfully].....Teach [ this phrase is usually meant as an insult .
So Miles can you walk the walk?
or just talk the talk ?
Perhaps Brad can do a lap as a benchmark ?
see if you can beat him ?[with your team??]
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Isn't that exactly what MH. is saying?
It sounds like a fair way to show pin/pout.
There could be little room for argument.
John.
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Chet, understanding how inductors and capacitors really work is 100 times more important than hacking into an old dishwasher motor.
-
Minnion
The Challenge to MH was never about Pulse motor build offs and all the other
Fluff he intimated..
It was about Results on the bench
Power in power out !
A Challenge , as he has now posted one possible method , perhaps there is yet hope
for a competition ....
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You call a really good challenge to lift up a mass using the energy stored in some supercaps "fluff?" If that's fluff then what is the pulse motor build off? Aphid bellybutton lint?
"Power in power out!" or "Watch me lose energy to heat with my contraption that does nothing?"
With that metric all the builds you can imagine will be inferior to two thick wires between the power input and the power output.
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Miles
Your Posts regarding the build off where you alleged that was the challenge from your "student ::)"
Twas not.
Indeed never was the challenge.
Power in ... power Out... is the challenge... always was. [not the Fluff you intimated prior to your first attempt
at a test protocol above ]
*Also
I see you make fun of Tinmans ability to accomplish a great deal of experimenting on a very tight budget [your reference to washing machine motors Dishwashers etc etc.
I consider this part of his gift , the ability to see what he needs done [or experimented with] in the resources around him.
instead of dumping thousands into ground up builds... he harvests from his environment of well engineered Donors .
for some of us this is the only option and greatly appreciated when pointed out by fellow builders.
Sans his Universal Motor build suggestion... for the power in power out Challenge.
Work performed over measured input power.
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Chet, stop the over-the-top rhetoric. I did not make fun of his building, I questioned the utility of what he is building. I speak the truth sometimes, something often enough you can't do.
I am all for a beginner building a pulse motor but not discussing "radiant energy." Rather, they should be discussing what it is really doing and how it works, the good old time constant in parallel with the influence of the magnet pass. They should also be measuring the characteristics of the output pulse. But there is no point in building another 10 pulse motors after you have built your first pulse motor. This is a generic comment and has nothing to do with Brad.
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Milehigh
quote
I speak the truth sometimes, something often enough you can't do.
end quote
-------
What does this mean >>>>> "something often enough you can't do""
??
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It means that when you see stuff that is dead wrong or even stupid idiotic nonsense from one of "the builders," and you know better, and you have actively participated the the thread in question, you won't say anything, be it very diplomatically or with some straight talk. You are afraid to speak, you hide inside a straitjacket.
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Sorry if I offend you in this way , It is not my intent,[which most likely rings hollow to you , but it is true.
see MH you are on the batting a 1000 side of the fence ,the Show me your electric bill for proof side, the always
winning side.
everybody loves the underdog ,
and honestly "we're " the underdogs in this battle .
all of us !
Suppression and Greed have held the day , I get the feeling Greeds days are numbered.
just one mans observation and opinion !
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Living in your own little North Korea inside your head can't be fun.
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Your overthinking things
that isn't any fun either.
Relax
The earths magnetic poles are flipping ,,,someone is bombarding us with radiation and tomorrows gonna be another day !
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Who says I am over thinking things? I am the one that is free. This all started on the other thread when a "resonant Joule Thief" project was getting underway and Smoky2 was talking the big talk about his brother with "resonant Joule Thieves" that supposedly "ran indefinitely" as long as they were "tuned" properly. I am the free thinker that said, "Hold on boys, that doesn't even make any sense." And as of now, there is no "resonant Joule Thief" in sight and in a few more months assuming no positive news we can put that nonsense to bed.
The benefits of free and unrestrained thinking.
-
Chet, stop the over-the-top rhetoric. I did not make fun of his building, I questioned the utility of what he is building. I speak the truth sometimes, something often enough you can't do.
I am all for a beginner building a pulse motor but not discussing "radiant energy." Rather, they should be discussing what it is really doing and how it works, the good old time constant in parallel with the influence of the magnet pass. They should also be measuring the characteristics of the output pulse. But there is no point in building another 10 pulse motors after you have built your first pulse motor. This is a generic comment and has nothing to do with Brad.
MH
I am not talking about a pulse motor as such,although a brushed DC motor will always have pulses associated with it.
Im talking about a transformer that has a rotary aspect to it. This allows for a second output in the way of mechanical energy,along with the primary output of the transforming action.
The challenge is to get the primary output (electrical), to equal that of the input.
The mechanical output can then be used as desired--some may wish to use that output to further the electrical output of the device.
If you say your full bottles on inductors and magnetic fields,then this should be a walk in the park for you.
Perhaps we can lower the bar a bit,and say achieve a 98% electrical P/in to P/out as a starting point--forgetting about the mechanical output for the time being.
It would be your knowledge on inductors V me knowing how to use them.
Actions speak much louder than words MH--are you willing to be heard?
-
I'm really amazed sometimes at some of the things I read in this thread. :-[
DC power distribution:
https://en.wikipedia.org/wiki/High-voltage_direct_current
Rotoverters etc. :
http://www.ronkelectrical.com/rotoverter-type-4c.php
https://en.wikipedia.org/wiki/Motor%E2%80%93generator
Chet: Nice trike! I'll bet you can get all kinds of sideways on that! Love the tractor seat. Cheezburgers on me this time. ;)
-
Good Koala,
the high voltage link Wiki article is amazing.
The things they got up to a hundred years and more ago!
I hope the old tinman reads all this stuff, there should be
a fair bit of inspiration in that lot.
I reckon the tinman would have loved the synchronous
condensers, huge electric motors with no output shaft.
Some of those things ran for decades, it just shows how
good the initial design and construction was for a then
new technology.
John.
-
Having seen the trike can I enter Daisy into
"The most horrid Kludge competition"?
It's an old centre pivot steer dumper adapted
to knock in fence posts. It's a dinosaur!!
John.
-
author=minnie link=topic=16589.msg485575#msg485575 date=1464859198]
I reckon the tinman would have loved the synchronous
condensers, huge electric motors with no output shaft.
Some of those things ran for decades, it just shows how
good the initial design and construction was for a then
new technology.
As i said,i have installed many of these on farms--units up to 60Kw.
Polyphase converters are used,as most rural power over here is still 440 single phase,and most electrical farm machinery is 3 phase.
But dont tell MH,as he seems to think they have no common place here on earth.
Brad
-
440 single phase....
thattle rattle yah for sure !!
@Minnion
I hope you live forever !!
Gotta say I Luv that One ,Its a shame to Chain her to the ground pounder tho.[some other quick change assy's would be nice too]
Been gathering Bits for a more versatile articulating build myself .
Nice group of fellows here... that have stood the test of Time and all the associate "episodes".
Thx for the comments on my silly trike build ,
The things that people thro out in this country [like the 49 Harley Davidson rolled up trike frame and old 59 Austin Healey rear and Suzuki s40 motorcycle ,and yes [my favorite part] the old sulky seat].
Oh well
back to the grind...
we can't all sit around in the spa chewin on magnums down under ......
8)
-
I'm really amazed sometimes at some of the things I read in this thread. :-[
Rotoverters etc. :
http://www.ronkelectrical.com/rotoverter-type-4c.php (http://www.ronkelectrical.com/rotoverter-type-4c.php)
https://en.wikipedia.org/wiki/Motor%E2%80%93generator (https://en.wikipedia.org/wiki/Motor%E2%80%93generator)
That looks like a trademarked name for a rotary phase converter, "Rotoverter" by the company "Ronk."
I am referring to the magic free energy "rotorverter."
http://energyfanatics.com/2015/10/05/how-to-build-rotoverter-overunity-free-energy-generator/
The RV is an alternative energy device which is currently being utilized by open source engineers around the world in energy saving applications, and to transform and understand ZPE when configured in looped (self running mode) mode…When run in RV mode, these Baldor motors are the most efficient 1 HP electric motors in the world.
As engineer what is your choice for
a 1,000 drills 1,000 employee drill production
line.
Normal drill = 890,000 watt hours
RV drill =37,000 watt hours
It’s 24 times the money expense to run in
non RV mode and in full duty is still.
50% less power usage in worst case (all dr
ills making a hole at same time with.)
-
...as i am no longer bound by restrictions.
Brad
Tinman,
Any chance this means a return to RT measurements and self runner attempts?
PW
-
No,MH wrongly accused myself and others that we do not know the definition of an ideal voltage source. He clearly stated that we say that the voltage cannot change with time-and that is crap. 300 posts ago,i posted my understanding of an ideal voltage ,and it is correct,and i will not have MH bullshitting about me being wrong-full stop.
The voltage can only change if determind to do so by the user-fact.
So for MH to say i am wrong,is just bullshit-plane and simple.
Brad, the fact that you will never admit that you are wrong is so annoying sometimes that I am going to fully call your bluff. You caused untold problems and wasted so much time over whether or not an ideal voltage source can vary in time among other things that I am going to repost post #95 here verbatim to call your bluff and expose your nonsense.
http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg483584/#msg483584 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg483584/#msg483584)
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Here is the harder version of the question and the answer:
The question is what happens starting at t = 0
The answer:
The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
Time..........Voltage.........Current
0...............0.................0
1...............20...............1.33
5...............500.............166.67
10.............2000............1333.33
20.............8000............10666.67
50.............50000..........166666.7
Brad, you need to try to get up the learning curve such that you get to the point where you come back and acknowledge the answer given above is correct.
You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
Your original question clearly states an ideal voltage of 4 volts for 3 seconds.
The rest of your answer is not related to the original question,as the voltage is not 4 volts for 3 seconds.
https://en.wikipedia.org/wiki/Voltage_source (https://en.wikipedia.org/wiki/Voltage_source)
An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.
Brad
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The text highlighted in bold is you being dead wrong about an ideal voltage source varying in time and just one of countless examples of you causing problems on the thread.
I don't care if your head bloody well explodes. Why can't you just be a man and say that you were wrong? You need to adjust your behaviour going forward. You look like a clown to everybody when you refuse to ever admit that you are wrong.
MileHigh
-
Brad, the fact that you will never admit that you are wrong is so annoying sometimes that I am going to fully call your bluff. You caused untold problems and wasted so much time over whether or not an ideal voltage source can vary in time among other things that I am going to repost post #95 here verbatim to call your bluff and expose your nonsense.
http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg483584/#msg483584 (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg483584/#msg483584)
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
Your original question clearly states an ideal voltage of 4 volts for 3 seconds.
The rest of your answer is not related to the original question,as the voltage is not 4 volts for 3 seconds.
https://en.wikipedia.org/wiki/Voltage_source (https://en.wikipedia.org/wiki/Voltage_source)
An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.
Brad
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The text highlighted in bold is you being dead wrong about an ideal voltage source varying in time and just one of countless examples of you causing problems on the thread.
I don't care if your head bloody well explodes. Why can't you just be a man and say that you were wrong? You need to adjust your behaviour going forward. You look like a clown to everybody when you refuse to ever admit that you are wrong.
MileHigh
My answer is correct MH,no matter how you try and twist things around.
You just do not listen,or you try so hard to re arrange peoples statements to try and make them look wrong. You failed in your last attempt when you posted my !quote's! referring to an ideal voltage source,as they clearly stated a selected value.
I will say it once again--an ideal voltages value dose not change over time,and that time is the value that the user selects. When the user changes that value,then a new time period has started for the newly selected value.
You are becoming pathetic MH,and you need a new hobby.
Brad
-
WHAT IS WRONG WITH YOUR HEAD?
READ THIS: If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
I am not pathetic, but you are beyond pathetic and you should get your head examined.No,MH wrongly accused myself and others that we do not know the definition of an ideal voltage source. He clearly stated that we say that the voltage cannot change with time-and that is crap.
No, it's not crap, it's absolutely true that you stated that an an ideal voltage source cannot change in time. You are a low-life liar but it is beyond ridiculous because the proof is right on the screen in front of your face, what the hell is wrong with you? I don't know how you manage to function sometimes. You are not to be trusted at all because you are a compulsive liar and a compulsive denier that you can ever be wrong - even when the evidence is right in front of your face and everybody else can see it too.
You are beyond unbelievable. It's sick seeing your behaviour.
-
Tinman,
Any chance this means a return to RT measurements and self runner attempts?
PW
My challenge has been put to MH,and if that challenge is answered,then yes,we can continue on where we left off.
MH has said all to often that my knowledge of inductors and PMs are very limited,and so now is the time to see who has the greater understanding of the two mixed together.
If MH accepts my challenge,then a new thread devoted to this challenge,the parameters of the challenge,and our progress throughout the build process,will be posted on that thread.
If MH thinks im bluffing,then i ask him to call my bluff,and let the process begin.
Once we have both finished,and are happy with our build's,we then both send our devices to Poynt(if he is ok with this) for confirmation of P/in-P/out measurements taken.
If Mh refuses my challenge,then he can also stop with the !!001!! basic crap toward me,as his words mean nothing when it comes to what actually can be achieved with inductors and PMs.
No one was ever able to answer one simple question i asked about a simple test carried out by many here(including TK),as to why the motor would speed up,gain torque,and reduce power consumption ,when a load was drawn from the stator coil from one half of the AC cycle.
Luc was the only one that came close to achieving this goal alone.
Brad
-
You already know what my answer is.
You end up in the same boat as Wattsup and EMJunkie and you are giving up, unable to understand basic electronics. Not to mention the other serious problems you have that are covered in my previous posting.
-
WHAT IS WRONG WITH YOUR HEAD?
READ THIS:
You are beyond unbelievable. It's sick seeing your behaviour.
If the voltage increases,then it is not an ideal voltage,as an ideal voltage dose not change in time.
You need help MH--you really do.
An ideal voltage dose not change in time,and that time is the period at which the selected voltage remains unaltered. Once a new voltage value is selected,then a new time period starts. Its the very same when your driving down a street--you will continue to drive down the same street until you turn into another street. you will spend X amount of time driving down each street. When you turn off that street,then you do not keep timing how long it takes to drive down the previous street when your on a different one.
I am not pathetic, but you are beyond pathetic and you should get your head examined.
No, it's not crap, it's absolutely true that you stated that an an ideal voltage source cannot change in time. You are a low-life liar but it is beyond ridiculous because the proof is right on the screen in front of your face, what the hell is wrong with you? I don't know how you manage to function sometimes. You are not to be trusted at all because you are a compulsive liar and a compulsive denier that you can ever be wrong - even when the evidence is right in front of your face and everybody else can see it too.
I think all those books have turned you into a looney MH-->seek medical advice.
Each one of your steps in your question has a set time period,and the voltage dose not change in time with respect to those determined time period's--do you not understand your own question?.
If your so brilliant,then take me up on my challenge,and stop with all the !!i dont build! crap.
Brad
-
You already know what my answer is.
You end up in the same boat as Wattsup and EMJunkie and you are giving up, unable to understand basic electronics. Not to mention the other serious problems you have that are covered in my previous posting.
A coward that cannot back up his false claims in the real world.
Your nothing more than a !!it all looks good on paper!! person.
Brad
-
Brad:
You are just showcasing all of your problems and as far as I am concerned there is no hope for you. Forget about real electronics, just go back to amusing yourself on your bench doing whatever it is that you do. We are all fully aware that you will lie through your teeth whenever you want, and you live in your own dream world where you are infallible.
MileHigh
-
A coward that cannot back up his false claims in the real world.
Your nothing more than a !!it all looks good on paper!! person.
Bullshit, and you are nothing more than a bench tinkerer that barely knows what he is doing but believes that he knows it all. You have been fully exposed, and it was about time, and it's not a pretty sight at all.
-
Yes, Brad, I can get angry when somebody is so blatantly dishonest as you. That's why I am here, to go after dishonest people like Naima Faegin who said they were "just minutes away" from having a working QEG probably about two years ago now. The fact that you are not trying to scam money from people does not take away from the fact that you are blatantly dishonest. It is extremely distasteful to me. I can't fathom how you can actually conduct yourself like that.
<<< At T=5 seconds,MHs device explodes. >>>
Famous last words.
I have a challenge for you: Go onto a real science or physics forum and start a thread with this title, "After you strike a bell and hear it ringing it is not actually resonating."
Go ahead and join a forum and then link to the thread and we can all watch how well you do defending your proposition. I challenge you to do it.
This thread was an attempt to get you started on learning about real electronics and it failed. And in the process we learned a lot of nasty things about you. It is very dispiriting.
Good luck in doing whatever it is you do on your bench.
MileHigh
-
Bullshit, and you are nothing more than a bench tinkerer that barely knows what he is doing but believes that he knows it all.
Then take me on in my challenge to you,and back up your claim that i !!barely!! know what im doing.
You have made the claim,now back it up with evidence that puts truth to your claim.
You have been fully exposed, and it was about time, and it's not a pretty sight at all.
The only thing i have been exposed to MH,is your continuing unfounded claims,and your refusal to back up !your! claims with proof by way of a real world device--something you never do,because you cannot.
Brad
-
author=MileHigh link=topic=16589.msg485623#msg485623 date=1464913031]
Yes, Brad, I can get angry when somebody is so blatantly dishonest as you.
The only one being dishonest here,is you MH--and thats a fact.
That's why I am here, to go after dishonest people like Naima Faegin who said they were "just minutes away" from having a working QEG probably about two years ago now. The fact that you are not trying to scam money from people does not take away from the fact that you are blatantly dishonest. It is extremely distasteful to me. I can't fathom how you can actually conduct yourself like that.
More lies--and bad ones.
I have never made any such claim's as the likes of the QEG mob,nor Naima Faegin.
You trying to associate me with those people just go's to show what kind of a low life you really are.
What is extremely distasteful,is your lies--one after the other,and your unfounded claims against me.
I really dont care how mad you get,as you bring it on your self.
You continue to make false claims against me,but you avoid taking me on in any real world application of your book science. How did your book science go when the engineers built the Tacoma Narrows Bridge?--didnt work out to well for them-did it. Do you know why it didnt work out so well MH,regardless of the fact that it was designed and built by the worlds best engineers?-->because they did not take into account unforeseen circumstances where forces acting in perfect harmony could give rise to enough energy to bring the bridge down. Such forces exist in the electromagnetic world as well MH,whether your books like it or not. It is just a matter of finding the right balance at the right time-something you will never understand.
This thread was an attempt to get you started on learning about real electronics and it failed. And in the process we learned a lot of nasty things about you. It is very dispiriting.
What this thread shows,is how low you will stoop to try and make yourself look good.
There is nothing nasty about me MH,and the only reason you say that,is because you dont have the guts to take me on in the real world--thats a fact you have proven yourself here on this thread.
You are all words,and your words mean nothing at all. The fact that you think there is nothing in the rotoverter,just shows how far behind you are.
I have a challenge for you: Go onto a real science or physics forum and start a thread with this title, "After you strike a bell and hear it ringing it is not actually resonating
That shows how little you know.
You hit the bell,and the bell will ring--and it will ring down,and there for,it is not resonating at all. It is ringing down at it's natural frequency-slowly dropping in amplitude. When an object is resonating,it is oscillating at maximum amplitude at it's natural frequency. The fact that you dont know this,was your undoing in the JT thread.
If your scientific forum says any other than this,then you need to join another scientific forum.
The pure scientific meaning of resonance,is one object vibrating with maximum amplitude at it's natural frequency,and where an outside force is the provider of that energy required that is acting upon the resonant object--such as the Tacoma Narrows Bridge collapse. In this case,the bridge was bough down due to aeroelastic flutter.
Good luck in doing whatever it is you do on your bench.
I achieve much on my bench--what do you achieve?.
At T=5 seconds,MHs device explodes.
Yes,because you are to busy looking at your 5H inductor,and forget about what is happening within the ideal voltage source. A current flows through the ideal voltage source,as well as the ideal coil. The ideal coil has inductance,but the ideal voltage source dose not. The ideal coil has impedance,but the ideal voltage source dose not. At T=5 seconds,you place a voltage across !not only the coil!,but also the ideal voltage source that has current already flowing through it. This voltage polarity is opposite to that which created the current flow that is flowing through the ideal voltage source. But for you MH,the transition is just going to nice and smooth--isnt it?. How dose your !water through pipes! cope with this one MH?
Let me guess--the water just disappears,so as the flow can now start in the opposite direction :D
You only have the mind set to see what you want to see MH,and that only means you will never see reality.
You might be happy to live with that,but i am not.
I will be putting a simple rotoverter together this weekend,and i will be asking you a question.
Lets see how you go with that--lets see if you know more than me,when it comes to actual devices that involve inductors and magnetic fields.
You also need to back up your claim's,and take me up on my challenge--to prove to everyone that you do actually know more about inductors than i do,and how they react with magnetic fields.
Until such time,your words and accusations toward me, are nothing but rubbish and lies.
Brad
Your so happy making claims on everyone's abilities,but you have none of your own,nor can you/do you ever back up any of those claims by way of real world devices.
As i said--everything looks fine on paper to you-->as they did with the engineers that designed the Tacoma Narrows Bridge :D.
Carry on with your idiotic claims against me MH,but remember this-->you are the one that is afraid to take me on in a real word challenge,and that there is a fact.
Brad
-
I am going to give the answers to you that you couldn't figure out for yourself. I was hoping and praying that you would apply yourself and push yourself and actually get up the learning curve by yourself, perhaps with just a little bit of help if you showed a desire and were really trying. I am sure many others were hoping that you would do that too. But no, it was a just morass of stupid fighting and stupid battles about what amounted to a whole bunch of stupid time-wasting junk. You gave up and looked for your blanket in the form of wanting to play again and modify a motor. Then throw in the fact that you act like some bloody four-year-old child that lies when asked if he ate the last piece of chocolate, without realizing that he has melted chocolate at the corners of his mouth.
The answer is that the ideal coil integrates on voltage with respect to time to yield a current flow. This has already been stated many times, but not in plain English like I am telling you now. It's just like a shopping cart integrates on the force you push on it to yield a velocity. Beyond that you wouldn't even touch the three variations on the question and if you did, you would have come to realize that a capacitor integrates on current flow with respect to time to yield a voltage. Essentially the same as an inductor, you just have to swap voltage for current.
These are the most basic fundamental concepts that anybody that plays with electronics must understand, and all that you want to do is give up and play with another motor on your bench.
And in this day and age they make it so damn easy for you, there are actually integral calculators right on web sites. So even if you don't know how to do an integral, there are web sites that will do it for you. All that you need to have is an understanding of what integration means.
Partzman's question: You have an ideal inductor of 5 Henrys. If the ideal voltage source is a linear ramp that starts a zero seconds and ends after two seconds with a voltage of two volts, then what is the current?
That means that the equation for the current is i = t. That's it, it's as simple as that.
The integration web sites use 'x' as the variable. Therefore we can say that the equation for the current is i = x.
That means you just put 'x' into the integration calculator and press the button and get the answer.
Here: http://integrals.wolfram.com/index.jsp (http://integrals.wolfram.com/index.jsp)
Once that is done the question is 99% answered for you. Do you have what it takes to give the actual final answer for Partzman's question?
-
Now let's look at the already answered question:
Question: You have an ideal voltage source and an ideal coil of 5 Henrys. At time t=0 seconds the coil connects to the ideal voltage source. The voltage source waveform is 20*t^2. So as the time t increases, the voltage increases proportional to the square of the time.
Answer: The current through the ideal coil starts from zero at time t = 0 and then increases with this formula: i = 1.33*t^3.
So all that you have to do is put 20x^2 into the integral calculator.
Go ahead: http://integrals.wolfram.com/index.jsp
Now the question will be 99% answered for you. Do you have what it takes to arrive at the final answer that has already been given to you?
-
I am going to give the answers to you that you couldn't figure out for yourself. I was hoping and praying that you would apply yourself and push yourself and actually get up the learning curve by yourself, perhaps with just a little bit of help if you showed a desire and were really trying. I am sure many others were hoping that you would do that too. But no, it was a just morass of stupid fighting and stupid battles about what amounted to a whole bunch of stupid time-wasting junk. You gave up and looked for your blanket in the form of wanting to play again and modify a motor. Then throw in the fact that you act like some bloody four-year-old child that lies when asked if he ate the last piece of chocolate, without realizing that he has melted chocolate at the corners of his mouth.
The answer is that the ideal coil integrates on voltage with respect to time to yield a current flow. This has already been stated many times, but not in plain English like I am telling you now. It's just like a shopping cart integrates on the force you push on it to yield a velocity. Beyond that you wouldn't even touch the three variations on the question and if you did, you would have come to realize that a capacitor integrates on current flow with respect to time to yield a voltage. Essentially the same as an inductor, you just have to swap voltage for current.
These are the most basic fundamental concepts that anybody that plays with electronics must understand, and all that you want to do is give up and play with another motor on your bench.
And in this day and age they make it so damn easy for you, there are actually integral calculators right on web sites. Se even if you don't know how to do an integrate, there are web sites that will do it for you. All that you need to have is an understanding of what integration means.
Partzman's question: You have an ideal inductor of 5 Henrys. If the ideal voltage source is a linear ramp that starts a zero seconds and ends after two seconds with a voltage of two volts, then what is the current?
That means that the equation for the current is i = t. That's it, it's as simple as that.
The integration web sites use 'x' as the variable. Therefore we can say that the equation for the current is i = x.
That means you just put 'x' into the integration calculator and press the button and get the answer.
Here: http://integrals.wolfram.com/index.jsp
Once that is done the question is 99% answered for you. Do you have what it takes to give the actual final answer for Partzman's question?
Has anyone else taken up the challenge to answer the question?-was verpies correct?.
Where is this ideal coil and ideal voltage source?
Are you going to take up my challenge,and see how real world devices actually can be made to work?
Or are you going to continue with your unfounded claims and rants against me?
If so,your words have no meaning ,and carry no weight at all--actions speak louder than words MH.
It's all well and good to claim you know more than me about how inductors and magnetic fields react with one another on paper,but why not show that it is also true in the real world?
Lets see who is limited to there understandings on the subject matter.
My challenge stands MH.
Grow a pair,and take me up on my challenge.
Poynt will be doing the final measurement's,so what do you have to be afraid of?.
Brad
-
Brad, you are so impossibly thick-headed and dense sometimes that it amazes me.
That shows how little you know.
You hit the bell,and the bell will ring--and it will ring down,and there for,it is not resonating at all. It is ringing down at it's natural frequency-slowly dropping in amplitude. When an object is resonating,it is oscillating at maximum amplitude at it's natural frequency. The fact that you dont know this,was your undoing in the JT thread.
The "natural frequency" and the "resonant frequency" are synonymous, they mean the same bloody thing.
-
author=MileHigh link=topic=16589.msg485623#msg485623 date=1464913031]
The only one being dishonest here,is you MH--and thats a fact.
More lies--and bad ones.
I have never made any such claim's as the likes of the QEG mob,nor Naima Faegin.
You trying to associate me with those people just go's to show what kind of a low life you really are.
What is extremely distasteful,is your lies--one after the other,and your unfounded claims against me.
I really dont care how mad you get,as you bring it on your self.
You continue to make false claims against me,but you avoid taking me on in any real world application of your book science. How did your book science go when the engineers built the Tacoma Narrows Bridge?--didnt work out to well for them-did it. Do you know why it didnt work out so well MH,regardless of the fact that it was designed and built by the worlds best engineers?-->because they did not take into account unforeseen circumstances where forces acting in perfect harmony could give rise to enough energy to bring the bridge down. Such forces exist in the electromagnetic world as well MH,whether your books like it or not. It is just a matter of finding the right balance at the right time-something you will never understand.
What this thread shows,is how low you will stoop to try and make yourself look good.
There is nothing nasty about me MH,and the only reason you say that,is because you dont have the guts to take me on in the real world--thats a fact you have proven yourself here on this thread.
You are all words,and your words mean nothing at all. The fact that you think there is nothing in the rotoverter,just shows how far behind you are.
That shows how little you know.
You hit the bell,and the bell will ring--and it will ring down,and there for,it is not resonating at all. It is ringing down at it's natural frequency-slowly dropping in amplitude. When an object is resonating,it is oscillating at maximum amplitude at it's natural frequency. The fact that you dont know this,was your undoing in the JT thread.
If your scientific forum says any other than this,then you need to join another scientific forum.
The pure scientific meaning of resonance,is one object vibrating with maximum amplitude at it's natural frequency,and where an outside force is the provider of that energy required that is acting upon the resonant object--such as the Tacoma Narrows Bridge collapse. In this case,the bridge was bough down due to aeroelastic flutter.
I achieve much on my bench--what do you achieve?.
Yes,because you are to busy looking at your 5H inductor,and forget about what is happening within the ideal voltage source. A current flows through the ideal voltage source,as well as the ideal coil. The ideal coil has inductance,but the ideal voltage source dose not. The ideal coil has impedance,but the ideal voltage source dose not. At T=5 seconds,you place a voltage across !not only the coil!,but also the ideal voltage source that has current already flowing through it. This voltage polarity is opposite to that which created the current flow that is flowing through the ideal voltage source. But for you MH,the transition is just going to nice and smooth--isnt it?. How dose your !water through pipes! cope with this one MH?
Let me guess--the water just disappears,so as the flow can now start in the opposite direction :D
You only have the mind set to see what you want to see MH,and that only means you will never see reality.
You might be happy to live with that,but i am not.
I will be putting a simple rotoverter together this weekend,and i will be asking you a question.
Lets see how you go with that--lets see if you know more than me,when it comes to actual devices that involve inductors and magnetic fields.
You also need to back up your claim's,and take me up on my challenge--to prove to everyone that you do actually know more about inductors than i do,and how they react with magnetic fields.
Until such time,your words and accusations toward me, are nothing but rubbish and lies.
Brad
Your so happy making claims on everyone's abilities,but you have none of your own,nor can you/do you ever back up any of those claims by way of real world devices.
As i said--everything looks fine on paper to you-->as they did with the engineers that designed the Tacoma Narrows Bridge :D .
Carry on with your idiotic claims against me MH,but remember this-->you are the one that is afraid to take me on in a real word challenge,and that there is a fact.
Brad
Most of what you say is a bunch of crap and like I said, it's bloody hopeless with you for many things. You have lied so many times about so many things, that it's more like you have been dipped in chocolate.
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Most of what you say is a bunch of crap and like I said, it's bloody hopeless with you for many things. You have lied so many times about so many things, that it's more like you have been dipped in chocolate.
More lies.
Everything in that post is correct,from what resonance really is,to how and why the Tacoma Narrows Bridge collapsed.
This just shows you have an !automatic! crap button set for me,even though everything i say is correct in that post.
The biggest pile of crap is from you MH. Every claim you make against me,you cannot back up.
You know dam well that i will fry your ass in any actual device built around each of our understandings. The fact that you will not take me up on my challenge ,speaks volumes about your actual skills. So many claims at how much you know,and how skilled you are mechanically -along with your lathe skill's,but you dare not take me on--not even to build a simple JT.
And why will you not take me on?--because you know darn well that if i build the more efficient device,then everyone here will know your skill set is very low.
I mean-come on MH-->a JT for crying out loud--how hard can it be?
You claimed that your JT circuit was the most efficient of them all,and mine was nothing but a power hungry fail,so back up that claim ;).
Your just claim after claim--everything you know is the best of the best,and i know very little. Buy you refuse to take me on in any kind of actual device build.
No JT,no pulse motor,no rotary converter--nothing.
Your hollow words mean nothing to me MH,and i(along with others) have seen your true colors.
Your not here to help,your just here to see how much shit you can cause,and how much you can deter people from seeking the truth.
Your a bad influence--plain and simple.
Brad
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Yes,because you are to busy looking at your 5H inductor,and forget about what is happening within the ideal voltage source. A current flows through the ideal voltage source,as well as the ideal coil. The ideal coil has inductance,but the ideal voltage source dose not. The ideal coil has impedance,but the ideal voltage source dose not. At T=5 seconds,you place a voltage across !not only the coil!,but also the ideal voltage source that has current already flowing through it. This voltage polarity is opposite to that which created the current flow that is flowing through the ideal voltage source. But for you MH,the transition is just going to nice and smooth--isnt it?. How dose your !water through pipes! cope with this one MH?
Let me guess--the water just disappears,so as the flow can now start in the opposite direction
It's no surprise, you are completely and utterly lost. After all that work.
"You place a voltage source across a voltage source?" You have got to be kidding.
No, the water simply starts to slow down, it does not "disappear." It's bloody rocket science.
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No, I was here to try to help you and talk some sense into you, and that has proved to be nearly impossible.
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Miles
I Imagine a skilled person such as yourself should be able to "requisition" a build , along with
expected results ?
if you won't build it, write a PDF doc for what you want built ,
say... for something as simple as a Joule thief
with expected result/claims
You say Tinman is a Fumbling Bench Putz ??
Prove it.
set a benchmark to the Best Of "Your" ability ...
or at least explore the feasibility of this Path [a build] to a resolution ?
you've been _called out_ By the Tinman... may times here !!
You have probably spent a thousand hours here in this thread...
spend 10 minutes and write the requisition .
we'll see if Tinsel Can/will build it to your specs and How many cheeseburgers it will cost ?
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@MH
I don't know why you keep putting my @username up on your casualty list. I suggest you refrain from doing that again.
I told you but you do not read or listen to actual words written. I though your question required an explanation of all those voltage levels occurring on their own after the first 4 volts was applied. Why else would I have said "ideal voltage does not change". Sorry that was my mistake but your question was not properly formulated to start with. Ask an ambiguous question only leads to exactly what happened. Instead of you clarifying the question and specifically saying each subsequent voltage is applied manually. So now you have learned something as well. We are now even. Please refrain from using my @username as you have. It is just not cool.
I will leave you to spat with @tinman as this is no longer my concern. Just a total waste of time. Time which you guys seems to consider being an overflow event where in reality the damn fuse is very short. So just keep wasting time and good luck.
When I first came to this forum, it was like intellectual nirvana where there were so many good minds trying to expand the base of present acceptance and explore the possibilities of OU devices. It was a great time and guys were not afraid to open their minds and sound off each other with often crazy ideas but that's where the magic was. Now it is gone. I just want to congratulate you on a job well done. This forum is now toast and guys like you are the toasters. hahaha. Now all the standard EEers can migrate here and take lessons on how to quash an OU forum.
No problem. I already had my own forum on stand-by, left dormant since 5 years now while I finalized Spin Conveyance because it actually took 10 years in all because it first relates to physics as well as chemistry and not just EE. I will just dust off that forum and keep there from now on.
Your last stint with @tinman was the last confirmation that there is no hope for EEers and OUers to co-exist and mutually expand the same damn goal when each ones goal is totally adversarial. The OUers are required to not only float above the mundane foray but to also drag along the EE as an official witness. Better EE learn on its own when the OU deed is done. Then you will be the first to want to learn a new electrical construct. We will see. No more distractions.
I took a week or so to ponder this question. Had prepared a few posts but never posted them again since this place is just not the right place. Too much noise for @members to actually contemplate and inspire each other. This is my last post on this forum as well as on OUR since both are not exactly OU oriented except for name only. I will be migrating most of my more important posts from these forums to my forum. Then continue there with only a few @members, so much less crap to deal with everyday with @members posting 20 posts a day saying nothing. It's time........
So you win. One can now confirm there are no more real OUers left at OU as well as OUR. The stage is yours. Each have now become an archive of the past but where the present can no longer be the stimulus it was. Both forums still attract a majority of @members as logged out @readers that remain and hope to read anything that will inspire progress but who will never post here again because they know the wrath is always ready to pounce and distract and/or destroy conversations worth any effort.
wattsup
PS1: EE 101 starts in 5 minutes. Don't be late or the teacher will put you in the corner.
PS2: For those in the know. Soon. For others, once my forum is dusted off and ready to go, you will learn of it.
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Thanks for another big speech Wattsup. At least it is not nasty like the last goodbye. I will just repeat a few simple things to you. This thread is about basic electronics and not about OU and it was started by Brad of his own volition. There are many threads that are primarily about basic electronics and not OU, or secondarily about basic electronics. Hence many people on forums like this are interested in basic electronics. Unfortunately Brad could not grasp some basic electronics concepts so the answers were given. Note that this thread took a different tactic - figure out some basic stuff for yourself so that you will truly understand and retain the knowledge. You will find that I haven't touched any of the other free thinking threads on this forum at all. The forum has not been "overtaken" it's all in your head.
Oh yeah, and there was nothing wrong with the bloody question.
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Chet, you are just being a pain in the butt at this time with your self-imprisoned mind. Your poor buddy is shown that he made a clear and unambiguous statement that an ideal voltage source cannot vary in time and he flat-out denies it and states that he did not do that. You say nothing. It's just just another form of Orwellian mental totalitarianism, the two of you are peas in an iron pod. Freedom is slavery. Ignorance is strength.
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You say Tinman is a Fumbling Bench Putz ??
Prove it.
Get real Chet, your words not mine. You haven't seen threads before around Brad's builds where people like Poynt engage with him and the tension increases and increases because of basic disagreements over what is taking place in the experiment? "We don't see eye to eye" - you haven't seen that before? "Prove to me that magnets are not a source of energy" - how many times have you seen that battle? You are in a mental prison of your own making and you can't speak the truth. It must be awful.
But forget that, what is this thread about? It's about basic electronics, not a bench experiment. Sadly there was a failed attempt by Brad and others to answer a very simple and basic question by themselves. It's fundamental knowledge that can also be used on the bench. It's mind-blowing that people can play on a bench for years and years and not understand the most rudimentary and basic stuff about electronics but clearly it happens all the time.
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Brad, you are so impossibly thick-headed and dense sometimes that it amazes me.
The "natural frequency" and the "resonant frequency" are synonymous, they mean the same bloody thing.
Yes they do MH. But just because something vibrates at it's natural resonant frequency,dose not mean it is resonating. When something is resonating,it is vibrating at it's natural frequency at maximum amplitude to that of a given input.
It would pay you to learn the basics before trying to teach people.
Brad
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It's no surprise, you are completely and utterly lost. After all that work.
"You place a voltage source across a voltage source?" You have got to be kidding.
No, the water simply starts to slow down, it does not "disappear." It's bloody rocket science.
No--you place a voltage across a current flow,where that voltage is ideal,and wants to create a current flow in the opposite direction to that of what already exist.
So limited in your thinking.
-
Challenge to the tinman, who can come up with the biggest
pile of crap?
John.
-
Yes they do MH. But just because something vibrates at it's natural resonant frequency,dose not mean it is resonating. When something is resonating,it is vibrating at it's natural frequency at maximum amplitude to that of a given input.
It would pay you to learn the basics before trying to teach people.
Brad
Right now I need TK's emoticon for the head banging against a wall.
If you could only think properly about certain situations and have some basic intuitive sense and had the ability to apply knowledge about one situation to a different but related situation, but apparently sometimes that is an impossible thing for you to do. The fact that you can't realize or intuitively or scientifically understand that the bell is resonating after you strike it is mind boggling to me. You are just making a fool of yourself without being aware of it. You clearly believe that what you are saying is making sense and nothing is going to get through to you. However, not being able to get through to you is no surprise.
I suppose it's also possible that since you started this discussion about resonance and got off on the wrong track, that your inability to admit that you are wrong means that you are psychologically compelled to "stick to your story," even though it is completely ridiculous. So it's possible that you literally have a mental block, and admitting that the bell is resonating after you strike it is an impossible thing for you to do. Your compulsion to refuse to admit that your original understanding was wrong literally forces you to state that the bell is not resonating after you strike it. For you to admit that the bell was resonating would cause some kind of psychological implosion in your psyche.
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No--you place a voltage across a current flow,where that voltage is ideal,and wants to create a current flow in the opposite direction to that of what already exist.
So limited in your thinking.
There is no such thing as "placing a voltage across a current flow." Six year's worth of electronics experimentation and help from some very knowledgeable people and you still manage to state nonsense like that. That's the proverbial canary in the coal mine if there ever was one.
In desperation, let's try the flywheel this time. The flywheel is initially stopped, and you apply clockwise torque to the flywheel for three seconds. Note that as the flywheel speeds up, you still have to apply the same torque, and that means the faster the flywheel spins. the more power you have to put out.
For two seconds you apply no torque and the flywheel free spins with no change in RPM.
Then for two seconds you apply counter-clockwise torque. As you can imagine, the flywheel starts to slow down. If you apply counter-clockwise torque for an extended period of time, the the flywheel will stop and then reverse direction.
Now who is the person that is limited in their thinking?
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Miles Quote to TinMan
""Bullshit, and you are nothing more than a bench tinkerer that barely knows what he is doing but believes that he knows it all. You have been fully exposed, and it was about time, and it's not a pretty sight at all.""
end Quote
So I used a few less colorful words
your theme is and always has been self evident regarding Tinman.
and actually it has been your entire issue with most members here that experiment with resonance or timing or pulsing etc etc ad nauseum infinitum
Absolutely anything which has to do with the Blasphemous topic of Morons
Over unity
Miles Quote
" I can't wait to put this to bed once and for all""
end quote
-----------
so on this side of the line above ...we have a man Tinman who has made a discovery in which he claims he can make magnets do work and get more out than in ...has a unique understanding of the interaction between Magnets and inductors.
Miles feels the need to Put this guy in his place and show all here by Default that such a man could never
make such a discovery , and you have even recently started mumbling his name in sentences with noteworthy
dubious fraudsters ..
that's the real jist of what this is truly all about.
Only one clear resolution here ..
a contest !!
@ Note to Minnion above
If you don't live forever may you at least have the Glory of coming back as a particular type of beetle which holds the same passion for that pile............
I have to hand it too you John
You are a character !!
;D
Hugz
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Chet, you really shouldn't be Brad's sycophantic lapdog and think for yourself. There's not going to be a "contest," stop barking like a dog. Brad started this thread as a challenge for himself and failed. The other thread had an equal amount of madness and technical ridiculousness and failures in it. And I was wrong about resonance in an ICE, did you hear that? I don't know how a bloody JFET works. The next time Brad does an experiment and "discovers that energy can come from magnets" I think people will be thinking about his technical performance on this thread and the Joule Thief 101 thread. There is nothing wrong with the truth.
Why don't you contribute something technical to this discussion? Right, you are only here for completely biased colour commentary and you like to weld.
Tinman who has made a discovery in which he claims he can make magnets do work and get more out than in ...has a unique understanding of the interaction between Magnets and inductors.
Really? I haven't seen him demonstrate any kind of "unique" understanding but I have seen him demonstrate lots of a lack of understanding as well as complete misunderstanding.
and you have even recently started mumbling his name in sentences with noteworthy
dubious fraudsters ..
Yes, the man can be totally dishonest to the point of ridiculousness right in front of your face, but lapdogs like you only pant and lick and wag their tails, right?
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Miles
The technical discussion around Brad and his ability took Place quite some time ago,
You remember
Mark E and several other talented Fellows took his Rotary transformer thru every conceivable test
allowed at that time.
and they were stumped as to how he was getting this energy into the system.
Mark E was hired to investigate claims , he was Quite brilliant.
Stumped !
It was the first and only time that I personally witnessed this happen here.
and Now you Play the Pink Panther ....
-
Yes it seemed to be an enigma. However I have seen Poynt get to the bottom of many enigmas over the years and resolve them. Wasn't this the case where Brad apparently got "spooked" and took off and the whole thing became a mystery?
I really just wanted to try an experiment stemming from my own frustration: Show Brad unambiguous absolute proof that he made a statement, and see how he would respond. Then of course he came back and flat out denied that he made the statement even though the proof was right there in front of his face. That is simply an unworkable situation.
It explains all of the craziness and insanity going right back to the start of the discussion on the Joule Thief 101 thread. How can anybody possibly argue with, or bounce ideas off, or try to educate somebody like that? Don't say anything Chet, you won't allow yourself to.
Brad can stew in his own juices and do whatever he wants but he can't deny that he couldn't answer the two wine glass questions, nor could he solve the simple first question by himself. Some things just are what they are but I don't expect that reality to change anything for Brad.
There is a positive angle though. Hopefully many lurkers were paying attention and they "got it" and they will benefit from it when they work on their bench. Call them the silent majority.
MileHigh
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I have very high respect for Brads knowledge and abilities. I find he and I and some others, like Luc, think ahead on ideas, many times whether we are right or wrong, we are deep thinkers. We dont just sit back and be satisfied with what is supposedly known throughout the tech world.
For example. I had argued that the 50% loss in the cap to cap was not due to resistance, off and on for how many years now. Finally with some further, this way and that way and other ways of getting my reasoning through to you guys, and now just the other day Poynt finally agreed with me in the cap to cap thread. Even found some links to back up my thoughts. I really giggled at the one that stated that resistance, no matter what the value, 0ohm and up, only changed the time of the transfer from cap to cap. I had stated that was what I believed a day or 2 earlier here. And the big thing that got it for me was thinking deeper and basing those beliefs on the electron imbalance count, as I call it.
Not many if any others had put up the idea here such as I had. Not saying I beat anyone. Im just glad it was resolved and we can move on to find other deeper ideas or things that just dont seem right and bring them out here, or anywhere. Like I could have just accepted what you guys said that resistance was the cause of the loss and never discuss it or 'think' of it any 'further' than that. But my thoughts on it being deeper than that, found an answer to an argument that we have had for some time. Calling me a know nothing wanna be, or what ever.
Thinking deeper than the surface arguments here develops legit questions that should not be written off as nonsense. And if Brad has something to say in contrast, rather than brush it off as a waste of time, perhaps you should look deeper than the surface and try to understand where he is coming from before bashing him as not knowing anything at all, because that is not the case. Not in my book. ;)
Mags
-
With a capacitor do you have to look at it from the perspective of
electrons and sort of "holes"?
John.
-
Mags,
You do agree however that if we measure the energy burned up in the total circuit resistance involved in cap to cap transfers, it will indicate half of the total energy?
Do you not also agree that the value of the total circuit resistance makes no difference in the energy and that it does indeed always dissipate half the starting energy and that it determines the tau of the transfer?
The 0 Ohms case seems to be a special case, and one that we can not achieve.
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Chet, you really shouldn't be Brad's sycophantic lapdog and think for yourself. There's not going to be a "contest," stop barking like a dog. Brad started this thread as a challenge for himself and failed. The other thread had an equal amount of madness and technical ridiculousness and failures in it. And I was wrong about resonance in an ICE, did you hear that? I don't know how a bloody JFET works. The next time Brad does an experiment and "discovers that energy can come from magnets" I think people will be thinking about his technical performance on this thread and the Joule Thief 101 thread. There is nothing wrong with the truth.
Why don't you contribute something technical to this discussion? Right, you are only here for completely biased colour commentary and you like to weld.
Really? I haven't seen him demonstrate any kind of "unique" understanding but I have seen him demonstrate lots of a lack of understanding as well as complete misunderstanding.
Yes, the man can be totally dishonest to the point of ridiculousness right in front of your face, but lapdogs like you only pant and lick and wag their tails, right?
MH
You are without a doubt,the BIGGEST liar i have ever met.
You are also one of the most twisted people i have ever met. You lie about me in nearly every post you make,while the truth sit's idle on the very same threads.
Like i said--you need help-->but even then,i think it may be to late for you.
You are a COWARD-that much is true.
You try and degrade me every chance you get,and yet,dont have the guts to take me on--not even in a little old JT build.
This shows your stature--all mouth,no action.
The facts are
1--No-you do not know the difference between an object oscillating at it's natural resonant frequency,and an object in resonance.
2--no-you dont know much about ICEs,and how resonance increases both performance and efficiency in the ICE.
3--no-you dont know what a J/FET is--or should i say,did not know what it was ,when you made yet another idiotic claim against my idea on a low voltage JT.
4--and then there was your big bungle between collector/base,and emitter/base breakdown voltage,causing a !!death!! spike.
5--and then the big one-->the self resonating wine glass-->MH discovers the worlds first perpetual wine glass.
That was just in the JT thread alone.
Any time you want to put your skills up against mine MH,just grow some,and let me know.
As it stands now-->your nothing more than talk.
Brad
-
Challenge to the tinman, who can come up with the biggest
pile of crap?
John.
Nice self portrait there John.
Brad
-
Brad:
<<< No--you place a voltage across a current flow,where that voltage is ideal,and wants to create a current flow in the opposite direction to that of what already exist. >>>
Enough said right there, and there are a thousand other quotes of yours that say the same thing.
MileHigh
-
author=MileHigh link=topic=16589.msg485659#msg485659 date=1464977542]
The fact that you can't realize or intuitively or scientifically understand that the bell is resonating after you strike it is mind boggling to me. You are just making a fool of yourself without being aware of it.
The fact that you do not know the difference between an object resonating,and one that is ringing down,is very scary indeed.
When dose a coil resonate MH?,and when dose a coil ring down?-->what is the difference?
And to think that you want people to listen to you lol.
Try again to understand the difference between resonance,and oscillation at a natural resonant frequency. Resonance requires forced motion of an object at it's natural resonant frequency,to gain maximum amplitude. A bell ringing down,is not the bell in resonance.
https://www.youtube.com/watch?v=ZzHajoDf1fg
https://www.youtube.com/watch?v=YYlpePXdiCg
If you could only think properly about certain situations and have some basic intuitive sense and had the ability to apply knowledge about one situation to a different but related situation, but apparently sometimes that is an impossible thing for you to do. You clearly believe that what you are saying is making sense and nothing is going to get through to you. However, not being able to get through to you is no surprise.
The reason i do not listen to you MH,is because you do not know what you are talking about.
I suppose it's also possible that since you started this discussion about resonance and got off on the wrong track, that your inability to admit that you are wrong means that you are psychologically compelled to "stick to your story," even though it is completely ridiculous. So it's possible that you literally have a mental block, and admitting that the bell is resonating after you strike it is an impossible thing for you to do.
Like i said,you have no idea what resonance is. For the bell to resonate,it must be interacting with another object that is vibrating at the same natural resonant frequency as the bell,or in the case of the Tacoma Narrows Bridge,it will resonate at it's natural frequency due to aeroelastic flutter(BTW,you will notice that they name it aero!elastic! flutter,and not aero!stiffness! flutter :D. The bell will only resonate when receiving energy from an out side force at the correct frequency-->it will not resonate all by it self--it will only ring down at it's natural resonant frequency when not interacting with an outside force.
Please watch second video above,and see if you can learn the difference.
Your compulsion to refuse to admit that your original understanding was wrong literally forces you to state that the bell is not resonating after you strike it. For you to admit that the bell was resonating would cause some kind of psychological implosion in your psyche.
My compulsion is to not listen to those that do not know what they are talking about-->you are one of those that do not know what you are talking about.
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author=MileHigh link=topic=16589.msg485661#msg485661 date=1464978257]
There is no such thing as "placing a voltage across a current flow."
And yet this is exactly what happens in your question--aint that a hoot :D
Six year's worth of electronics experimentation and help from some very knowledgeable people and you still manage to state nonsense like that. That's the proverbial canary in the coal mine if there ever was one.
And blah blah blah.
For two seconds you apply no torque and the flywheel free spins with no change in RPM.
Then for two seconds you apply counter-clockwise torque. As you can imagine, the flywheel starts to slow down. If you apply counter-clockwise torque for an extended period of time, the the flywheel will stop and then reverse direction.
Now who is the person that is limited in their thinking?
Well,it seems you are.
Now make that torque ideal--like your voltage
Hows your thinking doing now?.
Brad
-
<<< Now make that torque ideal--like your voltage >>>
Go ahead Brad, what happens when you make the torque ideal?
-
Brad:
<<< No--you place a voltage across a current flow,where that voltage is ideal,and wants to create a current flow in the opposite direction to that of what already exist. >>>
Enough said right there, and there are a thousand other quotes of yours that say the same thing.
MileHigh
Your question clearly shows,and we have all agreed on this--that between T=3 second's,and T=5 second's,a current is flowing through the ideal voltage source. At T=5 seconds,a negative voltage is place across that existing current that is flowing through the voltage source. This negative !!IDEAL!! voltage wishes to create a current flow that is opposite to that which already exist. So tell us again how you cannot place a voltage across a current flow?
Is your question starting to come undone?.
Brad
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<<< At T=5 seconds,a negative voltage is place across that existing current that is flowing through the voltage source. >>>
Enough said again Brad. It's like a bottomless cup of coffee.
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<<< So tell us again how you cannot place a voltage across a current flow? >>>
Again. Six years of work and schooling and all that I got was a lousy t-shirt.
-
<<< Now make that torque ideal--like your voltage >>>
Go ahead Brad, what happens when you make the torque ideal?
An ideal torque that is applied to the flywheel,where the torque is a counter force against the stored energy in the flywheel,would stop the flywheel instantly,regardless of the mass of that flywheel, or stored energy in that flywheel.
Brad
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An ideal torque that is applied to the flywheel,where the torque is a counter force against the stored energy in the flywheel,would stop the flywheel instantly,regardless of the mass of that flywheel, or stored energy in that flywheel.
Brad
Enough said again. And to think that this is coming from a guy that has been working with engines all his life.
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<<< At T=5 seconds,a negative voltage is place across that existing current that is flowing through the voltage source. >>>
Enough said again Brad. It's like a bottomless cup of coffee.
I see that you actually do not understand your own circuit,and how it is operating.
Let me guess--the current just disappears :D-->like your stored energy in the inductor dose ;D
A bottomless cup of coffee would be great in the mornings MH--what is your point?. :D
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Here, I found something for you to contemplate:
http://www.dictionary.com/browse/resonance
Definition of "resonance:"
Physics.
a. the state of a system in which an abnormally large vibration is produced in response to an external stimulus, occurring when the frequency of the stimulus is the same, or nearly the same, as the natural vibration frequency of the system.
b. the vibration produced in such a state.
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Enough said again. And to think that this is coming from a guy that has been working with engines all his life.
That is the engineering definition of an ideal torque--which cannot,and dose not exist in the real world--much like your ideal voltage.
I think we are about to watch you get it all screwed up again,and try and apply real world !ideal torque!.
Lets see how you go--lets watch the ICE saga all over again ;)
Now,here is a challenge that you can do MH--without dragging your lazy ass out of your rocking chair.
I would like you to draw up a schematic for the ideal voltage source for the circuit that suits your question,where the current can continue to flow unimpeded through this ideal source during T=3 second's,to T=5 seconds. You said such an ideal voltage source exist,so lets see it--show us the schematic for such a voltage source.
Lets see how good you are MH.
I mean,it's your question,and you should be able to provide a circuit schematic to suit the question--is this not what is asked of us all here?.
Brad
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<<< That is the engineering definition of an ideal torque >>>
What is the engineering definition of an ideal torque?
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<<< I would like you to draw up a schematic for the ideal voltage source for the circuit that suits your question,where the current can continue to flow unimpeded through this ideal source during T=3 second's,to T=5 seconds. >>>
I will put that one into the "crazy question" category. See attached.
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<<< That is the engineering definition of an ideal torque >>>
What is the engineering definition of an ideal torque?
How you off for underwear MH?.
An ideal torque is an ideal twisting force,or the application of an ideal energy source-the very same as your ideal voltage source MH.
Your flywheel dose not represent the current flow BTW,it represents the stored energy of the inductor.
How fast is the flywheel spinning by the way?--5252rpm Perhaps?.
How is that schematic coming along for your ideal voltage source?.
Brad
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An ideal torque is an ideal twisting force,or the application of an ideal energy source-the very same as your ideal voltage source MH.
You are on a hot streak Brad. I am not going to give you any extreme leeway, you are wrong.
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Your flywheel dose not represent the current flow BTW,it represents the stored energy of the inductor.
No secret decoder rings allowed, hence another mistake, another nonsensical statement.
You have a long way to go to get where you want to be.
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A repost, just in case:
Here, I found something for you to contemplate:
http://www.dictionary.com/browse/resonance (http://www.dictionary.com/browse/resonance)
Definition of "resonance:"
Physics.
a. the state of a system in which an abnormally large vibration is produced in response to an external stimulus, occurring when the frequency of the stimulus is the same, or nearly the same, as the natural vibration frequency of the system.
b. the vibration produced in such a state.
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<<< I would like you to draw up a schematic for the ideal voltage source for the circuit that suits your question,where the current can continue to flow unimpeded through this ideal source during T=3 second's,to T=5 seconds. >>>
I will put that one into the "crazy question" category. See attached.
Ah--nice circuit.
See below my new JT circuit :D
All jokes aside,i see you cannot even provide a schematic for your own ideal voltage source,and yet you think your answer to your question is absolutely correct ::)
How many times have you told us to draw out the circuit,to work out the answer,and yet ,right here,on the very thread of your own question,you drop a minnie in there--a complete fail to provide a circuit to represent your own question.
The armchair guru cannot even provide an armchair answer to a question regarding his own question.
You really are lazy MH.
Brad
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i see you cannot even provide a schematic for your own ideal voltage source
You simply don't realize that it's an idiotic question. You are really on a roll.
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A repost, just in case:
Here, I found something for you to contemplate:
http://www.dictionary.com/browse/resonance (http://www.dictionary.com/browse/resonance)
Definition of "resonance:"
Physics.
a. the state of a system in which an abnormally large vibration is produced in response to an external stimulus, occurring when the frequency of the stimulus is the same, or nearly the same, as the natural vibration frequency of the system.
b. the vibration produced in such a state.
And there you go,you just dumped your self in it lol.
Do you not understand what you read MH?.
System-->a set of things working together as parts of a mechanism or an interconnecting network; a complex whole.
a set of principles or procedures according to which something is done; an organized scheme or method.
You just stated exactly what i have said all along lol.
That did not work out to well for you--did it ;)
Brad
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You just stated exactly what i have said all along lol.
Yes we are in the Brad bonus round now, a "super roll." I highlighted the second definition in an attempt to talk some sense into you and get you to wake up out of your stupor with respect to resonance. The second definition shuts down all of your nonsense due to your lack of ability to conceptualize that a ringing bell is resonating.
resonance == the vibration produced in such a state == a ringing bell after it has been struck
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Yes we are in the Brad bonus round now, a "super roll." I highlighted the second definition in an attempt to talk some sense into you and get you to wake up out of your stupor with respect to resonance. The second definition shuts down all of your nonsense due to your lack of ability to conceptualize that a ringing bell is resonating.
resonance == the vibration produced in such a state == a ringing bell after it has been struck
Lol-Nice try MH,but another fail lol
Quote:-->a. the state of a system in which an abnormally large vibration is produced in response to an external stimulus, occurring when the frequency of the stimulus is the same, or nearly the same, as the natural vibration frequency of the system.
b. the vibration produced in such a state.
You do realize that B is referring to the method of A--do you not?.lol.
Your a funny man MH.
But it's like i said--do you not understand what you are reading?.
http://www.regentsprep.org/regents/physics/phys04/bresonan/default.htm
Resonance
The increase in amplitude of oscillation of an electric or mechanical system exposed to a periodic external force whose frequency is equal to or some multiple of the natural frequency of the system.
Natural Frequency
The frequency an object will vibrate with after an external disturbance. These frequencies are usually discrete and depend only on the intrinsic physical quantities of the object.
So,as you can see MH,your bell will vibrate at it's natural frequency when hit once.
It will not resonate until it is exposed to an external force that has the same(or multiples of)frequency as the bells natural resonant frequency.
Nothing will resonate without the second part of the system.
I ask you once again--and we can find your answer all over this forum-->when dose a coil resonate,and when dose a coil just ring down?
When will a resonant circuit be in resonance,and when will it be just in oscillation?
You have answered this question many times before correctly,but now you wish to just change it all around ::),and why?--just so as you can make your wine glass answers look correct ::)
There is no end to your bullshit MH--it's bigger than minnies pile he posted not so long ago.
You two have to be related :D
Brad
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Is in resonance with the air,, as demonstrated by the sound you hear,, and the stored energy within the amplitude of that bell oscillation is reduced by said air interaction.
No Webby--that is dampened oscillation,not resonance.
https://en.wikipedia.org/wiki/Damping
Brad
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You simply don't realize that it's an idiotic question. You are really on a roll.
What i have realized is that you cannot even draw a schematic of your ideal voltage source.
You will not even accept a challenge from me to see who can build the most efficient rotoverter.
You will not accept a challenge from me to see who can build the most efficient pulse motor.
You will not accept a challenge from me to see who can build the most efficient JT
You cannot even draw a circuit of your ideal voltage supply,but are happy to claim that you can answer your question correctly-->without even having the slightest idea as to how your ideal voltage supply is actually constructed to perform the required task,upon which the answer to your question is based.
This would have to be the most pathetic scientific method of defining an answer i have ever seen.
The only one that would get there ass booted out of your beloved scientific forums,is you,for idiotic rubbish like you have posted -both in this thread,and the JT thread.
I cant believe that you cannot provide a schematic for your ideal voltage source.
Your answer to your question has just become null and void,until such time as you can provide the complete circuit for analysis.
Brad
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Actually Brad, it just never ends with you. For Christ's sake, you think that there is a "schematic" for an ideal voltage source. You've got problems. You can't understand what an ideal torque would be conceptually or how it would behave in real life, and you are still lost on what the primary and fundamental scientific definition of resonance truly is. You can't understand that the typical definition for resonance is the layman's definition which is really the !response! of a resonant system to an external stimulation at the resonant frequency.
There is a parallel between you stating that an ideal voltage source couldn't vary in time because you did not see that in the definition for it, and you sticking to the first definition that you see for resonance and not understanding the basic fundamental definition for it.
You couldn't understand that an ideal voltage source could vary in time. And you still can't understand what resonance truly is because you are blinded by the layman's definition. I finally found a reference for resonance that does not discuss the !response! of the resonant system and you can't cope with that so you skirt around it.
You are still just as lost as ever Brad. I really don't care, stay lost as long as you want to be lost. However, there is a chance if you apply yourself you will get found.
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without even having the slightest idea as to how your ideal voltage supply is actually constructed
A grand slam!
You are not the tinman, you are the scarecrow that never found Oz.
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Actually Brad, it just never ends with you. For Christ's sake, you think that there is a "schematic" for an ideal voltage source. You've got problems. You can't understand what an ideal torque would be conceptually or how it would behave in real life, and you are still lost on what the primary and fundamental scientific definition of resonance truly is. You can't understand that the typical definition for resonance is the layman's definition which is really the !response! of a resonant system to an external stimulation at the resonant frequency.
There is a parallel between you stating that an ideal voltage source couldn't vary in time because you did not see that in the definition for it, and you sticking to the first definition that you see for resonance and not understanding the basic fundamental definition for it.
You couldn't understand that an ideal voltage source could vary in time. And you still can't understand what resonance truly is because you are blinded by the layman's definition. I finally found a reference for resonance that does not discuss the !response! of the resonant system and you can't cope with that so you skirt around it.
You are still just as lost as ever Brad. I really don't care, stay lost as long as you want to be lost. However, there is a chance if you apply yourself you will get found.
MH-you are lying again--in everything you say above.
Everything i have posted(and even your own postings)show that you cannot define the difference between an object resonating,and oscillating at it's natural resonant frequency.
I asked you to describe a coil resonating,and one that is just ringing down-->what is the difference?. But you failed to do so,as you know it would show you to be incorrect about your objects resonating all by them self.
You have not provided one example where an object will resonate by it's self,and your bell,and wine glass examples have been proven to be wrong.
This is one fail on your behalf.
Second--i have provided the definition of an ideal torque,where torque is the application of energy to a system or object,and where that energy is ideal-->an ideal torque is an ideal energy source. An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
You not understanding this,is also another fail on your behalf.
Third--The alarm bells sound,when one claims to know how a circuit will function,but cannot provide a schematic for such a circuit. The reason you cannot,and will not provide a circuit for the ideal voltage source in question,is because it dose not,and cannot exist.
This means that your circuit needed to answer your question cannot and will never exist,as there is no such thing as an ideal voltage source.
You have not thought about your question,and neither have many others here that think they have answered it correctly.
Your ideal voltage source has no internal series resistance,and thus a current can continue to flow through this ideal source while the voltage value is 0v. At T=5 seconds,a negative voltage is placed across the current that flows through this ideal source. The internal series resistance dose not change in the ideal source at this time,and that resistance value remains at 0 ohms--the reason the current can flow through it unimpeded.
This is the action that takes place in your circuit,but there is no possible way to design such a circuit that can perform this action.
Your answer is based around a circuit that cannot exist--and the proof of this,is by way of you not being able to draw such a circuit for the ideal voltage source.
With people like you at the helm,it is clear as to why man has stalled in his development of energy supplies.
Brad
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A grand slam!
You are not the tinman, you are the scarecrow that never found Oz.
I did more than found it MH--i live in it ;)
https://www.youtube.com/watch?v=aZ4NuX0qWuY
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Yes it is a damped oscillation,, but it is at the resonant frequency and it is taking the energy out of the bell amplitude,, not changing its frequency,, ergo resonance.
The external stimuli can take energy or add energy to the amplitude,, but it can not change the frequency.
Yes.it oscillates at it's natural resonant frequency,but the bell dose not resonate.
Resonance is achieved when maximum amplitude is reached by the oscillating body--the same applies to inductors in a resonant circuit.
MH knows this,but as he wishes to cling to falsehoods associated to his wine glass,and now!ringing bell!,he will continue on with his rubbish.
Brad
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author=webby1 link=topic=16589.msg485757#msg485757 date=1465064199]
Resonance is when the external stimuli changes the amplitude without changing the frequency and this happens when the input is at or about the resonant frequency of the system.
Yes,so where is this input that is needed for the bell to resonate ?
More so,, when the input adds to the amplitude,, this can be a short pulse that reoccurs at a rate that is within the resonant frequency of the system
That is correct.
OR it can be a short pulse that reduces the amplitude
That is incorrect.
In physics, resonance describes when a vibrating system or external force drives another system to oscillate with greater amplitude at a specific preferential frequency.
When no interaction is taking place then the system will oscillate at its natural frequency forever with the same amplitude.
No it will not. The oscillating body has an elasticity value that will dampen the oscillations,and eventually the oscillations will stop.
There is no object that will oscillate,that dose not have this elasticity value,or a resistance to change,that would allow the oscillations to continue on for ever.
The amplitude can go up or down and if you think about it, if the input were to continue the amplitude would continue to increase,, with ideals it would grow to an infinite amplitude.
Lets stick to real world applications here,as we do not have ideal devices-they are a myth.
Brad
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Second--i have provided the definition of an ideal torque,where torque is the application of energy to a system or object,and where that energy is ideal-->an ideal torque is an ideal energy source. An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
You not understanding this,is also another fail on your behalf.
And you fall flat on your ass for the 10,000th time. For starters, there is no such thing as an "ideal energy source." Plus your bloody definition doesn't even make sense. Like I said, it just never ends.
Here is what an ideal torque would be: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
If you understood what has been discussed ad infinitum already, you would realize this right away, it would be a no-brainer. And you would never in a million years use the term "ideal energy source."
But no! But no!
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With a capacitor do you have to look at it from the perspective of
electrons and sort of "holes"?
John.
Well if we take electrons from the Pos plate, then there are what they call holes which leaves that plate positively charged. And if we take those electrons and put them on the Neg plate, it becomes negatively charged as we have more electrons on the Neg plate than a cap with 0v charge.
Mags
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Mags,
You do agree however that if we measure the energy burned up in the total circuit resistance involved in cap to cap transfers, it will indicate half of the total energy?
Do you not also agree that the value of the total circuit resistance makes no difference in the energy and that it does indeed always dissipate half the starting energy and that it determines the tau of the transfer?
The 0 Ohms case seems to be a special case, and one that we can not achieve.
"
You do agree however that if we measure the energy burned up in the total circuit resistance involved in cap to cap transfers, it will indicate half of the total energy?"
I agree agree in the real world. ;)
"Do you not also agree that the value of the total circuit resistance makes no difference in the energy and that it does indeed always dissipate half the starting energy and that it determines the tau of the transfer?"
I also agree, in the real world. ;)
"The 0 Ohms case seems to be a special case, and one that we can not achieve."
Darn tootin it is. ;D Here is my issue with it.
When we bring up the cap to cap loss, like back when we were talking about it when Woopy did his video and was very surprised by the 50% loss, the argument from you guys was that it was the resistance, no matter what value above 0ohm, is the cause for the loss. And you used the Ideal cap to cap, zero resistance transfer as an example of how we could get 7.07v in each cap from 10v. Well that cannot be used any longer as a proper explanation of how the energy was lost, because now we all know that we cannot get 7.07v in each cap from 10v in the ideal world. I think people reading should know this 'now'.
So it is 'seemingly' a special case. It can no longer be used in these arguments to prove the point that resistance is the loss. And as you say, "seems to be a special case, and one that we can not achieve", then maybe arguments using Ideal caps, ideal coils, and Ideal voltage sources that can not be achieved should not be used as examples either, because if we can not achieve them, we can not be certain of the outcome, just as we have found this kink in the cap to cap situation. Is it possible that we may find other kinks in these ideal world components as to how we thought they were by just thinking a little deeper? If we say not, then we have learned nothing in this cap to cap argument and we are just writing it off. ;)
Or, we could put our thoughts together an try to figure out if it is more than just a special case by thinking it through further than just settling on the idea that it is a special case without explanation. Why would we stop there? ;D
Mags
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Yes.it oscillates at it's natural resonant frequency,but the bell dose not resonate.
Alas, so near yet so far.
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You have not provided one example where an object will resonate by it's self,and your bell,and wine glass examples have been proven to be wrong.
Proven to be wrong in your head only. You are your own best enemy.
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The reason you cannot,and will not provide a circuit for the ideal voltage source in question,is because it dose not,and cannot exist.
Ah, so it was a "trick" question. Knowing you, I actually believed that you were literally asking for a circuit for an ideal voltage source. It's that bad.
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Your answer is based around a circuit that cannot exist--and the proof of this,is by way of you not being able to draw such a circuit for the ideal voltage source.
And I see we have gone full-circle here and we are starting the discussion over right from the beginning. We are back to the "problem child" at school that can't cope with using simple abstractions to better understand how circuits work. It's information overload.
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Not a problem.
or using the understanding to make an emergency power supply just in case the planes power supply failed when you could not deploy a prop driven generator.
A system in resonance,, it is kind of fun.
The air is interacting with the bell and its oscillation,, there is an exchange of energy in that transaction that will reduce the amplitude of the bells oscillation without changing the frequency. This interaction is soundly demonstrated by the very sound you here,, the pitch would change if it were not in resonance.no.
That is correct,and that is the bell oscillating at it's natural resonant frequency. The bell will ring down(the sound level from the bell will reduce over time)due to dampening by both the air it sits in,and the bells own resistance to change(elasticity).
In physics resonance describes the condition where the external stimuli interacts with ONLY the amplitude,, not only increasing it but any change to that amplitude
And that answers your question.
The bell has no external stimuli acting upon it,it has a dampening effect from the air it resides in-not a stimulant effect from the air it resides in.
The bell can only resonate when an external stimuli acts upon it to maintain or increase it's vibrational amplitude.
.and yet you have seen this with your pulse motors and PM's,, your RT,, you have shown many things that show this interaction being a two way thing.
The RT works by deforming the magnetic field of a PM,and then letting the field reform at the same time the electromagnetic stator field is collapsing.This causes a large reversal of the magnetic field the stator coil B see's. Due to the shape and design of the stator core,this field also travels around the stator core to the other side,to create a magnetic field at stator core A,due to the flux path of the core it self. This is why the motor speeds up,and gains torque when a load is placed on the outer coil of stator B.
I was schooled on what resonance is by a group of engineers that had to know there stuff,, I was very young but remember the differences between an oscillation and a system that is in resonance,, in there line of work it could be the difference between an airplane flying nicely through the air and one that rips itself apart,,
With the planes,that is aeroelastic flutter,the same thing that bought down the Tacoma Narrows Bridge. The outside force acting upon the plane,is the wind due to the planes own motion.
With some of the reply’s by others I am wondering if in the electrical world the difference is not taught because in that space there is no difference??
When an inductor resonates,it's amplitude is at a continuous maximum that can be gained from the outside force acting upon it.
Brad
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And you fall flat on your ass for the 10,000th time. Plus your bloody definition doesn't even make sense. Like I said, it just never ends.
But no! But no!
Here is what an ideal torque would be: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
An ideal torque is an ideal energy source. An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
Gee it's hard with you MH.
Im sorry to say MH,but in engineering,torque is not only related to flywheels,and so your answer is very limited(like your self),where as mine covers the whole spectrum.
Nice try,but you missed the boat again. :D
For starters, there is no such thing as an "ideal energy source."
And yet your question is based around such a device lol.
So it's much like asking--how fast could a flying pink pig go ?.
If you understood what has been discussed ad infinitum already, you would realize this right away, it would be a no-brainer. And you would never in a million years use the term "ideal energy source."
Your ideal voltage source !is! an ideal source of energy.
For a voltage to be placed across an inductor,and a current to flow through that inductor,requires a source of energy. Since your question only has two components,1-the inductor,and 2-the ideal voltage source,then the ideal voltage source must be providing the energy.
You never managed to provide an example of a voltage source that dose not contain energy ::)-but no surprise there ;)
It is funny to watch you try and squirm your way out of mistakes you know you have made lol.
You never like answering questions asked of you either-->like,when is an inductor resonating?,and when is it just ringing down at it's resonant frequency?.
I mean,we have all discussed this on many occasions,and TK has shown a coil ringing down,and a coil resonating many times. But you will not answer those two question's,as you know that means that your self resonating wine glass and bell theory will fall in a big heap.
I will try one last time to try and show you what resonance is,and when something is resonating,and what oscillating at a natural resonant frequency is.
It dose not come much more simple that this.
https://www.youtube.com/watch?v=XzFvhQgsS-Y
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[I will try one last time to try and show you what resonance is,and when something is resonating,and what oscillating at a natural resonant frequency is.
It dose not come much more simple that this.
https://www.youtube.com/watch?v=XzFvhQgsS-Y (https://www.youtube.com/watch?v=XzFvhQgsS-Y)
You are so utterly hapless and confused when it comes to this stuff sometimes Brad, it just blows my mind how you can't think for yourself and achieve a "normal" level of understanding.
https://en.wikipedia.org/wiki/LC_circuit (https://en.wikipedia.org/wiki/LC_circuit)
LC circuit
An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can act as an electrical resonator, an electrical analogue of a tuning fork, storing energy oscillating at the circuit's resonant frequency.
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An ideal torque is an ideal energy source. An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
Gee it's hard with you MH.
Im sorry to say MH,but in engineering,torque is not only related to flywheels,and so your answer is very limited(like your self),where as mine covers the whole spectrum.
Nice try,but you missed the boat again. :D
And yet your question is based around such a device lol.
So it's much like asking--how fast could a flying pink pig go ?.
Your ideal voltage source !is! an ideal source of energy.
For a voltage to be placed across an inductor,and a current to flow through that inductor,requires a source of energy. Since your question only has two components,1-the inductor,and 2-the ideal voltage source,then the ideal voltage source must be providing the energy.
You never managed to provide an example of a voltage source that dose not contain energy ::) -but no surprise there ;)
It is funny to watch you try and squirm your way out of mistakes you know you have made lol.
You never like answering questions asked of you either-->like,when is an inductor resonating?,and when is it just ringing down at it's resonant frequency?.
I mean,we have all discussed this on many occasions,and TK has shown a coil ringing down,and a coil resonating many times. But you will not answer those two question's,as you know that means that your self resonating wine glass and bell theory will fall in a big heap.
Since I tried to give you the real definition of an ideal torque and you rejected it, then I will say your comments about torque are completely idiotic. Not using the proper mechanical variables of torque and angular velocity for your "explanation" is completely idiotic. Making reference to an "ideal energy source" is also completely idiotic.
Im sorry to say MH,but in engineering,torque is not only related to flywheels,and so your answer is very limited(like your self),where as mine covers the whole spectrum.
That's another completely idiotic statement because I use a flywheel as a convenient example, that's all, and I am expecting your brain to be able to process that and understand it. Obviously, I was expecting too much from you.
And yet your question is based around such a device lol.
No, it is not based around an "ideal energy source." That is a meaningless term and if you are going to talk about this stuff then you have to use the proper terminology whether you like it or not. Failing to use the proper terminology and demonstrate a mastery over basic energy concepts makes you look like a fool.
Yes, there is no such thing as an "ideal energy source" and if you stated that in a physics or engineering class everybody would look at you like you were from Mars. Failure to think one more time Brad.
In the realm of what we are discussing you have the following:
Ideal voltage source
Ideal current source
Ideal torque source
Ideal angular velocity source
Ideal force source
Ideal linear velocity source
That is the deck of cards laid out for you. If in the future you continue to use the term "ideal energy source" you will look like a complete idiot.
You never managed to provide an example of a voltage source that dose not contain energy -but no surprise there
Failure to think again Brad.
You never like answering questions asked of you either-->like,when is an inductor resonating?,and when is it just ringing down at it's resonant frequency?.
I mean,we have all discussed this on many occasions,and TK has shown a coil ringing down,and a coil resonating many times. But you will not answer those two question's,as you know that means that your self resonating wine glass and bell theory will fall in a big heap.
I don't know what profound points or questions you have to make about an LC resonator. NOT an "inductor resonating" Brad, you have to use the proper terminology whether you like it or not.
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I asked you to describe a coil resonating,and one that is just ringing down-->what is the difference?.
Presumably you are talking about an ideal LC circuit vs. an LCR circuit that will ring down. There is nothing special there.
You have not provided one example where an object will resonate by it's self,and your bell,and wine glass examples have been proven to be wrong.
An LCR circuit will resonate by itself. So will a tuning fork, a bell, and a wine glass.
Here is your "big intellectual hurdle" that you must get over Brad to not stick out of the Electronics 001 class like a sore thumb: "Resonance" has two meanings. Now is that so hard to get into your head? There is the same old "driven resonance" that you always refer to and are stuck to like some poor hapless fly on flypaper.
Here is the second definition put into some easy-to-understand sentences:
For starters, keep this in mind, "An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can act as an electrical resonator, an electrical analogue of a tuning fork, storing energy oscillating at the circuit's resonant frequency."
Now, here we go:
An LC circuit is a resonant circuit that acts as an electrical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A tuning fork is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A wine glass is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A bell is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
Now, does that register in your brain or are you just going to stick to the single definition of resonance that you understand and completely ignore the second definition of resonance that is actually the more basic and fundamental definition of what resonance really is?
Which one is it going to be?
MileHigh
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Brad:
And since we have been talking about this stuff for a while where we use analogies, you should know that there are two separate systems for analogies. There is the "force-current" analogy and the "force-voltage" analogy.
When I talk about using the analogy of the flywheel and say that putting 4 volts across the 5 Henry inductor is like putting torque on a flywheel, I am using the force-voltage analogy. My shopping cart example was also using the force-voltage analogy.
So, there are two "analogy systems" and here is a very informative link about the two systems:
http://lpsa.swarthmore.edu/Analogs/ElectricalMechanicalAnalogs.html
That's just the way it is and people can choose whichever analogy system they want to use to discuss a given example. If you are a real keener, you will be able to automatically pick up which system the person you are conversing with is using.
MileHigh
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author=webby1 link=topic=16589.msg485784#msg485784 date=1465101608]
Is the air an external force?
The air is an impedance acting upon the oscillations of the bell.
Without the air would it ring down at the same rate as with the air?
No,it would take longer for the bell to ring down,as one of the impedance's acting upon the bell has been removed.
Is the air pressure waves you hear at the same frequency as the bell?Repeat the above questions.
Yes they are.
So the air responding to the oscillations of the bell is reducing the amplitude of those oscillations by converting the amplitude of those oscillations into sound waves,, aka pressure waves.
That is correct.
So the external stimuli is a negative value.
It is not a stimuli,it is an impedance.
The system will build up to the maximum that the outside stimuli can supply,, it stores that outside input within the amplitude of the oscillation.
That is correct--that is resonance.
But with the bell,the oscillations are decreasing in amplitude,they are not building up to a maximum,and there for,there is no resonating system.
Stimuli--a thing that arouses activity or energy in someone or something.
Impedance--An analogous measure of resistance to an alternating effect, as the resistance to vibration of the medium in sound transmission.
Can you get a coil\cap oscillating and use a zener diode to clip the peaks that are above the input voltage? can you see the pattern on a scope? what will the frequency of those output pulses be,, can you drop the zener to one that is lower than the input voltage,, running through a resistor,, and watch the amplitude of the coil\cap go down?
The coil and cap are a resonant system. The coil or cap will not resonate by them self.
A tank circuit will not become resonant,unless an outside force is applied to the tank system. That outside force must be maintained in order for resonance to continue. Once the outside force is removed,then the tank system will ring down to a stop.
Brad
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You are so utterly hapless and confused when it comes to this stuff sometimes Brad, it just blows my mind how you can't think for yourself and achieve a "normal" level of understanding.
https://en.wikipedia.org/wiki/LC_circuit (https://en.wikipedia.org/wiki/LC_circuit)
LC circuit
An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can act as an electrical resonator, an electrical analogue of a tuning fork, storing energy oscillating at the circuit's resonant frequency.
That is correct MH.
It is an LC circuit--a system,where two!!yes two!! components are working together.
Neither the capacitor or inductor will resonate alone.
Your bell will not resonate alone.
Please apply a pulse to either an inductor or capacitor alone,and show us all here how it resonates.
Who is the hapless and confused one MH?.
Brad
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author=MileHigh link=topic=16589.msg485787#msg485787 date=1465104924]
Since I tried to give you the real definition of an ideal torque and you rejected it, then I will say your comments about torque are completely idiotic. Not using the proper mechanical variables of torque and angular velocity for your "explanation" is completely idiotic.
Your definition of an ideal torque,was poor at best,and reflects against your very limited mechanical abilities. There dose not have to be any angular momentum in order for there to be a torque applied to an object or mass.
That's another completely idiotic statement because I use a flywheel as a convenient example, that's all, and I am expecting your brain to be able to process that and understand it. Obviously, I was expecting too much from you.
As i said before,torque dose not only apply to things in motion.
You failed at giving an accurate example of an ideal torque.
No, it is not based around an "ideal energy source." That is a meaningless term and if you are going to talk about this stuff then you have to use the proper terminology whether you like it or not. Failing to use the proper terminology and demonstrate a mastery over basic energy concepts makes you look like a fool.
A fool is some one that uses unreal devices--such as you have used in your question,to justify real world result's.
You used a voltage source that dose not exist,and one you cannot draw a circuit for to explain the actions of the current flowing through the circuit,and then make claim that you can answer this question correctly.
Yes, there is no such thing as an "ideal energy source" and if you stated that in a physics or engineering class everybody would look at you like you were from Mars. Failure to think one more time Brad.
There is also not such voltage source that is used in your question.
Guess you got kicked out of class as well. ;)
In the realm of what we are discussing you have the following:
Ideal voltage source
Ideal current source
Ideal torque source
Ideal angular velocity source
Ideal force source
Ideal linear velocity source
This is the realm of MHs wonderland,as none of the above exist.
That is the deck of cards laid out for you. If in the future you continue to use the term "ideal energy source" you will look like a complete idiot.
It is you that is the idiot MH,as this is what you claim to have in your ideal voltage source.
You are still yet to show anyone here a voltage source that dose not contain energy--and no,it just dose not disappear as you said earlier on in this thread.
Failure to think again Brad.
I don't know what profound points or questions you have to make about an LC resonator. NOT an "inductor resonating" Brad, you have to use the proper terminology whether you like it or not.
This silly attempt to explain your self resonating bell and wine glass was answered in my last post.
Brad
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Here is your "big intellectual hurdle" that you must get over Brad to not stick out of the Electronics 001 class like a sore thumb: "Resonance" has two meanings. Now is that so hard to get into your head? There is the same old "driven resonance" that you always refer to and are stuck to like some poor hapless fly on flypaper.
Here is the second definition put into some easy-to-understand sentences:
Now, here we go:
Which one is it going to be?
MileHigh
Presumably you are talking about an ideal LC circuit vs. an LCR circuit that will ring down. There is nothing special there.
No,i am not talking about MHs fantasy land--we are talking real world applications.
There is no such thing as an ideal LC circuit,nor is there such thing as a self resonating bell or wine glass.
An LCR circuit will resonate by itself. So will a tuning fork, a bell, and a wine glass.
No they will not.
They will oscillate for a short time,where each oscillation become smaller,until the oscillations stop.
Nothing will resonate by it self,there needs to be an outside force acting upon the system in order for resonance to occur.
For starters, keep this in mind, "An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can act as an electrical resonator, an electrical analogue of a tuning fork, storing energy oscillating at the circuit's resonant frequency."
Once again-in the hope it will sink in,the LC circuit is a system--two components,where the energy oscillates between the two energy storage systems. The bell and the wine glass are single entities,and no resonance occurs,as there is no second component to form a resonant system.
An LC circuit is a resonant circuit that acts as an electrical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
An LC circuit will not resonate without an external force acting upon it--this is fact.
An LC circuit also is a system that consist of two components--not !one! component like your bell and wine glass.
A tuning fork is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A tuning fork is not a system,it is a single component.
A tuning fork will oscillate at it's resonant frequency,but it will not resonate alone.
System-->a set of things working together as parts of a mechanism or an interconnecting network; a complex whole.
A wine glass is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
Once again,a wine glass is a single component--not a system.
It will not resonate without an outside force acting upon it.
A bell is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.[/b]
Once again,the bell alone is not a system,and will not resonate by it self.
Now, does that register in your brain or are you just going to stick to the single definition of resonance that you understand and completely ignore the second definition of resonance that is actually the more basic and fundamental definition of what resonance really is?
Do you know what a system is MH?--it is not one single component.
Did you watch the !very easy to understand! video i posted for you ,explaining the difference between oscillating at a natural resonant frequency,and resonance?.
Everything i have posted in regards to the difference between oscillating at a natural frequency ,and resonance is absolutely correct,and you do not get to change the meanings or definitions to suit your need to be correct.
You are flat out wrong,and once again,your inability to decipher the difference between oscillation at a natural frequency,and resonance just go's to show how lost you are.
Feel free to show us a capacitor or an inductor resonating by it self :D
Brad
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So Brad, we had this huge MASSIVE discussion about the wine glass and you are telling all of us that nothing sunk in? Nothing sunk in at all? So you are just a big blank slate right now, on autopilot.
It's like you time warped and missed it all, and here you are, a lost soul. I wish that I could say that it is all simply unbelievable, but it is clearly believable.
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So Brad, we had this huge MASSIVE discussion about the wine glass and you are telling all of us that nothing sunk in? Nothing sunk in at all? So you are just a big blank slate right now, on autopilot.
It's like you time warped and missed it all, and here you are, a lost soul. I wish that I could say that it is all simply unbelievable, but it is clearly believable.
As usual MH,you have it all ass about.
Your wine glass saga and answers were not agreed upon by anyone other than your self.
Even you mix up between !stiffness! and elasticity was tried to be explained to you by many on that thread.
I do not know how you keep coming up with--!!everyone but you agree's with me!! MH,but that is far from the truth. No one agreed with your wine glass explanation MH,and that is a fact that can be backed by the posts on the thread it self.
You have a hard time defining the difference between an object oscillating at it's natural resonant frequency,to that of an object being in resonance within a system.
You blatantly disregard every single link and video i post,to show you the meanings of the two, only so as you can try and maintain your nonsense.
Nothing will resonate on it's own MH,as it is not part of a system that is needed in order for resonance to occur.
Every single link and video i have posted regarding this matter,all say the same thing,and define the difference between an object vibrating at it's natural resonant frequency(like your bell and wine glass),and when that object resonates,or becomes resonant.
Although this will just once again ,fall on deaf ear's,here is another link,in the hope's that you will finally understand the difference.
http://science.howstuffworks.com/resonance-info.htm
Quote: Resonance, An object free to vibrate tends to do so at a specific rate called the object's natural, or resonant, frequency. (This frequency depends on the size, shape, and composition of the object.) Such an object will vibrate strongly when it is subjected to vibrations or regular impulses at a frequency equal to or very close to its natural frequency. This phenomenon is called resonance. Through resonance, a comparatively weak vibration in one object can cause a strong vibration in another. By analogy, the term resonance is also used to describe the phenomenon by which an oscillating electric current is strengthened by an electric signal of a specific frequency.
Surly it cant be this hard for you to understand MH.
Brad
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A tuning fork is not a system,it is a single component.
You are a blank slate Brad, and you are completely lost.
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And one last time MH,in the hope you will see the error of your thinking.
The physics behind resonance,and when an object will resonate.
Please try and understand what you are reading.
Once again,the below link tells the very same story that the other 20 or so links and video's i have provided over the two threads--this one,and the JT thread.
You will once again see how an object vibrating at it's natural resonant frequency,and the same object resonating are defined.
Your wine glass and bell are not resonating while they are ringing down--they are oscillating at there natural resonant frequency.
Please read carefully MH.
The 3 things needed to get an object to resonate.
These are things you cannot change to try and justify your nonsense MH,whether you like it or not.
Quote:
The ABC's of Resonance
Resonance causes an object to move back and forth or up and down. This motion is generally called oscillation. Sometimes the oscillation is easy to see such as the motion of a swing on a playground or the vibration in a guitar string. In other cases the oscillation is impossible to see without measuring instruments. For example, electrons in an electrical circuit can oscillate but it happens on a molecular level.
In resonance the oscillation occurs at a specific frequency. These oscillations build up rapidly to very high levels. Ultimately some of the energy in the oscillations has to be removed from the object or the size of the oscillations get so large that the object breaks.
Resonance requires 3 basic conditions:
A) An Object With a Natural Frequency: The object can be a mechanical device or an electronic circuit. An object's natural frequency is the frequency it tends to oscillate at when disturbed. The oscillation can be a mechanical vibration as is the case when the string of a guitar is strummed. In an electronic circuit the oscillation is a variable voltage or current. An object can have more than one natural frequency. These are called harmonics. A guitar string sounds musical because it vibrates with several harmonics when it is strummed.
B) A Forcing Function at the Same Frequency as the Natural Frequency: In mechanical systems the forcing function is a variable force. In electronic circuits it arises from a variable electric field. In either case the forcing function does work on the object it is applied to. Since work is a form of energy transfer it causes energy to build up in the object.
C) A Lack of Damping or Energy Loss: For an object to resonate, mechanical or electrical energy has to build up in the object. Anything which removes these forms of energy tends to interfere with resonance. Damping is a means of removing electrical or mechanical energy by converting it to heat. The term damping should not be confused with the term dampening which means to make something slightly wet. Friction, air resistance, and viscous drag can all provide damping in mechanical systems. Electrical resistance performs the same function in electronic circuits. Other forms of energy loss can include sound (musical instruments) or light emissions (lasers).
When the forcing function's frequency matches the natural frequency of an object it will begin to resonate. The forcing function adds energy at just the right moment during the oscillation cycle so that the oscillation is reinforced. This makes the oscillation's amplitude grow larger and larger. These oscillations would eventually become infinitely large. However, as mentioned earlier, long before the oscillations reach infinity one of three things happens: 1) the object's dynamics change so that the resonant frequency and forcing functions no longer match, 2) the energy lost as heat, sound, or light becomes equal to the energy input. or 3) the object breaks
http://www.intuitor.com/resonance/abcRes.html
You have not supplied one link MH,that says an object will resonate without this forcing function.
The reason you have not done this,is because an object will not resonate by it self--it will only vibrate/oscillate at it's natural resonant frequency-->but it will not resonate.
It is clear that you have lost the ability to learn,and the falsehoods you have become to believe ,are set in stone with you.
This is not going to be very helpful to those here wishing to learn the truth.
I have provided more than enough evidence to squash your silly understandings on resonance.
But of course,everyone else will be wrong,and MH will be right.
Brad
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You are a blank slate Brad, and you are completely lost.
The two forks on a tuning fork,will oscillate 180* out of phase to each other,and not in phase-->as far as motion is concerned. This means that the two forks will spread apart at the same time,and they will come together at the same time-they will not sway from left to right in unison--or in resonance.The only thing they have in common,is the oscillation frequency--they are not resonating together.
Brad
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Brad:
You are still completely and utterly lost. For this subject matter, your ability to conceptualize something all by yourself is essentially nil. Sometimes you have almost no innate capacity to figure something out by yourself.
A tuning fork is not a system,it is a single component.
No in fact a tuning fork is a mechanical system. You know what an LC resonator is, a capacitor connected to an inductor. The simple model for a tuning fork, a wine glass, and a bell, is an LC resonator. All four of them are resonators that all work in fundamentally the same way.
Here is what you fail to realize even after countless attempts to explain this to you in the case of the wine glass: The mass of the arms of the tuning fork, using the force-current analogy, is modeled as a capacitance. Likewise, stiffness of the arms of the tuning fork to deflection (the springiness) is modeled as an inductance. A tuning fork is simply a mechanical LC resonator. See the attached graphic.
What is the etymology for the word "resonance?" It comes from French, meaning to "re-sound." In other words, sound coming back, or sound bouncing back and forth. Where is this "bounce" in resonance? In the case of the tuning fork, the moving arms translate their motion and energy into the spring of the tuning fork and compress it. Then the energy that is in the spring "re-sounds" or "bounces back" and the arms are moving again. This process repeats over and over. That is fundamentally what resonance is.
As such, an LC circuit, a tuning fork, a wine glass, and a bell are all LC resonators that resonate at their resonant frequency and manifest the phenomenon of resonance. They don't have to be externally driven by an excitation that is at the resonant frequency, they are perfectly fine to resonate all by themselves and ring down if energy is put into the system. i.e.; striking a tuning fork.
The act of ringing down is an example of resonance. The fact that the system rings down due to the damping effects of a resistance to the oscillation does take away from the fact that the system is resonating.
Now if only you could understand this.
MileHigh
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The two forks on a tuning fork,will oscillate 180* out of phase to each other,and not in phase-->as far as motion is concerned. This means that the two forks will spread apart at the same time,and they will come together at the same time-they will not sway from left to right in unison--or in resonance.The only thing they have in common,is the oscillation frequency--they are not resonating together.
Brad
I could slice and dice through that and try to talk some sense into you but instead I am going to do a few postings with some links and copy/pasting and hope something sticks.
If you don't get what I say, then stay forever lost in your fog of ignorance. There is only so much work that can be expended in trying to talk some sense into you and getting you to think straight about this important subject matter.
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Whether right or wrong, decaying oscillations of a resonant system are often referred to as still resonating.
By the definition given in the attachment, an LC circuit is a resonant system, as is also an air resonant cavity.
I suspect that everything that can resonate has an energy exchange process within itself, even after the stimulus is removed.
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From HyperPhysics:
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html#resdef (http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html#resdef)
[The first definition that they give:]
Resonance
In sound applications, a resonant frequency is a natural frequency of vibration determined by the physical parameters of the vibrating object. This same basic idea of physically determined natural frequencies applies throughout physics in mechanics, electricity and magnetism, and even throughout the realm of modern physics.
[The second definition that they give, the one you are obsessing on:]
Ease of Excitation at Resonance
It is easy to get an object to vibrate at its resonant frequencies, hard at other frequencies. A child's playground swing is an example of a pendulum, a resonant system with only one resonant frequency. With a tiny push on the swing each time it comes back to you, you can continue to build up the amplitude of swing. If you try to force it to swing a twice that frequency, you will find it very difficult, and might even lose teeth in the process!
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https://en.wikipedia.org/wiki/Tuning_fork
Tuning fork
A tuning fork is an acoustic resonator in the form of a two-pronged fork with the prongs (tines) formed from a U-shaped bar of elastic metal (usually steel). It resonates at a specific constant pitch when set vibrating by striking it against a surface or with an object, and emits a pure musical tone after waiting a moment to allow some high overtones to die out. The pitch that a particular tuning fork generates depends on the length and mass of the two prongs. It is frequently used as a standard of pitch to tune musical instruments.
[What they say later is that the pitch is also determined by the springiness of the metal of the tuning fork, where they discuss Young's modulus.]
The main reason for using the fork shape is that, unlike many other types of resonators, it produces a very pure tone, with most of the vibrational energy at the fundamental frequency, and little at the overtones (harmonics)
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http://www.giangrandi.ch/electronics/ringdownq/ringdownq.shtml
Measuring the Q-factor of a resonator with the ring-down method
Introduction
Resonance is a very common phenomenon, especially in electronics, acoustics, mechanics and optics. When a resonance is desired, special devices are built, called resonators, that have the property of naturally oscillating at some frequency, called resonant frequency, with (much) greater amplitude than at others.
All resonators are characterized by their resonant frequency f0 and their quality factor Q: this page is about a simple method of measuring Q, called the ring-down method.
In electronics, LC circuits are a common kind of resonator, often called resonant circuit, tuned circuit or tank circuit. They are all composed by an inductor (labelled L) and a capacitor (labelled C) connected together. The resistor (labelled R) is responsible for the losses and the final Q-factor: it's often ignored or omitted and rarely added as a physical component, but always present as any losses in the resonator will appear as a resistor. So, every practical LC circuit is actually an RLC circuit, even if just called LC, as it's also the case in this page. Usually, the inductor is responsible for the majority of the losses.
This page is mainly oriented on electrical LC circuits, but the ring-down method applies to all kinds resonators, because the equations describing their behavior have the same form.
All the previous examples were electrical circuits. Let's have a look now at a mechanical resonator, as the ring-down method applies to almost any resonator. I choose a 440 Hz tuning fork used by guitar players to tune their instrument. To measure the amplitude of the oscillations it has been coupled to a piezoelectric transducer and connected to the oscilloscope, as shown in the picture below. The piezoelectric transducer works here as a microphone. Here, the choice of the probe is not important, but the way to hold the fork in place is critical: I ended up tying it to a long wooden stick with thin copper wire, being careful in not tightening it too much.
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Here we go again:
An LC circuit is a resonant circuit that acts as an electrical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A tuning fork is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A wine glass is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A bell is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
All of the above systems are modeled by the attached circuit. This is a simplified model that does not include the resistor.
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author=MileHigh link=topic=16589.msg485787#msg485787 date=1465104924]
Your definition of an ideal torque,was poor at best,and reflects against your very limited mechanical abilities. There dose not have to be any angular momentum in order for there to be a torque applied to an object or mass.
As i said before,torque dose not only apply to things in motion.
You failed at giving an accurate example of an ideal torque.
No, in fact my definition of an ideal torque was 100% correct and yours was wrong. You can't say that my mechanical abilities are "very limited," that's just nonsensical spinning and you have nothing to backup that false claim.
More importantly, I never said that there had to be angular momentum for there to be torque applied to an object. You are falsely trying to put words into my mouth.
Likewise, I never stated that torque only applies to things in motion. One more time, you are falsely trying to put words into my mouth.
Again, my example for an ideal torque was 100% accurate.
An LC circuit will not resonate without an external force acting upon it--this is fact.
That is complete and utter nonsense. If you connect a charged capacitor to an inductor the LC circuit will resonate and ring down specifically because it is an LC resonator.
At this point, I hope and pray that you understand what resonance is and what an ideal torque is.
All of your attempts to be dismissive and reject concepts like an ideal voltage or current source, or an ideal force or velocity source are just you showing your severe limitations and the fact that you don't want to work to achieve an understanding of what these things are. I put in time and effort in an attempt to get you up the learning curve with respect to this stuff and I would hope that you can put in the effort to get to a satisfactory level of understanding for yourself.
Like it or not, you were blown out of the water, and it was for your own good. It was a Great Marianas Turkey Shoot and I was the shooter.
If you want to be fake and pretentious and pretend you are teaching me, then look at this:
A tuning fork is not a system,it is a single component.
Once again,a wine glass is a single component--not a system.
Once again,the bell alone is not a system,and will not resonate by it self.
Each one of the mechanical systems above is a mechanical LC resonator with two components - a mass and a spring. The reason you are saying what you say is because you don't understand how to model a physical system with an analogous electrical circuit. I tried to explain that to you with the wine glass and put in considerable effort and I am trying to explain that to you again. If you don't get it and refuse to consider it and do some research on your own because you think you know better then that is your loss, and you will be lost the next time you encounter a similar situation.
I am giving you the real deal and I know what I am talking about. Don't feign that you are trying to teach me and then talk foolishness, it only makes you look more foolish.
I am done with this and if you don't get it, then you don't get it and you remain lost.
MileHigh
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Is tinman on a winning streak at the moment?
John.
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An LC circuit will not resonate without an external force acting upon it--this is fact.
That is complete and utter nonsense. If you connect a charged capacitor to an inductor the LC circuit will resonate and ring down specifically because it is an LC resonator.
You had to use an external voltage and current source to charge the capacitor in the first place.
Try connecting an uncharged capacitor to an inductor. Will it start to resonate without first having applied an external force to the circuit or one component of the circuit (the capacitor)?
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Is tinman on a winning streak at the moment?
John.
If I were you John, I would be looking for a very large shovel, as evidenced by your photo.
Bill
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That is complete and utter nonsense. If you connect a charged capacitor to an inductor the LC circuit will resonate and ring down specifically because it is an LC resonator.
You had to use an external voltage and current source to charge the capacitor in the first place.
Try connecting an uncharged capacitor to an inductor. Will it start to resonate without first having applied an external force to the circuit or one component of the circuit (the capacitor)?
No of course it will not start to resonate. Charging the capacitor is equivalent to striking a tuning fork to get it to resonate.
Brad is always focused on "resonance" being an external driving force at the resonant frequency getting the resonator to resonate. You don't need an external driving force, all that you need to do is put a one-shot injection of energy into the mechanical or electrical resonator to get it to resonate and manifest resonance. That will be a demonstration of the true core meaning of resonance.
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Whether right or wrong, decaying oscillations of a resonant system are often referred to as still resonating.
That is incorrect Poynt.
Show me just one video of a coil ringing down,where the operator says the coil is resonating.
Even in normal every day speech,do we say the bell is ringing or resonating?.
An object resonates when is is oscillating at a continuous maximum amplitude.
By the definition given in the attachment, an LC circuit is a resonant system, as is also an air resonant cavity.
That is correct.
When will the LC circuit resonate,and when is it said to be ringing down?
I suspect that everything that can resonate has an energy exchange process within itself, even after the stimulus is removed.
Yes,and that is due to the physical size,shape,and elasticity values of the object.
Brad
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From HyperPhysics:
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html#resdef (http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html#resdef)
[The first definition that they give:]
Resonance
In sound applications, a resonant frequency is a natural frequency of vibration determined by the physical parameters of the vibrating object. This same basic idea of physically determined natural frequencies applies throughout physics in mechanics, electricity and magnetism, and even throughout the realm of modern physics.
[The second definition that they give, the one you are obsessing on:]
Ease of Excitation at Resonance
It is easy to get an object to vibrate at its resonant frequencies, hard at other frequencies. A child's playground swing is an example of a pendulum, a resonant system with only one resonant frequency. With a tiny push on the swing each time it comes back to you, you can continue to build up the amplitude of swing. If you try to force it to swing a twice that frequency, you will find it very difficult, and might even lose teeth in the process!
And those two examples agree with what i am trying to tell you.]
Do you not read and understand the difference between an object oscillating at it's natural frequency,and resonating.
Brad
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Do you not read and understand the difference between an object oscillating at it's natural frequency,and resonating.
Brad
There is no difference, they are synonymous.
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author=MileHigh link=topic=16589.msg485815#msg485815 date=1465151477]
An LC circuit is a resonant circuit that acts as an electrical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
Provide just one video of an LC circuit ringing down,where the operator says it is resonating.
A tuning fork is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A tuning fork will vibrate at it's natural frequency when struck once--it is not resonating.
A wine glass is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A wine glass will ring at it's natural frequency when struck once--it is not resonating.
A bell is a resonant system that acts as a mechanical resonator that resonates at the resonant frequency and manifests the phenomenon of resonance.
A bell will ring at it's natural frequency when struck once--it is not resonating.
Brad
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Burn this into your psyche Brad: A tuning fork is an acoustic resonator. It resonates at a specific constant pitch when set vibrating by striking it against a surface or with an object.
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OMG look at this, a smoking tuning fork gun where they say that a struck tuning fork is resonating. Run for the hills.
Resonance, forced vibration, and a tuning forks demo
http://thekidshouldseethis.com/post/resonance-forced-vibration-and-a-tuning-forks-demonstration
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No of course it will not start to resonate. Charging the capacitor is equivalent to striking a tuning fork to get it to resonate.
snip...
In both cases energy input is a part of the resonating system. No energy input, whether continual or momentary, no oscillation or resonance.
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Provide just one video of an LC circuit ringing down,where the operator says it is resonating.
Here, my favourite guy, and in the first clip he says that the parallel LC circuit "has a resonant frequency."
The LC Circuit
https://www.youtube.com/watch?v=v3-HwZMThzQ
The LC Circuit (part II)
https://www.youtube.com/watch?v=t5yMPyNkdkI
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"When you connect an inductor and a capacitor in parallel you will always get this phenomenon called 'resonance.'"
Parallel Resonance Part 1
https://www.youtube.com/watch?v=WGyMy9QgkLs (https://www.youtube.com/watch?v=WGyMy9QgkLs)
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MileHigh
No, in fact my definition of an ideal torque was 100% correct and yours was wrong. You can't say that my mechanical abilities are "very limited," that's just nonsensical spinning and you have nothing to backup that false claim.
Your mechanical abilities !are! very limited--that much was obvious in the JT thread,and once again-here.
As i said,your flywheel and angular velocity analogy was very limited,and poor at best,as there dose not have to be motion for a torque to exist.
This once again,shows us how limited your thinking is.
More importantly, I never said that there had to be angular momentum for there to be torque applied to an object. You are falsely trying to put words into my mouth.
Those were your exact word's MH,i am putting no words into your mouth.
Your knickers are in a twist once again,because you know my example covered the whole spectrum of an ideal torque,while yours was very limited.
Likewise, I never stated that torque only applies to things in motion. One more time, you are falsely trying to put words into my mouth
Post 967--Quote: Here is what an ideal torque would be: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
Your own words MH--not mine.
Again, my example for an ideal torque was 100% accurate.
As we can see from your own words MH,your example was very limited.
That is complete and utter nonsense. If you connect a charged capacitor to an inductor the LC circuit will resonate and ring down specifically because it is an LC resonator.
Rubbish.
The stored energy will just oscillate back and forth,until it is dissipated by the resistance of the system. The system will not resonate until an outside force causes a maximum amplitude to be gained within that system,where that amplitude is determined by the outside force.
At this point, I hope and pray that you understand what resonance is and what an ideal torque is.
I understood it long ago,but you have some work to do MH.
All of your attempts to be dismissive and reject concepts like an ideal voltage or current source, or an ideal force or velocity source are just you showing your severe limitations and the fact that you don't want to work to achieve an understanding of what these things are.
I reject anything that dose not exist,or cannot be tested due to it's non existence.
I put in time and effort in an attempt to get you up the learning curve with respect to this stuff and I would hope that you can put in the effort to get to a satisfactory level of understanding for yourself.
I have put in just as much time trying to deliver to you the difference between an object that is resonating,and one that is oscillating and ringing down at it's natural resonant frequency.
Like it or not, you were blown out of the water, and it was for your own good. It was a Great Marianas Turkey Shoot and I was the shooter.
Im sorry MH,but you only have judged yourself.
You screwed up on the ICE issue
You screwed up on the J/FET issue
You screwed up on the stiffness V elasticity issue with your wine glass saga
Your attempt at explaining an ideal torque was very limited.
You have screwed up understanding the difference between an object oscillating at it's natural frequency,and when it is resonating.
And you screwed up on which JT circuit is most efficient--even when i gave a very good reason as to why !your! JT circuit would not be as efficient as the other one i put forward.
And you wish to use non existent !ideal! components to justify real world applications and outcomes.
Each one of the mechanical systems above is a mechanical LC resonator with two components - a mass and a spring. The reason you are saying what you say is because you don't understand how to model a physical system with an analogous electrical circuit. I tried to explain that to you with the wine glass and put in considerable effort and I am trying to explain that to you again. If you don't get it and refuse to consider it and do some research on your own because you think you know better then that is your loss, and you will be lost the next time you encounter a similar situation.
And im trying to explain to you,that none of those systems will resonate without an outside force acting upon those system,in order to gain maximum amplitude of the oscillations--which is needed in order for a system to be said it is resonating.
The examples you have given MH,are harmonic oscillators that are not resonating.
A harmonic oscillator will only resonate when an external time dependent force is present,and acting upon the harmonic oscillator.
Quote: Mechanical resonance is the tendency of a mechanical system to absorb more energy when the frequency of its oscillations matches the system's natural frequency of vibration than it does at other frequencies. It may cause violent swaying motions and even catastrophic failure in improperly constructed structures including bridges, buildings, trains, and aircraft. When designing objects, engineers must ensure the mechanical resonance frequencies of the component parts do not match driving vibrational frequencies of motors or other oscillating parts, a phenomenon known as resonance disaster.
If you want to be fake and pretentious and pretend you are teaching me, then look at this:
The only one here MH that is fake-is you.
You pride your self with such great knowledge,but you will never stand against me in any sort of challenge to put !your! great knowledge up against mine.
You even avoid going up against me in a simple JT build off,to see who actually has the good's.
I am giving you the real deal and I know what I am talking about. Don't feign that you are trying to teach me and then talk foolishness, it only makes you look more foolish.
There is no point in trying to teach you anything MH,as you are to far gone.
I am done with this.
Thank God for small mercies :D
Brad
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Brad:
I know that you don't realize this but we are in black comedy territory now.
As i said,your flywheel and angular velocity analogy was very limited,and poor at best,as there dose not have to be motion for a torque to exist.
Post 967--Quote: Here is what an ideal torque would be: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
Your own words MH--not mine.
Yes indeed, and any angular velocity can mean an angular velocity of zero. In other words, applying torque to an object that is not in motion.
Quoting myself in response to your foolish comments: More importantly, I never said that there had to be angular momentum for there to be torque applied to an object. You are falsely trying to put words into my mouth. Likewise, I never stated that torque only applies to things in motion. One more time, you are falsely trying to put words into my mouth.
My words indeed.
Let's look at the definition of an ideal voltage source: A voltage source that will maintain the same voltage regardless of the amount of current that it sources or sinks. Now, I would assume that you would agree with that definition, correct? Look at the attached chart and look at the force-voltage analogy.
You can see how voltage corresponds to force, or in our case since we are talking about a rotational system, torque. You can see how current corresponds to velocity, or in our case since we are talking about a rotational system, angular velocity. ----> Voltage = torque, current = angular velocity.
Now Brad, let's summarize:
Definition of an ideal voltage source: A voltage source that will maintain the same voltage regardless of the amount of current that it sources or sinks.
My definition for an ideal torque source: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
Your first definition for an ideal torque source: An ideal torque is an ideal twisting force,or the application of an ideal energy source-the very same as your ideal voltage source MH.
Your second definition for an ideal torque source: I have provided the definition of an ideal torque,where torque is the application of energy to a system or object,and where that energy is ideal-->an ideal torque is an ideal energy source. An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
Sorry, but when it came to defining an ideal torque source, you were lost and clueless. Hence the black comedy in your previous posting.
MileHigh
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There is no point in trying to teach you anything MH,as you are to far gone.
Brad
It was a bloody turkey shoot Brad, a black comedy at the end as shown in the quote above. You can have a good brain fry thinking about how you stuck to a bunch of untenable and totally incorrect positions like an automaton with the wrong programming wheel. What's worse is when you finally come to the realization of how ridiculous your incorrect position about this resonance business is, you are going to have a super brain fry.
Believe me, many people reading also know the truth and they are aghast at reading some of the stuff that you have been posting. Just take my example of deconstructing your inane definition of an ideal torque source as an example. You entered into territory that I know quite well, and all you got out of it was a brain fry instead of trying to learn some good and practical stuff.
MileHigh
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It was a bloody turkey shoot Brad, a black comedy at the end as shown in the quote above. You can have a good brain fry thinking about how you stuck to a bunch of untenable and totally incorrect positions like an automaton with the wrong programming wheel. What's worse is when you finally come to the realization of how ridiculous your incorrect position about this resonance business is, you are going to have a super brain fry.
MileHigh
Just take my example of deconstructing your inane definition of an ideal torque source as an example. You entered into territory that I know quite well, and all you got out of it was a brain fry instead of trying to learn some good and practical stuff.
Well lets just have a look at each of our definitions of an ideal torque-shall we.
Your idea of an ideal torque
Quote: Here is what an ideal torque would be: A system that applies the same torque to the spinning flywheel regardless of the angular velocity of the flywheel.
My idea of an ideal torque
Quote: An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
Now-who's model covers all situations MH,and who's model covers only one example.
Did you even bother to read my definition MH?
You say it is absolute rubbish,but it is saying the very same thing as your definition MH-only mine covers all situation's,while your definition is very limited.
Lets look at each part of our examples.
Quote your definition-->A system that applies the same torque to the spinning flywheel
Quote me: -->An ideal torque will maintain it's chosen value.
I know your English is not so good MH,but they mean the very same thing.
Now the second part
Quote your definition--> regardless of the angular velocity of the flywheel
Quote me: --> regardless of the opposition force placed upon this torque
Once again,my definition covers your limited definition exactly,but where as my definition covers all situations an ideal torque could be place in,while yours only covers that of your flywheel example.
You entered into territory that I know quite well
Well,if you knew this territory quite well,you would have given a more accurate definition of an ideal torque,and not limit it to just angular momentum.
You would have also noticed that my definition is exactly the same as yours,only it covers the whole spectrum of situations an ideal torque could be placed in.
Believe me, many people reading also know the truth and they are aghast at reading some of the stuff that you have been posting.
Well if they didnt before-they do now.
They will see that your chicken dance is all for nothing,and that my definition of an ideal torque is exactly the same as yours,only where mine is not limited as your is.
Face the music MH,you provided a !limited! definition of an ideal torque,while i gave the complete definition of an ideal torque,where my definition is not limited to motion.
Lets look at the definitions again
Yours-->A system that applies the same torque to the spinning flywheel
Mine--->An ideal torque will maintain it's chosen value-->applies the same torque
Yours-->regardless of the angular velocity of the flywheel
Mine--->regardless of the opposition force placed upon this torque-->your spinning flywheel in this case.
I mean MH,it's preatty funny you should mock my definition,when it is the same as your--only without your limitations :D
Im not sure about you MH,but when i torque up flywheel bolts on a motor,the flywheel is not spinning :D
Perhaps you have learned another lesson here today? ;)
Brad
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No, we haven't learned anything new today. We all know that you will defend any junk you say and try to twist it to make yourself appear to be "right." You are never enough of a man to admit you are wrong because you have a psychological block.
You do not state that the ideal torque source will maintain the torque regardless of the rotational speed of the object that the torque is being applied to. That is the critical piece of information that is missing and you cannot spin or backpedal out of that. You are wrong - face it like a man.
You are simply not even putting sentences together that give a simple straightforward explanation. As we have seen many times before, when you don't know what you are talking about you wander all over the map and offer up an awkward disjoint explanation that doesn't really make sense. Sorry, there are no secret decoder rings allowed, you either get it or your don't. And you didn't get it, nor could you offer up any appreciation for the true definition of the term that was clearly explained to you.
You just end up doing your usual BS song and dance when you are in a jam.
MileHigh
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MileHigh
No, we haven't learned anything new today. We all know that you will defend any junk you say and try to twist it to make yourself appear to be "right." You are never enough of a man to admit you are wrong because you have a psychological block.
You are delusional MH,as you have just described your self.
You do not state that the ideal torque source will maintain the torque regardless of the rotational speed of the object that the torque is being applied to. That is the critical piece of information that is missing and you cannot spin or backpedal out of that. You are wrong - face it like a man.
Quote: An ideal torque will maintain it's chosen value
Like i said--your delusional,and you need help.
You are simply not even putting sentences together that give a simple straightforward explanation
.
Quote: An ideal torque will maintain it's chosen value,regardless of the opposition force placed upon this torque.
Seems you really do need some English lessons MH.
As we have seen many times before, when you don't know what you are talking about you wander all over the map and offer up an awkward disjoint explanation that doesn't really make sense. Sorry, there are no secret decoder rings allowed, you either get it or your don't. And you didn't get it, nor could you offer up any appreciation for the true definition of the term that was clearly explained to you.You just end up doing your usual BS song and dance when you are in a jam.
MH
When posting on a forum,try not to look in the mirror,as you get things all mixed up.
My definition of an ideal torque was the same as your,only not limited to motion such as yours.
Your goose was cooked once again--perhaps some time off from the forum would do you good.
Brad
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That is incorrect Poynt.
Show me just one video of a coil ringing down,where the operator says the coil is resonating.
Even in normal every day speech,do we say the bell is ringing or resonating?.
An object resonates when is is oscillating at a continuous maximum amplitude.
I am conveying this from my own experience (and others'). It is not uncommon to use the term "resonating" when describing something that is still "ringing" after the stimulus is removed. Be it correct or incorrect, this IS the case.
That is correct.
When will the LC circuit resonate,and when is it said to be ringing down?
As I said above, "we" often use the terms interchangeably, right or wrong. To us, ringing down is the same as decaying resonance.
Yes,and that is due to the physical size,shape,and elasticity values of the object.
Those mainly determine what frequency something will resonate at, not whether it will resonate or not. I brought up the point of "energy exchange within itself" in response to your statements about tuning forks and wine glasses as being only single elements. The point was, regardless if an item appears to be a single element or not, if it is capable of resonating, then it does so by way of an energy exchange mechanism within itself and/or with its environment.
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My definition of an ideal torque was the same as your,only not limited to motion such as yours.
Brad
This is the second time that you have mentioned this nonsense, even though I dealt with it directly the first time you brought it up.
As i said,your flywheel and angular velocity analogy was very limited,and poor at best,as there dose not have to be motion for a torque to exist.
My response: <<< Yes indeed, and any angular velocity can mean an angular velocity of zero. In other words, applying torque to an object that is not in motion.
Quoting myself in response to your foolish comments: More importantly, I never said that there had to be angular momentum for there to be torque applied to an object. You are falsely trying to put words into my mouth. Likewise, I never stated that torque only applies to things in motion. One more time, you are falsely trying to put words into my mouth. >>>
So where were you Brad? Cloud Nine? In space cadet summer (or winter) school? My response passed right through you like you weren't even there? This has happened dozens and dozens of times before.
Your attempt to define an ideal torque source is a bloody train wreck, plain and simple. You use illogical terms like "ideal energy source." You talk about force when it's a discussion about torque. When you are going to define something it has to be right, and all that you can do is backpedal and spin instead of being a man and admitting that you were wrong.
Probably the biggest recent fiasco of yours is this illogical and totally irrational insistence that resonating wine glasses and tuning forks aren't actually resonating. You are from the bloody Salvador Dali School of Infinite Improbability Loco Physics for Dummies.
Read again what I said:
<<< What is the etymology for the word "resonance?" It comes from French, meaning to "re-sound." In other words, sound coming back, or sound bouncing back and forth. Where is this "bounce" in resonance? In the case of the tuning fork, the moving arms translate their motion and energy into the spring of the tuning fork and compress it. Then the energy that is in the spring "re-sounds" or "bounces back" and the arms are moving again. This process repeats over and over. That is fundamentally what resonance is.
As such, an LC circuit, a tuning fork, a wine glass, and a bell are all LC resonators that resonate at their resonant frequency and manifest the phenomenon of resonance. They don't have to be externally driven by an excitation that is at the resonant frequency, they are perfectly fine to resonate all by themselves and ring down if energy is put into the system. i.e.; striking a tuning fork. >>>
Is any of this going to sink in or are you just going to remain in the Dali loco school?
MileHigh
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It's such an exciting debate and I haven't a clue who's right or who's wrong.
When it comes to fundamentals the tinman is usually wrong but he must get
it right sometimes??
Poynt is obviously very clever but is economical in disclosing too much forcing
the reader to help him/herself as much as possible.
Oh well, it's back to the fields for me, the agricultural type that is.
Looking forward to the next instalment.
John
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This is the second time that you have mentioned this nonsense, even though I dealt with it directly the first time you brought it up.
My response: <<< Yes indeed, and any angular velocity can mean an angular velocity of zero. In other words, applying torque to an object that is not in motion.
So where were you Brad? Cloud Nine? In space cadet summer (or winter) school? My response passed right through you like you weren't even there? This has happened dozens and dozens of times before.
Read again what I said:
<<< What is the etymology for the word "resonance?" It comes from French, meaning to "re-sound." In other words, sound coming back, or sound bouncing back and forth. Where is this "bounce" in resonance? In the case of the tuning fork, the moving arms translate their motion and energy into the spring of the tuning fork and compress it. Then the energy that is in the spring "re-sounds" or "bounces back" and the arms are moving again. This process repeats over and over. That is fundamentally what resonance is.
As such, an LC circuit, a tuning fork, a wine glass, and a bell are all LC resonators that resonate at their resonant frequency and manifest the phenomenon of resonance. They don't have to be externally driven by an excitation that is at the resonant frequency, they are perfectly fine to resonate all by themselves and ring down if energy is put into the system. i.e.; striking a tuning fork. >>>
Is any of this going to sink in or are you just going to remain in the Dali loco school?
MileHigh
Your attempt to define an ideal torque source is a bloody train wreck, plain and simple. You use illogical terms like "ideal energy source." You talk about force when it's a discussion about torque. When you are going to define something it has to be right, and all that you can do is backpedal and spin instead of being a man and admitting that you were wrong.
Here we go--the old MH pick and choose as it suits my needs combo.
The question was-->define an ideal torque--nothing about source.
Please refer to your own question this thread is about,where you have only provided an ideal voltage source,and nothing about where the energy is stored--voltage is nothing without an energy source.
So my answer is fine,and you simply do not get to pick and choose when there dose and dose not have to be a need to provide every detail to suit your needs.
Quoting myself in response to your foolish comments:[/b] More importantly, I never said that there had to be angular momentum for there to be torque applied to an object. You are falsely trying to put words into my mouth. Likewise, I never stated that torque only applies to things in motion. One more time, you are falsely trying to put words into my mouth. >>>
I never put any words into your mouth at all--your definition was quoted word for word,and it was limited to motion.
My answer was the same as your,but not limited as your was---you asked to define an ideal torque,and i did so more accurately than your self--that is fact.
Probably the biggest recent fiasco of yours is this illogical and totally irrational insistence that resonating wine glasses and tuning forks aren't actually resonating. You are from the bloody Salvador Dali School of Infinite Improbability Loco Physics for Dummies.
They are not resonating unless being acted upon by an outside force.
Once again-please read the Physics behind resonance,and the 3 things required to achieve resonance.
You are confused between acoustic oscillation and resonance.
http://www.intuitor.com/resonance/abcRes.html
Brad
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The question was-->define an ideal torque--nothing about source.
Please refer to your own question this thread is about,where you have only provided an ideal voltage source,and nothing about where the energy is stored--voltage is nothing without an energy source.
At this point I am just correcting or clarifying things for you for the sake of doing it. I don't know if things are going to stick because we seem to have a serious Teflon problem with you and I don't really care at this point.
"Ideal torque" and "ideal torque source" mean exactly the same thing and you should realize this and it's (almost) shocking that you don't.
For the hundredth bloody time, we are talking about black-box abstractions and there is no such thing as a literal "energy store" or "energy source" for any of them.
So my answer is fine,and you simply do not get to pick and choose when there dose and dose not have to be a need to provide every detail to suit your needs.
Your answer is dead wrong because you had to say two things, 1) "constant torque," and 2) "any angular velocity" and you failed to do that. At this point you may as well go bark at the moon if you want to insist that you are right.
I never put any words into your mouth at all--your definition was quoted word for word,and it was limited to motion.
You are in "head banging against the wall" territory now Teflon Brad. THINK: Any angular velocity can mean zero angular velocity which means no rotation which means STOPPED and no motion. Now, do you understand that?
They are not resonating unless being acted upon by an outside force.
You have been given multiple references that state that resonance does not need action from an outside source and you are intentionally ignoring them.
Beyond that, forget about all of the references and think for yourself and arrive at your own conclusion based on the facts and your own intellect.
You can arrive at the correct conclusion all by yourself.
MileHigh
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snip...
Once again-please read the Physics behind resonance,and the 3 things required to achieve resonance.
You are confused between acoustic oscillation and resonance.
http://www.intuitor.com/resonance/abcRes.html (http://www.intuitor.com/resonance/abcRes.html)
Brad
ABC may be too hard for some to understand or perhaps clicking on the link and reading is too hard.?
Saving the trouble: Extract from http://www.intuitor.com/resonance/abcRes.html (http://www.intuitor.com/resonance/abcRes.html)
" Resonance requires 3 basic conditions:
A) An Object With a Natural Frequency: The object can be a mechanical device or an electronic circuit. An object's natural frequency is the frequency it tends to oscillate at when disturbed. The oscillation can be a mechanical vibration as is the case when the string of a guitar is strummed. In an electronic circuit the oscillation is a variable voltage or current. An object can have more than one natural frequency. These are called harmonics. A guitar string sounds musical because it vibrates with several harmonics when it is strummed.
B) A Forcing Function at the Same Frequency as the Natural Frequency: In mechanical systems the forcing function is a variable force. In electronic circuits it arises from a variable electric field. In either case the forcing function does work on the object it is applied to. Since work is a form of energy transfer it causes energy to build up in the object.
C) A Lack of Damping or Energy Loss: For an object to resonate, mechanical or electrical energy has to build up in the object. Anything which removes these forms of energy tends to interfere with resonance. Damping is a means of removing electrical or mechanical energy by converting it to heat. The term damping should not be confused with the term dampening which means to make something slightly wet. Friction, air resistance, and viscous drag can all provide damping in mechanical systems. Electrical resistance performs the same function in electronic circuits. Other forms of energy loss can include sound (musical instruments) or light emissions (lasers).
When the forcing function's frequency matches the natural frequency of an object it will begin to resonate. The forcing function adds energy at just the right moment during the oscillation cycle so that the oscillation is reinforced. This makes the oscillation's amplitude grow larger and larger. These oscillations would eventually become infinitely large. However, as mentioned earlier, long before the oscillations reach infinity one of three things happens: 1) the object's dynamics change so that the resonant frequency and forcing functions no longer match, 2) the energy lost as heat, sound, or light becomes equal to the energy input. or 3) the object breaks "
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MileHigh
At this point I am just correcting or clarifying things for you for the sake of doing it. I don't know if things are going to stick because we seem to have a serious Teflon problem with you and I don't really care at this point.
"Ideal torque" and "ideal torque source" mean exactly the same thing and you should realize this and it's (almost) shocking that you don't.
For the hundredth bloody time, we are talking about black-box abstractions and there is no such thing as a literal "energy store" or "energy source" for any of them.
Who is !we!,as it is only you that has a problem with this torque issue.
The question you asked was-define an ideal torque--nothing about the ideal torques source. Of course it has a bloody source MH,,just like your ideal voltage has a source.
So stop your nonsence,as your just dribbling on about something that is not an issue.
Your answer is dead wrong because you had to say two things, 1) "constant torque," and 2) "any angular velocity" and you failed to do that. At this point you may as well go bark at the moon if you want to insist that you are right.
My answer was correct MH,and more accurate than yours.
If the angular velocity is 0 MH,then there is no angular velocity.--> there dose not have to be any angular velocity for a torque to be applied to something. Your statement is idiotic,and you know it. Once again,you are doing the !big dribble! to try and save face--but that dose not work for you any more MH.
Once again--angular velocity dose not have to be included to describe an ideal torque,as a torque can exist where there is no angular velocity.
If we place 0 volts across your ideal coil MH--is there a voltage across your coil?
Thats how stupid your comments are becoming.
You are in "head banging against the wall" territory now Teflon Brad. THINK: Any angular velocity can mean zero angular velocity which means no rotation which means STOPPED and no motion. Now, do you understand that?
You have finally gone completely nut's MH,and that is what i understand.
If something is motionless(stopped),then there is no angular velocity MH,but a torque can still exist.
You have been given multiple references that state that resonance does not need action from an outside source and you are intentionally ignoring them.
What,from one or two sources that must have taken you hours to dig up?.
I have provided 10x's that,and all i have provided are correct. Your own little language dose not dismiss the true scientific meaning of resonance or resonating MH--like it or not.
I asked you to supply just one video,where an experimenter says that a coil is resonating when it is ringing down--just one,and you failed to do so.
Beyond that, forget about all of the references and think for yourself and arrive at your own conclusion based on the facts and your own intellect.
You can arrive at the correct conclusion all by yourself.
I have MH,and i do know when an object is resonating,and when it is just oscillating/vibrating at it's natural frequency.
To resonate,the amplitude must maintain a maximum value.not ring down to nothing.
I have provided page after page,and video after video,showing you the difference between a resonating object,and what is needed to gain resonance,and an object vibrating at it's natural frequency.
Everything on earth vibrates MH--are you saying everything is resonating? ::)
Brad
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Brad:
Of course it has a bloody source MH,,just like your ideal voltage has a source.
There is no "source" of anything Brad. It's just like watching Batman on TV. There is no Bat Cave, and there is no Batman, it's all imaginary.
Once again--angular velocity dose not have to be included to describe an ideal torque,as a torque can exist where there is no angular velocity.
You have comprehension problems.
If something is motionless(stopped),then there is no angular velocity MH,but a torque can still exist.
No kidding.
I have provided 10x's that,and all i have provided are correct. Your own little language dose not dismiss the true scientific meaning of resonance or resonating MH--like it or not.
Walk into any high school physics class where they are playing with tuning forks and say that when you strike a tuning fork that it is not resonating and the whole class and the teacher will burst out laughing.
I asked you to supply just one video,where an experimenter says that a coil is resonating when it is ringing down--just one,and you failed to do so.
In fact I did supply a video just the other day.
You can be stuck on this resonance/natural frequency problem as long as you want. It just shows how you have serious problems and how insanely difficult it is to get through to you.
MileHigh
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Brad:
There is no "source" of anything Brad. It's just like watching Batman on TV. There is no Bat Cave, and there is no Batman, it's all imaginary.
You have comprehension problems.
No kidding.
Walk into any high school physics class where they are playing with tuning forks and say that when you strike a tuning fork that it is not resonating and the whole class and the teacher will burst out laughing.
In fact I did supply a video just the other day.
You can be stuck on this resonance/natural frequency problem as long as you want. It just shows how you have serious problems and how insanely difficult it is to get through to you.
MileHigh
MH--seek help.
You have gone off the rail's.
Everything has a source MH,and if you do not know the difference between something that is ringing down and resonating,then you will go no further than you are today--which is just junk talk on a forum. An ideal torque can and dose exist in many applications. An ideal talk dose not have to be applied to something that has angular momentum,and so,once again,your definition of an ideal torque was limited,where as my definition covered all situations an ideal torque could be applied to.
I only hope that people here,that want to learn fact from fiction,do not listen to what you have to say. The fact that you cannot put all your !claimed! knowledge into a practical build,and take me on in a small JT build off,just go's to show how little you actually know when it comes to putting your self acclaimed brilliance into action-->i think they call that !being full of hot air!.
Those that have read this thread,and the JT thread,will be starting to get a very good idea as to who you are,and how you work--a man who calls some one very limited in knowledge,but dare not take on that man he accuses of having limited knowledge-->we all know why that is MH ;)
You enjoy your self now MH--i have better things to do with my time.
P.S
Just so you know your attempt at using resound as some sort of proof the wine glass or bell is resonating--here is the definitions of the two
Resonate means "to expand, to intensity, or amplify the sound of,"
Resound means "to throw back, repeat the sound of."
You will see the two have very different meanings.
The bell and the wine glass will not intensify or amplify the sound once they have been struck. They both will decrease in intensity and amplitude once they have been struck,and begin to ring.
Brad
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Brad:
Whether it be an ideal voltage source or an ideal velocity source, these things are just ideas. You seem to be suggesting that there is a "source" that forms part of one of these abstract concepts. There is no point in imagining anything beyond the fact that they simply exist as ideas. Imagining that there is some kind of energy store or energy source that is "feeding" an ideal voltage source is simply ridiculous. They are all just imaginary black boxes.
For the resonance business, there are simply two definitions. There is energy going back and forth resonance, call that "true resonance" if you want. Then there is the resonance that you always talk about.
Now why can't you simply accept that there are two legitimate definitions to the term and they are quite closely related to each other? Both definitions can exist alongside each other. Now why, why is it so hard for you to accept this? Why to you have to refuse the fact that you can say a struck tuning fork is resonating? What is stopping you from accepting that there are two definitions?
Seriously, if you can't simply accept that there are two related definitions for the word "resonance" then you are beyond being off the rails.
There have been countless black comedy and near-insane moments with you on both threads Brad. I am confident that the majority of the readers will recognize who is serious and they will listen to the person that they think is bringing the most sense and value to the table.
MileHigh
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I only hope that people here,that want to learn fact from fiction,do not listen to what you have to say. The fact that you cannot put all your !claimed! knowledge into a practical build,and take me on in a small JT build off,just go's to show how little you actually know when it comes to putting your self acclaimed brilliance into action-->i think they call that !being full of hot air!.
Brad
Like I have mentioned many times in the past, I threw away all my power supplies, 4000 series CMOS chips, TTL chips, LEDs, switches, capacitors, 555 timers and breadboards many years ago, before you even knew what a transistor was.
I couldn't even build and test anything if I wanted to. Even if I was fully equipped and had a nice bench, I still wouldn't build anything useless like you are suggesting. Rewiring a motor to get back spikes or whatever it is you want to do is a useless endeavour.
Beyond all of this, there is another comment for you to ponder. You are very frustrated because you couldn't answer the wine glass questions and you couldn't answer the first question about a power supply and one single component. Note that these are two pretty generic subjects that can be discussed on a forum and it is pretty much a level playing field, the only thing you need to know is some pretty basic physics and electronics knowledge.
To "get back at me" you are challenging me to do something that you have been doing for years and are very familiar with, hacking into motors and watching them spin. You want to "funnel" me into doing something that is in your comfort zone that you have lots of experience with. To make it a fair "build challenge" it would have had to be to build something that neither of us had built before, and see what happens in that case.
You are just trying to make a transparent attempt to stack the dice in your favour, that's what is behind all of your whining to get me to build some useless motor contraption. It's something you do all the time. The whole idea was a non-starter from the very beginning.
My actions are my words on this forum, and that is a level playing field for everyone.
I also found it ironic that I gave you and the other builders a great and fun build challenge - using some supercaps and a pulse motor and a pulley of your own design, see who can build the most efficient system for lifting up a weight. It encompasses real mechanical and electrical design and the output is measurable work. And you had nothing to say, just blank stares.
MileHigh
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author=MileHigh link=topic=16589.msg485958#msg485958 date=1465333973]
MileHigh
Rewiring a motor to get back spikes or whatever it is you want to do is a useless endeavour.
I will only respond this this part of your large ramble.
If only you knew how wrong you are.
But you will never learn that,because like i said--you are to far gone to allow any further education.
The fact that you believe that a PM can do no useful work,is your biggest stumbling block,and your ultimate road to no where.
Brad
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author=MileHigh link=topic=16589.msg485958#msg485958 date=1465333973]
I will only respond this this part of your large ramble.
If only you knew how wrong you are.
But you will never learn that,because like i said--you are to far gone to allow any further education.
The fact that you believe that a PM can do no useful work,is your biggest stumbling block,and your ultimate road to no where.
Brad
Well it's pretty obvious that you can't cope with the fact that there are two perfectly valid definitions for "resonance." The true definition that I am stating and the second "resonant system response" definition that you falsely believe is the only definition. It's the Krazy Glue in your brain that keeps you obsessively stuck to the second definition because accepting the true definition would make your mind snap.
It's a joke that you allege that I am too far gone to allow any further education when you and others were stuck like glue to a limited definition of an ideal voltage source and you practically had to be pried away from your incorrect fixation. I am always willing to learn, and my knowledge means I also have a good functioning BS filter.
Your blind belief that magnets can do useful work results in you doing pulse motor and related experiments and leading yourself down a garden path. It has already happened many times.
The biggie is your famous "rotary transformer." The thought experiment goes like this: You send it to Poynt and within two days max he finds your mistake and then it's all over and time to move on.
MileHigh
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Well it's pretty obvious that you can't cope with the fact that there are two perfectly valid definitions for "resonance." The true definition that I am stating and the second "resonant system response" definition that you falsely believe is the only definition. It's the Krazy Glue in your brain that keeps you obsessively stuck to the second definition because accepting the true definition would make your mind snap.
It's a joke that you allege that I am too far gone to allow any further education when you and others were stuck like glue to a limited definition of an ideal voltage source and you practically had to be pried away from your incorrect fixation. I am always willing to learn, and my knowledge means I also have a good functioning BS filter.
Your blind belief that magnets can do useful work results in you doing pulse motor and related experiments and leading yourself down a garden path. It has already happened many times.
The biggie is your famous "rotary transformer." The thought experiment goes like this: You send it to Poynt and within two days max he finds your mistake and then it's all over and time to move on.
MileHigh
The fact that you base your conclusion that magnets cannot do useful work on what has been seen so far,is proof that you have a closed mind,and simply follow like a sheep.
The second fact is,you do not know what the magnetic force is,and there for cannot make any accurate claims about any sort of potential a magnet has. It is like your trying to claim you know the top speed of a car,without knowing what kind of car it is. You base your assumption on what others have mannaged so far,but they are in the same boat as you-they too have no idea as to what the magnetic force is,and there for-like you,cannot make any accurate conclusion as to what that magnetic force can do.
My offer still stands MH-if you wish to challenge me to a rotoverter build,and see who actually has the better understanding of magnetic fields working in conjunction with inductors, then i will be more than happy to send my device-along with yours,for poynt to judge who's device is more efficient.
You have this in writiing right here.
But we know you will use any excuse under the sun,to avoid going up against me--to scared to take on the man you continuously put down.
Brad
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I reckon I can shift crap faster that MH. and tinman combined can
come up with it.
John.
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I am no sheep and there is going to be no rotorverter showdown at the O.K. Corral. I am not making up an excuse, I am telling you fact. What you learned in this and the other thread is that you have a long way to go up the learning curve with respect to electronics. You can act on that fact or not, it's up to you.
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I have a long way to go with my picture skills too!
John.
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Yep, I am all spent on dishing out crap. However, I have seen 500 times more crap than I dished out.
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I am no sheep and there is going to be no rotorverter showdown at the O.K. Corral. I am not making up an excuse, I am telling you fact.
What you learned in this and the other thread is that you have a long way to go up the learning curve with respect to electronics. You can act on that fact or not, it's up to you.
The best and only way to know who knows what,is by presenting your knowledge in way of an actual real world device. Words mean absolutely nothing at all--actions speak louder than words MH.
Your words will power nothing.
Brad
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Hey milesy
Keep an eye on this thread--you might learn something ;)
http://overunity.com/4612/david-bowlings-continuous-charging-device/msg485976/#new
Brad
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<<< Two batteries in series,and one in parallel,with the inverter in series with the two series batteries,to the parallel battery.The inverter will be run on the potential difference-see schematic below. >>>
I will put on my ring for you: You are driving a 12-volt inverter with three batteries in series, one of them reverse-polarity for net 12 volts to the inverter.
That is just a tired and worn out Houdini "trick" that never made sense in the first place.
Think of it like this:
You have one battery that is doing the work to run the inverter.
Then you have two batteries that cancel each other out. So the first battery charges the second battery. There are internal losses in the first battery to heat as it discharges, which is normal. There are internal losses to heat in the second battery while it charges, which is also normal.
What are the implications?
One battery is running the inverter like normal and the other two batteries do nothing except produce waste heat for no reason whatsoever.
For some reason people think that this is somehow going to give them "Houdini magic" when all it does is uselessly exercise two batteries that would be better off just sitting on a shelf waiting for their turn to drive the 12-volt inverter.
It's fool's gold that makes no sense thanks to the Cult of Houdini. But I know that you like doing this stuff and you have a new project to play with. It will never outperform three separate batteries attached to the inverter, one after the other.
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author=MileHigh link=topic=16589.msg485984#msg485984 date=1465381150]
<<< Two batteries in series,and one in parallel,with the inverter in series with the two series batteries,to the parallel battery.The inverter will be run on the potential difference-see schematic below. >>>
I will put on my ring for you: You are driving a 12-volt inverter with three batteries in series, one of them reverse-polarity for net 12 volts to the inverter.
Think of it like this:
That is just a tired and worn out Houdini "trick" that never made sense in the first place.
I agree.
You have one battery that is doing the work to run the inverter.
Then you have two batteries that cancel each other out. So the first battery charges the second battery. There are internal losses in the first battery to heat as it discharges, which is normal. There are internal losses to heat in the second battery while it charges, which is also normal.
I agree
What are the implications?
One battery is running the inverter like normal and the other two batteries do nothing except produce waste heat for no reason whatsoever.
I agree.
For some reason people think that this is somehow going to give them "Houdini magic" when all it does is uselessly exercise two batteries that would be better off just sitting on a shelf waiting for their turn to drive the 12-volt inverter.
I agree.
It's fool's gold that makes no sense thanks to the Cult of Houdini. But I know that you like doing this stuff and you have a new project to play with. It will never outperform three separate batteries attached to the inverter, one after the other.
I agree.
Brad
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Brad:
A final thought popped into my head about this resonance definition nonsense.
You go on and on about how the definition of "resonance" is only when an external driving force at the resonant frequency produces an increased amplitude response from the object that is resonating. According to you that is the "only" definition of resonance. You have probably insisted that this is the only definition for resonance about 30 times now.
Well, what about your ICE business that you have repeated about 75(?) times now?
The air intake resonance is simply a one-shot Helmholtz resonator that is repeatedly "primed" by the moving piston sucking in air. It has nothing at all to do with your "increased amplitude resonant system response" definition of resonance.
The extra resonant cavity in the piston cavity is there to set up a pressure shock wave that is opposite to the pressure shock wave that occurs when the fuel explodes. This causes wave cancellation which ensures a better and smoother compression cycle on the piston. This is another from of resonant response to a one-shot impulse that is repeated over and over. One more time this has absolutely nothing to do with your "increased amplitude resonant system response" definition of resonance.
So here you are pushing "MileHigh you were ignorant and knew nothing about resonance improving the efficiency of an ICE" and it doesn't even meet your definition of resonance.
MileHigh
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Brad:
A final thought popped into my head about this resonance definition nonsense.
You go on and on about how the definition of "resonance" is only when an external driving force at the resonant frequency produces an increased amplitude response from the object that is resonating. According to you that is the "only" definition of resonance. You have probably insisted that this is the only definition for resonance about 30 times now.
Well, what about your ICE business that you have repeated about 75(?) times now?
The air intake resonance is simply a one-shot Helmholtz resonator that is repeatedly "primed" by the moving piston sucking in air. It has nothing at all to do with your "increased amplitude resonant system response" definition of resonance.
The extra resonant cavity in the piston cavity is there to set up a pressure shock wave that is opposite to the pressure shock wave that occurs when the fuel explodes. This causes wave cancellation which ensures a better and smoother compression cycle on the piston. This is another from of resonant response to a one-shot impulse that is repeated over and over. One more time this has absolutely nothing to do with your "increased amplitude resonant system response" definition of resonance.
So here you are pushing "MileHigh you were ignorant and knew nothing about resonance improving the efficiency of an ICE" and it doesn't even meet your definition of resonance.
MileHigh
No MH
Resonance is a maintained maximum amplitude in one object that was induced by another vibrating object at the same natural frequency. You will note that in your example,that each shot !as you call it!,of vibration in the air intake chamber,is a direct result of the stroke of the piston that caused it.
In a four stroke engine,that is every fourth stroke,and in a 2 stroke engine,that is every second stroke. So on the inlet side,every intake stroke results in 1 vibration of the resonant chamber,and this is also true for the exhaust side as well.
The expansion chamber on the exhaust will resonate at a set RPM,and it's frequency of resonation will be exactly that of the exhaust stroke frequency of the engine.
The expansion chamber will not resonate without the piston driving the exhaust gases into it at the correct frequency.
It would also seem that i may have to retract some or all of my !!i agree!! statements from my previous reply,as some early experimenting seems to indicate that what you said is not correct,and that the 3 battery system is more efficient at running the inverter,than one single battery.
Brad
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No MH
Resonance is a maintained maximum amplitude in one object that was induced by another vibrating object at the same natural frequency. You will note that in your example,that each shot !as you call it!,of vibration in the air intake chamber,is a direct result of the stroke of the piston that caused it.
In a four stroke engine,that is every fourth stroke,and in a 2 stroke engine,that is every second stroke. So on the inlet side,every intake stroke results in 1 vibration of the resonant chamber,and this is also true for the exhaust side as well.
The expansion chamber on the exhaust will resonate at a set RPM,and it's frequency of resonation will be exactly that of the exhaust stroke frequency of the engine.
The expansion chamber will not resonate without the piston driving the exhaust gases into it at the correct frequency.
I am assuming that you are only discussing the air intake/exhaust, but you are not discussing the combustion chamber resonance. Is that correct?
The simple fact of the matter is that the combustion chamber resonance is essentially the same thing as the striking of a tuning fork resonance. Since you refuse to accept that a struck tuning fork is resonating, then you are screwed because you have been saying the whole time that there is resonance in the combustion chamber of a cylinder.
What you say above is just a word salad in a desperate attempt to massage the meaning to fit into your definition of resonance. The air intake is a one-shot Helmholtz resonator that has a time constant associated with it. You have a fixed time constant where the engine designers find the best compromise timing to match with the variable cycle frequency of the engine.
The expansion chamber on the exhaust will resonate at a set RPM,and it's frequency of resonation will be exactly that of the exhaust stroke frequency of the engine.
The expansion chamber will not resonate without the piston driving the exhaust gases into it at the correct frequency.
Your statements are bull crap, see what I say above. The speed of the engine is variable so what you are saying does not make sense.
So that's two strikes Brad. If you are going to stick to your nonsense then you are just back in brain fry territory.
The best thing you could do is admit that you are wrong, and admit that there are two perfectly good definitions for resonance and not just one. Then all of your statements about the ICE will not be self-contradictory and they will make sense.
MileHigh
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author=MileHigh link=topic=16589.msg486023#msg486023 date=1465446170]
MileHigh
I am assuming that you are only discussing the air intake/exhaust, but you are not discussing the combustion chamber resonance. Is that correct?
It is the expanding and contracting gases in the combustion chamber that is the source for the inlet and exhaust resonant effects.
The simple fact of the matter is that the combustion chamber resonance is essentially the same thing as the striking of a tuning fork resonance.
http://overunity.com/8341/joule-thief-101/510/#.V1kJ69R95kg
Quote post 514--No, an ICE doesn't resonate in any way, shape or form whatsoever.
post 519-same thread---It's all moot because we are not talking about ICEs except to state that they have nothing to do with resonance.
post 523--same thread--Do you get that? There is true mechanical resonance and it has nothing whatsoever to do with tuning a gas engine and the operating parameters of an engine.
post 540--Presumably the engine operates better, the timing is better, the gasses move in and out of the cylinders more efficiently - but that is NOT RESONANCE like a wine glass resonates by a long shot.
post 544--Your lack of use of language or your abuse of language is ridiculous sometimes. And the fact still remains that we are not talking about an ICE and none of what you are saying about an ICE meets the scientific definition of resonance.
And so on
Are you now changing your mind MH,and saying that an ICEs combustion chamber resonates like you think a tuning fork dose?.
Since you refuse to accept that a struck tuning fork is resonating, then you are screwed because you have been saying the whole time that there is resonance in the combustion chamber of a cylinder.
No i have not. The combustion process is what gives rise to the resonant systems around the ICE--E.G the exhaust and inlet resonant systems,and so the the combustion chambers actions are in resonance with the inlet and exhaust resonant systems.
What you say above is just a word salad in a desperate attempt to massage the meaning to fit into your definition of resonance. The air intake is a one-shot Helmholtz resonator that has a time constant associated with it.
That is correct,and that time constant must be in tune with the combustion chambers actions before it will resonate. At the correct RPM,the intake resonator and combustion chamber reach a resonant state,and the intake resonator will begin to resonate.
Why do you not understand how this works,and why the inlet and exhaust chambers are called !resonant! chambers?.
You have a fixed time constant where the engine designers find the best compromise timing to match with the variable cycle frequency of the engine.
And here you have answered half of your question on your own,but yet do not understand as to how or why it is called a resonator,and how it is able to resonate.
Your statements are bull crap, see what I say above. The speed of the engine is variable so what you are saying does not make sense.
Quote post 531 on the JT thread
Quote:--Indeed, for just about any gas engine there is a power band. It's maximum horsepower out vs. engine RPM.
MH
I would suggest at this point in time,that you go and study how these resonant systems work around the ICE. The two stroke engine would be your best starting point. Learn why the exhaust expansion chamber resonates,learn when it will resonate,and learn as to how this effects the engines output power and efficiency. You will then not make a statement like quoted above,and them claim my statements are bullcrap,as the engine has a wide rev range.
I am at a loss as to why this is so hard for you to understand.
First this-->The speed of the engine is variable so what you are saying does not make sense
Then this-->Indeed, for just about any gas engine there is a power band. It's maximum horsepower out vs. engine RPM
The power band is the RPM range where the resonant systems kick in,and maximum HP is delivered--The very same as reaching the correct frequency of input pulses into a tank circuit,where that tank circuit go's into resonance,and maximum amplitude is gained.
How can you not associate this action with a simple tank circuit?.
The cylinder/piston combo is your inductor,the exhaust expansion chamber is your capacitor,and the explosions of fuel inside the cylinder are your input pulses of energy. When the correct frequency of these explosions is reached,then the system(cylinder/piston,and expansion chamber)go into resonance,where maximum amplitude is reached--maximum HP output is gained.In most high performance two stroke engines,this resonant frequency can be 200 to 300 RPM wide,unlike your electrical tank circuit,which will have a much more definitive frequency range in order to be in the resonant frequency range.
So that's two strikes Brad. If you are going to stick to your nonsense then you are just back in brain fry territory.
MH
Unfortunately the brainfry is once again on you,due to your lack of understanding about how resonant systems work around the ICE.
Post 531 on the JT thread--Quote: The point being that it is a sweet spot and not "resonance" in the engineering mechanical or electrical sense.
Im sorry MH,but that !!sweet spot!! is at the resonant frequency of the resonant systems around the ICE.
The best thing you could do is admit that you are wrong, and admit that there are two perfectly good definitions for resonance and not just one. Then all of your statements about the ICE will not be self-contradictory and they will make sense.
First of all,none of my statements about the ICE are contradictory,nor will you find any that are.
Second,you will note that no resonance at all will happen without there being an input energy pulse at the correct frequency acting upon the resonator.
MH
You really do need to get your self sorted out,and understand things before posting rubbish,such as you just did here.
Brad
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Brad:
Are you now changing your mind MH,and saying that an ICEs combustion chamber resonates like you think a tuning fork dose?.
So you have gone into full brain fry mode and are asking me if I am "now changing my mind?" The combustion chamber resonance process was always an impulse-initiated process, even if I never explicitly used a tuning fork as an analogy for it. You are back in the bloody Twilight Zone Brad. Stating for the 76th time that I got it wrong about the resonance and ICE business is just more of the sizzling brain fry.
Also, for the combustion chamber resonance process, I am oversimplifying when I say "tuning fork analogy." From that Google book reference you linked to, they said a small resonant chamber was hollowed out in the top of the cylinder head to resonate from the combustion and set up a temporary standing wave that would be equal and opposite to the standing wave set up by the combustion process itself. Therefore there would be no regions of high and low density anymore and you would get a better fuel burn with a more even pressure stroke put onto the cylinder. That is not exactly a "tuning fork" but there is a resonance/anti resonance process taking place. Also, for what it's worth, I doubt this extra resonant chamber stuff is done in a modern ICE with four valves per cylinder and sometimes two separate spark plugs simply because in a modern high tech engine there are no undesirable combustion standing wave effects that need to be counteracted.
No i have not. The combustion process is what gives rise to the resonant systems around the ICE--E.G the exhaust and inlet resonant systems,and so the the combustion chambers actions are in resonance with the inlet and exhaust resonant systems.
Now you are getting all scrambled up and mushing everything together into one description. The combustion process is responsible for the resonance in the combustion chamber itself after ignition. The moving piston that draws air in and pushes the exhaust gasses out cause the Helmholtz resonator processes for the air inlet and exhaust gas outlet. That's three separate and distinct resonance processes.
At the correct RPM,the intake resonator and combustion chamber reach a resonant state,and the intake resonator will begin to resonate.
But there is no such thing as a "correct RPM" for an engine, the RPM is variable. But I do understand how you stated there is range of RPMs where the effects are all independently working, and as result you get a nice band were the engine RPM is "sweeter" and the engine works the best. Again, my point is that these are three separate ping-like events causing three resonance processes giving you an overall improved engine performance through multiple resonance effects all acting at the same time.
Why do you not understand how this works,and why the inlet and exhaust chambers are called !resonant! chambers?
Yes they are called resonant chambers, but they have nothing to do with your narrow-minded and restricted personal definition of resonance. Likewise the anti-resonant system in the cylinder itself that kicks in after the gas vapor explosion has nothing to do with your narrow-minded and restricted personal definition of resonance. And that is the key point.
The power band is the RPM range where the resonant systems kick in,and maximum HP is delivered
Yes I agree that there will be a power band where the resonant systems for the air inlet and exhaust outlet kick in. And the reason that there is a power band is because the cylinder drawing air in and then the valve closing is kind of like a "ping" or impulse event when the closed valve causes the inlet air to suddenly redirect to the Helmholtz resonator chamber. A similar process takes place on the exhaust gas outlet side although I think it's a stretch to call that one resonance.
But here is the key point: The air inlet and exhaust gas outlet resonance processes are initiated by what can loosely be called a ping or impulse event. So that means the resonance effect has nothing to do with the engine RPM, but more importantly the resonance effect has nothing to do with your narrow-minded and restricted personal definition of resonance at all.
And again, when the fuel ignition takes place in the cylinder itself, that is absolutely a ping or impulse event, and again that has nothing to do with your narrow-minded and restricted personal definition of resonance.
So in very general terms, we can say that all three resonance effects in the ICE are initiated by discrete ping or impulse events. That is akin to striking a wine glass or striking a tuning fork. That is why there are resonance effects over a range of engine RPMs, they are all initiated by ping-like events and have nothing to do with the engine RPM, and they have nothing to do with your definition of resonance at all.
So you are up a creek without a paddle.
The cylinder/piston combo is your inductor,the exhaust expansion chamber is your capacitor,and the explosions of fuel inside the cylinder are your input pulses of energy. When the correct frequency of these explosions is reached,then the system(cylinder/piston,and expansion chamber)go into resonance,where maximum amplitude is reached--maximum HP output is gained.In most high performance two stroke engines,this resonant frequency can be 200 to 300 RPM wide,unlike your electrical tank circuit,which will have a much more definitive frequency range in order to be in the resonant frequency range.
Really? Well for starters Brad like I said you can't just mush three separate and distinct types of resonance events all into one general statement. That makes no sense at all. Break it down into three separate things and let's see how you do identifying the mathematical model for each one.
Unfortunately the brainfry is once again on you,due to your lack of understanding about how resonant systems work around the ICE.
Read above and see how it is your lack of understanding.
First of all,none of my statements about the ICE are contradictory,nor will you find any that are.
None of them would be contradictory if you could bring yourself to admit that the resonance effects in the ICE are initiated by ping events and in that sense they are essentially the same as saying that a tuning fork resonates when you strike it.
https://en.wikipedia.org/wiki/Tuning_fork (https://en.wikipedia.org/wiki/Tuning_fork)
A tuning fork is an acoustic resonator in the form of a two-pronged fork ... It resonates at a specific constant pitch when set vibrating by striking it against a surface ...
So are you going to get real and simply admit that your narrow-minded and restricted definition of resonance was wrong or are you just going to sizzle and steam off into the sunset?
MileHigh
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=MileHigh link=topic=16589.msg486032#msg486032 date=1465466286]
MileHigh
So you have gone into full brain fry mode and are asking me if I am "now changing my mind?" The combustion chamber resonance process was always an impulse-initiated process, even if I never explicitly used a tuning fork as an analogy for it. You are back in the bloody Twilight Zone Brad. Stating for the 76th time that I got it wrong about the resonance and ICE business is just more of the sizzling brain fry.
It's nothing like that MH,and you know i am quoting the truth--they are your quote's.
First you argue with myself and others,that there is no resonance what so ever associated with an ICE,and now your trying to justify your resonance theory by saying that the resonance in the combustion chamber is the same thing as a tuning fork resonating.
It is very clear how you go against your own beliefs when the need to be correct kicks in for you.
It is clear as day,that on one thread you claim that there is no resonance what so ever associated with an ICE,and now,here in this thread,you seem to think the combustion chamber is resonating like a tuning fork-->what planet are you on?
Now you are getting all scrambled up and mushing everything together into one description. The combustion process is responsible for the resonance in the combustion chamber itself after ignition. The moving piston that draws air in and pushes the exhaust gasses out cause the Helmholtz resonator processes for the air inlet and exhaust gas outlet. That's three separate and distinct resonance processes.
Im getting scrambled up ???. Your the one changing his mind about resonant systems around an ICE to suit his needs--not me. I tried to tell you about resonant systems associated with ICEs,but you denied it left,right,and center,and called me all sorts of names under the sun. But now--now you want to use this !combustion chamber! resonance to try and justify your resonance claim,by saying that this resonance in the combustion chamber is like that of a tuning fork.
Get serious MH ::)
But there is no such thing as a "correct RPM" for an engine, the RPM is also variable.
MH--you have much to learn.
To give you an example. The 1990 Honda CR 250 in stock trim would punch out 49HP between 7900RPM,and 8600RPM. This is the correct RPM for maximum power.
Yes they are called resonant chambers, but they have nothing to do with your narrow-minded and restricted personal definition of resonance. Likewise the anti-resonant system in the cylinder itself that kicks in after the gas vapor explosion has nothing to do with your narrow-minded and restricted personal definition of resonance. And that is the key point.
They work exactly the same as my resonance description,where the driving force pulses are at the correct frequency to the resonant chambers natural frequency.
Your confusion here lies in the fact that you really have no idea as to how there could be such a wide RPM range where this resonance can exist,as you think everything has a very specific resonant frequency.
Go and do some research MH,and see if you can work out how there can exist such a wide frequency range for such resonant systems around the ICE.
Yes I agree that there will be a power band where the resonant systems for the air inlet and exhaust outlet kicks in. And the reason that there is a power band is because the cylinder drawing air in and then the valve closing is kind of like a "ping" or impulse event when the closed valve causes the inlet air to suddenly redirect to the Helmholtz resonator chamber. A similar process takes place on the exhaust gas outlet side although I think it's a stretch to call that one resonance.
MH,you are all over the place with rag doll descriptions and fumblings--you need to go and do some research if you wish to play ICEs.
First up,it is the exhaust that dose most of the efficiency increases through resonance--not the inlet. The inlet side of things has very little to do with power increases in ICEs,especially in four stroke engines. Some two stroke engines made use of the Helmholtz resonator chamber effect,and this was called the energy induction system-or EIS. This was used mainly by yamaha,on all there DT and IT range bikes.
But here is the key point: The air inlet and exhaust gas outlet resonance processes are initiated by what can loosely be called a ping or impulse event. So that means the resonance effect has nothing to do with the engine RPM, but more importantly the resonance effect has nothing to do with your narrow-minded and restricted personal definition of resonance at all.
It is funny you say that there needs to be a !ping! or !impulse event to causes this resonance effect--seems to be exactly what i am saying,where there needs to be a continual input pulse of energy into the resonator in order for it to resonate. You really do need to go and learn how resonators work on ICEs first,then come back and play shop with me,because ATM,you are just fumbling all over the place.
And again, when the fuel ignition takes place in the cylinder itself, that is absolutely a ping or impulse event, and again that has nothing to do with your narrow-minded and restricted personal definition of resonance.
Isnt it odd that there has to be this ignition of fuel(energy) for every one of your !pings! to take place. How many pings would there be without this ignition of fuel(energy)?.
So in very general terms, we can say that all three resonance effects in the ICE are initiated by discrete ping or impulse events. That is akin to striking a wine glass or striking a tuning fork.
MH-you are that messed up,that it's not even funny.
The resonant frequency of the exhaust when that resonator is resonating,is exactly the same as the engine RPM-for every single ping--there is a pong out the exhaust :D
You can measure the engine RPM of a two stroke,using a microphone near the exhaust,and a scope. The frequency shown on the scope will be your engine RPM.
That is why there are resonance effects over a range of engine RPMs, they are all initiated by ping-like events and have nothing to do with the engine RPM, and they have nothing to do with your definition of resonance at all.
You are a funny man MH--your good for a laugh at least lol.
As i said above,engine RPM is directly related to the frequency at the exhaust resonant chamber.
Like i said,you need to go and do some research on why this resonance can be maintained over a wide range of RPMs,and that resonance will be at the same frequency as the engine RPM
So you are up a creek without a paddle.
No MH--you have fell in the creek,and drowned.
If you want to talk ICEs with me,then go and learn something about how all these systems work first--then we can talk shop.
Really? Well for starters Brad like I said you can't just mush three separate and distinct types of resonance events all into one general statement.
All three effects come into play at the same time,and this gives rise to the resonant systems around the ICE at given RPMs--the power band.
That makes no sense at all. Break it down into three separate things and let's see how you do identifying the mathematical model for each one.
MH
It is clearly evident that it is you that needs to go and do some learning--i have been doing it for over 35 years now,and i do know what i am talking about when it comes to resonant effects around high performance engines,as this is my life.
Start with the 2 stroke engine MH,as this would be the easiest for you to understand,as most of the work is done by the exhaust expansion chamber.
Start there,and you will then see how there can be such a wide rev range,while being able to maintain resonance between the exhaust resonance chamber,and the cycles of the engine.
Read above and see how it is your lack of understanding.
The fact that you do not understand as to how the rev range can vary so much,while still maintaining resonance,is a clear indication that you need some education on how these resonant systems work around the ICE.
None of them would be contradictory if you could bring yourself to admit that the resonance effects in the ICE are initiated by ping events and in that sense there are essentially the same as saying that a tuning fork resonates when you strike it.
MH,there is only one ping event for every cycle(every vibration) of the resonant chamber,and that one ping event is the ignition of the gas mix inside the cylinder. As soon as the gas mix is stopped from igniting,there is no more resonance from the resonance chamber--no ping,no resonance.
So are you going to get real and simply admit that your narrow-minded and restricted definition of resonance was wrong or are you just going to sizzle and steam off into the sunset?
Not likely MH,as it is clear from your post,that you have no idea as to what you are talking about.
First go and learn as to how resonance can be maintain over a wide rang of RPM with a 2 stroke engine,then we can talk shop.Once you have done that,then your questions will start to answer them self,but i will be here in case you get stuck.
Brad
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THE WHOLE UNIVERSE IS IN RESONANCE IF IT WAS NOT,
IT WOULD HAVE NEVER EXISTED..
AND THE GLUE GOO THAT HOLD IT IN RESONANCE IS LUVE.
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Brad:
For starters enough of the insanity about challenging me on "being a new convert" to ICE resonance. When you showed me the right information I admitted that I was wrong right away and that was months ago. So why are you saying ridiculous things like "First you argue with myself and others,that there is no resonance what so ever associated with an ICE,and now your trying to justify your resonance theory by saying that the resonance in the combustion chamber is the same thing as a tuning fork resonating."
Why are you ridiculously spinning like this? I also edited my previous posting to state that it's a bit of a stretch to model the combustion chamber resonance like striking a tuning fork, that's too simple. It's more of an anti standing wave process, which is really a three-dimensional resonant tuning cavity process.
I fully realize that you have a lifetime's worth of working with engines and you are an expert with them. But what you don't have is a deeper and fundamental level of insight that a scientific or engineering education can give you. For example, you could not answer the two questions about the wine glass and you were not even close. Likewise, you were unable to come up with the simplified equivalent circuit/mathematical model for something as basic as a bell or a tuning fork. Nor could you visualize in your mind how they resonate.
Like it or not, even though the engine has an RPM range where the resonance effects are doing their magic and giving you better performance, it is not directly related to the RPM of the engine itself. Each of the three resonant effects are a ping-like event where the ping initiates a resonant response. That is loosely comparable to striking a tuning fork.
Like it or not, your personal definition for resonance does not apply, because the resonance effects in the ICE are not directly tied into the engine RPM acting as a periodic stimulus resulting in an enhanced resonant response from the resonating element.
They work exactly the same as my resonance description,where the driving force pulses are at the correct frequency to the resonant chambers natural frequency.
No, absolutely not. You are back to trying to put a square peg into a round hole because you would nearly have a nervous breakdown to admit that you are wrong. In this case I am the "little guy" and you are the "big guy" and the little guy is teaching the big guy because the big guy with all of his 35 years of mechanical experience with ICE's, still was unable to identify how a bell can resonate and visualize and create the mathematical model for it. Like it or not, these are facts.
It's the driving force pulses themselves that elicit the resonant responses in the ICE that cause improved performance in the ICE, and NOT the correct frequency of the driving force pulses.
The resonant chamber frequency in the combustion chamber has nothing to do with the frequency of the driving force pulses due to the engine RPM, nothing.
The one-shot resonant response of the intake Helmholtz resonator will be amenable to a certain frequency range of the driving force pulses due to the engine RPM, but when you really understand what is going on, the two things are actually decoupled from each other.
The one-shot resonant response of the exhaust gas expansion chamber quasi Helmholtz resonator will be amenable to a certain frequency range of the driving force pulses due to the engine RPM, but when you really understand what is going on, the two things are decoupled from each other.
So your narrow-minded definition of resonance does not apply to the ICE, even though an ICE will operate better through some forms of resonance.
First go and learn as to how resonance can be maintain over a wide rang of RPM with a 2 stroke engine
I understand that as clear as a bell.
So one more time, all of your problems will go away if you can simply admit the following is true and there are two definitions for resonance:
A tuning fork is an acoustic resonator in the form of a two-pronged fork ... It resonates at a specific constant pitch when set vibrating by striking it against a surface ...
The little guy is talking, and if you were wise you would listen. You will not have a nervous breakdown if you admit that you were wrong with the limited definition of resonance that you are currently stuck to like a fly on flypaper.
MileHigh
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Brad:
Don't be an old dog, you can learn some new tricks.
Look at this clip, you will see an amazing ping-initiated RESONATOR in action that actually has a resonant frequency that is a function of time. Talk about a mind blowing brain bender, eh? A resonant frequency that changes in time? Go check the rule books.
https://www.youtube.com/watch?v=TXxVA2idyL0
It's not a bloody "natural frequencyerator," it's a bloody RESONATOR.
MileHigh
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Brad:
Look at this clip, you will see an amazing ping-initiated RESONATOR in action that actually has a resonant frequency that is a function of time. Talk about a mind blowing brain bender, eh? A resonant frequency that changes in time? Go check the rule books.
https://www.youtube.com/watch?v=TXxVA2idyL0
It's not a bloody "natural frequencyerator," it's a bloody RESONATOR.
MileHigh
Don't be an old dog, you can learn some new tricks.
MH,i am not the one that needs to learn here,in regards to the resonant effects surrounding an ICE.
Talk about a mind blowing brain bender, eh? A resonant frequency that changes in time? Go check the rule books.
If you are saying that a resonant frequency cannot change in time in regards to the ICE issue we are discussing,then you had better go and do some research,and begin to understand how the resonant chamber on the exhaust of the 2 stroke ICE can indeed change with time,and why the resonance can continue over a wide range or RPM.
If you do not think that the resonant frequency of the expansion chamber can change,without physically changing the shape of the resonant chamber,then you do have much to learn.
I can tell you in one short post how this is achieved,but you need to do some learning of your own.
If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change? ;)
Brad
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Brad:
For starters enough of the insanity about challenging me on "being a new convert" to ICE resonance. When you showed me the right information I admitted that I was wrong right away and that was months ago. So why are you saying ridiculous things like "First you argue with myself and others,that there is no resonance what so ever associated with an ICE,and now your trying to justify your resonance theory by saying that the resonance in the combustion chamber is the same thing as a tuning fork resonating."
Why are you ridiculously spinning like this? I also edited my previous posting to state that it's a bit of a stretch to model the combustion chamber resonance like striking a tuning fork, that's too simple. It's more of an anti standing wave process, which is really a three-dimensional resonant tuning cavity process.
I fully realize that you have a lifetime's worth of working with engines and you are an expert with them. But what you don't have is a deeper and fundamental level of insight that a scientific or engineering education can give you. For example, you could not answer the two questions about the wine glass and you were not even close. Likewise, you were unable to come up with the simplified equivalent circuit/mathematical model for something as basic as a bell or a tuning fork. Nor could you visualize in your mind how they resonate.
Like it or not, even though the engine has an RPM range where the resonance effects are doing their magic and giving you better performance, it is not directly related to the RPM of the engine itself. Each of the three resonant effects are a ping-like event where the ping initiates a resonant response. That is loosely comparable to striking a tuning fork.
Like it or not, your personal definition for resonance does not apply, because the resonance effects in the ICE are not directly tied into the engine RPM acting as a periodic stimulus resulting in an enhanced resonant response from the resonating element.
No, absolutely not. You are back to trying to put a square peg into a round hole because you would nearly have a nervous breakdown to admit that you are wrong. In this case I am the "little guy" and you are the "big guy" and the little guy is teaching the big guy because the big guy with all of his 35 years of mechanical experience with ICE's, still was unable to identify how a bell can resonate and visualize and create the mathematical model for it. Like it or not, these are facts.
It's the driving force pulses themselves that elicit the resonant responses in the ICE that cause improved performance in the ICE, and NOT the correct frequency of the driving force pulses.
The resonant chamber frequency in the combustion chamber has nothing to do with the frequency of the driving force pulses due to the engine RPM, nothing.
The one-shot resonant response of the intake Helmholtz resonator will be amenable to a certain frequency range of the driving force pulses due to the engine RPM, but when you really understand what is going on, the two things are actually decoupled from each other.
The one-shot resonant response of the exhaust gas expansion chamber quasi Helmholtz resonator will be amenable to a certain frequency range of the driving force pulses due to the engine RPM, but when you really understand what is going on, the two things are decoupled from each other.
So your narrow-minded definition of resonance does not apply to the ICE, even though an ICE will operate better through some forms of resonance.
I understand that as clear as a bell.
So one more time, all of your problems will go away if you can simply admit the following is true and there are two definitions for resonance:
A tuning fork is an acoustic resonator in the form of a two-pronged fork ... It resonates at a specific constant pitch when set vibrating by striking it against a surface ...
The little guy is talking, and if you were wise you would listen. You will not have a nervous breakdown if you admit that you were wrong with the limited definition of resonance that you are currently stuck to like a fly on flypaper.
MileHigh
MH
I am not sure how many times i have to tell you this,but the way i define resonance is exactly how the resonant systems around the ICE work--for every explosion in the cylinder at the correct frequency(correct RPM),the resonant chamber will also resonate at that same frequency. If there is no explosion in the cylinder,then the resonant chamber will not resonate. It is exactly like i have been saying it is,for resonance to exist,there needs to be an input pulse that is the same frequency,or a multiple of the actual resonant frequency of the resonant chamber. Resonance is an interaction between the two--the resonant chamber will not resonate without this continual input pulse of energy at the resonant frequency.
Brad
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If you are saying that a resonant frequency cannot change in time in regards to the ICE issue we are discussing,then you had better go and do some research,and begin to understand how the resonant chamber on the exhaust of the 2 stroke ICE can indeed change with time,and why the resonance can continue over a wide range or RPM.
If you do not think that the resonant frequency of the expansion chamber can change,without physically changing the shape of the resonant chamber,then you do have much to learn.
I can tell you in one short post how this is achieved,but you need to do some learning of your own.
If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change? ;)
Brad
I am not going to look anything up, but I think in some engines they simply change the length of the exhaust expansion chamber to match the engine RPM. That's to ensure a synchronicity between the piston pulse rate to empty the exhaust gasses and the tuned expansion chamber helping suck the exhaust gasses out of the cylinder, but it is not resonance. It might be called a tuned exhaust port or a variable tuned exhaust port or something like that but it is not resonance.
If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change?
I know what you are trying to say but it's still bloody annoying because we are primarily discussing electronics and inductors do not resonate all by themselves.
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MH
I am not sure how many times i have to tell you this,but the way i define resonance is exactly how the resonant systems around the ICE work--for every explosion in the cylinder at the correct frequency(correct RPM),the resonant chamber will also resonate at that same frequency. If there is no explosion in the cylinder,then the resonant chamber will not resonate. It is exactly like i have been saying it is,for resonance to exist,there needs to be an input pulse that is the same frequency,or a multiple of the actual resonant frequency of the resonant chamber. Resonance is an interaction between the two--the resonant chamber will not resonate without this continual input pulse of energy at the resonant frequency.
Brad
For starters, you are going to have to have the intellectual capacity to make a distinction between "motor shop talk resonance" and the resonance we have been discussing this whole time. So this sentence, "the way i define resonance is exactly how the resonant systems around the ICE work" is an absolute non-starter.
Like it or not, resonance is the exchange of energy back and forth in a system between two forms. Typical examples would be between a capacitor and an an inductor, or a moving mass and a spring. Of course, what I just said is something you are currently completely blind to for some strange and inexplicable reason. You want to insist that resonance is just the observation of an increased response of a resonant system to an external stimulus at the resonant frequency. That is an acceptable second definition for resonance, but to claim that it is the only definition like you are insisting is completely and totally ridiculous.
And now it would seem you want to "squeeze in" a new definition for resonance, which is some kind of "motor shop talk resonance" which has nothing to do with an energy exchange back and forth between two components like a moving mass and a spring, and that simply will not fly and is totally unacceptable.
for every explosion in the cylinder at the correct frequency(correct RPM),the resonant chamber will also resonate at that same frequency.
NO, when there is an explosion in the cylinder, that impulse of energy sets up a resonant standing wave pattern inside the cylinder cavity that is deemed undesirable, and so a secondary resonant cavity is set up in the cylinder to counteract that. That standing wave resonance will happen at its own unique frequency. That is in no way, shape or form, "resonating at the same frequency of the explosion."
Resonance is an interaction between the two--the resonant chamber will not resonate without this continual input pulse of energy at the resonant frequency.
No resonance is not an interaction between the two. The explosion initiates a separate and distinct resonant standing wave in the cylinder cavity. The resonance is the resonance in the cavity itself, and not the explosion.
Moving on to the Helmholtz resonators, they just respond to an impulse stimulus and that's it. The frequency of the stimulus is irrelevant. The "resonance like" effect in the Helmholtz resonator is that gasses rush into the resonator chamber, and that is a moving mass. Then the chamber itself acts like a spring. That is the resonance - moving air as a moving mass and air in the chamber acting like a spring. That has nothing whatsoever to do with the impulse that initiated the event or the frequency of the impulse that initiated the event.
Note also that there is not really any cycling back and forth of the same energy as you have in true resonance. It's a one-shot process, kinetic energy goes in, gets stored temporally as potential energy, and then the air leaves, and then new air rushes into the Helmholtz resonator chamber. Even though the same energy and same mass is not cycling back and forth like there is in true resonance, the principles at play are essentially the same.
So when you mistakenly talk about the air inlet and the exhaust gas outlet being "in resonance" with the cylinder explosions, then what is it really? It's certainly not resonance even if the boys in the shop call it "resonance" in their own "shop talk" language. With respect to the cylinder explosions and the input and output ports, there is no cycling of energy back and forth between two forms so it is not resonance.
Here is what it really is: There is a nice synchronicity between the cylinder explosions and the Helmholtz resonators pushing air into the cylinder and then also sucking exhaust gasses out of the cylinder. The fact that the cycle times for the Helmholtz resonators line up with the cylinder timing to make gas move into and out of the cylinder more efficiently is great but it is not resonance. The resonance is in the Helmholtz resonators themselves. What it really is is the Helmholtz resonators act as timing elements in the operation of the engine to ensure that the engine runs synchronously.
Here is the synchronous operation of the engine as a sequence of timing events one after the other: 1) push air into the cylinder, 2) explosion, 3) suck exhaust gasses out of the cylinder. This is a nice advantageous synchronous operation facilitated by the actions of the Helmholtz resonators that makes the engine run better but it is not resonance. There is no resonant cycling of energy back and forth in two forms in steps 1, 2, and 3 which is the true signature for resonance.
All that being said, if you would just accept that a tuning fork resonates, then you could accept that the Helmholtz resonators resonate all by themselves without having anything to do with the cylinder explosions and then you would be fine.
MileHigh
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For starters, you are going to have to have the intellectual capacity to make a distinction between "motor shop talk resonance" and the resonance we have been discussing this whole time. So this sentence, "the way i define resonance is exactly how the resonant systems around the ICE work" is an absolute non-starter.
Like it or not, resonance is the exchange of energy back and forth in a system between two forms. Typical examples would be between a capacitor and an an inductor, or a moving mass and a spring. Of course, what I just said is something you are currently completely blind to for some strange and inexplicable reason. You want to insist that resonance is just the observation of an increased response of a resonant system to an external stimulus at the resonant frequency. That is an acceptable second definition for resonance, but to claim that it is the only definition like you are insisting is completely and totally ridiculous.
And now it would seem you want to "squeeze in" a new definition for resonance, which is some kind of "motor shop talk resonance" which has nothing to do with an energy exchange back and forth between two components like a moving mass and a spring, and that simply will not fly and is totally unacceptable.
NO, when there is an explosion in the cylinder, that impulse of energy sets up a resonant standing wave pattern inside the cylinder cavity that is deemed undesirable, and so a secondary resonant cavity is set up in the cylinder to counteract that. That standing wave resonance will happen at its own unique frequency. That is in no way, shape or form, "resonating at the same frequency of the explosion."
No resonance is not an interaction between the two. The explosion initiates a separate and distinct resonant standing wave in the cylinder cavity. The resonance is the resonance in the cavity itself, and not the explosion.
Moving on to the Helmholtz resonators, they just respond to an impulse stimulus and that's it. The frequency of the stimulus is irrelevant. The "resonance like" effect in the Helmholtz resonator is that gasses rush into the resonator chamber, and that is a moving mass. Then the chamber itself acts like a spring. That is the resonance - moving air as a moving mass and air in the chamber acting like a spring. That has nothing whatsoever to do with the impulse that initiated the event or the frequency of the impulse that initiated the event.
Note also that there is not really any cycling back and forth of the same energy as you have in true resonance. It's a one-shot process, kinetic energy goes in, gets stored temporally as potential energy, and then the air leaves, and then new air rushes into the Helmholtz resonator chamber. Even though the same energy and same mass is not cycling back and forth like there is in true resonance, the principles at play are essentially the same.
So when you mistakenly talk about the air inlet and the exhaust gas outlet being "in resonance" with the cylinder explosions, then what is it really? It's certainly not resonance even if the boys in the shop call it "resonance" in their own "shop talk" language. With respect to the cylinder explosions and the input and output ports, there is no cycling of energy back and forth between two forms so it is not resonance.
Here is what it really is: There is a nice synchronicity between the cylinder explosions and the Helmholtz resonators pushing air into the cylinder and then also sucking exhaust gasses out of the cylinder. The fact that the cycle times for the Helmholtz resonators line up with the cylinder timing to make gas move into and out of the cylinder more efficiently is great but it is not resonance. The resonance is in the Helmholtz resonators themselves. What it really is is the Helmholtz resonators act as timing elements in the operation of the engine to ensure that the engine runs synchronously.
Here is the synchronous operation of the engine as a sequence of timing events one after the other: 1) push air into the cylinder, 2) explosion, 3) suck exhaust gasses out of the cylinder. This is a nice advantageous synchronous operation facilitated by the actions of the Helmholtz resonators that makes the engine run better but it is not resonance. There is no resonant cycling of energy back and forth in two forms in steps 1, 2, and 3 which is the true signature for resonance.
All that being said, if you would just accept that a tuning fork resonates, then you could accept that the Helmholtz resonators resonate all by themselves without having anything to do with the cylinder explosions and then you would be fine.
MileHigh
It's like i said MH--you need to further your understanding on how the resonant systems around an ICE work.
The 2 stroke engine is your best starting point.
I see from one of your comments that you do not understand that some of the charge expended into the exhaust resonant chamber,actually returns back into the cylinder.
You do need to brush up on ICEs MH.
Brad
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I am not going to undertake to learn seriously about ICE's but I am reasonably certain that what I said is quite sound and makes sense. I am assuming that you had no idea how resonance actually works in a Helmholtz resonator until I stated it. I think your refusal to engage says something right there. And your "motor shop talk" definition of "resonance" is a no-go. It must be resonance in the form of energy cycling back and forth between two distinct and complimentary forms. There will never be movement on that issue because that's what resonance really is.
Ultimately you are still stuck, you think a struck tuning fork or a struck bell is not resonating. It's almost unbelievable but knowing you it is believable.
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I am not going to look anything up, but I think in some engines they simply change the length of the exhaust expansion chamber to match the engine RPM. That's to ensure a synchronicity between the piston pulse rate to empty the exhaust gasses and the tuned expansion chamber helping suck the exhaust gasses out of the cylinder, but it is not resonance. It might be called a tuned exhaust port or a variable tuned exhaust port or something like that but it is not resonance.
I know what you are trying to say but it's still bloody annoying because we are primarily discussing electronics and inductors do not resonate all by themselves.
" inductors do not resonate all by themselves."
Actually they do. Inductors do have capacitance no matter how small. Ive done these tests along with bifi comparisons where the increased capacitance lowers the freq of resonance compared to a normal wound inductor.
Mags
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I agree but it's really all about good commonsense practices when discussing electronics. An inductor resonating because of its own inherent self-capacitance is really just a curiosity and Brad's statement could easily be misinterpreted. The right thing to do would have been to talk about the resonant frequency of an LC resonator changing because you change the permeability of the core material in the inductor.
Original:
If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change?
Modified using good practices:
If you change the permeability of the magnetic material of the core of an inductor, while maintaining the physical size of that inductor, will the resonant frequency of an LC circuit made with that inductor change?
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If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change?
Modified using good practices:
If you change the permeability of the magnetic material of the core of an inductor, while maintaining the physical size of that inductor, will the resonant frequency of an LC circuit made with that inductor change?
Interestingly, actually increasing the density of the core (e.g. by compressing it with sound waves) changes the permeability of the core. This is known as the Villari effect.
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@MH
I am not going to look anything up, but I think in some engines they simply change the length of the exhaust expansion chamber to match the engine RPM. That's to ensure a synchronicity between the piston pulse rate to empty the exhaust gasses and the tuned expansion chamber helping suck the exhaust gasses out of the cylinder, but it is not resonance. It might be called a tuned exhaust port or a variable tuned exhaust port or something like that but it is not resonance.
Actually it is resonance MH just like a Helmholtz resonator and it is not designed to suck anything in a two stroke engine but rather push any excess fuel/air back into the cylinder also pressurizing the cylinder. Here is a pretty cool animation of the process, https://en.wikibooks.org/wiki/Engineering_Acoustics/Sonic_Supercharging_of_2_Stroke_Engines
We should also note it is more like a turbo charger than a supercharger as it is the reclaimed energy in the exhaust gas which aids the process.
AC
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Thanks for the link and it was a very interesting read. Note that the "straight pipe" helps draw out gases with a reflected negative pressure wave, and the "tune pipe" is essentially a "leaky" version of what appears to be a Helmholtz resonator but in fact it is not. The "tune pipe" returns a reflected positive pressure wave as shown in the animation. That is not what a Helmholtz resonator does, although I will agree that it is similar in function.
I suspected that there was no resonance operating on the exhaust side of the engine, it is more of a fixed time delay event that promotes better engine operation at a certain RPM. So we are back at something that helps the engine run better with a synchronous event to the engine RPM with a fixed time delay, but it is not resonance. And like I said before, if it is called "resonance" in the world of motor shop talk, that's fine, but on this thread and the Joule Thief 101 thread we are discussing resonance in the true scientific and engineering sense of the word.
MileHigh
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When I was in my two stroke days we called it Kadenacy.
I've got an LC 350 and it's just so much better than the
air cooled I had previously.
This whole thing just goes to prove that when you've dug
yourself in to a hole-stop digging.
John.
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For resonance there are no "cross discipline differences." That point has been made many times with references. An LC resonator and a mass and spring resonator or a swinging pendulum resonator are the same thing with respect to resonance.
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Thanks for the link and it was a very interesting read. Note that the "straight pipe" helps draw out gases with a reflected negative pressure wave, and the "tune pipe" is essentially a "leaky" version of what appears to be a Helmholtz resonator but in fact it is not. That is not what a Helmholtz resonator does, although I will agree that it is similar in function.
So we are back at something that helps the engine run better with a synchronous event to the engine RPM with a fixed time delay, but it is not resonance. And like I said before, if it is called "resonance" in the world of motor shop talk, that's fine, but on this thread and the Joule Thief 101 thread we are discussing resonance in the true scientific and engineering sense of the word.
MileHigh
I suspected that there was no resonance operating on the exhaust side of the engine, it is more of a fixed time delay event that promotes better engine operation at a certain RPM.
And as usual,you have got it all wrong again.
You obviously took no notice at all at the animation showing the precise timing needed in order for the returning pressure wave to re-inject the gas mix back into the cylinder at the correct position of the piston. When this timing between piston position and reverse gas flow is correct,the system is in resonance,and at this particular frequency(RPM) engine power and efficiency is at a maximum.
This is resonance in the purest sense,where maximum amplitude(maximum explosive force)is reached at the systems natural resonant frequency.
And do not get this mixed up with turbo charging or super charging of a 4 stroke engine,as they are not the same. The only thing they have in common,is that they all increase engine power.
This (in the animation)is the very same way your tuning fork work's,but where as maximum amplitude can be maintained in the two stroke resonant system,meaning it remains in resonance,while the tuning fork just ring's down-amplitude decreases the instant it has been struck-->Quote: In physics, resonance describes when a vibrating system or external force drives another system to oscillate with greater amplitude at a specific preferential frequency. Increase of amplitude as damping decreases and frequency approaches resonant frequency of a driven damped simple harmonic oscillator.
The "tune pipe" returns a reflected positive pressure wave as shown in the animation.
Just as i tried to tell you earlier on in this thread--but you knew better-once again-->hey MH ;)
Like i told you,if you want to discus ICEs with me,then you need to brush up on how they work,as im simply not going to waste my time talking or arguing with some one that has no idea as to what they are talking about.
Brad
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@Tinman
[size=0px]This (in the animation)is the very same way your tuning fork work's,but where as maximum amplitude can be maintained in the two stroke resonant system,meaning it remains in resonance,while the tuning fork just ring's down-amplitude decreases the instant it has been struck-->Quote: In physics,[/size][size=0px] resonance describes when a vibrating system or external force drives another system to oscillate with greater amplitude[/size][size=0px] at a specific preferential frequency. Increase of amplitude as damping decreases and frequency approaches resonant frequency of [/size][size=0px]a driven[/size][size=0px] damped simple harmonic oscillator.[/size][size=0px]
I would think the tuned pipe is a slight variation of the Helmholtz resonator although they are so similar it's hardly worth debating. It reminds me of an interesting story... about 20 years ago I was into a similar technology called valve-less pulse jet engines. My engine was about two feet long and about 2" in diameter at the neck and made one hell of a racket. However I tend to over do things and decided to see if I could push it into a what is called pulse detonation mode by introducing O2. Well it did reach this mode I believe for about two or three cycles and I could hear a noise similar to thunder echoing across the whole damn city, lol. Scared the shit out of me and I rattled all my neighbors windows. You cannot possibly imagine how loud it was and I swear my whole body and the ground was physically vibrating. After that episode I never ran it again and it has been collecting dust in my shed ever since. In retrospect it was a very loud hand grenade and disaster was imminent... fun times. I'm not really sure why but I have done some really crazy shit in the past and I'm surprised I made it this far.
AC
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And as usual,you have got it all wrong again.
You obviously took no notice at all at the animation showing the precise timing needed in order for the returning pressure wave to re-inject the gas mix back into the cylinder at the correct position of the piston. When this timing between piston position and reverse gas flow is correct,the system is in resonance,and at this particular frequency(RPM) engine power and efficiency is at a maximum.
This is resonance in the purest sense,where maximum amplitude(maximum explosive force)is reached at the systems natural resonant frequency.
And do not get this mixed up with turbo charging or super charging of a 4 stroke engine,as they are not the same. The only thing they have in common,is that they all increase engine power.
This (in the animation)is the very same way your tuning fork work's,but where as maximum amplitude can be maintained in the two stroke resonant system,meaning it remains in resonance,while the tuning fork just ring's down-amplitude decreases the instant it has been struck-->Quote: In physics, resonance describes when a vibrating system or external force drives another system to oscillate with greater amplitude at a specific preferential frequency. Increase of amplitude as damping decreases and frequency approaches resonant frequency of a driven damped simple harmonic oscillator.
Just as i tried to tell you earlier on in this thread--but you knew better-once again-->hey MH ;)
Like i told you,if you want to discus ICEs with me,then you need to brush up on how they work,as im simply not going to waste my time talking or arguing with some one that has no idea as to what they are talking about.
Brad
No Brad, I did not get it wrong, and you saying that "like usual I got it all wrong again" is just you doing your same old shtick.
I obviously took notice of the animation because I made reference to it. You will also note in the great link provided by AC there is not a single reference to resonance and the word "resonance" or "resonant" is never used.
This is resonance in the purest sense,where maximum amplitude(maximum explosive force)is reached at the systems natural resonant frequency.
No, it is not even remotely close to resonance which by definition involves energy cycling back and forth between two different forms at the resonant frequency - like in a tuning fork or a wine class. This has been covered for months now, has any of it sunk into your head?
In this case the maximum amplitude (maximum explosive force) is reached when the piston firing time lines up with the optimum timing for the returning pressure wave from the tune pipe. Effectively it means that the echo off of the back of the tune pipe is at optimum timing. This is not resonance in any way, shape, or form. So a good chunk of the 75+ times you have been haranguing me about this "ICE resonance" business was you digging yourself into a hole.
I assume that you have heard of a PLC controller?
http://www.allaboutcircuits.com/textbook/digital/chpt-6/programmable-logic-controllers-plc/ (http://www.allaboutcircuits.com/textbook/digital/chpt-6/programmable-logic-controllers-plc/)
They are used in all sorts of industrial processes and manufacturing processes. One of the many things they do is orchestrate a sequence of events with the proper timing to operate some kind of production or process line properly. For example, "When sensor switch A goes ON, turn on relay #5 exactly three seconds later." That is akin to what is happening with the tune pipe when the engine is at the correct RPM - you get the optimal timing at that RPM. That hasn't the slightest thing to do with resonance at all.
I will throw a hypothetical example at you. In the Kellogg's factory they make Corn Flakes. At the input to the production line there are corn kernels, sugar, salt, whatever else. At the output to the production like there are raw unboxed Corn Flakes. There is going to be a PLC controller that controls all sorts of stuff on the line. For example, say 50 grams of salt are put into the liquid Corn Flakes goop every 20 seconds. If the line stops, a signal goes to the PLC controller and the PLC controller stops adding the 50 grams of salt.
The PLC controller is critical in the production of the Corn Flakes and controls literally hundreds of events, and for each event there is a programmed timing that is entered into the PLC controller. If the Corn Flakes tasters on the end of the line tell the production manager that the Corn Flakes are starting to taste too salty, the production line manager figures out where the problem is and corrects it.
Now, when the Kellogg's plant manager stops by and asks the Corn Flakes production manager how the line is running, do you think he says, "Good news Jim, the line is in resonance?" The answer is NO, he says that the event timings for the PLC controller are all good, the sensors are all good, the actuators are all good, and the line is producing raw Corn Flakes without any problems.
So you are barking up a wrong tree Brad, you are just deceiving yourself about the exhaust cycling for a two-stroke engine, it has nothing to do with resonance.
MileHigh
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Like i told you,if you want to discus ICEs with me,then you need to brush up on how they work,as im simply not going to waste my time talking or arguing with some one that has no idea as to what they are talking about.
Like really, kiss my butt with the fake-ass "waste my time" attitude business. What about the hundreds of hours that people like Poynt and Picowatt and others have put into helping you? You have had no idea what you were talking about many times and they put in the time. And it's very ironic that you identify the exhaust timing with resonance, it feels like hundreds and hundreds of hours put in to help you have been in vain, and a waste of time. But people still work to help you anyway.
Look at the business on the other thread with the attempt to characterize the input of the inverter. You say, "The inverter is quite reactive--see scope shot below across CVR to inverter input." From what I can see that is a totally ridiculous statement. On top of that you haven't even come close to characterizing the inverter input. And one more time, the handful of people interested in the thread are saying nothing and think you have it right. So right now, you are leading your group down the wrong garden path. One more time, it appears you looked at a DSO display that you though was "right" and you were satisfied with that and posted it and you believe that it's time to move on in the investigation. Your investigative skills leave a lot to be desired because they are extremely shallow and you are convinced that you are "right" the moment that you get something that "looks right" on your DSO display. When I look at your DSO screen capture I see what I am quite certain is junk, and if that's it as far as the investigation goes then it's way incomplete.
MileHigh
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I would think the tuned pipe is a slight variation of the Helmholtz resonator although they are so similar it's hardly worth debating.
They are actually very dissimilar and I will explain why.
The Helmholtz resonator is based on a "plug" of air mass in the neck that pushes against the "spring" of compressible air in the air cavity of the resonator. So, this looks like any other LC-type resonator where the resonant frequency and associated cycle time is based on the square root of L x C. There is no pressure wave at all in the model for the Helmholtz resonator.
For the tune pipe in your Wikibooks link, for starters, there is no resonant frequency at all, there is only a cycle time. In addition the cycle time is dependent on the length of the tune pipe, just like the cycle time for an echo depends on how far you are away from the wall that the sound waves bounce off of. From the link, "the goal is to have the diverging section create a returning rarefaction wave and the converging section create a returning pressure wave." So there is no modelling of this in any kind of "resonant LC device" way.
In a nutshell, you are looking at the difference between a true LC resonator (that can be operating in a one-shot mode) with a cycle time, and a device that is based on a pressure wave bouncing off the back of the tune pipe with it's related speed of the wave and length of the pipe to give you a cycle time.
No matter how you look at it, those are two different beasts. One is a resonant device, and the other one is simply a time-delay device.
MileHigh
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No matter how you look at it, those are two different beasts. One is a resonant device, and the other one is simply a time-delay device.
MileHigh
Post 1044-The moving piston that draws air in and pushes the exhaust gasses out cause the Helmholtz resonator processes for the air inlet and exhaust gas outlet.
Today--They are actually very dissimilar and I will explain why.
Lol-Your all over the show MH
One day it is,and the next it is not.lol.
For the tune pipe in your Wikibooks link, for starters, there is no resonant frequency at all, there is only a cycle time. In addition the cycle time is dependent on the length of the tune pipe, just like the cycle time for an echo depends on how far you are away from the wall that the sound waves bounce off of.
And when that cycle time aligns perfectly with the cycle time of the pistons port position,we have what between the two that gives rise to a maximum amplitude of pressure in the combustion chamber?. When do you obtain resonance in an LC circuit?--when the cycle time is correct :D
There is no pressure wave at all in the model for the Helmholtz resonator.
Quote: By one definition a Helmholtz resonator augments the amplitude of the vibratory motion of the enclosed air in a chamber by taking energy from sound waves passing in the surrounding air. In the other definition the sound waves are generated by a uniform stream of air flowing across the open top of an enclosed volume of air.
From the link, "the goal is to have the diverging section create a returning rarefaction wave and the converging section create a returning pressure wave." So there is no modelling of this in any kind of "resonant LC device" way.
In a nutshell, you are looking at the difference between a true LC resonator (that can be operating in a one-shot mode) with a cycle time, and a device that is based on a pressure wave bouncing off the back of the tune pipe with it's related speed of the wave and length of the pipe to give you a cycle time.
Quote: A tuning fork serves as a useful illustration of how a vibrating object can produce sound. The fork consists of a handle and two tines. When the tuning fork is hit with a rubber hammer, the tines begin to vibrate. The back and forth vibration of the tines produce disturbances of surrounding air molecules. As a tine stretches outward from its usual position, it compresses surrounding air molecules into a small region of space; this creates a high pressure region next to the tine. As the tine then moves inward from its usual position, air surrounding the tine expands; this produces a low pressure region next to the tine. The high pressure regions are known as compressions and the low pressure regions are known as rarefactions. As the tines continue to vibrate, an alternating pattern of high and low pressure regions are created. These regions are transported through the surrounding air, carrying the sound signal from one location to another.
Quote the s stroke resonator--This pipe consists of an expansion chamber which serves to create both the returning rarefaction and pressure waves.
Holly crap MH--they do the same thing-->the tuning fork and expansion chamber :D
But one of them resonates,and the other dose not--you just have them mixed ass about.
See what i mean about your !picking and choosing! to suit your need to be correct ;)
Brad
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Brad:
You clearly make no attempt to seriously respond to the technical argument that I made that clearly shows that there is no resonance at all in operation on the exhaust side as shown in the link provided by AC.
Instead, you do a chicken dance and try throwing spaghetti against the wall and hoping some of it will stick. It's just a lousy performance and I will deal with it in another posting.
But the saddest thing of all, is that you simply couldn't admit that the way the exhaust system works to optimize the performance of the engine is a timing-based function and not a resonance-based function. It is absolutely clear to me that this is the case and I am quite certain that the majority of readers would agree. Instead of just admitting to it like a man, you shrink away from it and try to hide behind fake lol's and smiley faces. And I have seen countless examples of this before and I think that is sad.
MileHigh
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Brad:
Okay, now I am going to deal with your chicken dance.
One day it is,and the next it is not.lol.
Ha ha ha, big joke. Here you are like a hawk plucking quotes of mine from way back in the discussion. If you are such a hawk then you saw how several times that I expressed doubts that on the exhaust side that there was any form of true resonance in play. The AC provided a good link and it confirmed my doubts as well as being informative and teaching me.
And all that you can do is dance like a funky chicken and try to do a "set up" to "prove" that I am contradicting myself.
And when that cycle time aligns perfectly with the cycle time of the pistons port position,we have what between the two that gives rise to a maximum amplitude of pressure in the combustion chamber?. When do you obtain resonance in an LC circuit?--when the cycle time is correct :D
This is smiley-faced dancing chicken bullshit. You are ignoring everything technical I said and falling flat on your face.
Quote: By one definition a Helmholtz resonator augments the amplitude of the vibratory motion of the enclosed air in a chamber by taking energy from sound waves passing in the surrounding air. In the other definition the sound waves are generated by a uniform stream of air flowing across the open top of an enclosed volume of air.
And this says absolutely nothing about pressure waves inside the Helmholtz resonator. Rather, it discusses how sound waves external to the resonator can be picked up and amplified by the Helmholtz resonator. It also discusses how a Helmholtz resonator can generate sound waves external to the resonator. So more useless dancing chicken. Plus I am pretty sure based on all of the discussions that we have had together that you didn't have slightest idea how a Helmholtz resonator actually worked until I explicitly told you how one worked. See attached diagram.
By the way, the "K" is for the spring constant, and the symbol should obviously not be confused for a resistance, it's a symbol for a spring. Note the "Rm" and the associated symbol is for the "resistor." I put resistor in parenthesis because in fact an electrical resistor in the electrical circuit world is in reality modeled by a "damper" in the physical world. It's like a car shock absorber without the spring.
MileHigh
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Brad:
contradicting myself.
This is smiley-faced dancing chicken bullshit. You are ignoring everything technical I said and falling flat on your face.
Okay, now I am going to deal with your chicken dance.
Ha ha ha, big joke. Here you are like a hawk plucking quotes of mine from way back in the discussion. If you are such a hawk then you saw how several times that I expressed doubts that on the exhaust side that there was any form of true resonance in play. The AC provided a good link and it confirmed my doubts as well as being informative and teaching me.
And all that you can do is dance like a funky chicken and try to do a "set up" to "prove" that I am
And that is what you have done time after time.
The fact is,that it is the exhaust side that dose 90% of the work by way of a resonant system. I tried to tell you this earlier on in this discussion,but you just kept on dribbling away.
I also tried to tell you to go and learn a thing or two,before trying to work out how it all work's,but i can see it was left for others to do for you--no surprise there.
And this says absolutely nothing about pressure waves inside the Helmholtz resonator. Rather, it discusses how sound waves external to the resonator can be picked up and amplified by the Helmholtz resonator. It also discusses how a Helmholtz resonator can generate sound waves external to the resonator. So more useless dancing chicken. See attached diagram.
Helmholtz Resonance
A Helmholtz resonator or Helmholtz oscillator is a container of gas (usually air) with an open hole (or neck or port). A volume of air in and near the open hole vibrates because of the 'springiness' of the air inside.
Sound-- is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles.
Plus I am pretty sure based on all of the discussion that you didn't have slightest idea how a Helmholtz resonator worked until I explicitly told you how one worked.
MH,you are clueless as to what i know.
You think that no one here knows anything ,unless you tell them.
The fact that pressure waves do exist inside a Helmholtz resonator,just shows how little you know.
I have not seen anyone try and steer people in the wrong direction more than you do.
I only hope that there is not to many that take notice of your rubbish.
Brad
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Brad:
Okay, moving on to the bitter end.
Quote: A tuning fork serves as a useful illustration of how a vibrating object can produce sound. The fork consists of a handle and two tines. When the tuning fork is hit with a rubber hammer, the tines begin to vibrate. The back and forth vibration of the tines produce disturbances of surrounding air molecules. As a tine stretches outward from its usual position, it compresses surrounding air molecules into a small region of space; this creates a high pressure region next to the tine. As the tine then moves inward from its usual position, air surrounding the tine expands; this produces a low pressure region next to the tine. The high pressure regions are known as compressions and the low pressure regions are known as rarefactions. As the tines continue to vibrate, an alternating pattern of high and low pressure regions are created. These regions are transported through the surrounding air, carrying the sound signal from one location to another.
More dancing chicken. I state that the tune pipe generates a time delay inside the pipe based on a returning pressure wave echo. So you do a dance and produce a quote about how a resonating tuning fork produces sound (pressure waves) in the external air around the tuning fork. As we know, and as you yourself stated, a tuning fork producing sound in the air represents the draining of energy out of the tuning fork and putting it into the air.
What does a tuning fork producing sound in the external air have to do with a tune pipe and it's associated delayed pressure wave inside the pipe? NOTHING.
Holly crap MH--they do the same thing-->the tuning fork and expansion chamber :D
But one of them resonates,and the other dose not--you just have them mixed ass about.
Holy crap Mr. Chicken! They don't do the same thing at all - it's a false equivalency! Mr. Chicken is guilty of many false equivalencies. Smiley faces will not fix that!
And of course, you have it ass about. The tuning fork clearly resonates by exchanging kinetic and potential energy back and forth just like an LC resonator exchanges inductive and capacitive energy back and forth. And the tune pipe/expansion chamber is clearly a time delay device and you haven't provided a single shred of evidence that it resonates. Isn't that funny?
MileHigh
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Brad:
You are just throwing more useless spaghetti against the wall.
Helmholtz Resonance
A Helmholtz resonator or Helmholtz oscillator is a container of gas (usually air) with an open hole (or neck or port). A volume of air in and near the open hole vibrates because of the 'springiness' of the air inside.
Sound-- is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles.
Yes, the "'springiness' of the air inside" is the SPRING in the Helmholtz container. Pressure waves do not travel through the spring, rather, the spring is a spring.
Your citing of a definition for "sound" is meaningless. You make no attempt whatsoever to put your own intellectual content in here. You are just throwing two strings of spaghetti against the wall and adding zero added value and zero brainpower. You are just making another false equivalency, and a ridiculous one at that.
MH,you are clueless as to what i know.
Since you demonstrated no knowledge about what resonance actually is, I can make a very strong inference that you had no clue whatsoever how a Helmholtz resonator actually works.
The fact that pressure waves do exist inside a Helmholtz resonator,just shows how little you know.
That's my cue for 10 smiley faces. The model for a Helmholtz resonator is such that the volume inside the resonant cavity acts like a spring. That means that the wavelength of sound associated with the resonant frequency is much larger than the dimensions of the cavity. Therefore, it's impossible for any pressure waves to exist inside the cavity. At any given time, the pressure in the cavity is only a "small portion of a sine wave" and therefore the pressure is more or less constant throughout the cavity as it cycles up and down. Another thing that you just learned Brad!
I have not seen anyone try and steer people in the wrong direction more than you do.
I only hope that there is not to many that take notice of your rubbish.
The truth is that you have learned a hell of a lot of stuff from me on these two threads but your big brain fry won't let you say that so all that you can say is the hollow fake-ass "rubbish" line.
MileHigh
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Brad:
Another select morsel from Wikipedia with the mad hope that you will get it and the insane hope that you will simply admit that you get it.
Note that they discuss the two meanings for resonance. Have a good brain fry over that.
https://en.wikipedia.org/wiki/RLC_circuit
Natural frequency
The resonance frequency is defined in terms of the impedance presented to a driving source. It is still possible for the circuit to carry on oscillating (for a time) after the driving source has been removed or it is subjected to a step in voltage (including a step down to zero). This is similar to the way that a tuning fork will carry on ringing after it has been struck, and the effect is often called ringing. This effect is the peak natural resonance frequency of the circuit and in general is not exactly the same as the driven resonance frequency, although the two will usually be quite close to each other. Various terms are used by different authors to distinguish the two, but resonance frequency unqualified usually means the driven resonance frequency. The driven frequency may be called the undamped resonance frequency or undamped natural frequency and the peak frequency may be called the damped resonance frequency or the damped natural frequency. The reason for this terminology is that the driven resonance frequency in a series or parallel resonant circuit has the value[1]
ω = 1 / Sqrt(L*C)
This is exactly the same as the resonance frequency of an LC circuit, that is, one with no resistor present. The resonant frequency for an RLC circuit is the same as a circuit in which there is no damping, hence undamped resonance frequency. The peak resonance frequency, on the other hand, depends on the value of the resistor and is described as the damped resonant frequency. A highly damped circuit will fail to resonate at all when not driven. A circuit with a value of resistor that causes it to be just on the edge of ringing is called critically damped. Either side of critically damped are described as underdamped (ringing happens) and overdamped (ringing is suppressed).
No spaghetti here.
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Brad:
Revenge of the wine glass. The attached pdf discusses how to determine the natural resonant frequency for a wine glass. It's the real thing, and it's full of integrals. However, if you were a keener and tried to follow it, it will become readily apparent that a wine glass is just another version of a bloody LC resonator.
Remember I said I did a 20-minute search to back up the answers to the two wine glass questions?
MileHigh
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What's more interesting than the philosophical issue whether a resonance can exist without an unbalance of energy in the resonating/resonant system, is why the Mythbusters could not break the wine glass with a single tone, but could do it with two tones?
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@MH
For the tune pipe in your Wikibooks link, for starters, there is no resonant frequency at all, there is only a cycle time. In addition the cycle time is dependent on the length of the tune pipe, just like the cycle time for an echo depends on how far you are away from the wall that the sound waves bounce off of. From the link, "the goal is to have the diverging section create a returning rarefaction wave and the converging section create a [/size]returning pressure wave[/size]." So there is no modelling of this in any kind of "resonant LC device" way.[/size]
My assumption was that the tuned pipe was not necessarily a "one shot" device and that once the exhaust port closed the returning pressure wave would partially reflect off the closing port back to the open end. We could model the pipe like a transmission line with one open end. An impulse from our exhaust port/HV coil travels down the line and part of the impulse reflects back towards the source which created it. However if the exhaust port closes or the HV coil is detached from it's source then we should see another reflection.
I don't know if the tuned pipe pressure wave was designed to oscillate within the chamber or simply reflect from the open end back to the exhaust port like a one shot device. If I designed a tuned pipe I would want the pressure wave to oscillate (more than one reflection) and do so covering a wide rpm range.[/size]
AC
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Brad:
Another select morsel from Wikipedia with the mad hope that you will get it and the insane hope that you will simply admit that you get it.
Note that they discuss the two meanings for resonance. Have a good brain fry over that.
https://en.wikipedia.org/wiki/RLC_circuit
Natural frequency
The resonance frequency is defined in terms of the impedance presented to a driving source. It is still possible for the circuit to carry on oscillating (for a time) after the driving source has been removed or it is subjected to a step in voltage (including a step down to zero). This is similar to the way that a tuning fork will carry on ringing after it has been struck, and the effect is often called ringing. This effect is the peak natural resonance frequency of the circuit and in general is not exactly the same as the driven resonance frequency, although the two will usually be quite close to each other. Various terms are used by different authors to distinguish the two, but resonance frequency unqualified usually means the driven resonance frequency. The driven frequency may be called the undamped resonance frequency or undamped natural frequency and the peak frequency may be called the damped resonance frequency or the damped natural frequency. The reason for this terminology is that the driven resonance frequency in a series or parallel resonant circuit has the value[1]
ω = 1 / Sqrt(L*C)
This is exactly the same as the resonance frequency of an LC circuit, that is, one with no resistor present. The resonant frequency for an RLC circuit is the same as a circuit in which there is no damping, hence undamped resonance frequency. The peak resonance frequency, on the other hand, depends on the value of the resistor and is described as the damped resonant frequency. A highly damped circuit will fail to resonate at all when not driven. A circuit with a value of resistor that causes it to be just on the edge of ringing is called critically damped. Either side of critically damped are described as underdamped (ringing happens) and overdamped (ringing is suppressed).
No spaghetti here.
Well thats fantastic MH,you posted a post on damped and undamped resonant/Natural frequencies.
Please point out where it says anything about when such systems are resonating,or when they are just oscillating at there resonant frequency.
I see this-->The resonance frequency is defined in terms of the impedance presented to a driving source.
Other than that,your post means didly squat about resonating.
nice try,but not good enough,as you are going over ground that we already know.
Yes--there is still spaghetti MH,and lots of it.
Brad
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What's more interesting than the philosophical issue whether a resonance can exist without an unbalance of energy in the resonating/resonant system, is why the Mythbusters could not break the wine glass with a single tone, but could do it with two tones?
Thats Mythbusters for you.
They dont often get things right.
Did you ever see there attempt at a Bedini pulse motor lol--and this was there electronics guru that tried to build one ::)
Brad
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Brad:
But the saddest thing of all, is that you simply couldn't admit that the way the exhaust system works to optimize the performance of the engine is a timing-based function and not a resonance-based function. It is absolutely clear to me that this is the case and I am quite certain that the majority of readers would agree. Instead of just admitting to it like a man, you shrink away from it and try to hide behind fake lol's and smiley faces. And I have seen countless examples of this before and I think that is sad.
MileHigh
You clearly make no attempt to seriously respond to the technical argument that I made that clearly shows that there is no resonance at all in operation on the exhaust side as shown in the link provided by AC.
Instead, you do a chicken dance and try throwing spaghetti against the wall and hoping some of it will stick. It's just a lousy performance and I will deal with it in another posting.
MH,as i said--you have no idea as to what resonance is,and this is your downfall.
Im not going to argue with a clown that has limited knowledge on the ICE--as we seen on the JT thread.
I mean,look at the palava comment below
Quote-optimize the performance of the engine is a timing-based function and not a resonance-based function.
This comment just shows how out of touch you are,as all states of resonance are timing based functions. The fact that you dont-or cant put it altogether,is no fault of mine.
Just as an LC circuit will only resonate at the correct frequency,so it is with the expansion chamber and combustion cycle. The frequency(rpm) has to match the frequency of the expansion chamber before maximum amplitude is gained--this is a resonant circuit.
I have tried to explain it to you before,but as you do when you need to be right--you just pay no attention to what is told to you,and you keep on babbling away like you are doing now.
There is a reason they call it a resonator MH--because it resonates at the correct engine RPM(frequency). At this very point,the maximum HP amplitude is reached.
It is no different to an LC circuit,where the gas charge is cycled back and forth between the cylinder and expansion chamber,until at the correct RPM(frequency)a maximum amplitude is reached. The very same happens in an LC circuit,where the power is cycled back and forth between the capacitor and inductor,and at the right frequency,maximum amplitude is reached---the resonant frequency.
Both are driven circuit's,and both are resonant circuits.
Take another look at the animation on the link AC provided,and have a good hard look at the gas flow to that of the pistons position. At resonance(the correct rpm),the piston will be at the correct position in relation to the exhaust port,so as it matches the exact time that the returning pressure wave of gas can enter the exhaust port. Either side of this frequency(RPM),and this timing is out ,where the piston will either be covering most of the exhaust port,or it will not be close enough to it,and so the gas will enter the exhaust port,build cylinder pressure,and then start to flow back out of the exhaust port before the piston can close it off.
As i have said--over and over--if you wish to discuss (or argue as you do most ofter) ICEs with me,then go and learn up a bit first.
Brad
-
Brad:
You just made two ridiculous arguments.
Please point out where it says anything about when such systems are resonating
Right here: "The driven frequency may be called the undamped resonance frequency or undamped natural frequency and the peak frequency may be called the damped resonance frequency or the damped natural frequency."
That's your smoking gun right there. The "damped resonance frequency" is in reference to a system that is resonating by itself and not being driven.
If a system has a resonance frequency then it is a resonating system.
A resonating system has a resonance frequency.
Can you comprehend that? What is this foolishness? Get out of the Twilight Zone and get real.
What is resonance? It's when energy oscillates back and forth in a system in two complimentary forms. You must be able to identify the two complimentary forms of energy and the oscillation to call it resonance.
nice try,but not good enough,as you are going over ground that we already know.
This nonsense with you has been going on long enough.
This comment just shows how out of touch you are,as all states of resonance are timing based functions.
There is a reason they call it a resonator MH--because it resonates at the correct engine RPM(frequency). At this very point,the maximum HP amplitude is reached.
We are specifically discussing the scientific and engineering definition for resonance.
With the tune pipe can you identify the two complimentary forms of energy?
With the tune pipe can you identify the oscillation method for the alleged two forms of energy?
I don't think you can, and without that all you are left with is "resonance" in this case being "engine shop talk slang." We are not talking about slang here.
Take another look at the animation on the link AC provided,and have a good hard look at the gas flow to that of the pistons position.
Yes and I can tell you exactly what you are looking at. You are looking at an impulse-driven pressure wavefront that travels down the tune pipe until it hits the end of the pipe. That means the tune pipe is an acoustic transmission line and the wave front hits a discontinuity in the transmission line at the end of the pipe and is reflected back. The timing of the wave front at a certain engine RPM will be such that the fuel is put back into the cylinder for combustion. That is not bloody resonance that is an acoustic transmission line being used as a selective delay line device.
You disagree? Then prove me wrong and identify the two complimentary forms of energy and the oscillation mechanism.
Like it or not, you are not going to "throw a new slang definition of resonance into the mix."
MileHigh
-
Brad:
I know it looks like a duck and walks like a duck and squawks like a duck. But in this case it's not a duck.
On the inlet side, it's based around a Helmholtz resonator, and that's definitely an example of resonance in action to make an ICE run more efficiently.
On the exhaust outlet side, it's using an exhaust pipe as a timing device, a delay line, to make the ICE run more efficiently.
I will say to you what you often say to me: Find some references that state that resonance is used in the exhaust system to make an ICE run more efficiently. AC's link clearly does not state that there is any resonance at play on the exhaust outlet side. I would be more than happy to read them and if I am wrong I will state that right away. (Note that mufflers don't count here because they do not improve the efficiency of the engine in the context of our discussion.)
MileHigh
-------------------------------
On another more serious note. Sorry to my American friends and I know how it feels.
Even in our sleep, pain which cannot forget
falls drop by drop upon the heart,
until, in our own despair,
against our will,
comes wisdom
through the awful grace of God.
- Aeschylus
-
@MH
My assumption was that the tuned pipe was not necessarily a "one shot" device and that once the exhaust port closed the returning pressure wave would partially reflect off the closing port back to the open end. We could model the pipe like a transmission line with one open end. An impulse from our exhaust port/HV coil travels down the line and part of the impulse reflects back towards the source which created it. However if the exhaust port closes or the HV coil is detached from it's source then we should see another reflection.
I don't know if the tuned pipe pressure wave was designed to oscillate within the chamber or simply reflect from the open end back to the exhaust port like a one shot device. If I designed a tuned pipe I would want the pressure wave to oscillate (more than one reflection) and do so covering a wide rpm range.[/size]
AC
I fundamentally agree with you that it is a transmission line. In the animation and the description they describe it as a "one-shot at the optimal engine RPM." If you noticed they also discuss a modified shape to extend the RPM range with less than optimal performance and so on. I am not going to try to become an "enthusiast" or "expert." What I am seeing is a transmission line used as a delay line to synchronize pushing fuel back into the cylinder at the optimum RPM.
I tried searching on many variations on "delay line" and "exhaust," "engine" etc., but could not find a good link, probably because I am not using the right terminology for engines. You can find all sorts of electronic acoustic delay lines, and of course you always find the ancient computer memory mercury delay line. That's a trip in itself, to think that in the 50's mainframe computers used long tubes of mercury for memory!
Anyway, I am out of gas on this stuff and if Brad wants to believe what he believes so be it. Or if he can find a link that makes his case, I will be happy to read it. But I am seeing an acoustic delay line in the exhaust system to optimize the combustion process, and not resonance.
MileHigh
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Loner
Funny I was thinking about you today [the race track]
good to read you here and your valuable contributions.
I know few here have your experience with an ICE and Racing .
I have to just drop this in from another racer/engine designer "Johan 1955" for you to see , a very dependable 2 stroke
8HP per cubic inch N.A. and climbing ...as they continue to dial it in.
https://www.youtube.com/watch?v=1zDmlOYiaTI
Yes its a screamer [perhaps the NA[normally aspirated] goes out the window ??] ,But they also play with resonance and a huge standing wave in some very tricky ways.
BTW your comments here are in no way off topic !
regardless whichever side of the fence your on.
respectfully
Chet K
-
I fundamentally agree with you that it is a transmission line. In the animation and the description they describe it as a "one-shot at the optimal engine RPM." If you noticed they also discuss a modified shape to extend the RPM range with less than optimal performance and so on. I am not going to try to become an "enthusiast" or "expert." What I am seeing is a transmission line used as a delay line to synchronize pushing fuel back into the cylinder at the optimum RPM.
I tried searching on many variations on "delay line" and "exhaust," "engine" etc., but could not find a good link, probably because I am not using the right terminology for engines. You can find all sorts of electronic acoustic delay lines, and of course you always find the ancient computer memory mercury delay line. That's a trip in itself, to think that in the 50's mainframe computers used long tubes of mercury for memory!
Anyway, I am out of gas on this stuff and if Brad wants to believe what he believes so be it. Or if he can find a link that makes his case, I will be happy to read it. But I am seeing an acoustic delay line in the exhaust system to optimize the combustion process, and not resonance.
MileHigh
MH'
The resonance state is between the piston and pressure wave that returns the gas charge back into the cylinder. The timing is critical,and only happens at a set frequency(RPM) range--we are talking about the two stroke engine here. At a set RMP (frequency) range(the resonant range),the entire gas charge held in the expansion chamber,is returned to the cylinder ,through the exhaust port. If the RPM(frequency) is to low,then that gas charge will enter the cylinder,and begin to exit the cylinder again,before the piston closes off the exhaust port. When this happens,you will have very little compression,and thus,very little power--anyone that has ridden a high performance motocross bike will know this to be true--very little torque at low RPM. If the frequency(RPM) is too high,then the piston closes off the exhaust port before the complete charge can enter the cylinder,and so the engine will run lean,and once again,result in a power drop--along with a damaged motor soon enough.
At the resonant frequency(correct RPM), when all of the charge that was held in the expansion chamber will enter the cylinder,the result is a higher cylinder pressure--this is what can be seen as the supercharging effect,and the end result is a much higher explosion force within the cylinder--more power. The resonance is the precise timing between the pistons position,and the pressure wave created within the expansion chamber,where all of that wave front of gas charge has completely entered the cylinder at the precise time the piston closes off the exhaust port,so as that pressurized gas charge cannot escape the cylinder. This results in a maximum amplitude of pressure in the cylinder,and a maximum amplitude in power.
Perhaps this link can explain it a little better.
http://www.roost.si/articles/exhaust/exhausts_work.htm
Brad
-
Rats...
Tinman, I am sorry to have to respond to that, but I'm afraid I must "sorta" agree with MH on that specific point.
I want to ensure you understand what I mean, so I am posting this, even though I stated I would not comment. This is really a matter of semantics. Removing electrical resonance for a moment, though the data would apply in another way, the simplest way to describe physical/mechanical resonance would be an oscillation between potential and kinetic energy. This IS what is happening inside the exhaust, and is what is providing the described pressure wavefront, however the alignment of the piston at the correct point on the exhaust's pressure wave would (In my opinion...) have to be considered "Timing" and not part of the actual exhaust resonance. Yes, I am picking nits here, but that was the major point I was trying to make previously.
To put it another way. Pick an RPM. To make the best power at that RPM, you want to have the exhaust resonate at a specific frequency. To get this effect, you ONLY have to modify the exhaust, as the action of the piston will not change. (I'm not explaining this well, so please forgive me. I'm trying...) While the amount of power will change, due to increase charge density, the actual frequency (RPM) of the piston does not change. The piston is acting as the signal injector, at a "Fixed" frequency and when the resonance of the exhaust matches, then...
This is where I always had so much trouble, as increasing the power in other ways could change the charge density enough to alter the exhaust freq. while the engine is still spinning the same RPM. All of a sudden my tuning to increase power caused a decrease. I do realize that 2 stroke is MUCH more sensitive to these effects than 4 stroke where the situation is different. Therefore, while I would agree 100% that the exhaust has a physical resonance going on inside (Both acoustic and pressure...), the true physical resonance is ONLY going on in the exhaust. The fact that this wavefront is matched to the correct position of the piston is not really part of the exhaust resonance, even though it IS dependent on it. I'm quite certain you are aware of Q and bandwidth, although you might view it as the width of the power band instead. Same thing to me. So, while these are very synchronized, and very timing dependent, in the true sense of the concept the exhaust and engine are not in resonance with each other, they are just correctly timed for the desired effect. The exhaust IS in resonance by itself and so is the engine. (I doubt we need to discuss crankcase volume, etc., as that is another whole story.)
All it really comes down to is how nit-picky we all want to be. There are those in the engine area that will lean more towards your view and discuss intake reed valve tensions as being part of the engine resonance and on and on and on, but I have always maintained that while they are timed and synchronized, the actual resonance applies separately to intake, engine and exhaust. In real life I can accept that, while at the track, while you won't be doing engine mods, you will be re-jetting and swapping resonance chambers depending on conditions. This makes it easier to look at the whole thing as a single resonant system, but I look at it as more complex than that and try to keep them separate in my mind. End result? While bolting on a different chamber between heats, it's a single resonant system. While sitting on the couch or at the computer, it is three separate systems. As to which is correct? Ask the person sitting on the couch and he IS correct. Ask the person who just won the race, HE is correct. For me, both are correct for what they are trying to do. There will always be differences in perception between the academics and application people in complex systems.
I am definitely too old for this stuff.
You are basically saying what i am.
The expansion chamber is the resonant source,but for that resonant source to have the desired effect,then the pistons position must also align to that resonant frequency of the expansion chamber. If the RPM of the engine is not correct,then the resonant chamber dose not have the desired efffect-->engine frequency must be the same as the resonant frequency of the expansion chamber.
This makes a resonant system as a whole,and for maximum pressure amplitude to be reached inside the cylinder,then this system as a whole must exist.
Hope that helps
Brad
-
Brad:
As Loner says, and as your link says. the tuning of the expansion chamber shape, and especially length, is an exercise in optimizing the exhaust timing to the engine at a certain RPM.
The correct technical term would be to synchronize the events for optimum performance at a given RPM.
This thread started a discussion about resonance in terms of the true scientific and engineering sense of the word. And that is the basis for this thread, period. So a huge chunk of this "ICE resonance" nonsense and berating over and over is because you failed to distinguish between true resonance and motor shop talk "resonance."
Why do they call it "resonance" for expansion chambers instead of "synchronization?"
The answer is simple, it's because "resonance" sounds way cooler and sexier than "synchronization." That's all there is to it.
A whole mountain of endless discussion for something as nonsensical as this. It has happened before with you.
From your link:
These waves have the caratteristics of reflecting as a negative wave (suction) if they meet an open end of a tube. On the other way if they encounter an closed end of a tube they reflect as a positive wave (stuffing).
Those are classic characteristics of an acoustic or electrical transmission line.
The rpm at which the pipe will be in resonance depend on the length of it and the temperature of the gasses.
There is your smoking gun. Adjust the length of the transmission line to get the proper required delay to synchronize events with the cylinder at a given RPM.
For probably the sixth or seventh time, this is NOT resonance.
It annoys me to think of how much crap we went through when the whole time you damn well knew that I was talking about true resonance, not "resonance" for two-stroke engine enthusiasts.
MileHigh
-
You are basically saying what i am.
The expansion chamber is the resonant source,but for that resonant source to have the desired effect,then the pistons position must also align to that resonant frequency of the expansion chamber. If the RPM of the engine is not correct,then the resonant chamber dose not have the desired efffect-->engine frequency must be the same as the resonant frequency of the expansion chamber.
This makes a resonant system as a whole,and for maximum pressure amplitude to be reached inside the cylinder,then this system as a whole must exist.
Hope that helps
Brad
You are talking crap again to avoid the frying pan.
-
You are talking crap again to avoid the frying pan.
And your unfounded dribble is becoming boring.
Go and look up--to be in resonance with something-then come back and try a re-dribble.
Brad
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And your unfounded dribble is becoming boring.
Go and look up--to be in resonance with something-then come back and try a re-dribble.
Brad
We are specifically discussing the scientific and engineering definition for resonance.
With the tune pipe can you identify the two complimentary forms of energy?
With the tune pipe can you identify the oscillation method for the alleged two forms of energy?
I don't think you can, and without that all you are left with is "resonance" in this case being "engine shop talk slang." We are not talking about slang here.
-
We are specifically discussing the scientific and engineering definition for resonance.
With the tune pipe can you identify the two complimentary forms of energy?
With the tune pipe can you identify the oscillation method for the alleged two forms of energy?
I don't think you can, and without that all you are left with is "resonance" in this case being "engine shop talk slang." We are not talking about slang here.
Forget it MH--as i said,you are past the learning stage of life.
The last link clearly explained it-picture by picture-word for word.
If you cannot relate that to the scientific definition of resonance,then you never will.
I have no more time to waste on you,so you enjoy your small closed in world.
Brad
-
Now you are just bluffing Brad because you know that you can't answer those questions that ask you to define resonance as a scientific term for what you are pitching. I understood every word of what you linked to and suggesting that I "can't learn" is just more bluffing on your part.
Here is more bluffing by ignoring:
Right here: "The driven frequency may be called the undamped resonance frequency or undamped natural frequency and the peak frequency may be called the damped resonance frequency or the damped natural frequency."
That's your smoking gun right there. The "damped resonance frequency" is in reference to a system that is resonating by itself and not being driven.
If a system has a resonance frequency then it is a resonating system.
A resonating system has a resonance frequency.
Can you comprehend that? What is this foolishness? Get out of the Twilight Zone and get real.
Whoops, if you admitted that you could understand "If a system has a resonance frequency then it is a resonating system" then your whole pitch about "driven resonance being the only resonance and nothing esle counts" falls flat on its face and so do you. Then of course you are trying to squeeze in a fake definition for resonance which is just the synchronous operation of the components of an engine.
I can hear the sizzling from here.
MileHigh
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Loner:
Here is the context: On another thread some people said that they were going to make a "resonant Joule Thief" and we even had some Big Fish stories about the supposed miraculous properties of a resonant Joule Thief. I said, "Hold on, a Joule Thief is not even a device based on resonance at all, it is a pulse circuit built around L/R-type time constants. By definition a Joule Thief is not supposed to resonate and will not resonate."
That caused a ruckus and then we explored what resonance really means in terms of electronics and in terms of physical systems. The context is that this was always about the scientific and engineering definition of resonance. I asked two simple questions about a resonating wine glass that nobody in the "resonant Joule Thief" group could answer.
A recurring theme was that an ICE was a machine that took advantage of resonance to get higher performance. That was indeed true for certain aspects. And then what finally came out in the end is that what's going on in the expansion chamber/tune pipe is not resonance at all. It turned out that it was just optimized synchronous operation of the expansion chamber-cylinder system at a certain RPM. That's all fine and dandy but it is not resonance.
The reason it went that far is that "resonance" is a very charged term, it's a very abused term, and it is a term that is used to manipulate unsuspecting people or wanna-believers all the time. I think it's safe to say that every single day that someone new makes a fake pitch using the magic word "resonance" to try to con money out of people.
So the goal was to get everyone on the same page with respect to what the scientific and engineering term "resonance" really is, what it means, and how it is actually defined.
That goal met with partial success, and I think it's safe to say many lurkers learned a lot about it and it shook off a lot of preconceptions. I am hoping that the next time somebody makes a resonance pitch, that somebody will say, "What specifically do you mean by 'resonance' in your system, please define it." For sure, that will make some resonance pitch artists choke because they won't be able to define it, they are just using it as a meaningless buzz word.
So I hope that gives you some understanding of the context in this whole conversation. Delay lines are used all the time in electronic circuits, and you can buy delay line chips. Case in point: Delay line chips are advertised as delay lines, not as magic devices that will make your circuit resonate.
MileHigh
-
Yes Miles taught the kiddies plenty ...
Quote
No, an ICE doesn't resonate in any way, shape or form whatsoever.
end quote
we learned right here that Miles Pulls out all the stops when it comes to winning, even if it means he manufactures - facts-
from thin air.
Aside from the Simplest of ICE's the WW2 Buzz bomb [ICE In Complete cavity resonance]
it would also seem that resonance in an ICE is showing that the impossible [laws of thermodynamics ] is indeed possible.
a 50CC N.A. 2 stroke should not be doing what it shows on the Dyno ,and resonance is soooo much a part of what is happening there.
8 HP per cubic inch displacement.
that's 400 HP per liter ,[ not a 4sec Blown monster on Nitro] ,runs and runs and runs.
breaking the rules.....
with resonance.
and yes MH I know your goal is to quote
"put an end to this resonance nonsense once and for all"
end quote
fact is things come apart under resonant conditions, NMR.. NAR ...LENR....
The -TUNE- of resonance ..only the beginning MH ...Not the End.
thanks for the lesson !
-
Yes Miles taught the kiddies plenty ...
Quote
No, an ICE doesn't resonate in any way, shape or form whatsoever.
end quote
we learned right here that Miles Pulls out all the stops when it comes to winning, even if it means he manufactures - facts-
from thin air.
Aside from the Simplest of ICE's the WW2 Buzz bomb [ICE In Complete cavity resonance]
it would also seem that resonance in an ICE is showing that the impossible [laws of thermodynamics ] is indeed possible.
a 50CC N.A. 2 stroke should not be doing what it shows on the Dyno ,and resonance is soooo much a part of what is happening there.
8 HP per cubic inch displacement.
that's 400 HP per liter ,[ not a 4sec Blown monster on Nitro] ,runs and runs and runs.
breaking the rules.....
with resonance.
and yes MH I know your goal is to quote
"put an end to this resonance nonsense once and for all"
end quote
fact is things come apart under resonant conditions, NMR.. NAR ...LENR....
The -TUNE- of resonance ..only the beginning MH ...Not the End.
thanks for the lesson !
No point in flogging a dead horse Chet,MH has his own definition of resonance.
To quote the scientific meaning of resonance
Quote: Resonance is the forced motion in tune with the natural oscillation frequency of a system, which is called the resonant frequency. Resonance is created when pushing the system in the right direction that increases its amplitude.
MH cannot understand that the expansion chamber has a resonant frequency,which is the frequency of the gas charge moving back and forth within that expansion chamber.
He also dose not understand,that in order for this resonant frequency to be reached,the engine RPM has to be correct,nor dose he understand that the driving force behind it all,is the the expanding gases within the cylinder from the ignition of the fuel/air mix.
Now he is trying to !!some how!! infer that it is just some sort of delay line--which it is nothing of a sort.
Delay line-->a device producing a specific desired delay in the transmission of a signal.
There is no such delay rubbish in the two stroke expansion chamber. Fresh gas mix is drawn out of the cylinder,into the expansion chamber,and then it is returned back into the expansion chamber. This is an oscillating action,it is not a delay at all. This oscillating action has a specific frequency,and maximum amplitude of pressure inside the cylinder can only take place when the engine RPMs match the resonant frequency of that expansion chamber. If the engines RPM(frequency of oscillation of the piston)do not match the resonant frequency of the expansion chamber,then maximum amplitude of pressure in the combustion chamber will not be reached.
When the pistons oscillation frequency matches the natural resonant frequency of the expansion chamber,then maximum amplitude in pressure is reached in the combustion chamber-->the supercharging effect,and maximum power is developed by the engine.
MH just cannot put two and two together,and see that the piston is an oscillating object,that must oscillate at the same frequency as the natural resonant frequency of the expansion chamber,in order for maximum amplitude to be reached.
The system as a whole ,fits the very definition of a resonant system,where a driving force(the exploding gas mix) is the force that creates both the oscillation of the piston,and the oscillating gas charge within the expansion chamber. A small amount of energy is dissipated out through the expansion chamber,but most remains within the system,and is delivered to a load. The very same is true with an LC tank circuit,where some of the energy is dissipated as heat,but the bulk of the energy remains in the system,and may be delivered to a load.
There are some Chet,that can understand how to use resonance to our advantage,while there are others that will be stuck hitting a tuning fork with a hammer,and watching the world go by as they listen to there tuning fork oscillating at it's natural frequency.
Brad
-
There are some Chet,that can understand how to use resonance to our advantage,while there are others that will be stuck hitting a tuning fork with a hammer,and watching the world go by as they listen to there tuning fork oscillating at it's natural frequency.
Right, you have been presented with overwhelming evidence that a struck tuning fork resonates. Resonance has been properly defined for you because you were unable to define if for yourself. We all grew up hearing that a bell or a tuning fork or a wine glass resonates when it is struck and it all makes perfect sense.
But no, you saying "a struck tuning fork resonates" would mean that you would be admitting that you were w.... from your statement from a month or two ago.
So you and at least Chet are forced to live in some kind of "Brad's Bizarro World" to prevent your head from exploding.
Brad in chains.
-
Now he is trying to !!some how!! infer that it is just some sort of delay line--which it is nothing of a sort.
Delay line-->a device producing a specific desired delay in the transmission of a signal.
There is no such delay rubbish in the two stroke expansion chamber. Fresh gas mix is drawn out of the cylinder,into the expansion chamber,and then it is returned back into the expansion chamber. This is an oscillating action,it is not a delay at all. This oscillating action has a specific frequency,and maximum amplitude of pressure inside the cylinder can only take place when the engine RPMs match the resonant frequency of that expansion chamber. If the engines RPM(frequency of oscillation of the piston)do not match the resonant frequency of the expansion chamber,then maximum amplitude of pressure in the combustion chamber will not be reached.
When the pistons oscillation frequency matches the natural resonant frequency of the expansion chamber,then maximum amplitude in pressure is reached in the combustion chamber-->the supercharging effect,and maximum power is developed by the engine.
Yes, it's a delay line, you can completely forget about the expansion chamber resonating in terms of the operation of the two-stroke engine. It's simply a device that was designed to generate a reverse pressure wave with the right synchronous delay at a given RPM to push the fuel mixture back into the cylinder before firing. Your own link said that.
But it's more fun and cooler and sexier sounding to say "resonance," not to mention that "resonance" was your initial pitch and we couldn't have you admitting that you were w.... because that would make your head explode.
-
Yes Miles taught the kiddies plenty ...
Quote
No, an ICE doesn't resonate in any way, shape or form whatsoever.
end quote
we learned right here that Miles Pulls out all the stops when it comes to winning, even if it means he manufactures - facts-
from thin air.
Aside from the Simplest of ICE's the WW2 Buzz bomb [ICE In Complete cavity resonance]
it would also seem that resonance in an ICE is showing that the impossible [laws of thermodynamics ] is indeed possible.
a 50CC N.A. 2 stroke should not be doing what it shows on the Dyno ,and resonance is soooo much a part of what is happening there.
8 HP per cubic inch displacement.
that's 400 HP per liter ,[ not a 4sec Blown monster on Nitro] ,runs and runs and runs.
breaking the rules.....
with resonance.
and yes MH I know your goal is to quote
"put an end to this resonance nonsense once and for all"
end quote
fact is things come apart under resonant conditions, NMR.. NAR ...LENR....
The -TUNE- of resonance ..only the beginning MH ...Not the End.
thanks for the lesson !
What about the bloody pistol shrimp?
When you say "an ICE uses resonance to work better and produce more power" what do you think of first? I am willing to bet you the average person thinks of a modern four-stroke fuel-injected four or six-cylinder gasoline engine used in any modern European, North American, or Japanese car.
I am not an expert but I would not be surprised if the following were true:
1. There is no type of Helmholtz resonator to help put air into the cylinders before combustion
2. There is no need for an "anti-resonance" resonant cavity in the cylinder head
3. There is no expansion chamber on the exhaust gas outlet because it is a four-stroke engine and it has a stroke for expelling the exhaust gasses.
So, if all that is indeed true, and assuming that the statement applies to the most common type of modern ICE used in a car, then stating that there is "no resonance in an ICE in any way, shape, or form" is not so unreasonable a statement, is it? Especially when you are talking about the true scientific and engineering definition of resonance and not something that you would read in the classified section of Hot Rodder magazine.
Of course, you can always come back after the initial generic statement about ICE's and resonance and say, "Even through I did not specify anything, I was really talking about competitive two-stroke gas engines used for racing." That's the ticket!
Yes Miles taught the kiddies plenty ...
Quote
No, an ICE doesn't resonate in any way, shape or form whatsoever.
end quote
we learned right here that Miles Pulls out all the stops when it comes to winning, even if it means he manufactures - facts-
from thin air.
Yeah, I am a real hard-core manufacturer of facts from thin air. Hmmm.... I seem to remember that I took back my statement about "ICE's not resonating in any way, shape, or form whatsoever" when presented with the facts about competitive two-stroke engines having Helmholtz resonators on the front end and with some obscure reference to the fact that somewhere in the past for some unknown engine they had to hollow out an "anti-resonance" resonant chamber in the cylinder head.
Now, why don't you run along and make a "Top 100" list of all of the incorrect and/or totally ridiculous statements that Brad has made that he has never admitted to as well as making a separate "Top 25 admissions that if they were made would make Brad's head explode" list? There is more than enough material for you to work with.
No? Oh I get it, you just want to remind me over and over about a statement that I already admitted was wrong. It sounds like Brad is rubbing off on you.
-
MH
Its not about your interaction with Brad here so much as your wanting to "End"
Quote
this nonsense resonance rhetoric at an OU forum which sees Resonance or tuning as a necessary component
worthy of investigation .
you position yourself an authority of all things resonant and By default assume that all who venture
into the study of resonance or resonant tuning .. as it may apply to OU are lost ignorant or uneducated fools !
and this you gleefully do at an OU forum and hope to Teach your perspective to all.. and guide them
to the Light which shines from your unresonant presence.
and yes the Pistol shrimp [I took the Bait] is a nice example of what can happen in a softer medium with a properly tuned resonant cavity and an impulse .
A Bug Knocking photons out of orbit should not be so readily dismissed with a Yawn.....
and cavity resonance and water cavitation would definitely be an area worthy of
experiment ...
at an OU forum.
-
Oh stop being a jilted resonance fetishist and get over it. I don't position myself as an "authority of all things," that's a ridiculous statement. Stop repeatedly putting words in my mouth that I never spoke. Just bloody well stop it already.
Years ago I saw a posting from you about resonance where you were jumping for joy in some kind of expression of resonance mental orgasmic bell-ringing Nirvana. Can you point me to an OU system based on resonance? If not then just keep searching and don't bother me about it.
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author=MileHigh link=topic=16589.msg486217#msg486217 date=1465827168]
When you say "an ICE uses resonance to work better and produce more power" what do you think of first? I am willing to bet you the average person thinks of a modern four-stroke fuel-injected four or six-cylinder gasoline engine used in any modern European, North American, or Japanese car.
I am not an expert but I would not be surprised if the following were true:
1. There is no type of Helmholtz resonator to help put air into the cylinders before combustion
2. There is no need for an "anti-resonance" resonant cavity in the cylinder head
3. There is no expansion chamber on the exhaust gas outlet because it is a four-stroke engine and it has a stroke for expelling the exhaust gasses.
Being on a forum that researches OU,why would we be talking about generic !off the shelf! engines.
Weekly i fit extractors to !standard! motor vehicles,to increase efficiency,power and performance.
Why have the motor do work to push out exhaust gases,when you can have extractors that suck it out. With one simple modification,we have removed the need for the engine to do work it dose not have to do.
You have such a negative attitude MH,and that helps no one.
Brad
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author=MileHigh link=topic=16589.msg486217#msg486217 date=1465827168]
Being on a forum that researches OU,why would we be talking about generic !off the shelf! engines.
Weekly i fit extractors to !standard! motor vehicles,to increase efficiency,power and performance.
Why have the motor do work to push out exhaust gases,when you can have extractors that suck it out. With one simple modification,we have removed the need for the engine to do work it dose not have to do.
You have such a negative attitude MH,and that helps no one.
Brad
So what you are really saying to me is that if you make a reasonable assumption that your unqualified reference to an internal combustion engine is for a modern four or six-cylinder four-stroke fuel-injected engine found in a modern mainstream car, then the statement that there is no resonance at play to improve the performance of the engine is perfectly valid. So a couple of months worth of haranguing from you about the "ICE resonance" issue was all pretty much nonsense. Your communication skills are so weak that it didn't even occur to you to qualify what type of ICE you were talking about when you said that there was resonance used in an ICE to improve performance. And then when that is finally looked at in detail the only resonance at play is the Helmholtz resonator for the air intake.
Months of being harangued and almost harassed by you over a bloody Helmholtz resonator.
And you still can't bring yourself to say that a struck wine glass, bell, or tuning fork will resonate.
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Being on a forum that researches OU,why would we be talking about generic !off the shelf! engines.
I didn't have my Ouija board, it was at the shop.
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Miles
if your gonna steal my Line, at least get it right, its a crystal Ball
not a Weeegy Board.
anyhoo
Yes ,
years ago I became aware that a very small input in a properly designed cavity resonator could do things
which seemed implausible.
a Pistol Shrimp Knocks photons out of orbit and causes a biological sonoluminescent event with an accompanying 9000C temperature spike.
so now I like shrimp
Bubba....
\well actually more so Water and its very simple design and potential, it is after all very very close to rocket fuel
on the "chain"
and to be honest with the advances being made at the race track with 50CCtwo stroke engines and cavity resonance
making 8HP per cubic inch
the whole thing [8hp per cubic inch 2 stroke] is one huge resonant monster which is making more power than the laws of thermodynamics say is possible .
and you also learned here that Honda and others are injecting water into the back side of this huge standing wave at the exhaust outlet to Tune and so forth. [Brad seems to be doing something above which works here too ??]
water under resonant pressure does some odd things ...Bubba ...just ask the shrimp .
Contrary to you hearts desire.... resonance and resonant Tuning is most definitely NOT GOING AWAY anytime soon around here .
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the whole thing [8hp per cubic inch 2 stroke] is one huge resonant monster which is making more power than the laws of thermodynamics say is possible .
So you somehow get more energy out than is in the gasoline itself? I think it's your resonance daydreams that are sweeping you off of your feet.
Resonance is just a mechanism for storing energy from an external source by bouncing it back and forth between two different forms. It's not a Dirac sea inverse discombobulator, sorry.
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Resonance is just a mechanism for storing energy from an external source by bouncing it back and forth between two different forms.
And proven, Resonance is making things more Efficient!
See: https://www.youtube.com/watch?v=nAseG7z_GQo (https://www.youtube.com/watch?v=nAseG7z_GQo)
All below or above Nen-Drehzahl is more current!
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First, one MUST consider, in the case of an ICE, that you have three separate systems, EACH at it's own Resonant frequency. The idea is to synchronize these three in a way that improves the operation, and this is NOT simple. (For a reality check, think Tesla and his circuits that had different sections that resonated at different frequencies. How many understand that setup?)
Asked by a UK-friend, to read the last ICE now here?, and what a bogus, typical journalist Campus-Pup-Slang.
Meaning HEMI was already old on the moment from introduction, beside that also stolen from ............!?
Nicky, Why you don'''t report them to: http://www.fraud.org (http://www.fraud.org)
Loner to make it short:
Can you supply us to 2-Plots from your Software,
Take your ideal 125cc 2-Stroke for Race or MX,
1-Plot, like is being like you're ideal 2-stroke,
2-Plot, same engine, but a 3mm below the Cilinder, and 3 mm longer Connection-Rod.
Succes, Johan
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Please some one: What is a TPU-Elite meaning?
Maybe: Eatable, Religious, Campus-Club-Extremist or ........... ?
Please some spec's, with independent 3e party proof, rest is only Campus-Pup Pasta against nicky's Alu-Dome?
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author=MileHigh link=topic=16589.msg486217#msg486217 date=1465827168]
Being on a forum that researches OU,why would we be talking about generic !off the shelf! engines.
Weekly i fit extractors to !standard! motor vehicles,to increase efficiency,power and performance.
Why have the motor do work to push out exhaust gases,when you can have extractors that suck it out. With one simple modification,we have removed the need for the engine to do work it dose not have to do.
You have such a negative attitude MH,and that helps no one.
Brad
Dear Brad.
Ever heard of the " Petter Super Scavenge " Diesel engine?
This opened a whole new world of, dare I mention the " R " and " T " word? Particularly in the design of exhaust systems.
Cheers Grum.
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Johan
The TPU was fastidiously investigated by a very skilled independent 3rd party , and Loner is no slacker or keyboard couch potato.
and I can assure you he doesn't like these names attached to his Posts [Elite ,Hero etc etc].
Stefan Attached these handles to people who spent countless hours of their lives attempting to Crack the TPU [persons who shared their efforts like Loner has always done]
actually in his case I am glad I explained it here, he is a wonderful fellow !
respectfully
Chet K
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Dear Johan.
I wanted to insert your quote about the HEMI, but it read web page unavailable ?
As far as I'm aware this engine from I F Allman ( 1891 ) was the first to employ a full hemispherical combustion chamber.
http://www.google.co.uk/patents/US453071
I built one too...........
Cheers Grum.
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Dear Johan.
I wanted to insert your quote about the HEMI, but it read web page unavailable ?
As far as I'm aware this engine from I F Allman ( 1891 ) was the first to employ a full hemispherical combustion chamber.
http://www.google.co.uk/patents/US453071
I built one too...........
Cheers Grum.
Yes, but Don Garlits never used one of those...it was always the Chrysler 426 hemi for him, ha ha. Those were the days, 425 H.P. stock right from the factory and over 10,000 H.P. when modified.
Bill
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Yes, but Don Garlits never used one of those...it was always the Chrysler 426 hemi for him, ha ha. Those were the days, 425 H.P. stock right from the factory and over 10,000 H.P. when modified.
Bill
425 H.P. stock right from the factory and over 10,000 H.P. when modified.
10 000HP?
Perhaps you mean 1000HP?. :D
Brad
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Bill wrote.
" Yes, but Don Garlits never used one of those...it was always the Chrysler 426 hemi for him, ha ha. Those were the days, 425 H.P. stock right from the factory and over 10,000 H.P. when modified.
Bill "
Dear Bill.
Surely a typo ?? 10,000 HP ?? Or were they biddy little horses needing 10 to make one good old British " Shire " ? :)
Cheers Grum.
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Dear Brad.
Ever heard of the " Petter Super Scavenge " Diesel engine?
This opened a whole new world of, dare I mention the " R " and " T " word? Particularly in the design of exhaust systems.
Cheers Grum.
No,not heard of them. We had the Peterbilt engines in some of our trucks though ;D
But my fav has always been the Detroit V8 turbo fed supercharged 2 stroke 8). There is nothing that sounds like them working at full noise. ;)
Brad
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OOHHH
Now you touched a nerve...
the 2 stroke Detroit with a Blower[only came that way] is an acquired taste...a sound which sends Kiddies scurrying for
cover !
I've been staring at a wee 471 in my Buddies toasted Dozer for quite some time trying to justify
hacking it out and putting it in something...
anything !!
we use to have A 16 Cyl Detroit Genset [two Blowers] running the crushing plant and 100 HP electric motors.
There were times when it looked like that lightning bolt making Tesla monster TK posted a link to in the "Ere" thread
and you just had to stand back and wait for it to run out of Fuel or get the Guts up to hit the Kill switch!!
Yes the poor mans Diesel ....
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Grum
Yes Don Garlits made the Hemi notorious over here back in the Dragster days of Yore
and yes they did throw around Big HP numbers at the Time ,I can remember arguing with My A+P instructor
about that in School.
those engines had a Life expectancy of 0 to half a minute at full throttle .
I am quite certain Your Hemi would last much longer ..
that is "yours" in the pic ..Grumbuilt ?
what does it use for fuel ?
thx
Chet
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Dear Chet.
Yes indeed, " Grumbuilt " !! :)
A friend found the patent drawings. I then chose a scale from a suitable flywheel that I already had ( 9" dia ) and made all the wooden patterns to suit. A few trips to the Iron and Brass foundry and a few extra hours on the lathe and milling machines, and viola, a running Gas engine. I even made my own timing gears.
The picture is the original prototype I built and there are a couple of others here in the UK. It runs on Propane for both fuel and ignition ( Hot tube ).
Cheers Grum.
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10 000HP?
Perhaps you mean 1000HP?. :D
Brad
Yes, I meant 10,000. Just about all of the top fuel dragster run engines based on the Chrysler 426 hemi engine design. Some make a lot more HP than this.
"The calculated Power output of these engines is most likely somewhere between 8500 and 10,000 horsepower (approximately 6000-7500 kilowatts), which is about twice as powerful as the engines installed on modern Diesel locomotives, and approaches the power output of the largest aviation turboprop engines, with a torque output of approximately 6000 lbf·ft (8135 N·m) and a brake mean effective pressure of 80–100 bar (8.0-10 MPa"
Bill
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http://www.sccoia.org/articles/top-fuel-dragster-fast-facts/ (http://www.sccoia.org/articles/top-fuel-dragster-fast-facts/)
"One Top Fuel dragster 500 cubic-inch Hemi engine makes more horsepower than the first 4 rows at the Daytona 500."
Bill
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Bill wrote.
" Yes, but Don Garlits never used one of those...it was always the Chrysler 426 hemi for him, ha ha. Those were the days, 425 H.P. stock right from the factory and over 10,000 H.P. when modified.
Bill "
Dear Bill.
Surely a typo ?? 10,000 HP ?? Or were they biddy little horses needing 10 to make one good old British " Shire " ? :)
Cheers Grum.
https://www.youtube.com/watch?v=CN4uAQzI1rs (https://www.youtube.com/watch?v=CN4uAQzI1rs)
Video of a 10,000 HP Hemi.
https://www.youtube.com/watch?v=jxyEtC6G5U4 (https://www.youtube.com/watch?v=jxyEtC6G5U4)
Video of an 11,000+ HP Hemi
https://www.youtube.com/watch?v=2GX0A_-FRtY (https://www.youtube.com/watch?v=2GX0A_-FRtY)
8,000 Horsepower VS 10,000 Horsepower (Both are Hemis)
Bill
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Yes, I meant 10,000. Just about all of the top fuel dragster run engines based on the Chrysler 426 hemi engine design. Some make a lot more HP than this.
"The calculated Power output of these engines is most likely somewhere between 8500 and 10,000 horsepower (approximately 6000-7500 kilowatts), which is about twice as powerful as the engines installed on modern Diesel locomotives, and approaches the power output of the largest aviation turboprop engines, with a torque output of approximately 6000 lbf·ft (8135 N·m) and a brake mean effective pressure of 80–100 bar (8.0-10 MPa"
Bill
Its odd to think about it, that say 5 or 6 electric space heaters could equal that sort of power.
"On the P85D, Tesla pretty much maintained the existing high-performance rear motor--at 350 kilowatts (470 horsepower)--and added an additional 165-kW (221-hp) motor up front."
http://www.greencarreports.com/news/1094911_tesla-model-s-dual-motor-is-quicker-has-higher-range-too-how-do-they-do-that
Hmm. I wonder how they come up with those numbers?
Mags
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Its odd to think about it, that say 5 or 6 electric space heaters could equal that sort of power.
"On the P85D, Tesla pretty much maintained the existing high-performance rear motor--at 350 kilowatts (470 horsepower)--and added an additional 165-kW (221-hp) motor up front."
http://www.greencarreports.com/news/1094911_tesla-model-s-dual-motor-is-quicker-has-higher-range-too-how-do-they-do-that (http://www.greencarreports.com/news/1094911_tesla-model-s-dual-motor-is-quicker-has-higher-range-too-how-do-they-do-that)
Hmm. I wonder how they come up with those numbers?
Mags
I have no idea to be honest.
Bill
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Its odd to think about it, that say 5 or 6 electric space heaters could equal that sort of power.
Perhaps you meant to say 5 or 6 thousand electric space heaters...
PW
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Perhaps you meant to say 5 or 6 thousand electric space heaters...
PW
Lol. Yes you are correct. I was wrong.. Dont know what I was thinking. ;D
Mags
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1.21 gigawatts!
Just looking it over again, if we say 6 to 7.5MW, it sounds pretty monstrous.
7500 heaters. For 3 seconds.
375 heaters for 60 seconds.
6.25 heaters for an hour
So the total amount of power, 7.5MW for 3 seconds, is enough to run 1 space heater for about 6 hours. Hmm, kinda makes me think about inductive field collapse spikes.
lol, is that correct? Ive been known to be wrong, today. ;D
Mags
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Clunks,bangs and whistles lol.
Almost like a band playing.
https://www.youtube.com/watch?v=WXzSZVgQwts
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10 Hp
gotta Luv that
it does sound like a Hollywood sound effects machine ,just needs a couple Horn squeaks mixed in .
I wonder how efficient it was to run?
Grum would probably have a good idea
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Hi Chet.
For some reason I can't use the quote to reply function on this thread, strange.
The video that Brad linked to was of a Blackstone " Lamp start " hot bulb ignition semi Diesel from the mid 1920's. It's fuel would have been lamp oil now commonly known as Kerosene with you and Paraffin over here.
Not very fuel efficient compared to modern day but still running despite the serious cylinder blow by and nearly 100 years of active service.
I have attached a picture of my attempt at a quarter scale Hornsby Akroyd from 1891 engine number 193.These were the first engines to successfully operate on the hot bulb ignition system, it's so early that the starting lamp pre dates the pressure blow lamp hence the strange looking object under the bulb shroud. Sadly it never ran very well so nine months work of scaling and patternmaking were for nought.
https://www.youtube.com/watch?v=rZanAMesCeY
It makes you think........... Perhaps in this area of research trying to scale down things is a mistake? My own experience in the model engineering world is the smaller they are the harder they are to get going. Well apart from steam......
Cheers Grum.
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Loner wrote.
"
As to all the posts between your question and this reply, I think think the thread has been fully hijacked. Interesting stuff I suppose. I don't visit the forum enough to keep up, these days.
How a discussion of ideal Inductor and voltage came to this... "
Dear Loner.
My apologies for the hijack. If my posts seem irrelevant, please advise, I can remove them far quicker than it took to post them.
Resonance and tuning both play a great part to the efficient running of an ICE both internally and externally.
Cheers Grum.
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The thread is long since done, you can hijack it all you want.
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In an attempt to enlighten the non-believers (those having difficulty understanding currents through voltage sources), let's alter/simplify MH's question to the following:
- same ideal voltage source and ideal 5H inductor connected across each other.
- between t=0 and t=3, V=+4V
- between t=3 and t=6, V=-4V
- from t=6 to infinity, V=0V
(see scope shot)
We know from previous discussions that between t=0 and t=3, the circuit current will ramp up linearly to 2.39A. I think everyone agrees with this, even the non-believers. ;) We can also calculate the power and conclude that the power delivered by the voltage source ramps up from 0W to 9.56W during the same period of time. But since we know that the current and voltage in a voltage source are 180º out of phase, the power will actually ramp down to -9.56W.
What happens between t=3 and t=6 when the voltage inverts from +4V to -4V? Well, the non-believers have stated the following:
Loner
I would not bother with this question based around a voltage source that dose not exist.
MH is also not able to understand that an ideal voltage cannot be placed across a conductor that has 0 ohms of resistance,and current flowing against that that the ideal voltage wants to create.This is like placing an ideal voltage across an ideal capacitor.
At T=3 seconds--kaboom--bye bye equipment and components.
But how can that be? Real world experiments certainly don't result in the catastrophic end of the earth, and a simulation debunks this notion as well. Well, the non-believers argue that the L/R ratio of 5000:1 is not close enough to ideal (5H/1m), yet I have shown via sim that a ratio of even 100:1 is close enough for a 5% error. That converts to a total series resistance of 50m Ohms.
The fact is, most high quality high power audio amplifiers have an output damping factor of about 400:1, which means the output resistance is on the order of 20m Ohms (based on 8 Ohm load). So a big audio power amp is a good ideal voltage source.
The other fact is that we can indeed short out an ideal inductor that has current flowing through it, by ideal wire or ideal voltage source. If in our example the inductor is shorted by an ideal wire right at t=3, what happens? does the inductor and the world blow up? I think we all agree that the current would remain at 2.39A. If the voltage source went to 0V rather than -4V at t=3, we know that it would act the very same way as the previous case of the ideal wire, and the current would remain at 2.39A and there would be no explosions.
But my example switches the voltage from +4V to -4V, right at the instant 2.39A is flowing in the coil and voltage source. What happens next is the opposite from the period between t=0 and t=3; the current ramps down from 2.39A to 0A, and the power instantly changes from -9.56W to +9.56W, and ramps back down to 0W. The energy stored in the inductor is returned to the voltage source. No energy was dissipated when the inductor was energized, and none is dissipated when it de-energizes.
Green=voltage Source
Red= Circuit Current
Purple= Voltage Source Power
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Loner wrote.
"
As to all the posts between your question and this reply, I think think the thread has been fully hijacked. Interesting stuff I suppose. I don't visit the forum enough to keep up, these days.
How a discussion of ideal Inductor and voltage came to this... "
Dear Loner.
My apologies for the hijack. If my posts seem irrelevant, please advise, I can remove them far quicker than it took to post them.
Resonance and tuning both play a great part to the efficient running of an ICE both internally and externally.
Cheers Grum.
Aint that the truth ;)
Brad
-
In an attempt to enlighten the non-believers (those having difficulty understanding currents through voltage sources), let's alter/simplify MH's question to the following:
- same ideal voltage source and ideal 5H inductor connected across each other.
- between t=0 and t=3, V=+4V
- between t=3 and t=6, V=-4V
- from t=6 to infinity, V=0V
(see scope shot)
We know from previous discussions that between t=0 and t=3, the circuit current will ramp up linearly to 2.39A. I think everyone agrees with this, even the non-believers. ;) We can also calculate the power and conclude that the power delivered by the voltage source ramps up from 0W to 9.56W during the same period of time. But since we know that the current and voltage in a voltage source are 180º out of phase, the power will actually ramp down to -9.56W.
What happens between t=3 and t=6 when the voltage inverts from +4V to -4V? Well, the non-believers have stated the following:
But how can that be? Real world experiments certainly don't result in the catastrophic end of the earth, and a simulation debunks this notion as well. Well, the non-believers argue that the L/R ratio of 5000:1 is not close enough to ideal (5H/1m), yet I have shown via sim that a ratio of even 100:1 is close enough for a 5% error. That converts to a total series resistance of 50m Ohms.
The fact is, most high quality high power audio amplifiers have an output damping factor of about 400:1, which means the output resistance is on the order of 20m Ohms (based on 8 Ohm load). So a big audio power amp is a good ideal voltage source.
The other fact is that we can indeed short out an ideal inductor that has current flowing through it, by ideal wire or ideal voltage source. If in our example the inductor is shorted by an ideal wire right at t=3, what happens? does the inductor and the world blow up? I think we all agree that the current would remain at 2.39A. If the voltage source went to 0V rather than -4V at t=3, we know that it would act the very same way as the previous case of the ideal wire, and the current would remain at 2.39A and there would be no explosions.
Green=voltage Source
Red= Circuit Current
Purple= Voltage Source Power
Even the best some times make mistakes.
Quote post 63-Poynt
My blown universe post was a bit of a ruse. In fact it implied the opposite of what would theoretically happen, that is, "nothing".
Quote post 74-me
So you are saying that at T=0--the instant the ideal voltage is placed across the ideal inductor,nothing would happen?--no voltage would appear across the ideal inductor?.
quote post 81-Poynt
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever.
Quote post 84-MH
Brad:
You have actually been given part of the answer, and you see that you were dead wrong. Turn that into a learning experience.
Seems at this time,both myself and Poynt are wrong. :D
Quote post 106-Poynt
Unless I'm overlooking something, or don't correctly understand the question, there will be no current, and the voltage across the inductor will be whatever the voltage source is at any one time, from t=0 to the end of time.
Given that tau=infinity, there can be no change in either I or V. Indeed if R is non-zero, there will be a current and the voltage change over time.
Quote post 123-Poynt
For your test (13s of a few different voltages), the different voltages have no affect on the outcome.
So the question could have been asked with one voltage and still have the same answer, correct?
I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.
I think we can conclude from these results that my answer is correct.
So here a very small value of resistance was used in the sim,and an answer given by the sim.
Odd that as soon as we increase the resistance of the coil,the sim starts showing different results.
Was the sim unable to replicate the actual question?.
Quote post 56-MH
The sim will work perfectly
What happens when the sim dose not show the results MH wants to see
Quote post 127-MH
Perhaps forget about the sim and do it in your head :D
Quote post 328-verpies
It is impossible to connect such voltage source across a shorted ideal inductor, because in such case this voltage source would see a load, which does not have any resistance nor reactance
And this is the part you are all missing here.
We have agreed that between T=3s and T=5s,when the voltage value is 0v,a current of 2.4 amps will continue to flow through the ideal coil and ideal voltage source circuit,and will not fall in value,due to there being no resistance in this loop. This can only mean that the loop is a dead short,or shorted loop-continual loop with no resistance.So the ideal voltage source !is! the ideal short across the ideal coil,and this inductor has no resistance,and since the current flow is steady at 2.4 amp's,it also has no reactance. At T=5s,we are now going to try and place a negative voltage across this shorted ideal coil :o
Quote post 7--MH
no,a voltage cannot exist across an ideal inductor that has a DC current flowing through it.
Quote post 336-Poynt
All inductors, whether ideal or real will have a voltage across them when there is current through them, regardless if the current is changing or not.
Who is correct here?.
But my example switches the voltage from +4V to -4V, right at the instant 2.39A is flowing in the coil and voltage source. What happens next is the opposite from the period between t=0 and t=3; the current ramps down from 2.39A to 0A, and the power instantly changes from -9.56W to +9.56W, and ramps back down to 0W. The energy stored in the inductor is returned to the voltage source. No energy was dissipated when the inductor was energized, and none is dissipated when it de-energizes.
Quote post 425-MH
An ideal voltage source does not "contain energy"
It would seem that there needs to be a few things ironed out,as no correct answer can be obtained from those that are trying to give it,being in disagreements with each other.
First things first
MH-a voltage cannot exist across an ideal inductor that has a DC current flowing through it
Poynt-All inductors, whether ideal or real will have a voltage across them when there is current through them, regardless if the current is changing or not
Second
MH-An ideal voltage source does not "contain energy
Poynt-TThe energy stored in the inductor is returned to the voltage source
Brad
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And this is the part you are all missing here.
We have agreed that between T=3s and T=5s,when the voltage value is 0v,a current of 2.4 amps will continue to flow through the ideal coil and ideal voltage source circuit,and will not fall in value,due to there being no resistance in this loop. This can only mean that the loop is a dead short,or shorted loop-continual loop with no resistance.So the ideal voltage source !is! the ideal short across the ideal coil,and this inductor has no resistance,and since the current flow is steady at 2.4 amp's,it also has no reactance. At T=5s,we are now going to try and place a negative voltage across this shorted ideal coil :o
And when the applied voltage goes negative (changes), the inductor's reactance limits the change in current...
PW
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Resonance and tuning both play a great part to the efficient running of an ICE both internally and externally.
Yes, it's easy to say those things. But assuming that we are talking about the true scientific and engineering definition for resonance, so far the only thing that I am aware of is Helmholtz resonators for the air intake of a two-stroke engine. For a modern four-stroke engine in a typical car, I am aware of nothing at all.
The word resonance is a ridiculously abused, misunderstood, and recklessly applied concept on the free energy forums. In Russ' forum on the Rodin coil testing thread, someone posted this "resonance" clip called "Resonance in a bifilar coil."
https://www.youtube.com/watch?v=qtI1CPBSm-o (https://www.youtube.com/watch?v=qtI1CPBSm-o)
The clip has absolutely nothing whatsoever to do with resonance, nada. However, presumably most of the readers of the thread are gobbling it up and believing it does.
If you can make valid points about resonance in an ICE, I would be most interested in learning about it. But just throwing the term around like a marketing buzz word or some mechanic's shop talk will not work for me.
MileHigh
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Even the best some times make mistakes.
The most cynical part of that posting is that Poynt got off to a shaky start at one point in the discussion and part of it was because he got thrown off by what his sim was saying. His bad sim was reinforcing his mistaken preliminary thoughts. Within one or two days clarity came back to him and he retracted his incorrect statements. Everybody following the thread was witness to this.
And here you are like a clown repeating some of his incorrect statements that he already retracted as part of a setup for your posting where you show conflicting viewpoints being expressed by some people.
Do you understand how doing that is beyond ridiculous on your part? It's just shameless unethical and incorrect behaviour.
Beyond that, what you should do is do a followup posting where you demonstrate all of your new knowledge and resolve all of the apparent conflicts and explain the rationale for each resolution. Enough work has been put into this thread by many people. A countless number of your misunderstandings, mistakes, or obstinate refusals to budge from wrong positions have been argued out in a sincere effort to bring this question to a successful conclusion.
So that's my suggestion to you: Do a bit of shining and list the apparent conflicts and disagreements on the technical points one by one and and then resolve each one with the correct answer with a full explanation for each answer where you demonstrate competency in the subject matter.
MileHigh
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I know you can do much better than that Brad.
I put time and effort into that post, which clearly illustrates what happens. I'd be interested in your thoughts on that particular post and why you still believe the results shown are incorrect.
Even from a layman's point of view (and I'm not implying you are a layman), I would think the scope shot makes perfect sense.
For example, do you not agree that the calculated power from t=3 to t=6 ramps from +9.56W to 0W? We know there is 2.39A of current flowing, and now that the voltage has reversed, it is actually in-phase with the current, so the power goes positive, i.e. +2.39 x -(-4) = +9.56W.
Green=Voltage Source Voltage
Red=Circuit Current
Purple=Voltage Source Power
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Don't ya just have to love the old poynt?
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Dear MileHigh.
For some strange reason I still cannot " quote reply " it comes back with page unavailable.
I wasn't actually referring to car engines but more to the " Stationary " engine side where the fixed RPM creates a fixed frequency. By tuning the exhaust pipe correctly the expanding gasses can actually scavenge the combustion chamber reducing the effort required on the intake side.
I have attached a couple of references to exhaust tuning and I got a surprise to read that Ferrari are employing tuned extractor manifolds on their V 10 engine.
http://www.endtuning.com/exhaustsystems/
https://en.wikipedia.org/wiki/Tuned_exhaust
Cheers Grum.
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Grum
Don't confuse Miles with FACTS ...his mind is already made up...
Just one small example from the resonance propaganda page you linked to
Snip
The exhaust pipes can be thought of like an Organ pipe. For each diameter and length, there is a resonant frequency, in the same way Organ pipes are different sizes and diameters to produce different notes.
Exhaust tuning uses this resonance to help evacuate the gasses from the cylinders.
This is the main point.
A finely tuned exhaust not only reduces the back pressure to minimal levels, it can actually pull the gasses out of the cylinders!
When correctly designed, the exhaust can be tuned to resonate and the pressure vibrations in the exhaust can be timed to have a low pressure wave arrive at an exhaust valve as it opens, pulling the gasses out. This tuning isn't something you can easily modify without advanced modeling of fluid dynamics but many performance systems are set up with this in mind.
--------------
Some lessons just take time to sink in...
no matter how much we hold our breathe and Shake our heads No,No No...
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Grum
Don't confuse Miles with FACTS ...his mind is already made up...
Chet, I have some advice for you: Stop acting like a jackass.
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https://www.youtube.com/watch?v=Tr21QKE8Ui0 (https://www.youtube.com/watch?v=Tr21QKE8Ui0)
No resonance as of yet but..it is a 4 stroke and I am still working on it. My neighbors don't give a damn about resonance, they think this is loud for some reason, ha ha. (It is) I am adding another muffler system soon....I went from 100 mpg to over 110 mpg. Not too bad.
Bill
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Dear MileHigh.
For some strange reason I still cannot " quote reply " it comes back with page unavailable.
I wasn't actually referring to car engines but more to the " Stationary " engine side where the fixed RPM creates a fixed frequency. By tuning the exhaust pipe correctly the expanding gasses can actually scavenge the combustion chamber reducing the effort required on the intake side.
I have attached a couple of references to exhaust tuning and I got a surprise to read that Ferrari are employing tuned extractor manifolds on their V 10 engine.
http://www.endtuning.com/exhaustsystems/ (http://www.endtuning.com/exhaustsystems/)
https://en.wikipedia.org/wiki/Tuned_exhaust (https://en.wikipedia.org/wiki/Tuned_exhaust)
Cheers Grum.
Okay I going to pull the key quote from the first link for starters.
<<< pipes can be thought of like an Organ pipe. For each diameter and length, there is a resonant frequency, in the same way Organ pipes are different sizes and diameters to produce different notes.
Exhaust tuning uses this resonance to help evacuate the gasses from the cylinders.
This is the main point.
A finely tuned exhaust not only reduces the back pressure to minimal levels, it can actually pull the gasses out of the cylinders!
When correctly designed, the exhaust can be tuned to resonate and the pressure vibrations in the exhaust can be timed to have a low pressure wave arrive at an exhaust valve as it opens, pulling the gasses out. >>>
I am not going to pretend that I am an expert on this stuff but let me tell you what I think.
An organ pipe is basically a big whistle. Here is a clip explaining how a whistle or organ pipe works and how to make one:
https://www.youtube.com/watch?v=z8uwLv3s9w8 (https://www.youtube.com/watch?v=z8uwLv3s9w8)
Okay for starters, exhaust pipes don't really act like whistles or organ pipes. So the comparison being made is incredibly weak at best.
In the description they are describing an exhaust pipe that helps scavenge the cylinder of exhaust gasses. This is done with an exhaust pipe with no chamber, just a straight pipe. Under those circumstances you get a reflection at the open end of the pipe that travels back up the pipe to the cylinder as a negative pressure wave. When the wave front of the negative pressure wave reaches the cylinder that will help scavenge the exhaust gasses out of the cylinder.
What you are looking at here is what I already covered with Brad, but this time it is for a negative-pressure reflected wave, and not a positive-pressure reflected wave.
That means that the exhaust pipe is not resonating at all, rather, it is acting like a time delay device to synchronize the returning negative pressure wave with the scavenging of exhaust gasses out of the cylinder.
Since it is a timing delay device, and the engine has a repetition rate for the firing and exhausting of gasses from the cylinder, there is an optimum frequency for the engine, or a near-optimal frequency range for the engine for increased performance.
Does adjusting the length of the exhaust pipe change the optimum engine RPM for the effect? Of course it does, because you are changing the amount of time delay for the arrival of the negative pressure wave, but this is not resonance.
So, my conclusion for the first link is that they are just using non-scientific marketing/shop talk when they talk about tuning the exhaust pipe for "resonance." There is nothing actually resonating in the pipe. Rather, it is acting like a short sound echo chamber.
I have no issue if you refer to this as "resonance" in your vernacular when working on engine exhausts, but relative to the true scientific and engineering definition for resonance, the exhaust pipe is not acting like a resonator. That's in contrast to a pipe organ or a whistle, where the tube is acting like a resonator and kinetic and potential energy is resonating back and forth in a standing sound wave inside the tube.
It's all about truly understanding what is happening in the exhaust pipe and not just throwing a cool-sounding word at the process.
I will now review the second link.
MileHigh
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Grum:
Now for your second link.
The first sentence:
<<< A tuned exhaust system is an exhaust system for an internal combustion engine which improves its efficiency by using precise geometry to reflect the pressure waves from the exhaust valve or port back to the valve or port at a particular time in the cycle. >>>
That seems sum it up nicely and is basically what I just said in my previous posting. This is not resonance.
<<< In a two-stroke engine, tuned expansion chambers are used to reduce loss of the new charge caused by late closing of the exhaust port by delivering a pulse of positive pressure after the exhaust gases have left the cylinder.
In a four-stroke engine, tuned extractor manifolds are used to promote scavenging of the exhaust gases by delivering a pulse of negative pressure just before the exhaust valve closes. >>>
Again, we are talking about synchronizing fixed-delay timing events to a certain engine RPM. This is not resonance and we are not going to have any resonance monkeyshines talk from the resonance fanbois.
It's quite impressive how the exhaust system designers came to the revelation in the 1950s to use geometry and reflected sound waves to their advantage when before that it was probably not even something that was considered.
In summary, both of your links do not show any evidence of true resonance being used in an ICE. At the same time, who am I to change the common vernacular used by ICE enthusiasts when talking about engines and engine exhaust systems. Just keep in mind that even if you may use the word, it is not true resonance and this thread and some related threads are about true resonance.
A ringing wine glass is an example of true resonance, a tuned exhaust system is not.
MileHigh
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Obeewannabee
Your tune is not resonating with reality ,in addition to Many, many other factors in ICE design the speed of sound is most relevant ... to remove resonant tuning and replace it with some purely semantic word salad and declare it as fact and not relevant to resonance is
at the very least ignorance ..
and while we're on the topic of your ignorant semantic rants...
they are 99.9 percent semantic
.099 % substance
and .001% useful on Brads bench whilst he tunes for resonance
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Obeewannabee
Your tune is not resonating with reality ,in addition to Many, many other factors in ICE design the speed of sound is most relevant ... to remove resonant tuning and replace it with some purely semantic word salad and declare it as fact and not relevant to resonance is
at the very least ignorance ..
and while we're on the topic of your ignorant semantic rants...
they are 99.9 percent semantic
.099 % substance
and .001% useful on Brads bench whilst he tunes for resonance
No technical rebuttal, just a bunch of sore loser BS.
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Oh
the aforementioned .001% non semantic "useful" contribution on Brads bench
purely for humor as he giggles about your useless semantic contributions on his real world bench.
If you had posted the material that smokey had posted and its relevance to NMR , NAR and LENR
perhaps it would have been useful to an OU experimenter on his bench
Your semantic Diatribes regarding resonance are of no use whatsoever to Brad.
they do seem to be very important to you ...
and your "Whine" glass !!
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And you are still full of crap. True resonance has been properly defined and explained and that makes you mad.
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author=MileHigh link=topic=16589.msg486597#msg486597 date=1466338366]
The most cynical part of that posting is that Poynt got off to a shaky start at one point in the discussion and part of it was because he got thrown off by what his sim was saying. His bad sim was reinforcing his mistaken preliminary thoughts. Within one or two days clarity came back to him and he retracted his incorrect statements. Everybody following the thread was witness to this.
And here you are like a clown repeating some of his incorrect statements that he already retracted as part of a setup for your posting where you show conflicting viewpoints being expressed by some people.
Exactly what i thought you would say--you hypocrite.
How many threads,over how many months,have we listen to you harp on about how EMJ and wattsup could not answer the very question this thread is about-->how many Mr hypocrite?.
Do you understand how doing that is beyond ridiculous on your part? It's just shameless unethical and incorrect behaviour.
Do you now understand how the rest of us has had to endure the very same thing from you over the past 10 months.? ::)
Beyond that, what you should do is do a followup posting where you demonstrate all of your new knowledge and resolve all of the apparent conflicts and explain the rationale for each resolution.
Sure--right after some one here can back up the claimed correct answer with a circuit that accurately follows the description of the circuit in the question--the scientific method. ;)
Enough work has been put into this thread by many people. A countless number of your misunderstandings, mistakes, or obstinate refusals to budge from wrong positions have been argued out in a sincere effort to bring this question to a successful conclusion.
The question will be bought to a successful conclusion right after the above stated is carried out. No question is answered correctly based around assumptions--that is not the scientific method you harp on about all the time here.
So that's my suggestion to you: Do a bit of shining and list the apparent conflicts and disagreements on the technical points one by one and and then resolve each one with the correct answer with a full explanation for each answer where you demonstrate competency in the subject matter.
My suggestion to you is-->do some shining of your own,and back up your claimed answer with solid proof,base around a circuit that accurately represents the circuit in your question.
Anything short of that will not be accepted as a correct answer.
You bought the !ideal! into this,so now you must back it up.
Brad
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From what Ive 'seen', an initial pulse to a device/object that has a resonant freq, can be in a situation that it is only allowed to be excited for a single cycle, or even just the first half cycle, then be damped till the next pulse. If we ping the wine glass, and only allow it to ring for 1 cycle, that one cycle is the strongest cycle that would occur if it were allowed to ring further than 1 cycle.
So if we have a situation that an ice is at an rpm that excites the tuned pipes, for even 1 cycle or a half cycle then is damped and waits for the next pulse, then I have to say that resonance does occur and has an effect on the operation in that band of rpm. And I can see where there may be an rpm that could produce a resonant situation in the pipes that has no down time and is in sync with the exhaust pulse.
Mags
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I know you can do much better than that Brad.
I put time and effort into that post, which clearly illustrates what happens. I'd be interested in your thoughts on that particular post and why you still believe the results shown are incorrect.
Even from a layman's point of view (and I'm not implying you are a layman), I would think the scope shot makes perfect sense.
For example, do you not agree that the calculated power from t=3 to t=6 ramps from +9.56W to 0W? We know there is 2.39A of current flowing, and now that the voltage has reversed, it is actually in-phase with the current, so the power goes positive, i.e. +2.39 x -(-4) = +9.56W.
Green=Voltage Source Voltage
Red=Circuit Current
Purple=Voltage Source Power
Because there is(for example).000000000000000001% difference between unity and overunity.
One is possible,and the other is not-apparently ;)
The difference between the two is enormous.
The difference between 0 resistance(no resistance)and .000000000000001ohm is also just as enormous,as the difference between 20 000 000 000 watts of power,is no where near an infinite amount of power.
Your sim needs some sort of resistance to even start to compute the numbers--it will not compute the question as asked--we have seen this already.
Near enough is not good enough to claim OU,and so near enough is not good enough to answer a given question. Your sim shows power being dissipated,and that is not what would happen with the device defined in the question.
Can the circuit described in the question be built to verify the claimed answer?
How do you know for sure that there is not some huge change when resistance is removed altogether,like the removal of that .00000000000001 ohm resistance has on power calculations?.
Why dose a voltage appear across an inductor(coil) before current starts to flow?--and i dont mean just throw in inductive reactance,or some simple term like that.I mean--what is the mechanism taking place that delays the current flow?.
All to often,we just get as close as we can,and that then becomes good enough--but this is not the scientific method we have all been taught to stick to.
Near enough has not yet been good enough to get the TPU up and running ;)
Brad
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The most cynical part of that posting is that Poynt got off to a shaky start at one point in the discussion and part of it was because he got thrown off by what his sim was saying. His bad sim was reinforcing his mistaken preliminary thoughts. Within one or two days clarity came back to him and he retracted his incorrect statements. Everybody following the thread was witness to this.
And here you are like a clown repeating some of his incorrect statements that he already retracted as part of a setup for your posting where you show conflicting viewpoints being expressed by some people.
MileHigh
Exactly what i thought you would say--you hypocrite.
How many threads,over how many months,have we listen to you harp on about how EMJ and wattsup could not answer the very question this thread is about-->how many Mr hypocrite?.
Brad
I am challenging you that what you say above does not make a single stitch of logical sense. Why do you allege that I am a hypocrite, and explain your reasoning. Go ahead and explain how what you say makes any sense, if you can.
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I am challenging you that what you say above does not make a single stitch of logical sense. Why do you allege that I am a hypocrite, and explain your reasoning. Go ahead and explain how what you say makes any sense, if you can.
Simple
You harp on about how some of us have to keep reminding you about your blunder in regards to resonance having nothing what so ever to do with the ICE,but at the same time,you harp on about EMJ and wattsup not being able to answer your 'ideal' question.
This means you are complaining about something that is being done to you,when you do the very same thing to others=hypocrite.
Now-you and Poynt seem to be at odds regarding voltage across an ideal coil while a steady current flows through it-->something that is relevant to the question,and also your ideal voltage source being able to contain energy--this is also vital to Poynts last explanation. If you are correct,and the ideal voltage source dose not contain energy,then Poynts last explanation is incorrect.
If you are wrong,then Poynts explanation could make sense--but you'd have to be wrong,and we all know how much you would hate that-->MH dosnt quite know what an ideal voltage source is.
I do expect some form of spagetti explanation to be presented about this indiscretion :D
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Simple
You harp on about how some of us have to keep reminding you about your blunder in regards to resonance having nothing what so ever to do with the ICE,but at the same time,you harp on about EMJ and wattsup not being able to answer your 'ideal' question.
This means you are complaining about something that is being done to you,when you do the very same thing to others=hypocrite.
For starters you have exaggerated how many times I mentioned the question with regards to Wattsup and EMJunkie. I also used it as an illustration about the abysmal state of electronics knowledge among some electronics experimenters even though they have had many years of experience on the bench. More so when it comes to EMJunkie because he positions himself as someone that "teaches" other people about coils. EMJunkie even had the nerve to try to deny it about a month or two ago which was outrageous.
And for the 80th time, I owned up to being wrong about a Helmholtz resonator being used on the input for a two-stroke engine because of my ignorance. So I learned something new. And of course we can't forget that your communication skills are so weak that you didn't even qualify your statement about ICE's and resonance. I was thinking about a typical modern car engine when I made my statement, and in that sense I was not really wrong. It's only when we lower the bar and bend over ass-backwards and accept your limitations and realize that you were actually talking about a two-stroke performance engine does resonance become relevant. But the most important thing of all, is that I owned up to my mistake.
If you were normal you would have accepted my owning up to my mistake and just moved on and not have mentioned it again. But no, since you have very little to go after me with you have repeated the same thing over and over. And the fact that I owned up to it and you still keep repeating it makes you a dumbass that has nothing new to say.
Going back to what started this exchange, you make a totally dumbass posting where you knowingly and intentionally quote Poynt out of context. You haven't retracted your statements.
What I said about EMJunkie and Wattsup was a true statement. And when you posted Poynt's stuff you were knowingly and willfully making false statements. You owe Point an apology for your dumbass behaviour.
Yes, I used the story about EMJunkie and Wattsup for illustrative purposes. My statements were true, and it doesn't make me a hypocrite to complain about your repeated restatements about a mistake I owned up to.
MileHigh
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For starters you have exaggerated how many times I mentioned the question with regards to Wattsup and EMJunkie. I also used it as an illustration about the abysmal state of electronics knowledge among some electronics experimenters even though they have had many years of experience on the bench. More so when it comes to EMJunkie because he positions himself as someone that "teaches" other people about coils. EMJunkie even had the nerve to try to deny it about a month or two ago which was outrageous.
And for the 80th time, I owned up to being wrong about a Helmholtz resonator being used on the input for a two-stroke engine because of my ignorance. So I learned something new. And of course we can't forget that your communication skills are so weak that you didn't even qualify your statement about ICE's and resonance. I was thinking about a typical modern car engine when I made my statement, and in that sense I was not really wrong. It's only when we lower the bar and bend over ass-backwards and accept your limitations and realize that you were actually talking about a two-stroke performance engine does resonance become relevant. But the most important thing of all, is that I owned up to my mistake.
If you were normal you would have accepted my owning up to my mistake and just moved on and not have mentioned it again. But no, since you have very little to go after me with you have repeated the same thing over and over. And the fact that I owned up to it and you still keep repeating it makes you a dumbass that has nothing new to say.
Going back to what started this exchange, you make a totally dumbass posting where you knowingly and intentionally quote Poynt out of context. You haven't retracted your statements.
What I said about EMJunkie and Wattsup was a true statement. And when you posted Poynt's stuff you were knowingly and willfully making false statements. You owe Point an apology for your dumbass behaviour.
Yes, I used the story about EMJunkie and Wattsup for illustrative purposes. My statements were true, and it doesn't make me a hypocrite to complain about your repeated restatements about a mistake I owned up to.
MileHigh
As i though-you avoided most of everything that post was about--as you do.
I owe Poynt nothing except thanks for the help he has given me--but that dose not mean i am going to agree with everything he says outright.
The statements i quoted are correct and not in anyway false.
Poynt says that a voltage exists across a coil(even an ideal coil) when there is a current(be it varying of stable)flowing through that coil.
You say that no voltage can be measured across an ideal coil that has a steady DC current flowing through it--and before you get your knickers in a twist,i would say that i have to agree with you,unless i have misunderstood what Poynt was saying.
Second-you clearly stated that an ideal voltage source dose not contain energy,and Poynt clearly stated that energy is returned back to the source--Quote post 1136-The energy stored in the inductor is returned to the voltage source.
So do not lie and say i knowingly and willfully making false statements,as what i said is absolutely correct and true--your lying is becoming way to obvious MH.
So ,as i !correctly! stated--one of you is wrong.
If you are correct,then Poynt needs to find some where else for that energy to be returned to,and there is no where else.
So for Poynt to be correct--you have to be wrong about your ideal voltage source.
Brad.
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Brad:
The statements i quoted are correct and not in anyway false.
Here is what you quoted for one of Poynt's statements:
quote post 81-Poynt
Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever.
Did you get kicked in the head by a goat? Did you walk and smack your head into a barber shop pole? That is a statement that Poynt retracted after he got his proper bearings you dumbass.
Your statement is 100% false and have a good sizzling extra crispy brain fry over that.
Second-you clearly stated that an ideal voltage source dose not contain energy,and Poynt clearly stated that energy is returned back to the source--Quote post 1136-The energy stored in the inductor is returned to the voltage source.
So do not lie and say i knowingly and willfully making false statements,as what i said is absolutely correct and true--your lying is becoming way to obvious MH.
I guess your are mentally challenged and will never have the intellectual capacity to understand this very basic stuff about ideal voltage sources. You think that there is a conflict between me stating that an ideal voltage source does not contain energy and Poynt saying that the energy stored in the inductor is returned to the voltage source. In fact there is no conflict at all. It's all simply just too much for your limited sizzling brain to understand.
My suggestion to you is-->do some shining of your own,and back up your claimed answer with solid proof,base around a circuit that accurately represents the circuit in your question.
Anything short of that will not be accepted as a correct answer.
You bought the !ideal! into this,so now you must back it up.
And here we are back in the business where your brain is too limited and you can't just work with things conceptually so your "big comeback" is the usual old line: "An ideal voltage source dose not exist so what you are saying dose not make sense because it dose need to be shone with a real circuit that dose exist."
Meanwhile you have been told multiple times now that a good audio amplifier could be used as an approximation of an ideal voltage source and a a reasonable facsimile of the circuit could be built and tested.
Now let's get into the ultimate brain fry mode, the mother of all of Brad's brain fries:
Here is the equation that shows how you determine a resistor's voltage:
V = IR
Here is the equation that shows how you determine a resistor's current:
I = V/R
Here is the equation that shows how you determine an inductor's voltage:
V(t) = L di/dt
Here is the equation that shows how you determine an inductor's current:
I(t) = 1/L integral(V)dt
That's it, if you could understand this stuff then you could answer the question no problem and nothing has to be built. You just have to have the intellectual capacity to understand it.
MileHigh
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Dear MileHigh.
Many thanks for your interesting interpretation of the links I shared. The story goes that the Petter Super scavenge engine came about by accident. Upon load testing one day the engineers saw a marked reduction in fuel consumption for the load applied, during their investigation they found that someone had forgotten to replace the crankcase doors after a spot of maintenance. Being a Two stroke design using crankcase compression/transfer obviously something else was recharging the cylinder...... The exhaust !!
I'm having to copy and paste as my browser keeps coming back with " page unavailable. "
You wrote. " That's in contrast to a pipe organ or a whistle, where the tube is acting like a resonator and kinetic and potential energy is resonating back and forth in a standing sound wave inside the tube. "
If I have read you correctly? You're saying that an organ pipe is a " True " resonator ?
My question is, what's the difference?
In an organ pipe we have air under pressure passing the " flue " that creates a series of pressure waves to make a sound of a given frequency.
The same thing is happening in an exhaust pipe, the only difference is in the way the pulses are generated.
From my point of view I see the same picture. I realise that my posts are irritating to some so this will be my last on this subject, I will, however look forward to reading your reply.
Kind regards, Grum.
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author=MileHigh link=topic=16589.msg486693#msg486693 date=1466426611]
Here is what you quoted for one of Poynt's statements:
Did you get kicked in the head by a goat? Did you walk and smack your head into a barber shop pole? That is a statement that Poynt retracted after he got his proper bearings you dumbass.
I see you have resorted to your rude insults again.
Lets have a look at the real context of my statement--which of course you have left out-->as you do.
My statement of what Poynt said,that you think is false.
Quote: Yes, nothing will happen with the ideal inductor, i.e. it will have 4V (or whatever the voltage is at any point in time) across it and zero current through it for ever and ever.
Now-here is the vital piece you missed,so as you could once again,try and make me out to be the bad guy.
Before any of those statements were quoted in post 1138,i said this first-as can be clearly seen.
Quote: Even the best some times make mistakes. And then i quoted the mistakes made.
So another epic fail on your behalf MH,as i was only quoting the mistakes that the best of the best can make--along with the rest of us.
You need to read a bit better,or understand what you are reading-->and stop this urge you have to lie.
Your statement is 100% false and have a good sizzling extra crispy brain fry over that.
It would seem you have had your own brain fry this time-again ::)
I guess your are mentally challenged and will never have the intellectual capacity to understand this very basic stuff about ideal voltage sources. You think that there is a conflict between me stating that an ideal voltage source does not contain energy and Poynt saying that the energy stored in the inductor is returned to the voltage source. In fact there is no conflict at all. It's all simply just too much for your limited sizzling brain to understand.
Go ahead Einstein,tell us all how energy is sent back to something that cannot contain that energy?--this should be good ;D
To contain-->have or hold (someone or something) within<--just incase you dont understand the meaning of contain ;)
And here we are back in the business where your brain is too limited and you can't just work with things conceptually so your "big comeback" is the usual old line: "An ideal voltage source dose not exist so what you are saying dose not make sense because it dose need to be shone with a real circuit that dose exist."
Shone?-->past and past participle of shine
Do you mean shown perhaps?.
Yes,that is the scientific method to validate a claim. You are making the claim,and now it is time for you to validate that claim by actually testing the DUT in question.
Meanwhile you have been told multiple times now that a good audio amplifier could be used as an approximation of an ideal voltage source and a a reasonable facsimile of the circuit could be built and tested.
Well this is good for you MH,as you should be able to obtain the equipment needed in order to validate your claim. Your ideal voltage source must have 0 internal resistance,and allow for the current to continue to flow at 2.4 amps for 2 seconds. Your 5H coil must also have 0 resistance. These two items will then be an accurate account of the items needed for the test in question.
But lets be honest here MH--you know you will find no such voltage source,nor will you be able to come up with a coil of 5H that has 0 resistance. So you cannot qualify your answer.
Now let's get into the ultimate brain fry mode, the mother of all of Brad's brain fries:
Here is the equation that shows how you determine a resistor's voltage:
V = IR
Here is the equation that shows how you determine a resistor's current:
I = V/R
Here is the equation that shows how you determine an inductor's voltage:
V(t) = L di/dt
Here is the equation that shows how you determine a inductor's current:
I(t) = 1/L integral(V)dt
That's it, if you could understand this stuff then you could answer the question no problem and nothing has to be built. You just have to have the intellectual capacity to understand it.
And how are you going to show us all that when you pass that threshold of going from a circuit that has resistance,to that of one which has none,an infinite change dose not occur?
You are taking a !guess!,and this is a guess you cannot back up with a test carried out based around the actual described device in your question.
For me, there are only three outstanding issues and I will mention them again and I will put them in a better sequence this time:
1. MH gets up the learning curve and understands the original question and Carries out the needed test to qualify his answer
2. MH admits that he pics and chooses parts of posts,and then reassembles them into lies,to make others out to be bad people,when the truth is quite the opposite.
3. MH admits that he dose not know what an ideal voltage source is.
Brad
-
Dear MileHigh.
Many thanks for your interesting interpretation of the links I shared. The story goes that the Petter Super scavenge engine came about by accident. Upon load testing one day the engineers saw a marked reduction in fuel consumption for the load applied, during their investigation they found that someone had forgotten to replace the crankcase doors after a spot of maintenance. Being a Two stroke design using crankcase compression/transfer obviously something else was recharging the cylinder...... The exhaust !!
I'm having to copy and paste as my browser keeps coming back with " page unavailable. "
You wrote. " That's in contrast to a pipe organ or a whistle, where the tube is acting like a resonator and kinetic and potential energy is resonating back and forth in a standing sound wave inside the tube. "
If I have read you correctly? You're saying that an organ pipe is a " True " resonator ?
My question is, what's the difference?
In an organ pipe we have air under pressure passing the " flue " that creates a series of pressure waves to make a sound of a given frequency.
The same thing is happening in an exhaust pipe, the only difference is in the way the pulses are generated.
From my point of view I see the same picture. I realise that my posts are irritating to some so this will be my last on this subject, I will, however look forward to reading your reply.
Kind regards, Grum.
Not at all Grum.
It will be irritating to only one,as it is not inline with his limited beliefs and parameters.
Brad
-
A good friend of mine made this video and it is so so apt
https://www.youtube.com/watch?v=yrvRAjq3h1g
Regards
Mike
PS. I do not make many videos public, only private, and I put in years of bench time, just in case a comment is made.
-
A good friend of mine made this video and it is so so apt
https://www.youtube.com/watch?v=yrvRAjq3h1g (https://www.youtube.com/watch?v=yrvRAjq3h1g)
Regards
Mike
PS. I do not make many videos public, only private, and I put in years of bench time, just in case a comment is made.
Sure Mike, let's deal with this one right away and put this puppy to bed.
Here is what I said to the commenters on that clip:
<<<<<<<<<<<<<<<<<<<<<<<<<
Hello, this is User2718218 and I am forced to post this on your clip to defend myself against the allegations that I am a troll made by Robert Murray Smith on his clip, "On User2718218 A Troll And What To Do About Him" because he banned my comments. His allegations are NOT TRUE and I will explain why using some postings of mine in defense of myself that Robert Murray Smith banned you from seeing.
I engaged with Robert because he made extravagant claims about his supercapacitors without offering up any credible measurements at all. I have a technical background and I was smelling something that wasn't right. Robert has consistently refused to comment on any of my legitimate technical questions or justifiable criticisms and instead he tried to impugn my character by insulting me. This clip is more about Robert than it is about me. To see an unfiltered debate between myself and Robert where the truth comes out, please go to Lasersaber's channel and look at the comments on the "Homemade Graphene Supercapacitors - First Tests " clip. Most of his comments on the Lasersaber clip have been removed, so it looks mostly like a one-way conversation. Presumably all the comments where he insults me like a troll and attacks my character have been removed.
The Lasersaber clip with my debate with Robert Murray Smith: https://www.youtube.com/watch?v=d5cOebnCvXo
Part 2 of my defense of my character and the false allegations of Robert Murray Smith:
It is perfectly legitimate to observe someone's technical presentation and comment on it without replicating it. That's how real science works, it's called peer review. I don't have to replicate anything when Robert makes a clip where he is supposedly measuring the energy output of one of his devices over time. In the clip he measures the current output but does NOT measure the corresponding voltage and he does NOT factor in the fact that the voltage is continuously dropping because he simply isn't measuring it. That is a purely nonsensical unscientific measurement that is totally meaningless data, and yet he expresses pride in a nonsensical measurement that would make him the laughing stock in any grade ten physics class. I am being absolutely serious about this, his "measurement" is pure junk. It is that bad and I felt compelled to speak up and engage with him because of this outrageous nonscientific behaviour that he was doing. All that he could do was insult me and he has never responded once to any of my 100% legitimate technical comments and criticisms. Please go to the Lasersaber clip for more information.
What is one of my primary interests on YouTube? What I really like to do is comment on fraudulent scammers that try to sell fake free energy devices. I do this purely out of altruism towards my fellow man, and I have helped in busting professional free energy scammers over the years. There are too many people being taken advantage of when it comes to this stuff and I try to stop it.
Robert Murray Smith is not a free energy scammer. I looked at his clips because I was and still am enthusiastic about the advances in technology when it comes to supercapacitors. However, to my shock, I saw shoddy practices and totally useless and illegitimate "measurements" that are simply lies. And I saw unsubstantiated outrageous claims with no measurements. I felt compelled to engage with him about these serious measurement issues and the related issue of scientific credibility. Robert has never once responded to my legitimate questions about his ridiculous measurements that make no technical sense and to my questions related to how grossly inaccurate his measurements where and how his conclusions about those grossly inaccurate questions were not credible. Instead he insulted me and attacked my character like a troll himself.
I am here to do GOOD, I am not a troll. That is the honest truth. I challenged Robert Murray Smith because he needed and deserved to be challenged.
The fundamental issue is this: Robert Murray Smith made false and misleading measurements and associated claims about his supercapacitors. One of his measurements is actually an invalid and technically incorrect measurement that makes no logical sense, it is a complete failure. I challenged him about these serious serious issues and he refused to respond to the technical issues and he also insulted me and criticized my character, A typical response from him to my serious technical question was "You are an idiot." He said that because he has no technical argument to argue that he was correct, because he was incorrect.
In life we have to have principles that we must live by, we can't be morally apathetic. Sometimes when you see something that is wrong, you are just and good in saying that it is wrong.
I am no troll, I assure you, and I do not need to replicate his experiments. The experiments themselves are not the issue. The issue is the false and misleading and incorrect measurements made by Robert Murray Smith.
False and misleading measurements lead to false and misleading claims.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I come out smelling like roses and RMS stinks to high heaven.
MileHigh
-
Mike:
Like I already said, on the Lasersaber video clip, RMS deleted all of his comments and ran away. None of his comments ever dealt with the technical issues I was raising and the whole time he was a faker. He would say things like, "You don't know what you are talking about" or "You're an idiot" or he would try to nervously and dismissively laugh off what I was saying to him. In other words he was being totally pretentious.
Only half of the discussion remains. Here are some of my choice comments for you to contemplate:
---------------------------------------------------------
+Robert Murray-Smith What Lasersaber, Tinman, and you need to do is make credible measurements of the capacitance of your home-made supercapacitors. Are you competitive with what is commercially available or not? Is your energy density competitive with what is commercially available or not? I looked at one of Tinman's clips and his claimed Farad capacity and what was shown in the clip was not credible. You three gentlemen need to make open, honest, and credible clips where you precisely measure the capacitance of your capacitors. Are you guys really onto something, or can anybody go onto Digikey and order supercapacitors that outperform your home-brew supercapacitors? We are talking about the difference between anecdotal demonstrations of what the supercapacitors can do vs. getting serious and making real measurements.
------------------------------------------------------------
+Robert Murray-Smith (https://www.youtube.com/user/RobertMurraySmith) No Robert, it's a perfectly sensible thing to say. You are building a capacitor, and you should make a measurement of your device. It's as plain as day. I am sensing that you might not know how to do it. Just Google it, learn about how to go about it, and then do some experiments.
-------------------------------------------------------------
+Robert Murray-Smith What I know is that I asked you on your channel to make measurements of the capacitance to back up your claims and you flinched there also just like you are flinching here. You made a serious technical mistake with your tap charging of your supercapacitors and you would not admit to it and instead of thanking me for politely pointing out the issue to you, you denied it and subsequently deleted all of my comments. So you seem to have some issues. A Maxwell K2Series BCAP 2000 Farad ultracapacitor is in a can that is 10 cm long x 6 cm in diameter. In one of your clips you claim that you made a home-brew 2000 Farad capacitor that is roughly the size of a credit card. Let us be conservative and say that you are claiming 10X the energy density by volume with your credit card sized capacitor that you claim is 2000 Farads. The onus is on you to prove that is true - that your credit-card-sized capacitor is 2000 Farads because right now I do not believe it. Apparently you are making the assumption that people don't want to see you make measurements to back up your rather fantastic claims on YouTube. I can assure you that many people do indeed want to see you back up your claims with measurements. You attract attention from free energy enthusiasts and that field is rife with people making fake claims and enthusiasts that almost never ask the basic questions that should be asked. 2000 Farads in a form factor roughly the size of a credit card does not smell right to me so I am asking you to back up your claims with credible, honest, and open measurements. Yet you are flinching and trying to be dismissive of my perfectly legitimate request and also trying to use deflection by trying to impugn my character. Why don't you just make measurements and back up your claims like any person building supercapacitors should be happy to do?
-----------------------------------------------------------------------------
+Robert Murray-Smith So much for all the big talk, you deleted your comments and ran away. My advice to you is just be real, don't be a poseur. Next time you make a home-made supercap clip, then try making a second clip where you measure the value of your supercap. This is a reasonable request and I hope you think about it seriously and honestly.
-
Because there is(for example).000000000000000001% difference between unity and overunity.
One is possible,and the other is not-apparently ;)
The difference between the two is enormous.
The difference between 0 resistance(no resistance)and .000000000000001ohm is also just as enormous,as the difference between 20 000 000 000 watts of power,is no where near an infinite amount of power.
Fortunately in the case we are dealing with, a small parasitic resistance in the circuit has essentially no impact on the results.
Your sim needs some sort of resistance to even start to compute the numbers--it will not compute the question as asked--we have seen this already.
Indeed, but the fact we have to add a very tiny resistance has no impact on the final result.
Your sim shows power being dissipated,and that is not what would happen with the device defined in the question.
Yes my circuit dissipates a tiny bit of power in the parasitic resistance, but it is quite small in comparison to the power flowing in the circuit. I have reduced the parasitic resistance to 1p Ohm, and as such the power dissipated by this resistor peaks at about 6pW (as shown in the attached). By comparison, the circuit power peaks at 9.56W. That is a ratio of 1.59 x 1012:1 which is a very big number (1,590,000,000,000).
How do you know for sure that there is not some huge change when resistance is removed altogether,like the removal of that .00000000000001 ohm resistance has on power calculations?.
We can keep dividing the parasitic resistance by a factor of 2 or even a factor of 10 and re-run the simulation, and all that happens is the dissipation in the resistor decreases. By observing the scope shot comparing the voltage source power and the resistor power you can see that the resistor power is inconsequential, even at a much higher dissipation. For example, if the parasitic resistance is two magnitudes higher at 1m Ohm, the results are essentially identical. That small resistor dissipation factor has no real bearing on the results. It is analogous to having one penny to your possession vs. 1/100th of a penny, in each case you essentially have no money and no buying power. Having a lower and lower fraction of a penny to your possession makes it closer and closer to having absolutely zero money, but what difference does it make? Compared to a monthly salary of say $2000, 1 penny is essentially zero money, agreed?
It is the same with this parasitic resistance; we only need go low enough so that the inductive reactance of the inductor (the monthly salary) completely and totally swamps it (our 1 penny) out (remember the L/R ratio I have mentioned several times?). As you go to a lower and lower value of parasitic resistance, there is essentially no difference in the resulting currents, voltages, and power measured in the circuit.
Why dose a voltage appear across an inductor(coil) before current starts to flow?--and i dont mean just throw in inductive reactance,or some simple term like that.I mean--what is the mechanism taking place that delays the current flow?.
If you are referring the MH's question, voltage and current occur simultaneously. Unless I don't understand your question. Look at the scope shot again, as soon as +4V appears across the inductor, the current begins to rise.
-
Mike:
You have a feeling for things from both sides now and are thinking differently a bit perhaps? Here are some doozie postings:
------------------------------------------------------------------------
+Robert Murray-Smith One more time Robert you have a serious serious problem in one of your clips. Your measurement of your device in the clip "A Perspective On The B Type EESD" is completely out of whack. It's so bad that it is shocking. I suggest that you review what you did, take down the clip, issue an apology clip, and then redo the test properly in a new clip.
------------------------------------------------------------------------
+Robert Murray-Smith Your clip is a total sham Robert because you do not multiply the current by the voltage to calculate the energy in your EESD device and then convert your correct measurement into ampere-hours @ 3.8 volts to make a fair and direct comparison with the lithium-ion cell. How can you possibly make so elementary a mistake as that? At 19:23 (http://www.youtube.com/watch?v=d5cOebnCvXo&t=19m23s) in the clip you say, "We've done that (the testing on your device) so we can make a direct comparison (with the lithium-ion battery)." But you totally fail to make a direct comparison and the clip is a sham. Your numbers do not show in any way, shape, or form that you have an advantage over a lithium-ion battery when it comes to the energy to weight ratio for your compounds in comparison to the compounds used in a lithium-ion battery. You should take down your clip, issue an apology, and then redo the clip properly. You are grossly exaggerating the energy density by weight of your cell. A preliminary estimate is that your exaggeration could be somewhere between 5X and 10X.
---------------------------------------------------------------
+Robert Murray-Smith In your clip <A Perspective On The C type EESD> you encourage your viewers to make a proper energy measurement by multiplying the current times the voltage times the time slice. In your clip <A Perspective On The B type EESD> You make the totally unbelievable error of measuring the current but not measuring the voltage output of your cell over time and then calculating the total energy output and then converting that into equivalent ampere-hours at 3.8 volts to put yourself on a level playing field with the lithium-ion battery. So what is your game? How could you do something as completely moronic as that and say it with a straight face? Could it be because you are a <chief technology> guy for a little Pink-Sheet-type of company and you want to impress the uneducated eyeballs with money that land on your YouTube clip? Those two clips are a complete and utter farce and as far as I am concerned you consciously committed an engineering mortal sin by making a farce clip where you only measure the current x time and ignore the voltage. There is no <that is just my perspective> like you posted in the comments on that clip. What the hell is your game?
----------------------------------------------------------------
+Robert Murray-Smith In your clip, <A Perspective On The B type EESD> you actually have not made a case for a higher energy to weight ratio for your compounds as compared to the compounds in a lithium-ion battery. Your measurement error for the weighing of your materials is roughly +/-25%. You have exaggerated the amount of measured energy in your cell by perhaps 5X to 8X. Combine the exaggeration in the energy content with the error tolerance in your weight measurement and you have nothing. So one more time, you are supposed to be a scientist and you make the most amateur half-assed measurement to claim you have a better energy to weight ratio for a lithium-ion battery. An astute chemistry student in grade 10 high school could make a way more accurate measurement than you without putting that much thought into it. You used your digital balance at the extreme low end of its measurement scale such that its error tolerance was sky high. All that you had to do was weigh the scrapings from 10 or 20 samples to lower your error tolerance on the weight measurement by a factor of 10 to 20. The clip is a farce, whats your game?
-------------------------------------------------------------
+Robert Murray-Smith The funny thing is that you made the same immature low-brow vulgar insults to me when I was talking to you that "Random Stranger" also made. So I would not be surprised if "Random Stranger" is just Robert Murray-Smith with a sock over his head. You are trying to drop a subliminal hint to Lasersaber to delete this discussion because you hate the fact that what I am saying is 100% correct and true. I hope that he does the right thing and leaves these comments up because they speak the truth about you. My technical comments about your flaws and outright failure in making your measurements are 100% true.
------------------------------------------------------------
So there you go Mike. That's the sad story and that's why, to my surprise, RMS made a clip about me alleging that I was a "troll" when all that I was trying to do was get him to retract his invalid clips, issue an apology, and then redo the measurements in the clips honestly and correctly.
His clip about me being a "troll" is completely and totally fake.
MileHigh
-
Dear MileHigh.
Many thanks for your interesting interpretation of the links I shared. The story goes that the Petter Super scavenge engine came about by accident. Upon load testing one day the engineers saw a marked reduction in fuel consumption for the load applied, during their investigation they found that someone had forgotten to replace the crankcase doors after a spot of maintenance. Being a Two stroke design using crankcase compression/transfer obviously something else was recharging the cylinder...... The exhaust !!
I'm having to copy and paste as my browser keeps coming back with " page unavailable. "
You wrote. " That's in contrast to a pipe organ or a whistle, where the tube is acting like a resonator and kinetic and potential energy is resonating back and forth in a standing sound wave inside the tube. "
If I have read you correctly? You're saying that an organ pipe is a " True " resonator ?
My question is, what's the difference?
In an organ pipe we have air under pressure passing the " flue " that creates a series of pressure waves to make a sound of a given frequency.
The same thing is happening in an exhaust pipe, the only difference is in the way the pulses are generated.
From my point of view I see the same picture. I realise that my posts are irritating to some so this will be my last on this subject, I will, however look forward to reading your reply.
Kind regards, Grum.
The difference is that in the organ pipe the standing-wave pressure waves are true manifestations of resonance. From what I read the air interference patterns at the "flue" are a random mix of frequencies. However, the frequencies that line up with the dimensions of the organ pipe are reinforced and all of the other frequencies don't "line up" and they undergo self-cancellation and/or they quickly die out. The net result is a pure tone coming from the organ pipe that is due to the resonant standing wave pattern in the organ pipe.
So here is the essence of the resonance in the organ pipe with respect to a one-centimeter cube of air in the pipe: That cube of air will alternate back and forth between being in motion (kinetic energy) or it will be stationary and compressed like a spring (potential energy). So the energy inherent in the standing wave action relative to the cube of air inside the pipe cycles back and forth between kinetic and potential energy. That is the true signature of resonance. if you don't have energy cycling back and forth between two forms in a stable pattern then it is not resonance. Again, the moving mass of the one-centimeter cube of air is the kinetic energy. When the one-centimeter cube of air is compressed to a higher pressure than the ambient pressure, that is the compressed air which is storing the energy as potential energy like a compressed spring. Essentially the same mechanism happens in a wine glass, a bell, or a tuning fork.
The exhaust pipe "resonator" does not do that. There is no energy storage alternating back and forth between two forms. Instead, you have a time delay for a shock wave to reach the end of the tube, and depending on the configuration you get a positive-pressure or negative-pressure shock wave returning back to the cylinder with essentially the same time delay.
In a Helmholtz resonator, you do have the true signature for resonance. The velocity of a mass of air in the neck of the resonator represents the kinetic energy. The compression of the air mass in the cavity of the resonator represents the potential energy. In a Helmholtz resonator, the energy cycles back and forth between kinetic and potential energy.
MileHigh
-
Brad,
In terms of voltages and currents in inductors, the following is true:
1) If the inductor current is steady (not changing), then the voltage across it must be 0V.
2) If the inductor current is changing, then there must be a non-zero voltage across it.
-
Miles
Quote
I come out smelling like roses
end quote
---------------------------------------------------------
:o
RE ICE and your resonant ignorance..
Do not perceive the silence here as capitulation to your self adulation...
The breeze being generated by you patting yourself on the back ...doth surely send a cringeworthy chill to -your- readers .
the pause is out of respect to Poynt and his efforts.
-
Brad:
I see you have resorted to your rude insults again.
My ass, if you intentionally act like a fool by quoting Poynt when he was temporarily mixed up and then quickly recovered within a short time you deserve it.
Now rub this in your face:
I hope you do not contaminate Russ's forum ,like you have contaminated this one.
How does a face covered with a rude insult feel like, you sick duck?
Even the best some times make mistakes.
More sick duck, no capacity to show personal integrity. The first half of that posting was statements that Poynt knows better about and he retracted them and you should never have posted them, period. That's in contrast to the second half of your posting that shows apparent conflicts that I asked you yourself to clarify to see if you could demonstrate some smarts. What you did is just another dim light bulb backfiring stunt just like your pathetic attempt to set me up with the "constant DC vs. changing DC" nonsense when it came to an inductor. You make yourself look badder than bad.
You need to read a bit better,or understand what you are reading-->and stop this urge you have to lie.
That's just the dancing chicken doing the "Brain Fry."
Go ahead Einstein,tell us all how energy is sent back to something that cannot contain that energy?--this should be good
It's like Santa Claus Brad, and his magic sack of presents that is bottomless and holds the presents for everyone in the world. The ideal voltage source has an invisible magic energy sack that the returned energy goes into.
Shone?-->past and past participle of shine
That's satire about you. You know, "The lady did she cover me in rose peddles, she blue my knows and then she spanked my bee hynde." It dose make cents now, dosent it?
But lets be honest here MH--you know you will find no such voltage source,nor will you be able to come up with a coil of 5H that has 0 resistance. So you cannot qualify your answer.
This has been explained to you over and over. Abandon hope.
MH admits that he dose not know what an ideal voltage source is.
Go see Santa Claus Brad.
-
Miles
Quote
I come out smelling like roses
end quote
---------------------------------------------------------
:o
RE ICE and your resonant ignorance..
Do not perceive the silence here as capitulation to your self adulation...
The breeze being generated by you patting yourself on the back ...doth surely send a cringeworthy chill to -your- readers .
the pause is out of respect to Poynt and his efforts.
I went over the concept with Grum but you won't listen. Just zone out and think about the Pistol shrimp.
In email the late MarkE said that you were a nutter. I was a little surprised and taken aback, but I can see now that he was spot on.
That's why I asked you to delete my coordinates and I hope you have done so. I seriously regret giving them to you.
Keep fighting for ignorance and stupidity. Have you hugged a Pistol shrimp lately?
-
Brad,
In terms of voltages and currents in inductors, the following is true:
1) If the inductor current is steady (not changing), then the voltage across it must be 0V.
Surely you mean to say this with regard to "ideal inductors", as in having no DC resistance...
PW
-
MH,
Your last post was "bad form" to say the least...
PW
-
Picowatt:
I am not going to disagree with you. But bad form can easily be a two-way street and one can get frustrated. Sometimes being real means that you let yourself get "colourful" to make some serious points. Always being nice in the face of near-endless frustration is not necessarily being genuine and true to yourself. For example, hypothetically, if you tried five times, then 10 times, then even 20 times to explain to Brad that a square wave is a summation of sine waves and he refused to believe you because "he couldn't see it on his bench," then you might get frustrated. Of course you can walk away. Poor Brad sill hasn't properly understood what an ideal voltage source is, for the 20th time. Poor Brad still plays the "you can't build something with ideal components" card for the 20th time. Sometimes some push back is just being real. It would be nice if the world was like a bunch of diplomats exchanging diplomatic notes with each other all the time, but it isn't.
The root cause for all of this is that I decided to deal with Brad just like I would with any other experimenter. I told him there was no logical reason for a "resonant Joule Thief" to exist which caused conflict and since then I have had many near-insane arguments with him.
MileHigh
-
MH,
I was referring to you revealing private comments made by the departed...
PW
-
Surely you mean to say this with regard to "ideal inductors", as in having no DC resistance...
PW
But even then, if the current is constant through the ideal inductor, what happened to the ideal voltage source? Did it also go to 0v, but is still allowing current? So did it change into an ideal current source at that point?
Mags
-
PW:
I don't disagree with that either, but I am fed up and that dose of harsh reality is to get him to back off.
MileHigh
-
But even then, if the current is constant through the ideal inductor, what happened to the ideal voltage source? Did it also go to 0v, but is still allowing current? So did it change into an ideal current source at that point?
Mags
I never mentioned an ideal voltage source...
PW
-
I never mentioned an ideal voltage source...
PW
I know you did not. But what voltage source is capable of 0v yet provides current to the ideal inductor? Sure we could just say that the inductor has no voltage across its leads but has steady current. But it seems in each case of whether it is current building up, or flat line current, if it is an ideal inductor we are talking about, then one question may come about as to the source. Current is rising in the inductor so there must be voltage across its leads? Steady current but no voltage across its leads? Id say the source needs more definition as to its capabilities in order for those to occur. Wouldnt you? ;) Its like the ideal source is not just a voltage source whether it is adjustable or not, if it is capable of current at 0v. Then it is no longer a voltage source.. Its just some magical source that is simply capable of anything imaginable. May as well be a source of light also. Capable of coherent laser light output also. Provides mechanical and sound output also. Etc, etc.
Mags
Mags
-
Surely you mean to say this with regard to "ideal inductors", as in having no DC resistance...
PW
Yes, of course PW. Thanks for clarifying that.
-
I know you did not. But what voltage source is capable of 0v yet provides current to the ideal inductor? Sure we could just say that the inductor has no voltage across its leads but has steady current. But it seems in each case of whether it is current building up, or flat line current, if it is an ideal inductor we are talking about, then one question may come about as to the source. Current is rising in the inductor so there must be voltage across its leads? Steady current but no voltage across its leads? Id say the source needs more definition as to its capabilities in order for those to occur. Wouldnt you? ;) Its like the ideal source is not just a voltage source whether it is adjustable or not, if it is capable of current at 0v. Then it is no longer a voltage source.. Its just some magical source that is simply capable of anything imaginable. May as well be a source of light also. Capable of coherent laser light output also. Provides mechanical and sound output also. Etc, etc.
We've gone over this a couple of times already, but we'll try to keep at it until it sinks in :)
An ideal voltage source with its voltage set to 0V is equivalent to an ideal piece of wire. Why then would it NOT allow the pre-existing circuit current to flow?
-
Brad,
In terms of voltages and currents in inductors, the following is true:
1) If the inductor current is steady (not changing), then the voltage across it must be 0V.
2) If the inductor current is changing, then there must be a non-zero voltage across it.
As i said to MH--i agree with this,and the reason i did not understand as to why you would say otherwise?
Quote: All inductors, whether ideal or real will have a voltage across them when there is current through them, regardless if the current is changing or not.
To me,if a current is not changing,then it is at a steady state,so to me,your statement reads that a voltage can exist across an ideal coil that has a steady current flowing through it.
In regards to the current flow lagging the voltage,i was referring as to why there is a delay in time for the current to rise to a maximum value after the voltage is applied to the inductor.
Is it not the CEMF produced by the changing magnetic field that causes this delay in current rise time?.
Brad
-
I went over the concept with Grum but you won't listen. Just zone out and think about the Pistol shrimp.
In email the late MarkE said that you were a nutter. I was a little surprised and taken aback, but I can see now that he was spot on.
That's why I asked you to delete my coordinates and I hope you have done so. I seriously regret giving them to you.
Keep fighting for ignorance and stupidity. Have you hugged a Pistol shrimp lately?
You pall -are the worst of the worst.
How dare you Bring some one that is no longer with us into this conversation,just to try and gain some sort of fantasy fame.
I cant believe even you would stoop so low to try and discredit another researcher-->that has done far more than you to help others in this game.
If there ever comes a time of a full world war,i would have Chet watch my back any time,and know i would be safe.
The only place i see you in that time,is hiding in a cave.
Brad
-
Go blow a gasket in your head Brad, you are overdue. Chet was being an ass and a schmuck. I stated many times that we are discussing the true scientific definition for resonance and he can't accept that and wants to be a pain in the ass. It's not the end of the world that I brought up what MarkE told me, you are just running with what PW said and being a drama queen for show. I didn't discredit him, I made him face up to his own ridiculous behaviour. Nor is he a researcher. If there ever was a war, I wouldn't even trust you to take out the garbage. You have compromised yourself so much that there is nothing left. You have never made a single mistake in the past three months, it's truly amazing.
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As i said to MH--i agree with this,and the reason i did not understand as to why you would say otherwise?
Quote: All inductors, whether ideal or real will have a voltage across them when there is current through them, regardless if the current is changing or not.
Apparently I was wrong. As you said, we all make mistakes.
In regards to the current flow lagging the voltage,i was referring as to why there is a delay in time for the current to rise to a maximum value after the voltage is applied to the inductor.
Is it not the CEMF produced by the changing magnetic field that causes this delay in current rise time?.
OK, I understand now. Your original wording did not seem to point that way.
As a general rule of thumb about inductors, they don't and can't change their current instantly, especially with high L/R ratio inductors. An inductor is a reactive component, which means it has an impedance whose value is dependent on frequency. With the simple addition of a series or shunt resistor, we can make high and low pass filters with capacitors and inductors because of this fact.
Inductive Reactance XL=2PIFL, so with a fixed frequency and inductance, the inductive reactance "seen" across the terminals of the ideal inductor is XL. We have gone over this before, but reactance (whether capacitive or inductive) is similar to a resistance, but at a given frequency. From the equation we can see that the higher the frequency, the higher is XL. This is true of ideal and real inductors, but real inductors have an "impedance" which is inductive reactance + resistance.
Since your question is in regards to real inductors, we'll use a real one as an example. If we have a 1H inductor and it has a 1 Ohm parasitic resistance, we know that the tau is L/R, which is 1s. So in 5s the current should reach a maximum once we apply our voltage source (let's assume an "ideal" DC step source of 1V). From this we can conclude that the final current will be 1A after 5s.
So why does the current ramp up rather than go up instantly? The reason is because the inductor can be viewed as a frequency-dependent resistor (inductive reactance XL). Since the edge of a square wave or a simple step voltage can be quite fast, depending on the source (10ns is not uncommon), we know that such an edge will contain many frequency components, possibly up to 100's of MHz. The industry "rule of thumb" for the frequency content (bandwidth) based on edge rise time is: BW=0.35/RT, where RT is rise time. So for an edge having a 10ns rise time, the bandwidth of frequencies contained in that edge are 0.35/10ns, which is 35MHz. If we plug this 35MHz into our inductive reactance equation, what do we get? Well, XL = 2PI x 35MHz x 1H = 219M Ohms. That is a pretty high "resistance" agreed? How much current is going to flow right at the start? The high frequency components die off with time so to speak until the inductive reactance is 0 Ohms, after around 5s in this case. So between t=0 and t=5, the reactance presented by the inductor to our step input goes from about 219M Ohms to 0 Ohms, at which time the parasitic 1 Ohm resistance limits the current to 1A.
That's how I view it anyway.
ETA: As a thought experiment, imagine you are simply using your variable DC power supply as the source voltage for our 1H and 1Ohm inductor. If you were at the control and you increased it from 0V slowly enough, would the voltage and current track perfectly? In other words, would there still be a delay with the current lagging the voltage? Why not try that on the bench?
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Apparently I was wrong. As you said, we all make mistakes.
OK, I understand now. Your original wording did not seem to point that way.
As a general rule of thumb about inductors, they don't and can't change their current instantly, especially with high L/R ratio inductors. An inductor is a reactive component, which means it has an impedance whose value is dependent on frequency. With the simple addition of a series or shunt resistor, we can make high and low pass filters with capacitors and inductors because of this fact.
Inductive Reactance XL=2PIFL, so with a fixed frequency and inductance, the inductive reactance "seen" across the terminals of the ideal inductor is XL. We have gone over this before, but reactance (whether capacitive or inductive) is similar to a resistance, but at a given frequency. From the equation we can see that the higher the frequency, the higher is XL. This is true of ideal and real inductors, but real inductors have an "impedance" which is inductive reactance + resistance.
Since your question is in regards to real inductors, we'll use a real one as an example. If we have a 1H inductor and it has a 1 Ohm parasitic resistance, we know that the tau is L/R, which is 1s. So in 5s the current should reach a maximum once we apply our voltage source (let's assume an "ideal" DC step source of 1V). From this we can conclude that the final current will be 1A after 5s.
So why does the current ramp up rather than go up instantly? The reason is because the inductor can be viewed as a frequency-dependent resistor (inductive reactance XL). Since the edge of a square wave or a simple step voltage can be quite fast, depending on the source (10ns is not uncommon), we know that such an edge will contain many frequency components, possibly up to 100's of MHz. The industry "rule of thumb" for the frequency content (bandwidth) based on edge rise time is: BW=0.35/RT, where RT is rise time. So for an edge having a 10ns rise time, the bandwidth of frequencies contained in that edge are 0.35/10ns, which is 35MHz. If we plug this 35MHz into our inductive reactance equation, what do we get? Well, XL = 2PI x 35MHz x 1H = 219M Ohms. That is a pretty high "resistance" agreed? How much current is going to flow right at the start? The high frequency components die off with time so to speak until the inductive reactance is 0 Ohms, after around 5s in this case. So between t=0 and t=5, the reactance presented by the inductor to our step input goes from about 219M Ohms to 0 Ohms, at which time the parasitic 1 Ohm resistance limits the current to 1A.
That's how I view it anyway.
ETA: As a thought experiment, imagine you are simply using your variable DC power supply as the source voltage for our 1H and 1Ohm inductor. If you were at the control and you increased it from 0V slowly enough, would the voltage and current track perfectly? In other words, would there still be a delay with the current lagging the voltage? Why not try that on the bench?
First up-thanks for taking the time for such an in depth answer,but most of that i already know.
I am after a more in depth answer-what is the mechanism behind the gradual buildup/ramp up of the current. I am thinking that it is the building of the magnetic field that is the root cause of the current building or ramping up over time. This magnetic field that changes over time,cuts the conducting windings,and we get our CEMF. This is what impedes on the current flow. As this magnetic fields change over time starts to slow in a linear fasion,we also see the current ramp up in the same linear fasion. The current reaches its maximum value when there is no change over time of the magnetic field.
Am i on the right track here?
Thanks
Brad
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snip...
Am i on the right track here?
Thanks
Brad
In one word, yes.
Cheers
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I've been waiting for that to come up!
The current, and the resulting magnetic field, are two sides of the same coin, so to speak. A mutual causal relationship.
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We've gone over this a couple of times already, but we'll try to keep at it until it sinks in :)
An ideal voltage source with its voltage set to 0V is equivalent to an ideal piece of wire. Why then would it NOT allow the pre-existing circuit current to flow?
Hmm. And the pre-existing circuit current, circuit being an inductor with a wire(ideal source at 0v) shorting its leads, continues to carry current at a constant level indefinately due to?? Like what are the specific mechanisms that make this happen?
Mags
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Hmm. And the pre-existing circuit current, circuit being an inductor with a wire(ideal source at 0v) shorting its leads, continues to carry current at a constant level indefinately due to?? Like what are the specific mechanisms that make this happen?
Mags
There is a very good reason why I ask. It is related to another discussion from earlier.
Mags
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Miles
Your aforementioned comments and the context in which you used them ..... you soiled yourself and are walking around trying to tell the rest of us you smell like a rose.
truly the epitome of Cringeworthy and actually a benchmark legacy.
and you own it.
never mind your continued abuse of the membership here regarding their investigation of resonance as a means to an end ,
And your implication that they don't know how to bounce a ball or ring a glass properly with out kissing your ring.
resonance??
Really ??
you are so full of yourself and your self importance it really is very hard to read ...and I mostly Can't !
Poynt and PW stand head and shoulders above you.
and honestly you will never win the battle here "once and for all" and "put this Resonance nonsense to bed".
and regardless what others have thought in the past , I absolutely believe in LENR and I absolutely believe water can be a fuel
https://www.youtube.com/watch?v=eF_3rfuT46g
link from Johan
https://sites.google.com/site/braxpeace2/waterinfuelblends
if that makes me nuts,
I'm fine with that.
and when it comes to Resonance in an engine and what it means and what it can do ,I'll take the word of a doer
like Johan [above vid] and Brad ..
and not give any pause whatsoever to a pencil licking mirror kisser such as yourself.
there is MUCH more that can be said on the topic of resonance, ICE engine design and water fuel here, However you and Minnion can go and see for yourselves
you were invited :o
and stop Kissing the Mirror in the mens room...your crusty drool is making it useless
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Yeah Chet,
What a dreadful, wretched posting that was. I simply defined true resonance and I am rejecting the casual application of the term to things that are not true resonance and you have issues with that. Like I took away your "resonance buzz" or something, and so you become this wretched ugly person? People can't run around dropping the term resonance and you are having withdrawal symptoms or something? It's fracturing your frail personalty so you resort one more time to straw man ad hominem attacks. That's about the fourth or fifth time you have done that now.
RE ICE and your resonant ignorance..
Do not perceive the silence here as capitulation to your self adulation...
Horror of horrors, an exhaust pipe is a time delay echo device and not a true resonant device. That must be eating into your brain like a parasite and driving you insane.
It's your posting that is a self-serving piece of crap because you are all of a sudden trying to become a Thought Control police man and you are a nervous wreck without your daily resonance fantasy. Kiss my ass with your absolute BS and grow up.
Why don't you go buy a generator from GDS Technologies?
What a truly ugly, despicable posting that was. Pull yourself together and act like a civil human being.
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author=MileHigh link=topic=16589.msg486769#msg486769 date=1466501690]
What a dreadful, wretched posting that was. I simply defined true resonance and I am rejecting the casual application of the term to things that are not true resonance and you have issues with that. Like I took away your "resonance buzz" or something, and so you become this wretched ugly person? People can't run around dropping the term resonance and you are having withdrawal symptoms or something? It's fracturing your frail personalty so you resort one more time to straw man ad hominem attacks. That's about the fourth or fifth time you have done that now.
You truly are a nut case MH,and as i stated before--a hypocrite.
Quote post 1175 :In email the late MarkE said that you were a nutter.
What kind of a person portrays another person like this,when that other person is no longer here to defend him self against such a statement--on the assumption that such a statement was ever made-->wouldnt be the first time you have taken things out of context,and turned them around to suit your needs MH ::).
This is not the MarkE that i spoke with-person to person,nor did he ever have anything bad to say about anyone,whether he agreed with them or not. The mere fact that after some of the exchanges himself an i had here on this forum,he still spoke to me in person like a true gentleman and friend,is telling me that there is something amiss with your claim.
Horror of horrors, an exhaust pipe is a time delay echo device and not a true resonant device. That must be eating into your brain like a parasite and driving you insane.
The only insane thing here MH,is the fact that you still do not understand how and why resonant systems exist in and around ICE engines--and no,no one ever mentioned in !all! ICEs-another of your failed attempts to turn things into something they never were.
The only one that needs to grow up MH,is you,and your little tanties when others do not agree with you.
What a truly ugly, despicable posting that was. Pull yourself together and act like a civil human being.
Dont try and turn it around on Chet,you little weasel.
Your the one that knows no bounds to being civil. Even dragging those who are not here to defend them selves,is not beyond your limits--just to suit your needs.
How sad you are.
Brad
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Get lost Brad. You have been on one continuous stressed out bender ever since you were just treated normally and to your great shock and surprise you discovered just how little you know, how little you have progressed, and just how far you have to go. And due to that "stress of being normal" we have all seen some pretty ugly extremes in your behaviour that leave a lot to be desired.
Chet is acting like a crazy person and he deserved that comment and it's bloody well true. For all your crazy allegations about me you know that I speak the truth. I don't care how many times you have accused me of lying, that is just a symptom of your continuous stressed out bender where you have completely compromised yourself and your integrity and your credibility.
I understand perfectly well why resonant systems and things that are mistakenly called resonant systems work in internal combustion engines. So you stop playing your straw man BS about that too.
I do my best to be civil but I am not perfect. Saying someone is a "contamination" is extremely uncivil. Saying that you have "crusty drool" is extremely uncivil. Being willfully ignorant is just plain stupid.
How sad you are that you can't conceptualize something as basic as an ideal voltage source. You got to the end of this thread and you were so burnt out and emotionally exhausted that you didn't even try following up on the answer to Partzman's linear ramp question or to the second question that was already answered for you.
Look where you are, "What is the mechanism behind the gradual buildup/ramp up of the current?" After all this time and effort, the weeks and weeks of going over the ideal voltage source question and answering hundreds of questions that came up in the discussion and explaining it over and over, and you ask that question. It's like you're back at square one and this thread didn't even happen.
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Any positive conclusions or I must wait till the page 3505 (or later) will be here ? I want to learn something but don't know what is the truth about coil :-( Too many opinions
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author=MileHigh link=topic=16589.msg486779#msg486779 date=1466511392]
Get lost Brad. You have been on one continuous stressed out bender ever since you were just treated normally and to your great shock and surprise you discovered just how little you know, how little you have progressed, and just how far you have to go. And due to that "stress of being normal" we have all seen some pretty ugly extremes in your behaviour that leave a lot to be desired.
Bullshit.
Thats all i have to say to that paragraph.
Chet is acting like a crazy person and he deserved that comment and it's bloody well true. For all your crazy allegations about me you know that I speak the truth. I don't care how many times you have accused me of lying, that is just a symptom of your continuous stressed out bender where you have completely compromised yourself and your credibility
.
I think you have shot your self in the foot this time MH--you went just to far--even for you--even to the point where PW had to tell you that it was bad form.
I understand perfectly well why resonant systems and things that are mistakenly called resonant systems work in internal combustion engines. So you stop playing your straw man BS about that too.
It is painfully obvious you do not.
I do my best to be civil but I am not perfect. Saying someone is a "contamination" is extremely uncivil. Saying that you have "crusty drool" is extremely uncivil. Being willfully ignorant is just plain stupid.
Sometimes the truth hurts MH,and now you drag a good mans name down in the mud with you.
How sad you are that you can't conceptualize something as basic as an ideal voltage source.
Quote post 1147-->It's like Santa Claus Brad, and his magic sack of presents that is bottomless and holds the presents for everyone in the world. The ideal voltage source has an invisible magic energy sack that the returned energy goes into.
Well,it's great to see you have a good understanding of an ideal voltage source MH ;D
You got to the end of this thread and you were so burnt out and emotionally exhausted that you didn't even try following up on the answer to Partzman's linear ramp question or to the second question that was already answered for you.
Burnt out you say ::) lol.
MH,i could run rings around you in regards to sustainability. I drove truck for 17 hours a day,for two years straight,and still managed some bench time,video's,family time,and some fishing to boot.I now take my 1 year break from trucks,and do a normal 42 hour week job. In 6 months time,i go back to the trucks for another two years at 17 hours a day.
You manage what?-a 6 hour shift on the computer in your rocking chair at best.
I can assure you that it will not be you that wears me down lol.
Look where you are, "What is the mechanism behind the gradual buildup/ramp up of the current?" After all this time and effort, the weeks and weeks of going over the ideal voltage source question and answering hundreds of questions that came up in the discussion and explaining it over and over, and you ask that question. It's like you're back at square one and this thread didn't even happen.
Go ahead--what is the root cause of the currents slow ramp up in an inductor?,and by slow,i mean not instant like that of the voltage placed across that inductor.
Brad
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There is no point in even trying to answer a question that has already been answered multiple times in multiple ways. The expectation is the answer would just pass right through you like you weren't even there and chances are in two days you will post something that makes that readily apparent.
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Forest
yes there is a conclusion [for myself]
Miles is bound and determined to force his will on all that believe resonance a means to an end in the quest for OU.
his goal is to "teach" you away from this resonant OU madness !
and there seems to be no limits to his Stoop..
a very Shameful use of a legacy , just to make a point in a very weak argument [resonance and OU]which holds no true
value to members here.
and is mostly to polish his own EGO...
it truly turns my stomach and I will leave you alone in your "karma" Miles...
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Hmm. And the pre-existing circuit current, circuit being an inductor with a wire(ideal source at 0v) shorting its leads, continues to carry current at a constant level indefinately due to?? Like what are the specific mechanisms that make this happen?
Mags
Since we are talking about an ideal inductor and voltage source, the mechanism that allows the current to maintain infinitely in time is that there are no losses in the circuit. There is no mechanism to burn away the energy as heat.
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First up-thanks for taking the time for such an in depth answer,but most of that i already know.
I am after a more in depth answer-what is the mechanism behind the gradual buildup/ramp up of the current. I am thinking that it is the building of the magnetic field that is the root cause of the current building or ramping up over time. This magnetic field that changes over time,cuts the conducting windings,and we get our CEMF. This is what impedes on the current flow. As this magnetic fields change over time starts to slow in a linear fasion,we also see the current ramp up in the same linear fasion. The current reaches its maximum value when there is no change over time of the magnetic field.
Am i on the right track here?
Thanks
Brad
I would tend to agree that the sluggishness is caused by its own self-induction and cemf. Although I would say it is the electric field which induces the cemf, but in the end it makes no difference as to which perspective is used.
This page does a nice job of explaining it all. (https://www.nde-ed.org/EducationResources/CommunityCollege/EddyCurrents/Physics/selfinductance.htm)
The reduction of current flow in a circuit due to induction is called inductive reactance. By taking a closer look at a coil of wire and applying Lenz's law, it can be seen how inductance reduces the flow of current in the circuit.
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There is no point in even trying to answer a question that has already been answered multiple times in multiple ways. The expectation is the answer would just pass right through you like you weren't even there and chances are in two days you will post something that makes that readily apparent.
Lol-a side step MH ;)
I am well aware of self inductance in an inductor or coil MH,and what it means.
The question is to see that we are all on the same page here,although i am not really to worried if your reading the wrong book in this point in time.
Brad
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I would tend to agree that the sluggishness is caused by its own self-induction and cemf. Although I would say it is the electric field which induces the cemf, but in the end it makes no difference as to which perspective is used.
This page does a nice job of explaining it all. (https://www.nde-ed.org/EducationResources/CommunityCollege/EddyCurrents/Physics/selfinductance.htm)
Good,so we agree on that,and the electric field/magnetic field thing-well thats for another day,and im sure we can rig up a device to test that theory--one day.
But anyway,now we know that the CEMF is what reduces the rise time of the current flow from being instant-as in,as soon as we place a voltage across the inductor,the CEMF stop's the current rising to it's peak value instantly.
1-Would it there for be correct to say that--if there was no CEMF,the current would rise to it's peak value as soon as a voltage was placed across the inductor-or coil?.
2-What is the cause of the self induced EMF(CEMF) to be of a lesser value than the applied EMF?.
Brad
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1-Would it there for be correct to say that--if there was no CEMF,the current would rise to it's peak value as soon as a voltage was placed across the inductor-or coil?.
I would agree.
2-What is the cause of the self induced EMF(CEMF) to be of a lesser value than the applied EMF?.
Good question. If you read that web page it tells you that the induced cemf is proportional to the number of turns in the coil. (you should read the link provided, it does explain everything).
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2-What is the cause of the self induced EMF(CEMF) to be of a lesser value than the applied EMF?.
Brad
And you are still stuck. Surprise surprise. The CEMF is identical to the applied EMF. This was also covered in the thread multiple times.
Plus ça change, plus c'est la même chose.
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Forest
yes there is a conclusion [for myself]
Miles is bound and determined to force his will on all that believe resonance a means to an end in the quest for OU.
his goal is to "teach" you away from this resonant OU madness !
and there seems to be no limits to his Stoop..
a very Shameful use of a legacy , just to make a point in a very weak argument [resonance and OU]which holds no true
value to members here.
and is mostly to polish his own EGO...
it truly turns my stomach and I will leave you alone in your "karma" Miles...
This is just more straw man junk from you.
The intention was to discuss what resonance really is and use the example of a wine glass. And as you saw, many people had no clue whatsoever about what resonance actually is. Then an offshoot of that was that some people suggested that some things were manifestations of resonance, but on closer examination it became apparent that that was not the case.
And that's pretty much the extent of it. And you have the nerve to construct this false narrative out of some kind of pro-resonance backlash from a "believer."
You can have as many bloody over unity fantasies about resonance as you want, I don't give a damn. Have your own pulsations in sync with the pulsations of your favourite Pistol shrimp if that makes you feel better.
What was done was good and informative and you are not going to take way from that with your ridiculous "hurt resonance boy" nonsense. Pull yourself together and get over it. What true resonance actually is has been made clear and the next time some flim-flam Joe Blow comes along with a fake resonance pitch and a crowd funding web page then some people will know better. And if you hate that then go wallow in your miserable well of self-imposed pity, ignorance and stupidity.
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And you are still stuck. Surprise surprise. The CEMF is identical to the applied EMF. This was also covered in the thread multiple times.
Plus ça change, plus c'est la même chose.
Really :)
We shall use this as a reference then-shall we?.
Brad
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2-What is the cause of the self induced EMF(CEMF) to be of a lesser value than the applied EMF?.
Brad
Here Brad, let's use the differential equation for a coil that relates the voltage and the current to solve for the question:
v(t) = L di/dt
Let's just look at the first three seconds.
We know that the voltage is 4 volts and it is unchanging. We know that the inductance is 5 Henrys. So let's just punch in the numbers then.
4 = 5 * di/dt
Let's rearrange.
di/dt = 4/5
Now, what are the units for di/dt? The answer is amperes per second.
Amperes/second = 4/5
Let's rearrange.
Amperes = 4/5 * second
Let's just rename the variables to make them more familiar.
i = 4/5 * t
i = 0.8t
For t = 3 seconds we get i = 2.4 amperes.
So you see, all of the weeks and weeks of agony could have been answered in 90 seconds flat if you just got up the bloody learning curve and threw away your ridiculous obstinate attitude and your ridiculous preconceptions.
Why am I saying this? It's because the "v" in v = L di/dt is the bloody applied EMF and the opposite CEMF at the same bloody time. You are supposed to know this by now but obviously you don't.
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2-What is the cause of the self induced EMF(CEMF) to be of a lesser value than the applied EMF?.
My short answer would be "geometry", with regard to flux cutting/coupling...
Consider a given length of conductor (wire). Stretched out straight it has a certain, lowest value of inductance. Coiled up it has more inductance. Change the diameter and/or spacing of the coiled turns and the inductance changes. In any configuration, changing the size and shape of the conductor's cross section also changes the inductance.
PW
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I went over the concept with Grum but you won't listen. Just zone out and think about the Pistol shrimp.
In email the late MarkE said that you were a nutter. I was a little surprised and taken aback, but I can see now that he was spot on.
That's why I asked you to delete my coordinates and I hope you have done so. I seriously regret giving them to you.
Keep fighting for ignorance and stupidity. Have you hugged a Pistol shrimp lately?
This has to be the lowest, most ignorant, vile and despicable posting I have ever read here on O.U.com, and believe me, that is really saying something. You have set a new low. I used to have some respect for your knowledge Sir, but no longer.
You have just singlehandedly redefined the word scumbag.
Nice going.
Judging from all of the emails, and postings, I am not alone in my assessment.
Bill
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I would agree.
Good question. If you read that web page it tells you that the induced cemf is proportional to the number of turns in the coil. (you should read the link provided, it does explain everything).
Yes,i read that page some time ago,and reviewed it again after your post with the link to it.]
Quote: The reduction of current flow in a circuit due to induction is called inductive reactance. By taking a closer look at a coil of wire and applying Lenz's law, it can be seen how inductance reduces the flow of current in the circuit. In the image below, the direction of the primary current is shown in red, and the magnetic field generated by the current is shown in blue. The direction of the magnetic field can be determined by taking your right hand and pointing your thumb in the direction of the current. Your fingers will then point in the direction of the magnetic field. It can be seen that the magnetic field from one loop of the wire will cut across the other loops in the coil and this will induce current flow (shown in green) in the circuit. According to Lenz's law, the induced current must flow in the opposite direction of the primary current. The induced current working against the primary current results in a reduction of current flow in the circuit.
It should be noted that the inductive reactance will increase if the number of winds in the coil is increased since the magnetic field from one coil will have more coils to interact with.
This still dose not explain as to where the loss is--why the CEMF is not equal to the induced EMF.
If the CEMF and EMF were of the same amount,then the current that flows in opposition to that which created it,would be of the same value,and no current would flow.
So where is this loss?
Could it be that some is due to the actual resistance value of the coil,and/or the fact that the outer windings and inner windings do not cut through as many other windings as those in the center of the coil do.
What i mean is,is this loss due to incomplete total flux linkage within the inductor?.
Just on that note.
MH has just said that the CEMF is equal to the EMF that created it.
Your thoughts on this?
Brad
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Here Brad, let's use the integral equation for a coil that relates the current and the voltage to solve for the question:
i(t) = 1/L integral v(t) dt
Let's just look at the first three seconds.
We know that the voltage is 4 volts and it is unchanging. We know that the inductance is 5 Henrys. So let's just punch in the numbers then.
i(t) = 1/5 integral 4 dt
Then you go to the integral web site and you get the solution for the integral. You were too emotionally exhausted and burnt out so you never went there.
i(t) = 1/5 (4t)
Rearranging and cleaning up:
i = 4/5 * t
i = 0.8t
For t = 3 seconds we get i = 2.4 amperes.
Same story. If you just got up the learning curve and changed your bad attitude all of the weeks and weeks of agony could have been answered in 90 seconds flat.
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PW
My short answer would be "geometry", with regard to flux cutting/coupling...
Ah,just read your post PW,as i just finished posting my last one.
Seems we are on the same page here.
Consider a given length of conductor (wire). Stretched out straight it has a certain, lowest value of inductance. Coiled up it has more inductance. Change the diameter and/or spacing of the coiled turns and the inductance changes. In any configuration, changing the size and shape of the conductor's cross section also changes the inductance.
Yes,i agree with all this.
So if we could achieve this perfect coupling/flux cutting,then the CEMF should be equal to the EMF that created it. In this case,no current would flow?
Brad
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Here Brad, let's use the integral equation for a coil that relates the current and the voltage to solve for the question:
i(t) = 1/L integral v(t) dt
Let's just look at the first three seconds.
We know that the voltage is 4 volts and it is unchanging. We know that the inductance is 5 Henrys. So let's just punch in the numbers then.
i(t) = 1/5 integral 4 dt
Then you go to the integral web site and you get the solution for the integral. You were too emotionally exhausted and burnt out so you never went there.
i(t) = 1/5 (4t)
Rearranging and cleaning up:
i = 4/5 * t
i = 0.8t
For t = 3 seconds we get i = 2.4 amperes.
Same story. If you just got up the learning curve and changed your bad attitude all of the weeks and weeks of agony could have been answered in 90 seconds flat.
Well that was boring MH,as i have already answered the question using the very formula you just used. Perhaps go back say 200 posts,and have a look.
I think the agony here,is having to keep going over the same stuff an endless amount of times with you.
Brad
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This still dose not explain as to where the loss is--why the CEMF is not equal to the induced EMF.
If the CEMF and EMF were of the same amount,then the current that flows in opposition to that which created it,would be of the same value,and no current would flow.
So where is this loss?
Could it be that some is due to the actual resistance value of the coil,and/or the fact that the outer windings and inner windings do not cut through as many other windings as those in the center of the coil do.
What i mean is,is this loss due to incomplete total flux linkage within the inductor?.
I think you have the basic concept, yes. Again, the fundamental frequency and the harmonic content influences how the inductor reacts. The higher the inductance, the higher the induced cemf for a given frequency. At some point (either relatively large L or high frequencies) the cemf will equal the applied voltage (or it may be more correct to say the induced current will equal the applied current) and the net resulting current will be minimal.
Just on that note.
MH has just said that the CEMF is equal to the EMF that created it.
Your thoughts on this?
I'll let MH explain that.
-
Welcome???
I have to take several "breaks" from this forum from time to time as the non-productive "attitudes" and outright craziness this forum sometimes erodes into is sometimes difficult to take. The last time I took a break for a while was just prior to this thread starting. At that time I believe models depicting shorted inductors and GB's flat Earth thing all just became a bit too much...
Anyway, I recently went back to the beginning of this thread to re-read it and I see right on page 2 of this thread, a first (and only) time poster going by "Didymus" posed the following:
Somebody has to go back to basics, it might as well be me.
The definition of an ideal inductor is a two-terminal device that obeys the current/voltage relationship:
V = L dI/dt where V is the applied voltage, L is the inductance in Henries and dI/dt is the rate of change of the current with time. The impedance of the voltage source and the resistance of the inductor are both assumed to be zero.
This definition can be rewritten as dI.dt = V/L. Given an initial current of zero, applying 4 V to a 5 H inductor leads to a current through the inductor that increases at 0.8 amps per second. After three seconds the current will be 2.4 amps. If the supply is not turned off the current will increase indefinitely at 0.8 A/second. There are no time constants involved.
For completeness, a capacitor is a two-terminal device the current through which is given by the equation:
I = C dV/dt where C is the capacitance in Farads. The current through the capacitor is proportion to the rate of change in the applied voltage times the capacitance. In this case applying a fixed current results in a voltage across the capacitor that increases indefinitely.
I don't believe anyone ever responded to this excellent post (correct me if I am wrong, perhaps I have not yet read far enough). Apparently, this was Didymus' first, only, and last post on this forum.
How long has this forum been around? 10 or 15 years?
I can remember a time long ago when this forum seemed a bit more polite and respectful. Heck even newbies, upon their first postings, were welcomed by members as they responded to their posts.
Perhaps we could all just ease up a bit on the emotional investments and show a bit more consideration for each other.
End of speech...
PW
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This has to be the lowest, most ignorant, vile and despicable posting I have ever read here on O.U.com, and believe me, that is really saying something. You have set a new low. I used to have some respect for your knowledge Sir, but no longer.
You have just singlehandedly redefined the word scumbag.
Nice going.
Judging from all of the emails, and postings, I am not alone in my assessment.
Bill
Take a chill pill Bill. If you recall MarkE was not exactly impressed when Chet wanted to organize a test for the infamous GDS Generator. I am sure many other things helped him formulate his opinion. All that Chet has been doing has been acting like a spoiled over unity brat filled with attitude. Having him know how a former respected member of the forum sized him up was appropriate since he wouldn't stop acting like a spoiled brat that didn't get his cookies. He can have his resonance fetish without trying to ruin my perfectly good discussion about true resonance. The ignorance enforcer boy got a well-deserved smack-down. Citing MarkE's opinion was not so "low, ignorant, vile and despicable." You are over dramatizing the situation.
Actively trying to impugn a perfectly good discussion about the true scientific meaning of resonance because that disturbs your resonance fantasies, as well as continuously making false straw man arguments about someone and just being a general overall nuisance became a bit much hence the smack-down.
There is no damn reason in the world that Chet can't have his resonance fantasies, hopes and dreams while I discuss the actual meaning of true resonance and evaluate systems that may or may not be truly resonant - NONE.
-
This has to be the lowest, most ignorant, vile and despicable posting I have ever read here on O.U.com, and believe me, that is really saying something. You have set a new low. I used to have some respect for your knowledge Sir, but no longer.
You have just singlehandedly redefined the word scumbag.
Nice going.
Judging from all of the emails, and postings, I am not alone in my assessment.
Bill
You should continue to respect his knowledge and help shutdown this site so people stop posting al that nonsense about OU!
Wake up all your wishful thinkers and let the real scientists discover better ways to get electricity.
Buy some solar panels if you want free energy.
-
Welcome???
I have to take several "breaks" from this forum from time to time as the non-productive "attitudes" and outright craziness this forum sometimes erodes into is sometimes difficult to take. The last time I took a break for a while was just prior to this thread starting. At that time I believe models depicting shorted inductors and GB's flat Earth thing all just became a bit too much...
Anyway, I recently went back to the beginning of this thread to re-read it and I see right on page 2 of this thread, a first (and only) time poster going by "Didymus" posed the following:
I don't believe anyone ever responded to this excellent post (correct me if I am wrong, perhaps I have not yet read far enough). Apparently, this was Didymus' first, only, and last post on this forum.
How long has this forum been around? 10 or 15 years?
Perhaps we could all just ease up a bit on the emotional investments and show a bit more consideration for each other.
End of speech...
PW
Mmm
Seems you are right PW.
I normally read all post in a thread,unless i enter the thread after page 20 or around abouts,but seems i missed that one altogether-along with everyone else. He joined the day of the post,and has not posted since,and it is the only post he made here.
I can remember a time long ago when this forum seemed a bit more polite and respectful. Heck even newbies, upon their first postings, were welcomed by members as they responded to their posts.
Yes,perhaps you are right,and i do feel bad about missing that post,although i do not know how i did,as he had the calculated answer up on the second page.
Brad
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And you are still stuck. Surprise surprise. This was also covered in the thread multiple times.
Plus ça change, plus c'est la même chose.
The CEMF is identical to the applied EMF.
I asked Poynt what he thought of your comment above,and he said--i will let MH explain that.
So could you please explain as to why you think the CEMF is identical to the EMF that created it?
Brad
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Anyway, I recently went back to the beginning of this thread to re-read it and I see right on page 2 of this thread, a first (and only) time poster going by "Didymus" posed the following:
I don't believe anyone ever responded to this excellent post (correct me if I am wrong, perhaps I have not yet read far enough). Apparently, this was Didymus' first, only, and last post on this forum.
It is indeed an excellent posting. Just look at the behavioural patterns and the answer is quite obvious. That early in the game and Brad dismissed it as nonsense because he supposedly knew better.
Brad's very first posting, the original posting with no number, in the thread:
My answer to this question is--you cannot place an ideal voltage across an ideal inductor.
The reason being,at T=0,when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity.
It probably took about 100-200 postings to get him to budge just a little from that original position.
We can't rewrite history.
MileHigh
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You should continue to respect his knowledge and help shutdown this site so people stop posting al that nonsense about OU!
Wake up all your wishful thinkers and let the real scientists discover better ways to get electricity.
Buy some solar panels if you want free energy.
But there not OU,and dont work so well in moon light ;D
and help shutdown this site
So you are against this site?
You should leave,before Stephan kicks you out.
Brad
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It is indeed an excellent posting. Just look at the behavioural patterns and the answer is quite obvious. That early in the game and Brad dismissed it as nonsense because he supposedly knew better.
Brad's very first posting, the original posting with no number, in the thread:
It probably took about 100-200 postings to get him to budge just a little from that original position.
We can't rewrite history.
MileHigh
And so you say that the CEMF is equal to the applied EMF,which would result in a total of 0 volts across your ideal coil that is suppose to have 4 volts across it from an ideal voltage source ???
Brad
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I asked Poynt what he thought of your comment above,and he said--i will let MH explain that.
So could you please explain as to why you think the CEMF is identical to the EMF that created it?
Brad
Yes, there are two answers to that. The first is the common sense answer. If I connect a battery to a coil, the battery will impose its voltage on the coil as long as it can. The coil is just reacting to what the battery is doing.
So the battery determines the voltage, period. Where is there room for some kind of difference in the voltage of the battery and any imaginable voltage from the coil? There is no room for that, they are connected together. You would have to have a resistor between the battery and the coil for there to be any possible voltage difference between the two.
Since we know that an action produces an equal and opposite reaction, then the coil has to be reacting equally and opposite to the battery. Same thing for a resistor.
So even though the battery is imposing its voltage on the coil, you need to be able to shift your perspective and go "inside" the coil and realize that the coil is pushing back with the same CEMF.
You can take a ridiculously simple example from the physical world: If you are balancing a water jug on your head, then your head is pushing up with the same force as the water jug is pushing down. It is as simple as that.
Or you just have enough common sense to realize the applied EMF and the CEMF are identical without even having to think about it.
Now if all of this stuff is elusive to you, then KVL to the rescue:
Kirchhoff's voltage law (KVL) The sum of all the voltages around the loop is equal to zero. This law is also called Kirchhoff's second law, Kirchhoff's loop (or mesh) rule, and Kirchhoff's second rule.
The applied EMF and the CEMF from the coil must add up to zero. Therefore, the CEMF must be equal and opposite to the EMF.
Just memorize it if it does not come naturally to you.
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And so you say that the CEMF is equal to the applied EMF,which would result in a total of 0 volts across your ideal coil that is suppose to have 4 volts across it from an ideal voltage source ???
Brad
This is the point where the seasoned violinist in the London Symphony Orchestra smashes his Stradivarius against the wall in a moment of extreme loss of composure.
The highest price paid for a Stradivarius violin is $16 million (£9.5 million). A rare viola made by the Italian artisan Antonio Stradivari in 1719 that will be sold by Sotheby's in a sealed bid auction in June is valued at $45 million (£27 million).
-
So if we could achieve this perfect coupling/flux cutting,then the CEMF should be equal to the EMF that created it. In this case,no current would flow?
I would think that if you could achieve perfect flux coupling/cutting geometries, using an ideal conductor, you would create an inductor with infinite inductance from which it follows that the current flow over time would be infinitely small.
PW
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Well that was boring MH,as i have already answered the question using the very formula you just used. Perhaps go back say 200 posts,and have a look.
I think the agony here,is having to keep going over the same stuff an endless amount of times with you.
Brad
I am not so sure about that. I think it's safe to assume that you never solved an integral in your life and you definitely did not go to the integral calculator web site.
The first three seconds of the question were solved using both the integral and differential equations for a coil in no time flat.
The point being that there was no need for all of the agony, and likewise even the useful tools of using visualizations and analogies and all that stuff was not really necessary. If you actually understood how a coil actually works, and you were familiar with and understood the two equations, then you yourself could have answered the full question in ten minutes flat without all of the drama and the totally ridiculous false technical arguments that you relentlessly put up as obstacles to learning. All that you had to do was apply the standard equations for a coil.
Will you learn from this experience? Unfortunately, I honestly doubt you will.
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I see it like this, and I could be wrong of course. ;)
The voltage across the coil terminals does not change, it is determined by the voltage source. But the induced cemf is in series opposing with the voltage source Vin, and its value is determined by the frequency of Vin and the inductance L.
So, from this perspective the induced cemf is usually not equal to the applied emf (Vin). It is usually lower.
-
I see it like this, and I could be wrong of course. ;)
The voltage across the coil terminals does not change, it is determined by the voltage source. But the induced cemf is in series opposing with the voltage source Vin, and its value is determined by the frequency of Vin and the inductance L.
So, from this perspective the induced cemf is usually not equal to the applied emf (Vin). It is usually lower.
I think that you are just going to confuse Brad with that diagram because he is going to see the CEMF being opposite the EMF and his is going to say again that there is no voltage across the coil.
I am puzzled why you would say the CEMF is not equal to the applied EMF.
its value (the induced CEMF) is determined by the frequency of Vin and the inductance L.
More like the induced current is determined by the frequency of Vin and the inductance L.
I am not sure where you are going with this, but here is a fact that I think we can agree on:
The voltage across the inductor is clamped to the applied EMF voltage, and it doesn't matter if the applied EMF is a DC value or some kind of variable frequency and amplitude AC value.
If you agree with this, then the CEMF is always equal and opposite to the applied EMF.
-
I think that you are just going to confuse Brad with that diagram because he is going to see the CEMF being opposite the EMF and his is going to say again that there is no voltage across the coil.
I don't think he will assume that. I believe he knows that even though the induced emf (cemf) is opposite in polarity to that of the applied voltage, it will almost always be less, and therefore there will still be a net applied emf and resulting current.
I am puzzled why you would say the CEMF is not equal to the applied EMF.
The EMF is applied by the user, while the cemf is self-induced; VL = L x di/dt. So according to the equation, the induced cemf can be any value and will vary depending on the frequency and inductance. The applied EMF never changes its value.
More like the induced current is determined by the frequency of Vin and the inductance L.
I believe that when there is an induced current, there is always an associated induced emf.
I am not sure where you are going with this, but here is a fact that I think we can agree on:
The voltage across the inductor is clamped to the applied EMF voltage, and it doesn't matter if the applied EMF is a DC value or some kind of variable frequency and amplitude AC value.
Yes, but this is a series circuit as well as a parallel circuit, and the induced cemf would be as I depicted.
If you agree with this, then the CEMF is always equal and opposite to the applied EMF.
As I mentioned above, the induced cemf can be any value, and is dependent on the input frequency and the inductance. I don't see any rules being broken here so help me out. Where am I going wrong?
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Take a chill pill Bill. If you recall MarkE was not exactly impressed when Chet wanted to organize a test for the infamous GDS Generator. I am sure many other things helped him formulate his opinion. All that Chet has been doing has been acting like a spoiled over unity brat filled with attitude. Having him know how a former respected member of the forum sized him up was appropriate since he wouldn't stop acting like a spoiled brat that didn't get his cookies. He can have his resonance fetish without trying to ruin my perfectly good discussion about true resonance. The ignorance enforcer boy got a well-deserved smack-down. Citing MarkE's opinion was not so "low, ignorant, vile and despicable." You are over dramatizing the situation.
Actively trying to impugn a perfectly good discussion about the true scientific meaning of resonance because that disturbs your resonance fantasies, as well as continuously making false straw man arguments about someone and just being a general overall nuisance became a bit much hence the smack-down.
There is no damn reason in the world that Chet can't have his resonance fantasies, hopes and dreams while I discuss the actual meaning of true resonance and evaluate systems that may or may not be truly resonant - NONE.
Holy cow, once again you make a statement that can not be proven because the person you claim said it has passed away.
Take a chill pill?
No.
Fuck you!
Asshole!
Bill
PS You can shove that chill pill up your ass...how about that?
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The weaker the argument the bolder he gets
..in this case ..resonance is the low hanging fruit of fraudsters fed to the ignorant and gullible ,and will never yield ..nor has ever been a driving force in OU [which is also for the ignorant].
this is the plate Miles sets ..screaming ever louder as he falls ever shorter
his technical resonance question and resonant ramblings are lame and completely irrelevant to Brads efforts on his Bench
and are 100% for HIS own benefit and EGO
the contributions earlier in this thread by Smokey 2 were of true Value to researchers here.
there is absolutely NOTHING miles has said to Brad about resonance which will yield him One fleas Butt hair worth of benefit on the bench
No, it was not about helping Brad
it was all about Miles and his greatness.. attempting to belittle another man and put him in his place
as well as most members of this forum hunting for OU thru the effects of resonance and Tuning
the low hanging fruit of OU fools
he will put an end to this resonance nonsense once and for all.
and to think my offer to investigate a claim makes me a Nutter [miles quote]
as does my belief in LENR
as does my belief in Water as fuel [chessnyt and others]
as does my belief in OU or harvesting energy from as yet undiscovered sources with any tool possible
especially RESONANCE..
good luck in your Box miles ...
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But there not OU,and dont work so well in moon light ;D
So you are against this site?
You should leave,before Stephan kicks you out.
Brad
Yes they are far from OU but they give you free energy. Unlike other device on this site ;D
I'm against this kind of sites because it spreads lies and misinformation to good people with poor knowledge.
If i can't share my opinion here and tell people what i have learned from my personal OU journey than Stephan can kick me out.
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Holy cow, once again you make a statement that can not be proven because the person you claim said it has passed away.
Take a chill pill?
No.
Fuck you!
Asshole!
Bill
PS You can shove that chill pill up your ass...how about that?
Yeah, I just forwarded you an email. You yourself read the same email less than a year ago as a recipient. You can swallow it, you don't have to go the other way.
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The weaker the argument the bolder he gets
..in this case ..resonance is the low hanging fruit of fraudsters fed to the ignorant and gullible ,and will never yield ..nor has ever been a driving force in OU [which is also for the ignorant].
this is the plate Miles sets ..screaming ever louder as he falls ever shorter
his technical resonance question and resonant ramblings are lame and completely irrelevant to Brads efforts on his Bench
and are 100% for HIS own benefit and EGO
the contributions earlier in this thread by Smokey 2 were of true Value to researchers here.
there is absolutely NOTHING miles has said to Brad about resonance which will yield him One fleas Butt hair worth of benefit on the bench
No, it was not about helping Brad
it was all about Miles and his greatness.. attempting to belittle another man and put him in his place
as well as most members of this forum hunting for OU thru the effects of resonance and Tuning
the low hanging fruit of OU fools
he will put an end to this resonance nonsense once and for all.
and to think my offer to investigate a claim makes me a Nutter [miles quote]
as does my belief in LENR
as does my belief in Water as fuel [chessnyt and others]
as does my belief in OU or harvesting energy from as yet undiscovered sources with any tool possible
especially RESONANCE..
good luck in your Box miles ...
https://en.wikipedia.org/wiki/Psychological_projection (https://en.wikipedia.org/wiki/Psychological_projection)
Psychological projection is a theory in psychology in which humans defend themselves against their own unconscious impulses or qualities (both positive and negative) by denying their existence in themselves while attributing them to others.[1] For example, a person who is habitually rude may constantly accuse other people of being rude. It incorporates blame shifting.
According to some research, the projection of one's unconscious qualities onto others is a common process in everyday life.
So whose benefit and whose ego are we really talking about?
-
Scratchbot, hang on in here.
What's needed is some good theoretical work to be done. I've been looking since
about 2005 and I haven't seen a proven watt, plenty of crap,though!
Check out old Leif Holmlid of Gothenburg, that's the sort of area something
could come from.
John.
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author=MileHigh link=topic=16589.msg486819#msg486819 date=1466523762]
Since we know that an action produces an equal and opposite reaction, then the coil has to be reacting equally and opposite to the battery. Same thing for a resistor.
So even though the battery is imposing its voltage on the coil, you need to be able to shift your perspective and go "inside" the coil and realize that the coil is pushing back with the same CEMF.
No it is not.
You are lost when you think that the total EMF is going to be converted only to a CEMF.
Every action dose not always equal !one only! opposite and equal reaction. The sum of reactions will equal the action.
E.G-3 pool balls on a pool table. Two placed side by side,and one at the other end of the table. The single ball is hit with the queue,and that single ball strikes the two at the other end of the pool table right in the center of the two balls. Each of the two balls takes of in different directions. We now have two reactions that summed together equal the action--the single ball that struck them-minus some loss due to sound.
You can take a ridiculously simple example from the physical world: If you are balancing a water jug on your head, then your head is pushing up with the same force as the water jug is pushing down. It is as simple as that.
It's not that simple at all.
Or you just have enough common sense to realize the applied EMF and the CEMF are identical without even having to think about it.
No they are not,as if they were,no current would flow,as no voltage would exist across the coil.
!OH!-unless that coil was !!ideal!! ;D,where the flux linkage/flux cutting was actually ideal ;)
Kirchhoff's voltage law (KVL) The sum of all the voltages around the loop is equal to zero. This law is also called Kirchhoff's second law, Kirchhoff's loop (or mesh) rule, and Kirchhoff's second rule.
The applied EMF and the CEMF from the coil must add up to zero. Therefore, the CEMF must be equal and opposite to the EMF.
Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply.
Brad
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author=poynt99 link=topic=16589.msg486830#msg486830 date=1466530196]
I don't think he will assume that. I believe he knows that even though the induced emf (cemf) is opposite in polarity to that of the applied voltage, it will almost always be less, and therefore there will still be a net applied emf and resulting current.
Of course i will not assume that.This is the very reason an electric motor will draw a lot of current at start up,and the current will reduce as the motor gains speed.
MH is just lost again.
The EMF is applied by the user, while the cemf is self-induced; VL = L x di/dt. So according to the equation, the induced cemf can be any value and will vary depending on the frequency and inductance. The applied EMF never changes its value.
I believe that when there is an induced current, there is always an associated induced emf.
Yes, but this is a series circuit as well as a parallel circuit, and the induced cemf would be as I depicted.
As I mentioned above, the induced cemf can be any value, and is dependent on the input frequency and the inductance. I don't see any rules being broken here so help me out. Where am I going wrong?
You are not going wrong Poynt,and i think MH is having a bad day.
As you would have seen in this thread,he laughed at some of us when we said that in an ideal coil,the CEMF would be equal to the applied EMF. But now-now he is saying the same thing he laughed at us for saying.
If the coil was indeed ideal,then that would be the case-->the CEMF would equal the applied EMF.
We know this is the case,and we can prove it with a thought experiment using a simple DC motor.
We apply 12 volts across a 12 volt DC motor.
The motor will draw maximum current on startup. As the rotor windings pick up speed,they cut through the stator magnetic fields quicker,and so see a magnetic field that has a greater change in time. This results in a larger value of CEMF,and so the total voltage seen across the coil is reduced,and so the current is reduced. Once running at it's top rated RPM,with no load attached to the motor,the least amount of current will be flowing through the motor,as the CEMF is now at it's greatest. Our motor is also acting as a generator<--something to remember in time to come,but say no more at this time,on this thread.
Now,if there were no resistive or frictional losses(the motor is ideal),how much current would need to flow through that motor to keep it spinning?
Brad.
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author=MileHigh link=topic=16589.msg486824#msg486824 date=1466527005]
I am puzzled why you would say the CEMF is not equal to the applied EMF.
Says the man that laughed at myself and Mags when we stated that in an ideal coil,the CEMF would be equal and opposite to that of the applied EMF.
As you say over there-You have drunk too much cool aid MH
then the CEMF is always equal and opposite to the applied EMF.
There you go Mag's--aint that a hoot :D
Brad
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Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply.
Brad
After six years, and all of the discussions that have taken place, that's just another jaw-dropping ridiculous outrageous goof that you have made that would make any poor electronics teacher want to smash his head against the wall and smash his Stradivarius violin into a thousand splinters.
I just don't know what to say. People are aghast? The sky is falling? We are at a private resort, Brad's Bizarro Retreat? Hit the resent button and hope for no BSOD?
It's just beyond belief sometimes. Somebody else can pick up the pieces with you.
-
Yeah, I just forwarded you an email. You yourself read the same email less than a year ago as a recipient. You can swallow it, you don't have to go the other way.
Its more of a moral issue. If Mark wrote that to you in 'private' then it was to be private. Like why pick and choose what to release? Why not just post all of his pms to you? Wouldnt be the right thing to do??? ;)
Mags
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Its more of a moral issue. If Mark wrote that to you in 'private' then it was to be private. Like why pick and choose what to release? Why not just post all of his pms to you? Wouldnt be the right thing to do??? ;)
Mags
The biggest moral issue for you is to not fall into the ugly trap of becoming a predatory harasser that enjoys the pain and suffering that he inflicts on other people. You need to keep your head space in the right place and not fall into that ugly trap and keep your moral compass pointed in the right direction. It's like you are a reformed alcoholic that needs to never touch a drop. Keep that in mind at all times.
I asked you to publicly state that you would not harass me any more and you refused to acknowledge my request and say anything. You still have issues to work on.
I did not post anything from MarkE at all but I did make reference to what he said and considering that Chet was starting to emulate the worst behaviours that I have seen from you, and potentially fall into the same kind of ugly trap, I have no qualms about telling him what I told him. He needs to reform himself and check his behaviour.
I am not perfect and I am no angel, but I know when I see wrongdoing.
MileHigh
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author=MileHigh link=topic=16589.msg486824#msg486824 date=1466527005]
Says the man that laughed at myself and Mags when we stated that in an ideal coil,the CEMF would be equal and opposite to that of the applied EMF.
As you say over there-You have drunk too much cool aid MH
Brad
And I think we are in super knickers twist territory here.
I would never have laughed at you if you stated that the CEMF would be equal and opposite the EMF because I agree with that. So I don't know where that is coming from but I can venture a guess.
For starters, I am assuming that we are back to discussing a coil and not a motor. When you state that the CEMF would be equal to the EMF you believe that no current would flow because the CEMF cancels out the EMF. You believe that for current to flow in a coil the CEMF must be less than the EMF.
Well, that's where you are wrong. When you apply EMF to a coil, the coil's CEMF is equal to the EMF and current flows through the coil. Right now in your head that doesn't make sense but that is really the way it is.
This idea you have in your head about the requirement for a voltage difference is wrong. And you are over confident with your little comments like "MH is just lost again" and "I think MH is having a bad day" and "aint that a hoot."
Unfortunately the joke is on you. I don't really know if I am prepared to argue it out with you. I am willing to try to close the loop with Poynt on this issue from an earlier posting but as far as I am concerned you are on your own. Believe what you want to believe or figure it out with someone else.
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Since we are talking about an ideal inductor and voltage source, the mechanism that allows the current to maintain infinitely in time is that there are no losses in the circuit. There is no mechanism to burn away the energy as heat.
So in an ideal conductor, say in a loop, when something occurs that causes the electrons flow in the loop and that something is taken away, the electrons maintain that flow until a situation occurs that would stop that flow?
If so, then the ideal conductor doesnt require energy for electrons to be stripped from atoms and move them from atom to atom, jumping shell to shell. I can understand the seeming inertial effects of an inductor on electrons in its conductors, but not inertial effects of moving electrons on their own. This might incur that electrons have mass. And the seeming inertial effects of electrons of the inductor are when the field is collapsing. In this situation there is no field collapse or motion of the fields at all. So what mechanism keeps the electrons flowing in the loop? What energy is 'stored' that keeps the flow going? What form is the energy stored as?
Mags
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The biggest moral issue for you is to not fall into the ugly trap of becoming a predatory harasser that enjoys the pain and suffering that he inflicts on other people. You need to keep your head space in the right place and not fall into that ugly trap and keep your moral compass pointed in the right direction. It's like you are a reformed alcoholic that needs to never touch a drop. Keep that in mind at all times.
I asked you to publicly state that you would not harass me any more and you refused to acknowledge my request and say anything. You still have issues to work on.
I did not post anything from MarkE at all but I did make reference to what he said and considering that Chet was starting to emulate the worst behaviours that I have seen from you, and potentially fall into the same kind of ugly trap, I have no qualms about telling him what I told him. He needs to reform himself and check his behaviour.
I am not perfect and I am no angel, but I know when I see wrongdoing.
MileHigh
I think the readers know the difference. Twist it all you want. Even your peers have spoken.
Mags
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Miles
your social ignorance is only surpassed by your nauseating arrogance ,you commit an appalling act of grotesque selfishness
involving the memory of a deceased member here and then you Nance around Playing spock and Freud .
you are so isolated from your own weirdness it is hard to witness.
the fellows who actually build and experiment here should not be part of your scam artist fraudster make believe super hero dementia.
go bother whoever it is you need to save the world from and we'll call you when a fraud seeking missile comes in the front door.
this an OU forum and we play with resonance and magnets
and whatever else we choose to do.
you poor demented Putz
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I think the readers know the difference. Twist it all you want. Even your peers have spoken.
Mags
I think it's all a tempest in a tea pot that is cynically being taken advantage of. Let's agree to disagree.
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author=MileHigh link=topic=16589.msg486824#msg486824 date=1466527005]
Says the man that laughed at myself and Mags when we stated that in an ideal coil,the CEMF would be equal and opposite to that of the applied EMF.
As you say over there-You have drunk too much cool aid MH
There you go Mag's--aint that a hoot :D
Brad
What was it, there are 2 kinds of conductors in the Ideal world. One kind has inductive/magnetic abilities and one kind has no inductive or magnetic properties. When I think about why that is, the 'more' ridiculous the ideal world becomes and is even more impossible than what we have covered here.
Mags
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Miles
your social ignorance is only surpassed by your nauseating arrogance ,you commit an appalling act of grotesque selfishness
involving the memory of a deceased member here and then you Nance around Playing spock and Freud .
you are so isolated from your own weirdness it is hard to witness.
the fellows who actually build and experiment here should not be part of your scam artist fraudster make believe super hero dementia.
go bother whoever it is you need to save the world from and we'll call you when a fraud seeking missile comes in the front door.
this an OU forum and we play with resonance and magnets
and whatever else we choose to do.
you poor demented Putz
Yeah, and you are a demented putz too. I explored the true scientific and engineering definition of resonance and then evaluated some engine components to see if they met that criteria. And you want to treat that like it is some kind of mortal sin and it is stepping all over your resonance fetish. Your pitch is completely nuts and you have gone off your rocker. You can talk about whatever resonance stuff you want and it's not going to bother me.
It's time for you to STAND DOWN from your ridiculous behaviour and just live and let live. Pull yourself together and regain your composure and stop posting like a bloody nutcase.
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Miles
Your not an engine designer nor a metallurgist and your ignorance of what is taking place in ICE design has become quite apparent here
Johan runs engines at full power on 50% water ,
he has built and designed Rotary engines which break all the rules , when he speaks I listen when you speak about ICE's
and try to present yourself an authority ...
I cringe
you now stand out as the Poser you are
There are men here that go beyond your limited understanding of what is possible... tuning and resonance are most definitely areas to explore.
your willingness to bluff your way thru an unfamiliar field and Pose as some sort of authority is Disgusting behavior.
as is your willingness to win at all costs
even dragging the memory of another here into your agenda.
and that I actually find quite appalling
and no amount of Freudzilla nonsense from your twisted perspective of reality will change that.
your Military Stand down orders are quite funny!!
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You are ridiculous. I never tried to present myself as an authority on engines. With respect to resonance, you can ring bells until you are blue in the face, I don't give a damn. Just stop and calm down.
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have a good night..
same time tomorrow ??
Yeesh...........
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And I think we are in super knickers twist territory here.
I would never have laughed at you if you stated that the CEMF would be equal and opposite the EMF because I agree with that. So I don't know where that is coming from but I can venture a guess.
For starters, I am assuming that we are back to discussing a coil and not a motor. When you state that the CEMF would be equal to the EMF you believe that no current would flow because the CEMF cancels out the EMF. You believe that for current to flow in a coil the CEMF must be less than the EMF.
Well, that's where you are wrong. When you apply EMF to a coil, the coil's CEMF is equal to the EMF and current flows through the coil. Right now in your head that doesn't make sense but that is really the way it is.
This idea you have in your head about the requirement for a voltage difference is wrong. And you are over confident with your little comments like "MH is just lost again" and "I think MH is having a bad day" and "aint that a hoot."
Unfortunately the joke is on you. I don't really know if I am prepared to argue it out with you. I am willing to try to close the loop with Poynt on this issue from an earlier posting but as far as I am concerned you are on your own. Believe what you want to believe or figure it out with someone else.
Well i am in agreeance with poynt,so if he is wrong,then so am i.
I might point out that poynt has been doing this far longer than me,and he is fare more verst in EE than i by a huge margin.
So what you say about me,must also apply to those that are in agreeance with-yes?.
So yes,you sort it out with poynt,as it is getting increasingly difficult to learn ,when there is two well versed EE guys disagreeing on something that is suppose to be simple.
Brad
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And I think we are in super knickers twist territory here.
I would never have laughed at you if you stated that the CEMF would be equal and opposite the EMF because I agree with that. So I don't know where that is coming from but I can venture a guess.
For starters, I am assuming that we are back to discussing a coil and not a motor. When you state that the CEMF would be equal to the EMF you believe that no current would flow because the CEMF cancels out the EMF. You believe that for current to flow in a coil the CEMF must be less than the EMF.
Well, that's where you are wrong. When you apply EMF to a coil, the coil's CEMF is equal to the EMF and current flows through the coil. Right now in your head that doesn't make sense but that is really the way it is.
This idea you have in your head about the requirement for a voltage difference is wrong. And you are over confident with your little comments like "MH is just lost again" and "I think MH is having a bad day" and "aint that a hoot."
Unfortunately the joke is on you. I don't really know if I am prepared to argue it out with you. I am willing to try to close the loop with Poynt on this issue from an earlier posting but as far as I am concerned you are on your own. Believe what you want to believe or figure it out with someone else.
To make it clear as to what i believe MH, the CEMF will create a current flow that apposes that which created it-it is in opposition to that of the induced current from the applied EMF.
This means that the CEMF is opposite to,but not equal to the applied EMF. --WE ARE TALKING NON IDEAL INDUCTORS HERE-not ideal. When myself and mags stated that the CEMF and EMF would be equal and opposite,we were talking about your ideal coil,where the flux linking/cutting would also be ideal-no losses as we have in real world inductors.
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Loner:
When it comes to electronics, you are not as smart as you think. Beyond that, don't you dare allege that I am a troll. I am making logical points and I am sincerely trying to debate with people, even if the debate can get heated. It takes two to tango. I am not buying your "wise man coming to share some pearls of wisdom" vibe, at all. If you have some issues with me, then say them straight to my face and we will debate them. Fair enough?
Current Flow IS determined by voltage, right? IF the Applied voltage WERE EXACTLY equal to the "CEMF" there would be NO CURRENT. Second, IF there were NO Current, there would be NO CEMF!!!
Come on people, a little common sense and logic is required to understand ANY of this, in a realistic OR ideal fashion. Just as, an IDEAL inductor will still have Impedance, which is really what this entire discussion was about, to begin with.
Sure, let's get real and use a little common sense and start off with a resistor.
You have a one-volt voltage source connected across a one-ohm resistor, which gives you one amp of DC current.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp flowing through the one-ohm resistor causing a one-volt voltage drop across the resistor.
The one-volt voltage drop across the resistor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the resistor.
Now let's repeat the whole process for an inductor:
You have a one-volt voltage source connected across a one-Henry inductor, which gives you one amp of current per second flowing through the inductor.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp of current per second flowing through the inductor causing a one-volt voltage drop across the inductor.
The one-volt voltage drop across the inductor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the inductor.
That's the real deal and that's the way it is modeled.
SO, the simple thing is, there IS a slight difference between the EMF and the CEMF or NO current would flow, which would prevent the CEMF from being generated in the first place. Simple enough?
So, you are wrong. There is no difference between the EMF and the CEMF and current flows for both the resistor and the inductor. Simple enough.
If you have a technical comment to the above discussion I am all ears. And again, if you want to say something to me then just say it.
MileHigh
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Okay, now it's brain twister time. I am going to use an analogy to model this EMF/CEMF business and if somebody gets it, great. If not, better luck next time.
Look at the attached graphic, we are going to use the Force-Voltage analogy for the first setup. Look at how the variables are modeled.
The setup is as follows: Imagine a long trough 50 meters long and 1/2 meter deep and 1/2 meter wide. You can fill the trough with water, or oil, and do experiments with moving boats or carts or masses and stuff like that, as they move back and forth in the trough. They have setups like that for testing model ships. See the attached pic.
Here is the voltage source-resistor model:
You have a wheeled cart that can move through the trough and the trough is filled with viscous oil. You push the cart though the viscous oil with a constant force of 100 Newtons.
The "EMF" is the 100 Newtons of force applied to make the cart move.
The "CEMF" is the 100 Newtons of resistance that the cart experiences from the viscous oil.
The "CEMF" is equal and opposite to the "EMF."
That's all there is to it, and the velocity of the cart corresponds to the current flow.
A constant rate of power is expended by the "voltage source" by applying a constant force to the cart of 100 Newtons times the velocity of the cart and this power is dissipated in the viscous oil and heats it up.
------------------
Look at the attached graphic, we are going to use the Force-Current analogy for the second setup. Look at how the variables are modeled. We are switching to the Force-Current analogy because inductance is modeled like a spring.
Now we have to change the setup. We empty the viscous oil out of the trough. We fill the trough with a long spring, and the there is no friction between the bottom of the spring and the trough.
Here is the voltage source-inductor model:
You push a wheeled cart down the trough at a constant velocity of one meter per second, and the front of the cart is connected to the long spring. The other end of the spring is fixed to the back wall of the trough. As the cart moves the spring slowly gets compressed.
The "EMF" is the the measurement of the constant velocity of the cart moving forward.
The "CEMF" is the the measurement of the constant velocity of the spring being compressed backwards.
The "CEMF" is equal and opposite to the "EMF."
The "Current" in this case is very interesting. It corresponds to the force that the cart impresses on the compressible spring. The further the cart moves down the trough the more force has to be impressed on the spring and the higher the mechanical power required to keep moving forward at a constant velocity.
The power expended by the "voltage source" all goes into the compressed spring. The spring stores (integrates) all of that expended power and stores it as potential energy.
I know that this stuff usually gets blank stares, but it is what it is.
MileHigh
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snip..
The power expended by the "voltage source" all goes into the compressed spring.
I know that this stuff usually gets blank stares, but it is what it is.
MileHigh
The power expended by the "voltage source" (cart) all goes into the compressed spring AND the springs retaining (trough) wall.
Without the trough wall the spring would simply move with the cart rather than be compressed by it. So any moving/pushing force from the cart is expended by both the spring AND trough wall.
In an 'ideal' scenario with an ideal cart without friction, and no internal spring losses, etc, not only would the cart and spring have to be ideal, but the wall would also have to be ideal and capable of total power reflection and no power absorption/dissipation.
Cheers.
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Loner:
MileHigh
When it comes to electronics, you are not as smart as you think. Beyond that, don't you dare allege that I am a troll. I am making logical points and I am sincerely trying to debate with people, even if the debate can get heated. It takes two to tango. I am not buying your "wise man coming to share some pearls of wisdom" vibe, at all. If you have some issues with me, then say them straight to my face and we will debate them. Fair enough?
Gee MH,you attack anyone that dose not agree with you.
There is also the fact that i did not see Loner mention your name once,but you think he is referring to you--guilty conscience maybe?.
Sure, let's get real and use a little common sense and start off with a resistor.
You have a one-volt voltage source connected across a one-ohm resistor, which gives you one amp of DC current.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp flowing through the one-ohm resistor causing a one-volt voltage drop across the resistor.
The one-volt voltage drop across the resistor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the resistor.
Now let's repeat the whole process for an inductor:
You have a one-volt voltage source connected across a one-Henry inductor, which gives you one amp of current per second flowing through the inductor.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp of current per second flowing through the inductor causing a one-volt voltage drop across the inductor.
The one-volt voltage drop across the inductor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the inductor.
That's the real deal and that's the way it is modeled.
So, you are wrong. There is no difference between the EMF and the CEMF and current flows for both the resistor and the inductor. Simple enough.
If you have a technical comment to the above discussion I am all ears. And again, if you want to say something to me then just say it.
Yep-you have finally lost your marbles.
Brad
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Gee MH,you attack anyone that dose not agree with you.
There is also the fact that i did not see Loner mention your name once,but you think he is referring to you--guilty conscience maybe?.
Yep-you have finally lost your marbles.
Brad
Brad:
You have the concepts of "attack" and "defend" mixed up and backwards in your head. Stop playing your "on stage" "dullest tool in the toolbox" games. Your silly comment is just another stunt that backfired.
You think that I have lost my marbles? The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
MileHigh
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The power expended by the "voltage source" (cart) all goes into the compressed spring AND the springs retaining (trough) wall.
Without the trough wall the spring would simply move with the cart rather than be compressed by it. So any moving/pushing force from the cart is expended by both the spring AND trough wall.
Cheers.
The retaining wall at the end of the trough is stationary and does not move. So think about the ramifications of that.
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Okay, now it's brain twister time. I am going to use an analogy to model this EMF/CEMF business and if somebody gets it, great. If not, better luck next time.
Look at the attached graphic, we are going to use the Force-Voltage analogy for the first setup. Look at how the variables are modeled.
The setup is as follows: Imagine a long trough 50 meters long and 1/2 meter deep and 1/2 meter wide. You can fill the trough with water, or oil, and do experiments with moving boats or carts or masses and stuff like that, as they move back and forth in the trough. They have setups like that for testing model ships. See the attached pic.
Here is the voltage source-resistor model:
You have a wheeled cart that can move through the trough and the trough is filled with viscous oil. You push the cart though the viscous oil with a constant force of 100 Newtons.
The "EMF" is the 100 Newtons of force applied to make the cart move.
The "CEMF" is the 100 Newtons of resistance that the cart experiences from the viscous oil.
The "CEMF" is equal and opposite to the "EMF."
That's all there is to it, and the velocity of the cart corresponds to the current flow.
A constant rate of power is expended by the "voltage source" by applying a constant force to the cart of 100 Newtons times the velocity of the cart and this power is dissipated in the viscous oil and heats it up.
------------------
Look at the attached graphic, we are going to use the Force-Current analogy for the second setup. Look at how the variables are modeled. We are switching to the Force-Current analogy because inductance is modeled like a spring.
Now we have to change the setup. We empty the viscous oil out of the trough. We fill the trough with a long spring, and the there is no friction between the bottom of the spring and the trough.
Here is the voltage source-inductor model:
You push a wheeled cart down the trough at a constant velocity of one meter per second, and the front of the trough is connected to the long spring. As the cart moves the spring slowly gets compressed.
The "EMF" is the the measurement of the constant velocity of the cart moving forward.
The "CEMF" is the the measurement of the constant velocity of the spring being compressed backwards.
The "CEMF" is equal and opposite to the "EMF."
The "Current" in this case is very interesting. It corresponds to the force that the cart impresses on the compressible spring. The further the cart moves down the trough the more force has to be impressed on the spring and the higher the mechanical power required to keep moving forward at a constant velocity.
The power expended by the "voltage source" all goes into the compressed spring.
I know that this stuff usually gets blank stares, but it is what it is.
MileHigh
MH
I think you are a little lost when it comes to understanding what CEMF is in an inductor-or anything for that matter.
Quote verpies post 230: The current would not increase if CEMF = EMF
You do know that CEMF is a function of reactance, not of resistance,and so i do not know what all that garble about CEMF across a resistor was all about ???
To say that there is a voltage drop of 1 volt across a 1 ohm resistor that is supplied a voltage of 1 volt from a voltage source,is just horse radish talk. There is no drop in voltage at all across the resistor,as the potential difference across the resistor is the very same as that supplied from the source--no drop in voltage. If we had two 1 ohm resistors in series,and we applied 1 volt across that resistor series,then we would see a voltage drop across each resistor of 1/2 a volt. Using the word !voltage drop! across a single resistor with a voltage of 1 volt placed across it from a voltage source,is just bollocks talk.
And then to try and say that resembles an equal and opposite CEMF is just more bollocks.
There is no self induction in a bloody resistor that is non inductive.
To quote Poynt,post 1231: The voltage across the coil terminals does not change, it is determined by the voltage source. But the induced cemf is in series opposing with the voltage source Vin, and its value is determined by the frequency of Vin and the inductance L.
So, from this perspective the induced cemf is usually not equal to the applied emf (Vin). It is usually lower.
Poynt post 1233 Quote: I don't think he will assume that. I believe he knows that even though the induced emf (cemf) is opposite in polarity to that of the applied voltage, it will almost always be less, and therefore there will still be a net applied emf and resulting current.The EMF is applied by the user, while the cemf is self-induced; VL = L x di/dt. So according to the equation, the induced cemf can be any value and will vary depending on the frequency and inductance. The applied EMF never changes its value.As I mentioned above, the induced cemf can be any value, and is dependent on the input frequency and the inductance. I don't see any rules being broken here so help me out. Where am I going wrong?
And from Loner,post 1258: IF the Applied voltage WERE EXACTLY equal to the "CEMF" there would be NO CURRENT. Second, IF there were NO Current, there would be NO CEMF!!!
So the first thing you did there,was attack him,because you believed he was talking about you. How do you know this to be the case?
I dont know what planet you are on MH,but the CEMF value is not the same as the EMF that created it.
Quote;Inductance is the name given to the property of a component that opposes the change of current flowing through it and even a straight piece of wire will have some inductance. Inductors do this by generating a self-induced emf within itself as a result of their changing magnetic field
So,if the CEMF was the same value as the EMF,then the current produced by the CEMF that flows in the opposite direction to that of the current induced by the EMF would be the same value,and there for,there would be no flow of current.
Quote: In an electrical circuit, when the emf is induced in the same circuit in which the current is changing this effect is called Self-induction, ( L ) but it is sometimes commonly called back-emf as its polarity is in the opposite direction to the applied voltage. Lenz’s Law tells us that an induced emf generates a current in a direction which opposes the change in flux which caused the emf in the first place, the principal of action and reaction.
So MH,Self-induced emf is the e.m.f induced in the coil due to the change of flux produced by linking it with its own turns. Only when total flux linkage/flux cutting is achieved,will the CEMF be equal to the EMF that created it--like in an ideal coil maybe :D
Brad
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Brad:
You have the concepts of "attack" and "defend" mixed up and backwards in your head. Stop playing your "on stage" "dullest tool in the toolbox" games. Your silly comment is just another stunt that backfired.
You think that I have lost my marbles? The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
MileHigh
MH
First we can look at this backwards,with using me example of a DC motor(or any electric motor for that matter).Lets say it's a 12 volt DC PM motor. When you place 12 volts across that motor,the current will be at it's highest,as the magnetic fields from the stator at this point in time,are cutting the rotor windings at it's lowest rate of change over time,and so the produced CEMF is also at it's lowest value. As the motor speeds up,the current draw begins to drop,becaust the rate of change of the magnetic fields has increased,thus increasing the CEMF value. At maximum RPM,the magnetic fields rate of change to that of the rotor windings is at it's greatest,and then so to is the CEMF value.
The reverse happens with the inductor,where the rate of change of the induced magnetic field is greatest the moment a voltage is applied across the inductor. This results in the highest value of CEMF produced,and so the lowest value of current flow. Over time,the rate of change of the magnetic field begins to decrease,and so the CEMF value also begins to decrease. This results in an increase of current flow through the inductor.
MH
It is the CEMF value to that of the EMFs value, that determines the current flow rise over time in an inductor. The CEMF is the current limiter of the inductor,be it in a coil,or an electric motor.
Brad
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snip...
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp flowing through the one-ohm resistor causing a one-volt voltage drop across the resistor.
The one-volt voltage drop across the resistor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the resistor.
snip...
In the unideal world, the one-volt voltage source is the EMF. = Correct
The CEMF is the one amp flowing through the one-ohm resistor causing a one-volt voltage drop across the resistor.= Incorrect
There is no CEMF, there is simply an applied EMF with an 'equal and opposite' reaction of heat dissipated by the resistor.
Now let's repeat the whole process for an inductor:
You have a one-volt voltage source connected across a one-Henry inductor, which gives you one amp of current per second flowing through the inductor.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp of current per second flowing through the inductor causing a one-volt voltage drop across the inductor.
The one-volt voltage drop across the inductor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the inductor.
That's the real deal and that's the way it is modeled.
This is where the difference between an inductor and resistor has to take account of changing current flow. At the very moment of connection, the inductance as well as the resistance will oppose the flow due to CEMF that arises from inductance, but as the coil reaches its maximum current and minimum change in current, the cemf will disappear leaving only the resistance to oppose the current and limiting it to 1 amp.
The resistor will exhibit an instantaneous 1 amp at connection for the first and ongoing seconds, but the inductor must necessarily inhibit the instantaneous flow on connection, to less than 1 amp (average) for the first second until the change in current ceases and becomes a steady flow of 1 amp per second thereafter. To maintain a steady state of 1 amp under steady current/voltage, the coil itself must still have 1 ohm resistance.
So, you are wrong. There is no difference between the EMF and the CEMF and current flows for both the resistor and the inductor. Simple enough
If you have a technical comment to the above discussion I am all ears. And again, if you want to say something to me then just say it.
MileHigh
If there were no difference in the reaction characteristics of resistors and inductors to current/voltage, in particular, changing current/voltage, we could just use resistors for everything that we currently use a coil for.
But as you already know, inductors are prized for their characteristic reaction to changing currents/voltages not so much for steady (DC) current/voltages. Though they are used to often to provide a steady (limited) current due their propensity for opposing changes in current.
I'd love to see a resistor that could do the job of a coil/inductor in most applications. Especially a resistor to replace a generator coil.
Cheers
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Brad:
You have the concepts of "attack" and "defend" mixed up and backwards in your head. Stop playing your "on stage" "dullest tool in the toolbox" games. Your silly comment is just another stunt that backfired.
When it comes to electronics, you are not as smart as you think. Beyond that, don't you dare allege that I am a troll. I am making logical points and I am sincerely trying to debate with people, even if the debate can get heated. It takes two to tango. I am not buying your "wise man coming to share some pearls of wisdom" vibe, at all. If you have some issues with me, then say them straight to my face and we will debate them. Fair enough?
Now,i re read the post again MH,and not once did i see your name mentioned.
But regardless of that,you went on the attack,and proceeded to tell Loner how he is not as smart as he thinks he is.
Then i see you say to him to tell you straight to your face about any issues he has with you--remembering that your name was never mentioned once in his post.
You also say he alleged that you were a troll,and yet(once again) ,your name was never mentioned.
So with no mention of your name at all,how can you say you were just defending your self?-->defending your self against what allegations ?.
I think Loner is a very smart man,and he also agrees with myself,Poynt and verpies-Added hoptoad--and im sure a whole lot of others,when it comes to !what! is CEMF.
Brad
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I am going to repeat my question to you Brad:
The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
Forget about the motor example, and keep it simple and use a coil. Give some examples providing all of the specifics and the EMF and CEMF values, the current flow, the whole nine yards.
You say the correct model is that the CEMF is less than the EMF? Go ahead and give some examples with all of the details laid out so we can see if your model works or not.
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The retaining wall at the end of the trough is stationary and does not move. So think about the ramifications of that.
The wall doesn't have to move to absorb energy and be a part of the energy dissipation equation. But in your analogy, without including the wall there will be no compression of the spring, merely movement of the spring in the same direction as the cart.
When you lob a tennis ball against a wall, some energy is lost in sound through the air, and some energy of the ball is lost through heat by the distortion and rebounding of the balls shape and some will be lost to the wall itself in the form of pressure, heat and internal sound.
Any pressure of one object on another will create heat. The greater the pressure, the greater the heat. As the cart pushes the spring, the spring pushes the wall. Each component places pressure on the other and generates heat, the amount of which, however miniscule or large, being dependent on the pressure exerted.
Of course I'm explaining in terms of the unideal world, you know, reality, not ideal. Thats why I said you need an ideal wall to go with your ideal cart and ideal spring, for an ideal scenario, in which one can endlessly postulate about the 'ideal XYZ'.
However reality provides a way of supplanting postulation with knowledge through empirical evidence gained by observational research.
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Hoptoad:
Here is the short definition for CEMF:
<<<
https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0
The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it.
>>>
If you reread my example for the resistor and the inductor keeping the definition for CEMF in mind it should make sense.
For the trough, the best way of looking at it is to keep things simple. You have a concrete trough that is hollowed out of the earth like a long and narrow swimming pool. All four walls of the trough are fixed and immovable. You put a long spring into the trough, and then a moveable cart moves forward with a constant velocity and pushes against the spring.
With that simple model all of the power expended to move the cart gets stored in the spring, and only in the spring.
MileHigh
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There is no difference between the EMF and the CEMF and current flows for both the resistor and the inductor. Simple enough.
MH,
CEMF is typically used with reference to inductance.
As such, I believe most of us understand CEMF to be more so along the following:
A current flowing thru a conductor creates a magnetic field. A portion of that magnetic field induces a rate of change dependent voltage into that same conductor. The polarity of that induced voltage opposes the initial current flow thru the conductor. It is that induced voltage, in opposition to the initial current flow, that is referred to as CEMF.
Can you provide a reference citing an example of your usage of CEMF with regard to resistors?
PW
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I am going to repeat my question to you Brad:
The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
Forget about the motor example, and keep it simple and use a coil. Give some examples providing all of the specifics and the EMF and CEMF values, the current flow, the whole nine yards.
MH
We have already done this with your ideal coil and ideal voltage.
We know the coil has a resistance value of 0 ohms--or no resistance.
What do you think it is that stops the current going straight to an infinite value,as soon as the voltage is placed across it?.
Why dose it take 3 seconds to reach a current of only 2.4 amp's,and not shoot up to an infinite amount of current flowing through that inductor.
What is the !reactance! in inductive reactance?-->what is reacting to what?
What is !self inductance! ?
You say the correct model is that the CEMF is less than the EMF? Go ahead and give some examples with all of the details laid out so we can see if your model works or not.
I have the feeling that this is just your way of making me waste my time on something that is already very clear--except to you it seems.
So i have voted not to fall for this !waste of time! ploy by you,and instead,i give you a video that should make it very clear to you. As you will see,the circuit to show the effective CEMF is quite simple,and im sure i could show what he explains in the video.
I hope you listen to this video very carefully,and then you will understand that if the CEMF was equal to the EMF that produced it,there would be no current flow,as there would be no voltage drop/or potential difference across the inductor.
https://www.youtube.com/watch?v=RGTRXlarKww
But even then,i have a feeling we are going to see you !once again! try and change physics to suit your needs.
Brad
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Hoptoad:
Here is the short definition for CEMF:
<<<
https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0 (https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0)
The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it.
>>>
If you reread my example for the resistor and the inductor keeping the definition for CEMF in mind it should make sense.
For the trough, the best way of looking at it is to keep things simple. You have a concrete trough that is hollowed out of the earth like a long and narrow swimming pool. All four walls of the trough are fixed and immovable. You put a long spring into the trough, and then a moveable cart moves forward with a constant velocity and pushes against the spring.
With that simple model all of the power expended to move the cart gets stored in the spring, and only in the spring.
MileHigh
I know what CEMF is and I know that even in the real world, technically every single circuit that has even a miniscule current will have some inductance, because a moving charge creates a magnetic field, and therefore exhibits a cemf opposing further changes to its own motion. I also know that in most real world circuits, inductance is disregarded when talking about resistors and semiconductors because the inductance of a resistor/semiconductor is so miniscule as to be irrelevent to its purposeful characteristics. When we want inductance we deliberately set about making it with a coil, not e.g. a carbon resistor.
As for your 'all four walls are fixed and immovable' in your cart analogy, if any single one of the walls is used as a backstop for the spring, then that wall becomes part of the energy dissipation system.( In reality, since all four walls are all part of the same entire mass of the trough, then the whole trough is part of the energy dissipation.)
You can not compress any spring from one side only. Try it without an anchor point like one of the walls, your spring would just move with the force applied to one side.
Go ahead, try to compress a spring by applying a force to one side without a backstop becoming an essential part of the system of components needed for the energy transfer required to compress it.
You don't need a concrete trough. Just a spring, your hand and .... whatever else is NEEDED to compress the spring.
Now I agree that most of the energy, even in a real world system, will get stored in the spring, but not all. The spring itself, unless ideal, will dissipate some of the compression energy it receives through heat due to lattice stress and displacement.
Only in an idealized world can perfect power transmission and storage take place. Sadly we don't live in that world, we live in the real world, with circuit losses incurred and components that will never be 'ideal'.
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MH
We have already done this with your ideal coil and ideal voltage.
We know the coil has a resistance value of 0 ohms--or no resistance.
What do you think it is that stops the current going straight to an infinite value,as soon as the voltage is placed across it?.
Why dose it take 3 seconds to reach a current of only 2.4 amp's,and not shoot up to an infinite amount of current flowing through that inductor.
What is the !reactance! in inductive reactance?-->what is reacting to what?
What is !self inductance! ?
I have the feeling that this is just your way of making me waste my time on something that is already very clear--except to you it seems.
So i have voted not to fall for this !waste of time! ploy by you,and instead,i give you a video that should make it very clear to you. As you will see,the circuit to show the effective CEMF is quite simple,and im sure i could show what he explains in the video.
I hope you listen to this video very carefully,and then you will understand that if the CEMF was equal to the EMF that produced it,there would be no current flow,as there would be no voltage drop/or potential difference across the inductor.
https://www.youtube.com/watch?v=RGTRXlarKww (https://www.youtube.com/watch?v=RGTRXlarKww)
But even then,i have a feeling we are going to see you !once again! try and change physics to suit your needs.
Brad
Brad:
There is nothing in that clip to back up what you are saying, it's just standard theory.
You are stalling, and in fact reading between the lines I think you are panicking. You are panicking because you think you can talk the talk but when you are asked to walk the walk you come up short.
So, again, in your own words, give us some simple and fully explained examples that back up your proposal that the CEMF is less than the EMF in a simple inductor circuit and the difference between the EMF and CEMF is a requirement for the current flow. You have to give actual values for everything and explain it.
No stalling and monkeyshines are going to work. Give some examples just like I gave two examples that I fully explained in my own words with all of the variables defined.
MileHigh
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MH,
CEMF is typically used with reference to inductance.
As such, I believe most of us understand CEMF to be more so along the following:
A current flowing thru a conductor creates a magnetic field. A portion of that magnetic field induces a rate of change dependent voltage into that same conductor. The polarity of that induced voltage opposes the initial current flow thru the conductor. It is that induced voltage, in opposition to the initial current flow, that is referred to as CEMF.
Can you provide a reference citing an example of your usage of CEMF with regard to resistors?
PW
The only reference I have right now is that Wikipedia link:
https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0 (https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0)
The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it.
I believe in your case it may simply be a case of not seeing the forest for the trees. We are so used to thinking about CEMF in terms of an inductor, that we forget about the basic bare-bones definition for CEMF. CEMF is just a manifestation of what happens to a two-terminal device when we push current through it.
Step back for a second and let's look at the term "counter-electromotive force." What does it really mean? It means that a black box is capable of generating some voltage if you push some current through it.
I love this YouTube guy Lasseviren1. One of his clips pertaining to EMF is this:
https://www.youtube.com/watch?v=B8CPGiK59f8 (https://www.youtube.com/watch?v=B8CPGiK59f8)
You don't have to watch it but I attached a still frame from the clip to this posting. You can see how he uses the symbol for little batteries next to the inductors to represent the CEMF.
So look at one of his little inductors with the CEMF battery next to it. What if we surround that inductor with a black box? What if while you are not looking we swap the inductor for a resistor and pump current through the black box? In that sense, all that you can say if you take a snaphot of the box is that something inside the box is generating counter-EMF.
In summary, CEMF is not necessarily restricted to inductors. Arguably any device that sustains a voltage drop in a current loop is a device that is manifesting CEMF.
MileHigh
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As for your 'all four walls are fixed and immovable' in your cart analogy, if any single one of the walls is used as a backstop for the spring, then that wall becomes part of the energy dissipation system.( In reality, since all four walls are all part of the same entire mass of the trough, then the whole trough is part of the energy dissipation.)
You can not compress any spring from one side only. Try it without an anchor point like one of the walls, your spring would just move with the force applied to one side.
Go ahead, try to compress a spring by applying a force to one side without a backstop becoming an essential part of the system of components needed for the energy transfer required to compress it.
You don't need a concrete trough. Just a spring, your hand and .... whatever else is NEEDED to compress the spring.
Now I agree that most of the energy, even in a real world system, will get stored in the spring, but not all. The spring itself, unless ideal, will dissipate some of the compression energy it receives through heat due to lattice stress and displacement.
Only in an idealized world can perfect power transmission and storage take place. Sadly we don't live in that world, we live in the real world, with circuit losses incurred and components that will never be 'ideal'.
I am just using a simple idealized model. In that model there is no movement in any of the four concrete walls of the trough. The spring is between the moving cart and the end of the trough. As the cart moves forward at a constant velocity the spring gets compressed. That is like energizing an electrical inductor with a constant voltage source.
I will use a similar example to yours to demonstrate I understand what you mean.
If you are in a house, and you are holding a large spring against a wall and you move forward with your body and compress it, where does the energy go? Most of it goes into the spring, but the gyprock wall in the house will flex and absorb some of the energy also. So the wall itself is like a second spring.
If you are outside and do the same thing against a concrete wall, the concrete wall will not flex and absorb any of the energy. In this case all of the energy goes into the spring.
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The only reference I have right now is that Wikipedia link:
https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0 (https://en.wikipedia.org/wiki/Counter-electromotive_force#cite_ref-Graf_1-0)
The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it.
I believe in your case it may simply be a case of not seeing the forest for the trees. We are so used to thinking about CEMF in terms of an inductor, that we forget about the basic bare-bones definition for CEMF. CEMF is just a manifestation of what happens to a two-terminal device when we push current through it.
Step back for a second and let's look at the term "counter-electromotive force." What does it really mean? It means that a black box is capable of generating some voltage if you push some current through it.
I love this YouTube gut Lasseviren1. One of his clips pertaining to EMF is this:
https://www.youtube.com/watch?v=B8CPGiK59f8 (https://www.youtube.com/watch?v=B8CPGiK59f8)
You don't have to watch it but I attached a still frame from the clip to this posting. You can see how he uses the symbol for little batteries next to the inductors to represent the CEMF.
So look at one of his little inductors with the CEMF battery next to it. What if we surround that inductor with a black box? What if while you are not looking we swap the inductor for a resistor and pump current through the black box? In that sense, all that you can say if you take a snaphot of the box is that something inside the box is generating counter-EMF.
In summary, CEMF is not necessarily restricted to inductors. Arguably any device that sustains a voltage drop in a current loop is a device that is manifesting CEMF.
MileHigh
MH
You have defiantly lost the plot.
First up,a resistor limits the flow of current--it is a restrictor.
An inductor resists a !change! in current-both an increase and decrease-inductive reactance.
I am in no way,shape,or form,going to bow down to your stupidity,and waste my time on something that should be common knowledge to you--as it is with everyone else here.
And to think,you thought you had the smarts to give EMJ a hard time on his understandings about inductors and coils--and me for that matter.
If you choose to argue the point with PW,Poynt,Loner,Hoptoad,and most everyone else on this forum,and they have the time to argue against such an idiotic argument,then so be it--but i will have no part in this rubbish.
I dont know what planet you are on,or if you fell into a drum of coolaid,and drank your way out,but if the CEMF was equal and opposite to the EMF,then the total voltage across the inductors terminals would be 0v,and no current would flow.
Your probably smashing out emails left,right,and center to PW and Poynt ATM,trying to get them to join you in your coolaid swimming pool of CEMF,but this foolishness is not for me.
You have yourself a great time MH,but i am done with your repeated stupidity,and re-writing of physics.
Brad
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snip...
In summary, CEMF is not necessarily restricted to inductors. Arguably any device that sustains a voltage drop in a current loop is a device that is manifesting CEMF.
MileHigh
I agree with you that CEMF is not restricted to inductors and can manifest from any change in current. As I explained in my previous post, technically any changing current at any level can produces a CEMF. Just as CEMF is not necessarily restricted to inductors, capacitance is not restricted to capacitors and resistance is not restricted to resistors. That's common knowledge, because none of our components are ideal, they have a blend of all those characteristics.
Only in an ideal world can we have ideal scenarios. Most here seem to know that capacitors leak, everything has some inductance and resistance is ever present. It is the degree to which a characteristic of a component contributes to a particular phenomena that we determine its practical purposes and what we expect it cause to happen in a circuit.
If I asked any electronics buff to give me an inductor, he is not going to hand me a capacitor or resistor and say this will do the same thing. Because he knows that each component is specifically designed to enhance one electrical characteristic and minimize the others.
Resistance is ever an present phenomenon, in both steady and changing fields in a circuit, while CEMF is an emergent force that manifests only with changes in electrical/magnetic fields, and disappears in steady unchanging fields. Resistance and CEMF are not the same thing.
-
.
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I am in no way,shape,or form,going to bow down to your stupidity,and waste my time on something that should be common knowledge to you--as it is with everyone else here.
And to think,you thought you had the smarts to give EMJ a hard time on his understandings about inductors and coils--and me for that matter.
You are just a transparent faker and a bluffer Brad. The simple truth is that you can't show anything to back up your claim at all. So you are just doing the chicken chicken dance right now.
It's all FAKE on your part now Brad, everything you are saying is transparently FAKE. The proverbial chicken on a hot plate doing a dance to stop his feet from burning.
Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply.
Brad
You are a bloody electronics rocket scientist Brad.
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snip...
if the CEMF was equal and opposite to the EMF,then the total voltage across the inductors terminals would be 0v,and no current would flow.
snip...
Brad
I agree. No potential difference, No current flow.
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I agree. No potential difference, No current flow.
No, the device connected to the EMF source is the same device that manifests the CEMF.
There is no such thing as the EMF source connected to the CEMF source connected to the device. That is the only possible way to have no potential difference.
i.e.; <EMF> --> <CEMF> --> <Device>
The above is NOT what is happening.
This is what you have: The EMF source connected to the device. At the same time the device itself is the source of the CEMF.
i.e.; <EMF> --> <Device>
Where <Device> is also the source of the <CEMF> at the same time.
i.e.; <EMF> --> <Device/CEMF>
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MH,
CEMF, at least in my forest full of trees, has always been used to describe a particular mechanism, or action, specifically related to inductors, and less so with regard to electrochemistry.
As well, it would seem that any device capable of producing a CEMF exactly equal to an applied EMF would prevent current flow.
Consider two identical voltage sources connected in parallel (positive to positive, negative to negative). One Vsource represents EMF and the other Vsource represents CEMF. As long as both sources produce identical voltage, there will be no current flow.
I think you will need to do a bit better with regard to finding a reference relating CEMF to the action of a resistor...
PW
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PW:
I can try to find something later.
If you have a battery EMF source facing an equal battery CEMF source then obviously no current flows. The same thing would apply if you had a capacitor.
However, if you have a battery EMF source facing a resistor or an inductor acting as a CEMF source then current flows.
There are four cases stated above. In all four cases if you walk around the loop with your voltmeter, you see the EMF source, and then you move your probes and you see the voltage drop associated with the CEMF source.
You can't tell just with your voltage probes if the source of the CEMF is a battery, a capacitor, a resistor, or an inductor. The only thing that you know is that your voltage probes are detecting the presence of a CEMF source.
Note that you have no interest at all to find out if current is flowing or not, you are just looking for the presence of a device that manifests CEMF. Indeed, some components stop the current flow when the CEMF is equal to the EMF. But others do not stop the current flow, even though they manifest equal and opposite CEMF.
Yes, it's a "black box type" of discussion, but usually that's how concepts are introduced at a very basic level.
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PW:
When current flows through a resistor, is there an electric field inside that resistor?
The answer of course is there is an electric field inside the resistor. When we do a line integral on the electric field from one end to the other end of the resistor we get an EMF.
There is no rule that says that the EMF being generated by the resistor cannot be called a CEMF.
MileHigh
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Surfing the web I found an MIT pdf covering Faraday's Law.
http://web.mit.edu/8.02t/www/materials/StudyGuide/guide10.pdf
Look at the attached page capture. Look familiar? How absolutely mind-blowing, the B field changes in time and has a trapezoidal waveform. They must be breaking the rules.
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PW:
Okay I tried for a while and I could not find anyone using "CEMF" nomenclature for the voltage drop across a resistor in a loop. I found multiple references where you had an EMF source driving the loop and the resistors or whatever had a "potential difference" across them equal and opposite to the EMF.
In the overall scheme of things we are just talking about voltage. So I don't mind if for a resistor you use the term "potential difference" or "PD" instead of "CEMF."
Here is a nice short clip showing a KVL loop with multiple voltage sources and multiple resistors. The presenter's discussion is voltage-centric, he calls the resistors voltage elements instead of resistors. That might give some readers the feel for how you can look at a loop and focus on the voltage gains and voltage drops in the loop.
https://www.youtube.com/watch?v=KjNwqX-DB2w
MileHigh
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Brad:
I can see you reacting to my previous posting to PW with a lot of nonsensical trash talk about me. Let me save you the trouble and let's look at a nice chunk of it:
<<<
And to think,you thought you had the smarts to give EMJ a hard time on his understandings about inductors and coils--and me for that matter. <-- This one sounds like a rude insult.
I dont know what planet you are on,or if you fell into a drum of coolaid,and drank your way out,but if the CEMF was equal and opposite to the EMF,then the total voltage across the inductors terminals would be 0v,and no current would flow.
You have yourself a great time MH,but i am done with your repeated stupidity,and re-writing of physics. <-- this one sounds like a rude insult
I think you are a little lost when it comes to understanding what CEMF is in an inductor-or anything for that matter. <-- This one sounds like a rude insult
You do know that CEMF is a function of reactance, not of resistance,and so i do not know what all that garble about CEMF across a resistor was all about
Gee MH,you attack anyone that dose not agree with you.
Yep-you have finally lost your marbles. <-- This one sounds like a rude insult
MH is just lost again. <-- This one sounds like a rude insult
i think MH is having a bad day.
You are lost when you think that the total EMF is going to be converted only to a CEMF.
I think the agony here,is having to keep going over the same stuff an endless amount of times with you.
>>>
So there you go Brad, I have done your trash talking for you.
Now, let's get down to some serious business.
There are three quotes of yours below. They are mind-blowing because they show that you sometimes still cannot master the most basic basics when it comes to electronics. It's actually shocking to read your quotes below. Sadly, these things seem to happen on a fairly consistent basis with you. What's the point of trying to teach you stuff or discuss circuits with you when sometimes it looks like you missed the first eight weeks of your very first course in electronics, Electronics 001?
The fact that you made the statements below is indicating that you have some serious problems understanding and conceptualizing basic electronics concepts.
You are a moderate electronics hobbyist, and you like doing this stuff? Then look at your quotes below and do whatever it takes to fix yourself and get yourself in shape so that you can talk sensibly and intelligently with your peers about electronics. The onus is on you to do what it takes so that you at least have a mastery of all of the basic electronics concepts.
-------------------------------------
1a) There is no drop in voltage at all across the resistor,as the potential difference across the resistor is the very same as that supplied from the source--no drop in voltage.
1b) Using the word !voltage drop! across a single resistor with a voltage of 1 volt placed across it from a voltage source,is just bollocks talk.
2) Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply.
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This is interesting.
I do see where MH is coming from, although I disagree with calling the voltage drop across a resistor "cemf".
Kirchhoff's KVL always holds, so the problem is perplexing, especially in light of the descriptions on self induction, whereby an opposing "self-induced emf" results from the changing flux in the coil. "Opposing" in what manner?
One argument is that if the EMF and CEMF were equal, no circuit current would flow. I think we may be arguing with an incorrect assumption in mind. We can envision the voltage source and the induced emf as two generators back to back, but is this accurate? A voltage source and a resistor in parallel also have voltages that are back to back, yet current flows. Isn't an inductor very much like a frequency-dependent resistor? If so, then maybe it makes sense for it to have a voltage drop across it.
The self-induced emf is present, but it is perhaps not what we might expect. When we use the term "emf" we expect it to mean there is or will be a resulting measurable voltage. When the voltage source is connected and the magnetic field begins building, the coil immediately starts inducing a cemf across its terminals. The coil has now become a generator; but there is a "twist". The load seen by the coil's terminals is the voltage source, and it would appear as a short circuit to the coil.
I made a statement a few posts back in that an induced current always has an associated induced voltage. I retract that and restate it this way: An induced current usually has an associated induced voltage. The fact is that a coil can have a current induced in it, even if the coil is shorted. This I believe is the scenario with the self-induced emf and current with our simple voltage source and inductor. So I am saying that the cemf induced in the coil goes to 0V, while the self-induced opposing current goes to some value, determined by the inductance and rate of flux change.
In terms of KVL, it holds fine, and the "drop" across the inductor is determined by the voltage source, just as in the case for the resistor, but it is NOT the cemf, if indeed emf is equated with voltage.
Is this explanation crazy? Perhaps, but I've not seen any other that makes sense to me.
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PW:
When current flows through a resistor, is there an electric field inside that resistor?
The answer of course is there is an electric field inside the resistor. When we do a line integral on the electric field from one end to the other end of the resistor we get an EMF.
There is no rule that says that the EMF being generated by the resistor cannot be called a CEMF.
MileHigh
There is no EMF being generated by the resistor.
A resistor is a current flow regulator,and determines how much current will flow through it,in relation to the voltage placed across it.
Reading your last 5 or 6 posts,with springs,shopping trollies,and the likes,i can see you are totally lost when it comes to equal action/reaction,when there is motion-or,potential or kinetic energy storage involved.
There will be no flow of current when the CEMF is equal to that of the applied EMF.
A 2kg lifting force will not raise a 2kg mass. The mass will become weightless as far as the ground it was sitting on is concerned,but there will be no motion. This is an equal and opposite force.
In order for that 2kg mass to rise/move/accelerate,there must be a difference between the two forces,where the applied force(the lifting force)is greater than the weight of the mass. Over time,this higher applied force is stored in the mass,and can become either kinetic or potential energy.
The same applied to water flow through a pipe. If the water is being pumped up hill by a pump,once that water in the pipe reaches a height where the head pressure equals that of which the pump can produce,there will be no flow of water through the pipe.
So like i(and many others have tried to tell you),once the CEMF (back pressure) equals that of the applied EMF(forward pressure),there will be no flow of current.
When a force meets an equal and opposite force--there will be no motion-period.
Brad
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snip...
The coil has now become a generator; but there is a "twist". The load seen by the coil's terminals is the voltage source, and it would appear as a short circuit to the coil.
snip...
The voltage source would only be seen as a short circuit if it had zero impedance i.e. an 'ideal' voltage/current source.
Since the title of this thread incorporates an 'ideal coil', then having an ideal voltage/current source is fine for hypothesis.
But in the practical real electronics world, nothing can actually be ideal outside of hypothesis, including the supply. It will have impedance of some value, the value of which is dependent on the nature of the source.
Cheers
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Reading your last 5 or 6 posts,with springs,shopping trollies,and the likes,i can see you are totally lost when it comes to equal action/reaction,when there is motion-or,potential or kinetic energy storage involved.
There will be no flow of current when the CEMF is equal to that of the applied EMF.
A 2kg lifting force will not raise a 2kg mass. The mass will become weightless as far as the ground it was sitting on is concerned,but there will be no motion. This is an equal and opposite force.
In order for that 2kg mass to rise/move/accelerate,there must be a difference between the two forces,where the applied force(the lifting force)is greater than the weight of the mass. Over time,this higher applied force is stored in the mass,and can become either kinetic or potential energy.
The same applied to water flow through a pipe. If the water is being pumped up hill by a pump,once that water in the pipe reaches a height where the head pressure equals that of which the pump can produce,there will be no flow of water through the pipe.
So like i(and many others have tried to tell you),once the CEMF (back pressure) equals that of the applied EMF(forward pressure),there will be no flow of current.
When a force meets an equal and opposite force--there will be no motion-period.
Brad
I am not "lost" in any way, shape, or form. I will revisit the "lost" theme with respect to you in a subsequent posting.
There will be no flow of current when the CEMF is equal to that of the applied EMF.
There certainly will be current flow for an inductor, it's happens in real life. But there will be no current flow for a capacitor. You have to think and analyze these types of situations on a case by case basis.
A 2kg lifting force will not raise a 2kg mass. The mass will become weightless as far as the ground it was sitting on is concerned,but there will be no motion. This is an equal and opposite force.
I am not sure what that has to do with the discussion but a 2 kg lifting force on a 1 kg mass will still result in an equal and opposite "force" of 2 kg.
In order for that 2kg mass to rise/move/accelerate,there must be a difference between the two forces,where the applied force(the lifting force)is greater than the weight of the mass. Over time,this higher applied force is stored in the mass,and can become either kinetic or potential energy.
Only a moderate amount of descrambling was required. But once you factor acceleration into the system then the forces are equal and opposite. We are talking basic Newton's Laws here.
So like i(and many others have tried to tell you),once the CEMF (back pressure) equals that of the applied EMF(forward pressure),there will be no flow of current.
When a force meets an equal and opposite force--there will be no motion-period.
As has been explained to you, for the case of an inductor, current flows and the CEMF is equal and opposite to the EMF. This is the basic application of KVL or in the physical world Newton's Third Law of Motion.
When a force meets an equal and opposite force, there will be no motion, or, there will be acceleration.
MileHigh
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Brad:
Are you a lost soul or are you a man with the conviction to stand up for what you say and back it up with a logical argument? Put meaning to your statements and show conviction or just be a space cadet? Which one is it going to be?
Let's look at two cases.
1) The unanswered request for you to put substance behind your claim with an actual example.
The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
Forget about the motor example, and keep it simple and use a coil. Give some examples providing all of the specifics and the EMF and CEMF values, the current flow, the whole nine yards.
You say the correct model is that the CEMF is less than the EMF? Go ahead and give some examples with all of the details laid out so we can see if your model works or not.
2) Who really has lost their marbles?
You have a one-volt voltage source connected across a one-Henry inductor, which gives you one amp of current per second flowing through the inductor.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp of current per second flowing through the inductor causing a one-volt voltage drop across the inductor.
The one-volt voltage drop across the inductor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the inductor.
That's the real deal and that's the way it is modeled.
There is no difference between the EMF and the CEMF and current flows through the inductor.
So Brad, you allege that I have "lost my marbles" with respect to the example above. Then you break down that example and show us exactly where and why it is wrong. If you can't do that then you are the one that has lost your marbles.
MileHigh
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Brad:
Are you a lost soul or are you a man with the conviction to stand up for what you say and back it up with a logical argument? Put meaning to your statements and show conviction or just be a space cadet? Which one is it going to be?
Let's look at two cases.
1) The unanswered request for you to put substance behind your claim with an actual example.
The ball is now in your court. You say that the CEMF must be lower than the EMF for current to flow? I have never seen any concrete examples of that from you. Now is the time. Show us some examples where the CEMF is lower than the EMF with all the specifics and all of the numbers crunched to explain how much current flows.
Forget about the motor example, and keep it simple and use a coil. Give some examples providing all of the specifics and the EMF and CEMF values, the current flow, the whole nine yards.
You say the correct model is that the CEMF is less than the EMF? Go ahead and give some examples with all of the details laid out so we can see if your model works or not.
2) Who really has lost their marbles?
You have a one-volt voltage source connected across a one-Henry inductor, which gives you one amp of current per second flowing through the inductor.
So where is the EMF and the CEMF? The one-volt voltage source is the EMF. The CEMF is the one amp of current per second flowing through the inductor causing a one-volt voltage drop across the inductor.
The one-volt voltage drop across the inductor is the CEMF. Look at that, the EMF and the CEMF are equal and opposite, and current flows through the inductor.
That's the real deal and that's the way it is modeled.
There is no difference between the EMF and the CEMF and current flows through the inductor.
So Brad, you allege that I have "lost my marbles" with respect to the example above. Then you break down that example and show us exactly where and why it is wrong. If you can't do that then you are the one that has lost your marbles.
MileHigh
This one volt voltage drop across the inductor is horse radish,and also makes things more confusing than they need to be.
The inductor dose not cause the voltage drop,as the voltage applied across the inductor by the source is exactly what will be across the inductor. You might as well say there is a 1 volt voltage drop across a 1 volt battery--how stupid dose that sound ::)
MH
You are doing nothing but adding some sort of idiotic confusion to everything everyone has learned.
I dont give a rats ass what you say,if the CEMF is equal to the applied EMF,then no current will flow through that inductor.
And this cods wallop about a resistor creating an equal and opposite CEMF to that of the applied EMF,is nothing short of insane.
You say that the CEMF must be lower than the EMF for current to flow?
Yep,as that is what stops the current through an inductor shooting straight up to a maximum value determined by the inductors winding resistance,when a voltage is placed across.
Same with water flowing through pipes-as i stated before. Once the head pressure pushing back against the pump equals the pumps maximum pumping pressure,there will be no water flow.
The pressure is your voltage,and the water flow rate is your current.
Say what you will MH,but i am no longer interested in what you have to say.
Brad
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snip...
There is no difference between the EMF and the CEMF and current flows through the inductor.
snip...
MileHigh
When an inductor is first connected to a Voltage Source at time=0 and counting, the EMF and CEMF are EQUAL and their is NO current flow.
At end of TC 1 (TC = time constant of the inductor) the CEMF will be .37 of The EMF and supply current is flowing.
At end of TC 2 the CEMF will be .14 of The EMF and supply current is flowing.
At end of TC 3 the CEMF will be .5 of the EMF and supply current is flowing.
At end of TC 4 the CEMF will be .2 of the EMF and supply current is flowing.
At end of TC 5 the CEMF will be .0 of the EMF = non existent and supply current is flowing.
Any moment after that, the current through the inductor will be steady, the EMF will be steady and there will be NO CEMF.
MH, for someone who insists that others use the correct nomenclature when referring to circuitry, you seem to be pretty liberal with how you apply it yourself. Voltage drop across a component is not CEMF. EMF is not CEMF. Constant EMF is sustainable, constant CEMF is not.
Here's a link showing the relationship of CEMF in a series LR circuit, with the resistance external to the inductor and the presumption of an ideal inductor. Step through the exercise and answer the questions.
https://www.wisc-online.com/learn/career-clusters/stem/ace5903/an-inductor-opposing-a-current-change (https://www.wisc-online.com/learn/career-clusters/stem/ace5903/an-inductor-opposing-a-current-change)
Cheers
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author=poynt99 link=topic=16589.msg486943#msg486943 date=1466638667]
In terms of KVL, it holds fine, and the "drop" across the inductor is determined by the voltage source, just as in the case for the resistor, but it is NOT the cemf, if indeed emf is equated with voltage.
Is this explanation crazy? Perhaps, but I've not seen any other that makes sense to me.
Isn't an inductor very much like a frequency-dependent resistor? If so, then maybe it makes sense for it to have a voltage drop across it.
How can it be Poynt. A resistor has no inductance,produces no magnetic field,and the value of resistance in a resistor dose not change over time.
Kirchhoff's KVL always holds, so the problem is perplexing, especially in light of the descriptions on self induction, whereby an opposing "self-induced emf" results from the changing flux in the coil. "Opposing" in what manner?
Opposing as in-producing a current that flows in opposition to that of which the applied EMF is trying to create.
As we discussed earlier,it is what stops the current going straight to a maximum value,once a voltage is placed across that inductor--what else would limit the rate of current increase in that inductor when a voltage is placed across it,if it is not the self induced EMF?.
One argument is that if the EMF and CEMF were equal, no circuit current would flow. I think we may be arguing with an incorrect assumption in mind. We can envision the voltage source and the induced emf as two generators back to back, but is this accurate?
No,that would not be accurate as far as i am concerned.
The applied EMF would be seen as a prime mover,and the self induced EMF(CEMF) would be the generator attached to the prime mover. The load drawn from the generator could be seen as the CEMF,as there is always losses,the CEMF (power dissipated in load),will always be less than the power being supplied to the generator by the prime mover-->(or we may see something different at the other place ;) )
A voltage source and a resistor in parallel also have voltages that are back to back, yet current flows.
A resistor is not a voltage source,and has no voltage across it until such time one is applied to it from a voltage source. At that point in time,the resistor now becomes a resistive heater-nothing more.
The self-induced emf is present, but it is perhaps not what we might expect. When we use the term "emf" we expect it to mean there is or will be a resulting measurable voltage. When the voltage source is connected and the magnetic field begins building, the coil immediately starts inducing a cemf across its terminals. The coil has now become a generator; but there is a "twist". The load seen by the coil's terminals is the voltage source, and it would appear as a short circuit to the coil.
The voltage source will not be seen as a load,as the self induced EMF is less than the applied EMF,due to transformer losses,and there for,a potential difference still exists,and the higher potential is the voltage source. So the inductor is still seen as the load,because it has the lowest value of the two potentials
If the self induced EMF was equal to the applied EMF,then there is no potential difference between the two,and current will not flow unless there is a potential difference.
I made a statement a few posts back in that an induced current always has an associated induced voltage. I retract that and restate it this way: An induced current usually has an associated induced voltage. The fact is that a coil can have a current induced in it, even if the coil is shorted. This I believe is the scenario with the self-induced emf and current with our simple voltage source and inductor.
Yes,this was told to us on this thread by verpies many pages back,and some others here decided to tell him to stop confusing the subject at hand,by introducing things not associated with the question.
But now we have seen a full circle,and we are right back to the point verpies was making :D
So I am saying that the cemf induced in the coil goes to 0V, while the self-induced opposing current goes to some value, determined by the inductance and rate of flux change.
Is that the case?-im not sure.
If the CEMF value is 0,then how can a current be produced without voltage,when that coil(as discussed above)is not an ideal coil with an ideal short across it's terminals. Only an ideal coil with an ideal wire across it's terminals will allow for a current to flow through it,without a voltage across it.
Has anyone ever wound a coil with a center tap,and measured the voltage across half of the inductors winding's,while being subjected to a rising and falling current--will it be equal to 1/2 of the applied EMF?.
Brad
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author=hoptoad link=topic=16589.msg486958#msg486958 date=1466674702]
At end of TC 1 (TC = time constant of the inductor) the CEMF will be .37 of The EMF and supply current is flowing.
At end of TC 2 the CEMF will be .14 of The EMF and supply current is flowing.
At end of TC 3 the CEMF will be .5 of the EMF and supply current is flowing.
At end of TC 4 the CEMF will be .2 of the EMF and supply current is flowing.
At end of TC 5 the CEMF will be .0 of the EMF = non existent and supply current is flowing.
It is good to see there is some one else that is not falling for MHs gobble doc.
But now 2 questions for you Hoptoad.
1-why dose the magnetic field that is inducing the CEMF,slowly decrease in change over time in an inductor from T=0-->moment of the applied voltage across the coil.
2-why is the CEMF equal to the applied EMF at the moment the voltage is placed across the coil?.
MH, for someone who insists that others use the correct nomenclature when referring to circuitry, you seem to be pretty liberal with how you apply it yourself.
As i have said many times,MH changes things when it suit's his needs.
Do as i say--not as i do. ;)
Voltage drop across a component is not CEMF. EMF is not CEMF. Constant EMF is sustainable, constant CEMF is not.
Indeed. ;)
Here's a link showing the relationship of CEMF in a series LR circuit, with the resistance external to the inductor and the presumption of an ideal inductor. Step through the exercise and answer the questions.
I doubt that will happen. MH is on a !!MH!! is right saga,and nothing gets in the way.
Brad
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But now 2 questions for you Hoptoad.
1-why dose the magnetic field that is inducing the CEMF,slowly decrease in change over time in an inductor from T=0-->moment of the applied voltage across the coil.
2-why is the CEMF equal to the applied EMF at the moment the voltage is placed across the coil?.
Brad, you know already why, because you'''re did demonstrate it before, its the change!
And Change we need all: Europe complete HOPEFULLY for a
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MileHigh,
You are apparently using the voltage drop across the coil as YOUR definition for CEMF. That is not what the rest of the electronics world uses as that definition. For the rest of us CEMF is the generated voltage that opposes the applied voltage. The CEMF is generated by the increasing magnetic field of the coil as the current rises. If your claim that the CEMF equals the EMF were true then no current would flow and that means the could NOT BE any CEMF. Sorry, but your argument makes no sense at all. I haven't read all the posts in this thread but it appears you are the only one that believes CEMF can equal EMF. I really don't think all the rest of us are wrong and you are the only one correct about this.
Respectfully,
Carroll
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snip...
But now 2 questions for you Hoptoad.
1-why dose the magnetic field that is inducing the CEMF,slowly decrease in change over time in an inductor from T=0-->moment of the applied voltage across the coil.
2-why is the CEMF equal to the applied EMF at the moment the voltage is placed across the coil?.
snip...
The magnetic field of the inductor is still increasing through each time constant until it is 100% maximum value derived from steady current at the end of TC5. Only the RATE of increase in the source current/magnetic field is getting less with each TC.
The CEMF does not arise from the source current/magnetic field of the inductor per se, it arises from Changes in the source current/magnetic field of the inductor. The level of cemf is most dependent on the Rate of change of the source current/magnetic field not necessarily the strength of the magnetic field or amount of source current. At actual time =0, in a real world inductor, nothing happens really. But at 0+ picoseconds to microseconds the RATE of change is highest causing the maximum cemf to arise.
But cemf is not self sustaining because it is an emergent phenomena with a value based on rate of change of current/magnetic field, and there can be no more change if emf = cemf, so the cemf begins to drop, and as it does, more source current flows. The diminishing cemf still opposes the Rate Of Change of the source, but not the actual flow of current per se. In opposing the rate of change it diminishes the cause of its own existence. So the cemf diminishes in the familiar TC curve we see in all inductors.
Cheers
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Well, I see we are now all unwitting players in some kind of Monty Python comedy sketch. We are a bunch of crazy people in a tizzy over Kirchhoff's voltage law. It's like we are all in electronics kindergarten, and it's the very first day. We are all running around with runny noses and bumping into walls.
We have our knickers in a super twist. It's the Mother of all Wedgies, and some of us have our brains in our cojones.
The question is, who has the cojones to state the truth?
This one volt voltage drop across the inductor is horse radish,and also makes things more confusing than they need to be.
The inductor dose not cause the voltage drop,as the voltage applied across the inductor by the source is exactly what will be across the inductor. You might as well say there is a 1 volt voltage drop across a 1 volt battery--how stupid dose that sound ::)
MH
You are doing nothing but adding some sort of idiotic confusion to everything everyone has learned.
I dont give a rats ass what you say,if the CEMF is equal to the applied EMF,then no current will flow through that inductor.
And this cods wallop about a resistor creating an equal and opposite CEMF to that of the applied EMF,is nothing short of insane.
Yep,as that is what stops the current through an inductor shooting straight up to a maximum value determined by the inductors winding resistance,when a voltage is placed across.
Same with water flowing through pipes-as i stated before. Once the head pressure pushing back against the pump equals the pumps maximum pumping pressure,there will be no water flow.
The pressure is your voltage,and the water flow rate is your current.
Say what you will MH,but i am no longer interested in what you have to say.
Brad
This one volt voltage drop across the inductor is horse radish,and also makes things more confusing than they need to be.
The inductor dose not cause the voltage drop,as the voltage applied across the inductor by the source is exactly what will be across the inductor. You might as well say there is a 1 volt voltage drop across a 1 volt battery--how stupid dose that sound
Gustav Robert Kirchhoff is rolling in his grave and wants to start walking again. This is one of those mind-blowing moments with you. Lock yourself in a room with half a dozen books on basic electronics don't come out until you have read through them and understood them.
Sorry, but you sound incredibly stupid. You have been playing with electronics all this time, for years, and you can't understand what a bloody voltage drop is?
I dont give a rats ass what you say,if the CEMF is equal to the applied EMF,then no current will flow through that inductor.
But you have been repeatedly asked to give an example with a coil where the CEMF is less than the EMF resulting in current flow and you refuse to do it because you can't do it.
Same with water flowing through pipes-as i stated before. Once the head pressure pushing back against the pump equals the pumps maximum pumping pressure,there will be no water flow.
The pressure is your voltage,and the water flow rate is your current.
No, because that example would be like connecting a capacitor across an EMF source. The head pressure in the pipe would be like the voltage across the capacitor, and no current flows. The equivalent and proper example would be a long pipe. Water flows through the long pipe and at the junction of the pump and the long pipe, the maximum pumping pressure of the pump and the head pressure in the pipe are the same. Then as you travel along the long pipe the pressure in the pipe decreases.
So Brad,
1) The unanswered request for you to put substance behind your claim with an actual example remains unanswered because you simply have no clue what to do and you can't show an example.
2) You could not break down my example and show us exactly where and why it is wrong because in fact it is correct. You didn't even try.
So no progress for you, a double fail on your part.
MileHigh
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Well with our ideal set up of inductor the current and time lead us
to a situation of infinity.
John.
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Well with our ideal set up of inductor the current and time lead us
to a situation of infinity.
John.
Indeed. Anybody got an ideal inductor?
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When an inductor is first connected to a Voltage Source at time=0 and counting, the EMF and CEMF are EQUAL and their is NO current flow.
At end of TC 1 (TC = time constant of the inductor) the CEMF will be .37 of The EMF and supply current is flowing.
At end of TC 2 the CEMF will be .14 of The EMF and supply current is flowing.
At end of TC 3 the CEMF will be .5 of the EMF and supply current is flowing.
At end of TC 4 the CEMF will be .2 of the EMF and supply current is flowing.
At end of TC 5 the CEMF will be .0 of the EMF = non existent and supply current is flowing.
Any moment after that, the current through the inductor will be steady, the EMF will be steady and there will be NO CEMF.
MH, for someone who insists that others use the correct nomenclature when referring to circuitry, you seem to be pretty liberal with how you apply it yourself. Voltage drop across a component is not CEMF. EMF is not CEMF. Constant EMF is sustainable, constant CEMF is not.
Here's a link showing the relationship of CEMF in a series LR circuit, with the resistance external to the inductor and the presumption of an ideal inductor. Step through the exercise and answer the questions.
https://www.wisc-online.com/learn/career-clusters/stem/ace5903/an-inductor-opposing-a-current-change (https://www.wisc-online.com/learn/career-clusters/stem/ace5903/an-inductor-opposing-a-current-change)
Cheers
Yes Hoptoad, you are just describing the standard inverse exponential curve for the energizing of an ideal inductor in series with a resistor. However you make a big fail in your reasoning and I will explain.
As the current increases through the (inductor + resistor) the net EMF presented across the inductor will be the original EMF minus the (resistor x current).
What that means is that over time the net EMF applied to the inductor decreases, and the CEMF generated by the inductor in response to the decreasing applied EMF is equal and opposite.
When an inductor is first connected to a Voltage Source at time=0 and counting, the EMF and CEMF are EQUAL and their is NO current flow.
And if the inductor was ideal and there was no resistance then after time=0 the CEMF will remain equal to the EMF and current will start to flow.
MH, for someone who insists that others use the correct nomenclature when referring to circuitry, you seem to be pretty liberal with how you apply it yourself. Voltage drop across a component is not CEMF. EMF is not CEMF. Constant EMF is sustainable, constant CEMF is not.
CEMF = counter electromotive force. All that really means is a voltage that is opposite to the applied voltage. Anything that generates an opposite voltage to the applied voltage can be considered a source of CEMF. The good old "backwards battery in the circuit for charging" is a CEMF source. Even a resistor can be considered a CEMF source but like I already posted, for clarity it is fine to call it a "potential difference" for a resistor.
I will repeat to you, a voltage drop across any component is actually a CEMF. However, for sure it makes sense to try and keep the nomenclature simple and understandable for all.
MileHigh
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Indeed. Anybody got an ideal inductor?
Every time you use the equation R = V/I, that assumes an ideal resistor.
Every time you use the equation v = L di/dt that assumes an ideal inductor.
Every time you use the equation i = C dv/dt that assumes an ideal capacitor.
All hobbyists and experimenters use the same equations day in and day out that are based on ideal components.
"Anybody got an ideal inductor?" is just bullshit talking. I know that many of you play this "it ain't real" game but at the same time you unwittingly use equations that assume ideal components.
Don't resist the application of knowledge and reason when it makes you "uncomfortable." Just get with the program because you are already assuming ideal components without even thinking about it.
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I didn't think I would have to spell it out in more detail, but looks as though I do.
Yes of course a real voltage source is not ideal, but compared to the output impedance of the coil, the voltage source is always going to appear as a heavy load, which is going to cause the cemf to go to practically 0V, if you were able to measure it, which of course you are not able to.
The point being, the cemf, no matter it's value, will effectively be shorted by the load. But as I explained there is no real consequence, because the resulting induced current does the job of limiting the current.
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author=hoptoad link=topic=16589.msg486958#msg486958 date=1466674702]
It is good to see there is some one else that is not falling for MHs gobble doc.
But now 2 questions for you Hoptoad.
1-why dose the magnetic field that is inducing the CEMF,slowly decrease in change over time in an inductor from T=0-->moment of the applied voltage across the coil.
2-why is the CEMF equal to the applied EMF at the moment the voltage is placed across the coil?.
As i have said many times,MH changes things when it suit's his needs.
Do as i say--not as i do. ;)
Indeed. ;)
I doubt that will happen. MH is on a !!MH!! is right saga,and nothing gets in the way.
Brad
No, MileHigh responded to Hoptoad and when you read the reply you will see that the inductor's CEMF is equal and opposite to the decreasing EMF. Hoptoad was wrong and it was clearly and unambiguously explained to him.
I have not changed a single thing to suit my needs. This is all just collective mass hysteria, Night of the Living Anti-Kirchhoff Zombie Pod People.
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CEMF = counter electromotive force. All that really means is a voltage that is opposite to the applied voltage. Anything that generates an opposite voltage to the applied voltage can be considered a source of CEMF. The good old "backwards battery in the circuit for charging" is a CEMF source. Even a resistor can be considered a CEMF source but like I already posted, for clarity it is fine to call it a "potential difference" for a resistor.
I will repeat to you, a voltage drop across any component is actually a CEMF. However, for sure it makes sense to try and keep the nomenclature simple and understandable for all.
MileHigh
I strongly disagree. A voltage drop across a resistor is simply that. It can not be considered a "source" of emf or cemf. A resistor dissipates energy supplied by an emf. See the attached definition by Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html).
An emf is a source of energy. The voltage measured across a resistor is an indication of the dissipation of energy. Let's not confuse the two.
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snip...
What that means is that over time the net EMF applied to the inductor decreases, and the CEMF generated by the inductor in response to the decreasing applied EMF is equal and opposite.
snipp...
I will repeat to you, a voltage drop across any component is actually a CEMF. However, for sure it makes sense to try and keep the nomenclature simple and understandable for all.
MileHigh
There is never a decrease or increase in the APPLIED EMF (voltage/current) source after connection. Remember - its an ideal voltage/current source to feed the ideal inductor.
Any variables like the varying resulting current through the inductor and its magnetic field strength are due to the variability of the emergent cemf that arises from the ideal Applied EMF. If the cemf was a steady value, all other factors would also be steady.
Of course in the real world unless your supply is very low impedance, when you connect an unloaded voltage source to a load, be it resistor or inductor the applied voltage source itself will fall slightly. How much it falls depends on the capacity of the source to deliver the required current into the load at a given maintained voltage.
Messing with the nomenclature seems to be the source of most of the tension in the discussion. There are times when it fails to communicate the concept or nuance of a particular issue, but that's when its time to look for a unique new descriptor to avoid confusion, not apply a well understood and widely used description of a phenomenon to another in which agreement and usage of another term is already common and well established.
Yes we use ideal equations to design circuits, work out currents, voltages etc.. We also know that our circuits and calculations contain error margins due to the fact that none of our components are ideal. We don't build perfect circuits but we still build good ones that are accurate enough for the tasks they are designed for.
Cheers
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I am going to repost this until you reply to it. You have clearly gotten confused between voltage drop and CEMF.
MileHigh,
You are apparently using the voltage drop across the coil as YOUR definition for CEMF. That is not what the rest of the electronics world uses as that definition. For the rest of us CEMF is the generated voltage that opposes the applied voltage. The CEMF is generated by the increasing magnetic field of the coil as the current rises. If your claim that the CEMF equals the EMF were true then no current would flow and that means the could NOT BE any CEMF. Sorry, but your argument makes no sense at all. I haven't read all the posts in this thread but it appears you are the only one that believes CEMF can equal EMF. I really don't think all the rest of us are wrong and you are the only one correct about this.
Respectfully,
Carroll
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I strongly disagree. A voltage drop across a resistor is simply that. It can not be considered a "source" of emf or cemf. A resistor dissipates energy supplied by an emf. See the attached definition by Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html).
An emf is a source of energy. The voltage measured across a resistor is an indication of the dissipation of energy. Let's not confuse the two.
I am not going to disagree with you strongly but I will add one caveat. For starters, I already mentioned that several searches used the term "potential difference" for a resistor in a current loop with an EMF source. So, indeed, a resistor is not a source of direct energy, but there is a tangible voltage associated with it. "A source or perhaps instance of potential difference (when current is flowing through the device)" is a reasonable thing to say.
Let me explore the caveat. Let's look at MOS-type semiconductors for a second. When you get into the details of how they are constructed and how they function, it quickly becomes apparent that it's all about electrons and the moving about of electronics. It starts to become an impediment to talk about current flow in these devices because it just gets too damn cumbersome. So that's why they use the terms "source" and "drain" in that realm. That refers of course to a source of electrons and a drain for electrons.
If you are in the realm of academic electrical engineering research, and looking at things on a deeper level, you may indeed use a different nomenclature. I am talking purely hypothetically here. When you start looking at voltage in detail, and you are snaking your way around a loop and observing the electric field, what do you see? You typically observe very weak electric fields in wires, strong electric fields in capacitors, and as you snake your way through a resistor, depending on the value and the current flow, you can observe say a moderate or a very strong electric field. In that realm of academic electrical engineering research, it may indeed be very convenient to refer to a resistor as a CEMF source because when you pass through it you can "go downhill" in terms of the electric field.
The realm of electronics and electrical engineering is so wide and so huge that different sectors will use their own rationalized units and use their own preferred nomenclature for devices and variables, etc.
So I am not "pushing" to say a resistor is a CEMF source, I am just saying that it may be valid to say that even if in this realm it's not an appropriate term.
MileHigh
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I strongly disagree. A voltage drop across a resistor is simply that. It can not be considered a "source" of emf or cemf. A resistor dissipates energy supplied by an emf. See the attached definition by Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html).
An emf is a source of energy. The voltage measured across a resistor is an indication of the dissipation of energy. Let's not confuse the two.
Thanks for posting that. In referring to nomenclature, that screenshot raises an issue which I had to deal with some years ago in trying to convey the nuance of difference between generating cemf and using it. As the picture says, EMF (CEMF)is not a force it is a potential.
For the purpose of explaining a concept I instead referred to the accepted CEMF as CEMP (Counter electromotive potential) to convey the difference between an unloaded flyback voltage, and CEMF (Counter electromotive force) comprising a loaded CEMP resulting in flyback current. Outside the particular examples I was trying to explain, I would not use the term. But as I said, occasionally the nomenclature we use lacks nuance without added descriptors. For example, BEMF or CEMF is a term that is widely used to describe a voltage that can be induced in a number of different ways that doesn't give clear insight into the specific method of its creation. Is it self induced back emf, rotor magnet induced back emf, collapsing field induced back emf. It is all the same thing but the mechanisms vary, while the name gives little nuance to any specific method of production.
The confusion can really become quite chaotic in pules motor operation descriptions because you have cemf that arises from the applied emf simply due to the inductor characteristics. Then you have cemf induced from the rotor magnets, and also cemf from the collapse of the magnetic field when the emf is removed again. If we had accepted unique names for the cemf according the method of creation, it would simply make it easier to understand and negate the need for additional descriptors to avoid confusion. Underlying all the methods is one commonality - changing current/magnetic fields. But a broader vocabulary would help the description process.
Cheers
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MileHigh,
You are apparently using the voltage drop across the coil as YOUR definition for CEMF. That is not what the rest of the electronics world uses as that definition. For the rest of us CEMF is the generated voltage that opposes the applied voltage. The CEMF is generated by the increasing magnetic field of the coil as the current rises. If your claim that the CEMF equals the EMF were true then no current would flow and that means the could NOT BE any CEMF. Sorry, but your argument makes no sense at all. I haven't read all the posts in this thread but it appears you are the only one that believes CEMF can equal EMF. I really don't think all the rest of us are wrong and you are the only one correct about this.
Respectfully,
Carroll
If you just read my long posting about the term "CEMF" applied to resistors then you will see there is a similar discussion that can be had about your posting above.
A voltage drop across a coil is not MY definition of CEMF. The simple fact is that they are synonymous. In the realm of electronics often enough there are multiple ways to state the same thing. There is nothing wrong with that, often a givien identical situation can be viewed from differing perspectives using different terminology that in the long run all mean exactly the same thing.
For the rest of us CEMF is the generated voltage that opposes the applied voltage.
Yes, and from the battery's perspective that generated voltage is causing the battery's voltage to drop through the coil. So the CEMF and the generated voltage that opposes the applied voltage and the voltage drop across the coil are all exactly the same thing.
If your claim that the CEMF equals the EMF were true then no current would flow and that means the could NOT BE any CEMF.
Yes, I know, we are still in zombie territory. Just like you can have multiple terms that mean exactly the same thing, you can have a device that behaves in a way where it is like two things happen at the same time.
In a coil, the CEMF is being generated as a result of the changing current flow through the coil (v = L di/dt) and this is all talking place because the battery is imposing EMF across the coil. Everything is awesome and it's all happening at the same time and it's all perfectly normal. It's NORMAL and nobody should be even flinching or questioning it. I suspect the root cause of the hysteria is "Brad's disease." Brad says something completely wrong and a bunch of zombie sycophants follow along because for some strange reason you latch onto what he says. THINK FOR YOURSELF, and wake up. You connect a battery to a coil and you measure 12 volts at the junction of the battery and the coil. By definition the EMF is 12 volts and by definition there is changing current in the coil generating a counter EMF of 12 volts. This is not rocket science, this is basic electronics.
The EMF and the CEMF are the same damn thing! The battery says, "I am imposing 12 volts across you." The coil says, "Oh shit, then I have to let changing current flow through me at a rate where I muster up the same 12 volts." They are the SAME THING. They both measure 12 volts with a volt meter and have the same polarity if you use the same ground reference. They HAVE to be the same potential because they are CONNECTED to each other.
If they are the same damn thing then why is one called CEMF? It's because you "travel though the loop" in ONE DIRECTION only. So if you go clockwise and you go UP in potential because of the EMF, then as you continue on your journey through the coil you go DOWN in potential. Hence the "counter." You go up in potential and then you counter that by going down in potential. But when you are not "in the loop" the EMF and the CEMF are EXACTLY THE SAME with the SAME polarity.
I will say again, there is nothing really to debate here. We are all zombies trapped in a Monty Python sketch. We need to bust out.
MileHigh
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The magnetic field of the inductor is still increasing through each time constant until it is 100% maximum value derived from steady current at the end of TC5. Only the RATE of increase in the source current/magnetic field is getting less with each TC.
The CEMF does not arise from the source current/magnetic field of the inductor per se, it arises from Changes in the source current/magnetic field of the inductor. The level of cemf is most dependent on the Rate of change of the source current/magnetic field not necessarily the strength of the magnetic field or amount of source current. At actual time =0, in a real world inductor, nothing happens really. But at 0+ picoseconds to microseconds the RATE of change is highest causing the maximum cemf to arise.
But cemf is not self sustaining because it is an emergent phenomena with a value based on rate of change of current/magnetic field, and there can be no more change if emf = cemf, so the cemf begins to drop, and as it does, more source current flows. The diminishing cemf still opposes the Rate Of Change of the source, but not the actual flow of current per se. In opposing the rate of change it diminishes the cause of its own existence. So the cemf diminishes in the familiar TC curve we see in all inductors.
Cheers
OK-good.
Now i want you to think about this very carefully Hoptoad-very carefully.
We have an ideal coil,and that is one free from any winding resistance. It is also void of a time constant--has none.
So from T=0,a voltage is applied across this ideal coil from an ideal voltage source-remember,no time constant,due to no winding resistance resistance.
At T=0,the current will continue to rise at a steady rate,and never reach a peak--the current rises to an infinite amount over an infinite amount of time. The CEMF as you said,is governed by the change in current flow induced by the applied voltage over time. But with our ideal coil,there is no change in current,as the current rises at a steady state for an infinite amount of time. So the current flow is the same as it was at T=0(-the moment a voltage was placed across the coil)for an infinite time.
Will the CEMF change from it's starting value(T=0),if the induced current from the applied voltage always rises at the same rate for an infinite amount of time?
P.S
To add your statement
Quote: If the cemf was a steady value, all other factors would also be steady.
Brad
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I strongly disagree. A voltage drop across a resistor is simply that. It can not be considered a "source" of emf or cemf. A resistor dissipates energy supplied by an emf. See the attached definition by Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html).
An emf is a source of energy. The voltage measured across a resistor is an indication of the dissipation of energy. Let's not confuse the two.
Thank you Poynt.
It is good to see some sanity still exist here.
Brad
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OK-good.
Now i want you to think about this very carefully Hoptoad-very carefully.
We have an ideal coil,and that is one free from any winding resistance. It is also void of a time constant--has none.
So from T=0,a voltage is applied across this ideal coil from an ideal voltage source-remember,no time constant,due to no winding resistance resistance.
At T=0,the current will continue to rise at a steady rate,and never reach a peak--the current rises to an infinite amount over an infinite amount of time. The CEMF as you said,is governed by the change in current flow induced by the applied voltage over time. But with our ideal coil,there is no change in current,as the current rises at a steady state for an infinite amount of time. So the current flow is the same as it was at T=0(-the moment a voltage was placed across the coil)for an infinite time.
Will the CEMF change from it's starting value(T=0),if the induced current from the applied voltage always rises at the same rate for an infinite amount of time?
Brad
Good question - I don't know. The scenario you paint seems a bit like those dastardly 'which came first, the chicken or the egg' situations
Will have to sleep on that.
Cheers
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I am not going to disagree with you strongly but I will add one caveat. For starters, I already mentioned that several searches used the term "potential difference" for a resistor in a current loop with an EMF source. So, indeed, a resistor is not a source of direct energy, but there is a tangible voltage associated with it. "A source or perhaps instance of potential difference (when current is flowing through the device)" is a reasonable thing to say.
Let me explore the caveat. Let's look at MOS-type semiconductors for a second. When you get into the details of how they are constructed and how they function, it quickly becomes apparent that it's all about electrons and the moving about of electronics. It starts to become an impediment to talk about current flow in these devices because it just gets too damn cumbersome. So that's why they use the terms "source" and "drain" in that realm. That refers of course to a source of electrons and a drain for electrons.
If you are in the realm of academic electrical engineering research, and looking at things on a deeper level, you may indeed use a different nomenclature. I am talking purely hypothetically here. When you start looking at voltage in detail, and you are snaking your way around a loop and observing the electric field, what do you see? You typically observe very weak electric fields in wires, strong electric fields in capacitors, and as you snake your way through a resistor, depending on the value and the current flow, you can observe say a moderate or a very strong electric field. In that realm of academic electrical engineering research, it may indeed be very convenient to refer to a resistor as a CEMF source because when you pass through it you can "go downhill" in terms of the electric field.
The realm of electronics and electrical engineering is so wide and so huge that different sectors will use their own rationalized units and use their own preferred nomenclature for devices and variables, etc.
So I am not "pushing" to say a resistor is a CEMF source, I am just saying that it may be valid to say that even if in this realm it's not an appropriate term.
MileHigh
Oh i see lol.
I say the very same thing as Poynt did,but i get a totally different reply.
To gutless to treat Poynt like you treat me?
Oh,and here is the kicker--the guy(me) that you think is such an amateur,and knows so little,gave the very same answer as Poynt,who is very well versed in EE--only i gave it first.
This speaks volumes about your true nature MH--your pathetic.
Brad
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There is never a decrease or increase in the APPLIED EMF (voltage/current) source after connection. Remember - its an ideal voltage/current source to feed the ideal inductor.
In your standard example of an EMF source driving a resistor in series with an ideal coil then what you MUST look at is the APPLIED EMF ACROSS THE IDEAL COIL, and not the unchanging EMF source before the resistor.
Why is this?
Because as more current flows through the resistor the resistor causes an EMF DROP.
The EMF drop results in a new lower EMF across the ideal coil.
The ideal coil responds to the lower EMF imposed across it with an equal CEMF.
The lower EMF and the lower CEMF MUST BE EQUAL because they are CONNECTED to each other.
I know that I am really just repeating myself, try to understand it this second time.
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Good question - I don't know. The scenario you paint seems a bit like those dastardly 'which came first, the chicken or the egg' situations
Will have to sleep on that.
Cheers
Indeed ;)
Perhaps Poynt,PW,verpies,and the likes,will give it some more thought as well,instead of falling into the world of MHs endless garden paths.
I really do love that saying of verpies-->just because everyone else makes mistakes,it dose not mean we have to.
Brad
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Oh i see lol.
I say the very same thing as Poynt did,but i get a totally different reply.
To gutless to treat Poynt like you treat me?
Oh,and here is the kicker--the guy(me) that you think is such an amateur,and knows so little,gave the very same answer as Poynt,who is very well versed in EE--only i gave it first.
This speaks volumes about your true nature MH--your pathetic.
Brad
First of all, I don't know which posting you are referring to. Secondly, kiss my ass.
Kiss my ass because Poynt made a long posting where he started to move significantly in my direction and your response was quite polite. If I had said the same thing you would have said I lost my marbles and used a lot of other colourful expressions. You were too gutless to treat Poynt like you have treated me?
In other words, your behaviour would be exactly the same as what you are accusing me of. Here is where you can actually apply the term "hypocrite" to your own behaviour.
You are a hypocrite Brad.
i.e.;
And to think,you thought you had the smarts to give EMJ a hard time on his understandings about inductors and coils--and me for that matter. <-- This one sounds like a rude insult.
You have yourself a great time MH,but i am done with your repeated stupidity,and re-writing of physics. <-- this one sounds like a rude insult
I think you are a little lost when it comes to understanding what CEMF is in an inductor-or anything for that matter. <-- This one sounds like a rude insult
Yep-you have finally lost your marbles. <-- This one sounds like a rude insult
MH is just lost again. <-- This one sounds like a rude insult
However, Brad, you might or might not know how after the fall of the Soviet Union in America they talked about the "peace dividend."
Well, let's say you got the "war dividend." You can be so unbelievably obstinate and your knowledge was so screwed up and so skewed that you were hopelessly trapped in a backwards electronics pre-kindergarten. You had to be battled with over and over and over to force some sense into you. You still have a long long way to go.
You had to get your ass kicked over and over. You were kicking and screaming all the way. You still have a serious mental block about admitting that you are wrong.
Nonetheless, you have progressed more in the past three months than you progressed in the past six years watching pulse motors turn.
Don't believe me? Just go read this thread from the very beginning and read yourself and what you have to say. So for you, being told straight to your face by me that what you just posted was idiotic and completely and totally wrong who knows how many times was ultimately for your benefit.
Just go read the this thread from the very beginning and see how completely idiotic most of what you say is from your current perspective.
It's like very Old School schooling where knowledge had to practically be beaten into your behind. And there is no way in hell I would keep this up.
Like it or not, you are 10 times smarter when it comes to electronics than you were three months ago. And you still need to lock yourself in a room for a month and read and understand some books on basic electronics so you will stop dropping outrageously ignorant and stupid comments that make it look like you were born just yesterday.
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I think what this is saying is that the Vsource is NOT the same V that the inductor sees,, the inductor is going to see Vsource-VdropR and so VdropR becomes the EMF that the inductor matches with CEMF,, and since Vsource is larger than VdropR+(CEMF=VdropR EMF) current will still flow.
So the CEMF from the inductor is less than EMF from the SOURCE because the inductor sees the EMF from the RESISTOR and NOT the source.
That's right. And if I was going to split hairs I would say, "the EMF from after the RESISTOR."
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I really do love that saying of verpies-->just because everyone else makes mistakes,it dose not mean we have to.
Brad
Exactly, so when is this mass hysteria about Kirchhoff's voltage law going to come to an end?
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This one is for the KVL hysterics.
Let's switch over to the physical world and discuss the bloody frictionless fully-loaded shopping cart.
Look at the attached graphic. This time we are going to use the Force-Voltage analogy. Pay attention to the variables.
You are pushing the shopping cart. The force you push on the cart with your hands is the voltage. The velocity of the cart is the current. The heavy shopping cart is the inductance.
If you push on the cart with a constant force then you know that you have to start running faster and faster down the aisle because the shopping cart is speeding up - it's accelerating.
You push on the cart - that's the EMF.
The cart pushes back on you with the SAME FORCE, that's the CEMF.
"For every action there is an EQUAL AND OPPOSITE reaction."
COMMON SENSE PEOPLE, take an example from REAL LIFE and THINK.
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Old Webby's gettin' a bit of steam up!!!
J.
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Old Webby's gettin' a bit of steam up!!!
J.
Speaking of which, let's take a break and give the boys, girls, and zombies a little dose of culture. And when I say "dose" I really mean "dose."
Sun Valley Serenade - Chattanooga Choo Choo
https://www.youtube.com/watch?v=V2aj0zhXlLA
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The EMF and the CEMF are the same damn thing! The battery says, "I am imposing 12 volts across you." The coil says, "Oh shit, then I have to let changing current flow through me at a rate where I muster up the same 12 volts." They are the SAME THING. They both measure 12 volts with a volt meter and have the same polarity if you use the same ground reference. They HAVE to be the same potential because they are CONNECTED to each other.
They measure the same, but not because the cemf is equaling the emf. It is because the emf source is holding the voltage constant. again, I think it is a very bad idea to equate a voltage drop with a cemf. They just simply are not the same, and historically have never been used interchangeably.
If they are the same damn thing then why is one called CEMF? It's because you "travel though the loop" in ONE DIRECTION only. So if you go clockwise and you go UP in potential because of the EMF, then as you continue on your journey through the coil you go DOWN in potential. Hence the "counter." You go up in potential and then you counter that by going down in potential. But when you are not "in the loop" the EMF and the CEMF are EXACTLY THE SAME with the SAME polarity.
I disagree. One is called cemf because that is precisely what it is; i.e. it is a generated voltage in this case. Going around the loop is simply confirming KVL, and it always holds.
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OK-good.
Now i want you to think about this very carefully Hoptoad-very carefully.
We have an ideal coil,and that is one free from any winding resistance. It is also void of a time constant--has none.
So from T=0,a voltage is applied across this ideal coil from an ideal voltage source-remember,no time constant,due to no winding resistance resistance.
At T=0,the current will continue to rise at a steady rate,and never reach a peak--the current rises to an infinite amount over an infinite amount of time. The CEMF as you said,is governed by the change in current flow induced by the applied voltage over time. But with our ideal coil,there is no change in current,as the current rises at a steady state for an infinite amount of time. So the current flow is the same as it was at T=0(-the moment a voltage was placed across the coil)for an infinite time.
Will the CEMF change from it's starting value(T=0),if the induced current from the applied voltage always rises at the same rate for an infinite amount of time?
P.S
To add your statement
Quote: If the cemf was a steady value, all other factors would also be steady.
Brad
Since the amps/sec is constant, the induced cemf should be steady.
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The EMF and the CEMF are the same damn thing!
I am going to have to disagree with this.
I believe I understand what it is you are saying with regard to your definition of CEMF. However, by your definition, even if your "black box" were empty (a perfect insulator), that perfect insulator would also be creating a CEMF equal to the "applied" EMF. And, by your definition, I can even see the argument that can be made to make the case for that being true.
However, this thread is about inductors and the definition of CEMF, regarding inductors, is very well defined. As defined, the CEMF related to inductors is generated by way of a very specific mechanism (induction). With all the harping on about the use of proper terminology, and to avoid confusion, it is perhaps best to stay with the existing definition of CEMF as it relates to inductors.
In the above you state that EMF and CEMF are the same thing. You make this case based solely on a voltage drop measured across the two terminals of the inductor. When connected across an ideal voltage source, the voltage measured across the inductor has little to do with the defined mechanism and actions of an inductor's CEMF. In fact, by using only a voltmeter to measure across the inductor, it is impossible to measure, or identify, any parameter related to the inductor's CEMF. By definition, the CEMF will oppose _current_ and in order to see the effects of CEMF (as defined), one must measure current.
The voltage portion of the definition related to an inductor's CEMF is, rather clumsily, something along the lines of "a rate of change dependent voltage induced into a conductor that produces a _current_ in opposition to the current that induced it". Whether or not the induced voltage related to an inductor's CEMF is realized externally across the inductor's two terminals will depend heavily on the impedances external to the inductor. In the case of being connected across an ideal voltage source, the effects of an inductor's CEMF will not manifest externally as a voltage. Only by measuring the rate of change dependent opposition to the flow of current can the effects of an inductor's CEMF be realized.
Tinman's question, "what if the EMF and CEMF were equal", with regard to an inductor connected to an ideal voltage source, had little to do with any _voltage_ measured at the two terminals of the inductor. In this instance, CEMF will only manifest by measuring current.
As I responded to Tinman, if it were somehow possible to cause all the magnetic flux created by a current flowing thru an ideal conductor to be confined to, and cut thru, that conductor in such a way as to make the inductor's CEMF be equal to the EMF, I believe that inductor would have infinite inductance. To avoid the "chicken or egg paradox" in answering whether current could flow thru such an inductor, I stated that I believed that an infinitely small current would flow over an infinitely long period of time.
At no time were we discussing CEMF in reference to any _voltage_ measured across the inductor.
Just my .02...
PW
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What have I learned today?
EMF is not a force.
J.
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What have I learned today?
EMF is not a force.
J.
May the EMF be with you...
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They measure the same, but not because the cemf is equaling the emf. It is because the emf source is holding the voltage constant. again, I think it is a very bad idea to equate a voltage drop with a cemf. They just simply are not the same, and historically have never been used interchangeably.
When I say, "The EMF and the CEMF are the same damn thing!" I am talking about the measurement of the voltage magnitude itself. i.e.; Are the EMF and the CEMF the same value or is there a "requirement" for there to be a difference between the two values for current to flow? The setup is an EMF source connected across a coil. Not too many people have chimed in on that one recently.
I don't think you should take issue with the term "voltage drop" when you put your KVL hat on. As you go around the loop there _is_ a tangible, measurable voltage drop as you spiral your way through the coil. Granted, it is not a voltage drop like a voltage drop in a resistor, but it is still a voltage drop. It's all a question of your perspective and your semantic approach to the issue. The CEMF due to the changing current flow through the coil and the measurable voltage drop as you go through the loop are one in the same. At least from my perspective there is no big issue using either term with the proviso that you establish the frame of reference for using the term. Or arguably, both contexts are mutually understood by the parties concerned and you can use either/or without ruffling too many feathers.
Take the example of a capacitor. If you are doing a KVL analysis of a loop in some circuit, the capacitor could represent a voltage drop or a voltage increase. Saying, "there is a voltage drop across that capacitor" sounds pretty ordinary and mundane to my ears.
I disagree. One is called cemf because that is precisely what it is; i.e. it is a generated voltage in this case. Going around the loop is simply confirming KVL, and it always holds.
I am not really going to disagree with you here but I will just restate what I have stated before. It is possible to put aside how closely CEMF is tied to changing current through an inductor, and simply work with the literal meaning of the term. A voltage that is counter to my reference voltage is a voltage that is opposite in polarity to my reference voltage. For example, say my reference voltage or reference EMF was -25 volts. If there is a two-terminal device in the loop that is +5 volts, then that device is a counter-EMF device when I am going about my business of summing voltages in the loop. I suppose this is an exercise in the technical use of the English language, and not really mainstream electronics. The point being that I have license to choose to use those words if I want to and if the people you are discussing something with are all on the same page, then it works.
MileHigh
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PW:
Your posting is a doozie and I am always amazed how sometimes it feels like you a permanently prepped to write a final exam because you have all of the hard-core theoretical and technical information at your fingertips, which is something that I don't have.
You responded to my statement, "The EMF and the CEMF are the same damn thing!" Just a quick recap from what I just posted: I am talking about the measurement of the voltage magnitude itself. i.e.; Are the EMF and the CEMF the same value or is there a "requirement" for there to be a difference between the two values for current to flow?
You bring the focus of the CEMF discussion back to inductors which is fine. I have conceded that point and said for resistors "potential difference" is more appropriate and less confusing.
When connected across an ideal voltage source, the voltage measured across the inductor has little to do with the defined mechanism and actions of an inductor's CEMF. In fact, by using only a voltmeter to measure across the inductor, it is impossible to measure, or identify, any parameter related to the inductor's CEMF. By definition, the CEMF will oppose _current_ and in order to see the effects of CEMF (as defined), one must measure current.
I agree and I cited Wikipedia and that is mentioned in the first sentence of the article, "The counter-electromotive force (abbreviated counter EMF, or CEMF), also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it."
What I am not saying and what is implicit is that if you measure CEMF on an inductor with your voltmeter, you are aware that increasing current is flowing through the inductor and that is the real mechanism at play. You don't even know the magnitude of the increasing current, you are only aware that the process is taking place.
I don't know if you _must_ measure the current. If you know the inductance, and you measure the voltage you at least know the rate of change of the current, but you don't necessarily know the magnitude of the current, unless you know the initial conditions, etc.
Whether or not the induced voltage related to an inductor's CEMF is realized externally across the inductor's two terminals will depend heavily on the impedances external to the inductor. In the case of being connected across an ideal voltage source, the effects of an inductor's CEMF will not manifest externally as a voltage. Only by measuring the rate of change dependent opposition to the flow of current can the effects of an inductor's CEMF be realized.
I am puzzled by that statement with respect to an ideal voltage source. Are you making reference to a real-world inductor with resistance? I didn't state it explicitly before but I am assuming an ideal inductor unless stated otherwise. If you do mean a real-word inductor then I agree, the CEMF could be mixed in with an IR voltage drop.
Tinman's question, "what if the EMF and CEMF were equal", with regard to an inductor connected to an ideal voltage source, had little to do with any _voltage_ measured at the two terminals of the inductor. In this instance, CEMF will only manifest by measuring current.
Are we back to a real-word inductor as I referenced above?
As I responded to Tinman, if it were somehow possible to cause all the magnetic flux created by a current flowing thru an ideal conductor to be confined to, and cut thru, that conductor in such a way as to make the inductor's CEMF be equal to the EMF, I believe that inductor would have infinite inductance. To avoid the "chicken or egg paradox" in answering whether current could flow thru such an inductor, I stated that I believed that an infinitely small current would flow over an infinitely long period of time.
I can't see where you are coming from for this one. In my mind the inductance value from a coil of an ideal conductor is still a function of geometry as per the derivation. So you can go to the Hyperphysics web site and punch in the coil parameters and then get your inductance value and take it from there. I can't envision an infinite inductance here.
When you say, "all the magnetic flux created by a current flowing thru an ideal conductor to be confined to, and cut thru, that conductor" to me that means a "perfect coil" where the magnetic flux still flows through the center of a coil, and then wraps back around the outside of the coil through all 3D space. I just don't see an infinite inductance with that model. I suppose if you had an infinite number of turns in the coil form that would be a different story.
MileHigh
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Good question - I don't know. The scenario you paint seems a bit like those dastardly 'which came first, the chicken or the egg' situations
Will have to sleep on that.
Cheers
Back some many pages ago I posted a possible scenario for this.
There must be something that happens first, as in applying input and that input must create some mag field before cemf is created. So we have to figure if just the tiniest amount of current from the input begins, the field should induce cemf instantaneously.
If at T0 there is no current, then nothing has happened yet. Why is that? Is there cemf at t0? It is an ideal conductor which should have immediately taken on current.
But the T0 point in time is supposedly a point that when the input is connected to the ideal inductor, but if we stop time at the point of connection, then current should not have happened yet, which is sort of hard to conceive considering ideal conductors. But I would have to say that at T0, the ends of the coil leads have charge potential from the input equaling the input. This is where it gets tough for me I admit. I may go as far to say that the inductor leads get some sort of say static charge even just before the contact is made, no matter how small the input voltage is. If so, could that static charge be enough to get anything moving in the inductor before the full connection is complete? Moving as in some electron flow that may set up a bit of cemf just before the connection is completed? ???
If so, then when the connection is finally made, could the cemf possibly be already in opposition to the input? Egg before chicken? ;)
Again, we will most likely never know for sure. When we see these demos of super conductors, they are most likely still far from ideal yet, as they need to be super cooled. Why? Because they still dissipate heat, thus the cooling, of which takes the heat away that IS being produced. I had seen a demo of a copper coil inductor with enough resistance that in series with a small light bulb and a source, the bulb was dim as compared to the bulb direct to the source. But then they dipped the coil in liquid nitro and the bulb seemed to come to full brightness. As I see it, the cooling helps to keep the heat generated by the coils resistance was just continuously taken away instead of being allowed to heat up more as current is flowing causing the resistance to become higher with the build up of heat.
A real world inductor has also capacitance. Even if it is super tiny amount of capacitance, that capacitance takes on a charge in the coil nearly immediately. I will be doing a test of that with the scope here when I get time. A bifi coil should have a larger spike of input when the source is applied as the capacitance is greater than a single winding coil, like Tesla said, the bifi windings take on input current as if the inductance was not there at all. I want to see if it is true.
Mags
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When I say, "The EMF and the CEMF are the same damn thing!" I am talking about the measurement of the voltage magnitude itself. i.e.; Are the EMF and the CEMF the same value or is there a "requirement" for there to be a difference between the two values for current to flow? The setup is an EMF source connected across a coil. Not too many people have chimed in on that one recently.
I don't think you should take issue with the term "voltage drop" when you put your KVL hat on. As you go around the loop there _is_ a tangible, measurable voltage drop as you spiral your way through the coil. Granted, it is not a voltage drop like a voltage drop in a resistor, but it is still a voltage drop. It's all a question of your perspective and your semantic approach to the issue. The CEMF due to the changing current flow through the coil and the measurable voltage drop as you go through the loop are one in the same. At least from my perspective there is no big issue using either term with the proviso that you establish the frame of reference for using the term. Or arguably, both contexts are mutually understood by the parties concerned and you can use either/or without ruffling too many feathers.
Take the example of a capacitor. If you are doing a KVL analysis of a loop in some circuit, the capacitor could represent a voltage drop or a voltage increase. Saying, "there is a voltage drop across that capacitor" sounds pretty ordinary and mundane to my ears.
I am not really going to disagree with you here but I will just restate what I have stated before. It is possible to put aside how closely CEMF is tied to changing current through an inductor, and simply work with the literal meaning of the term. A voltage that is counter to my reference voltage is a voltage that is opposite in polarity to my reference voltage. For example, say my reference voltage or reference EMF was -25 volts. If there is a two-terminal device in the loop that is +5 volts, then that device is a counter-EMF device when I am going about my business of summing voltages in the loop. I suppose this is an exercise in the technical use of the English language, and not really mainstream electronics. The point being that I have license to choose to use those words if I want to and if the people you are discussing something with are all on the same page, then it works.
MileHigh
"Granted, it is not a voltage drop like a voltage drop in a resistor, but it is still a voltage drop. It's all a question of your perspective and your semantic approach to the issue. "
Actually there should be a voltage drop for each winding of the coil. If we center tapped the coil, we should measure 5v across each half of the coil if 10v is applied.
I would say that even an ideal coil with an ideal voltage source would be measured the same, being that current will always be increasing along the way and not ever end up as steady dc current unless the current was controlled as such to be steady in an ideal situation.
But that still leads me to wonder, if the ideal voltage source were turned to 0v, like an ideal wire across the coil as described earlier, what keeps the current flowing steady in the coil? What mechanism keeps the electrons moving from atom shell to another atom shell? Does it not take energy to do such? Like why doesnt the field collapse when the source is switched out for an ideal piece of wire? What holds the field in place and not allow it to change, as in collapse? If it is a careful balance of initial emf and cemf, then that same ideal should hold for the explanation of cemf being equal to the input when we first apply the input to the ideal coil, in which there should be no current flow ever. ;) When does that careful balance begin and/or end? ;)
Mags
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What I am not saying and what is implicit is that if you measure CEMF on an inductor with your voltmeter, you are aware that increasing current is flowing through the inductor and that is the real mechanism at play. You don't even know the magnitude of the increasing current, you are only aware that the process is taking place.
My point was that if connected to an ideal voltage source, your voltmeter will tell you nothing with regard to an inductor's CEMF. When connected across an ideal V source CEMF can only be measured by looking at current.
The voltage across all two terminal devices connected across an ideal voltage source (as in your black box comments) will measure the same. Measuring current can identify L or C reactance, resistance, etc. In your particular definition of CEMF, anything and everything (or even nothing) in the black box is generating a CEMF equal to the EMF.
I think we should reserve CEMF only for use as defined regarding inductors.
I don't know if you _must_ measure the current. If you know the inductance, and you measure the voltage you at least know the rate of change of the current, but you don't necessarily know the magnitude of the current, unless you know the initial conditions, etc.
If an inductor is connected across an ideal V source, the voltage measured across that inductor says nothing about the inductance, DCR, or CEMF of that inductor.
Again, consider your black box. Who knows what was put in there? Measuring current will be more informative.
I am puzzled by that statement with respect to an ideal voltage source. Are you making reference to a real-world inductor with resistance? I didn't state it explicitly before but I am assuming an ideal inductor unless stated otherwise. If you do mean a real-word inductor then I agree, the CEMF could be mixed in with an IR voltage drop.
Regardless of whether or not the inductor is ideal, if connected across an ideal Vsource, the voltage across that inductor says nothing with regard to its inductance, DCR, or CEMF...
Are we back to a real-word inductor as I referenced above?
It does not matter, the question was a discussion of the hypothetical.
Agaiin, when connected across an ideal voltage source however, the voltage across the inductor has little to do with the discussion related to CEMF. One must measure current...
I can't see where you are coming from for this one. In my mind the inductance value from a coil of an ideal conductor is still a function of geometry as per the derivation. So you can go to the Hyperphysics web site and punch in the coil parameters and then get your inductance value and take it from there. I can't envision an infinite inductance here.
When you say, "all the magnetic flux created by a current flowing thru an ideal conductor to be confined to, and cut thru, that conductor" to me that means a "perfect coil" where the magnetic flux still flows through the center of a coil, and then wraps back around the outside of the coil through all 3D space. I just don't see an infinite inductance with that model. I suppose if you had an infinite number of turns in the coil form that would be a different story.
I was considering a simple length of wire as an inductor. We know that changing the geometry of the wire (i.e., winding it into a coil) increases the inductance of that same length and size of wire. If the increased inductance is due to increased flux cutting/coupling, than one might ponder what would happen if it were somehow possible to cause all the magnetic flux to losslessly induce a CEMF into the wire, would that CEMF be equal to the applied EMF, and if so, would current be able to flow thru it. With reference to that, I suggested that an inductor so constructed would possess infinite inductance.
An infinite number of turns would most likely result in an infinite inductance (using an ideal conductor), but then I suspect, upon first thought, that there might also be an infinite amount of loss due to radiated flux.
But these are just hypothetical discussions that are supposed to be somewhat lighthearted and enjoyable.
Your definition of CEMF derailed the train so to speak...
PW
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My point was that if connected to an ideal voltage source, your voltmeter will tell you nothing with regard to an inductor's CEMF. When connected across an ideal V source CEMF can only be measured by looking at current.
The voltage across all two terminal devices connected across an ideal voltage source (as in your black box comments) will measure the same. Measuring current can identify L or C reactance, resistance, etc. In your particular definition of CEMF, anything and everything (or even nothing) in the black box is generating a CEMF equal to the EMF.
I think we should reserve CEMF only for use as defined regarding inductors.
If an inductor is connected across an ideal V source, the voltage measured across that inductor says nothing about the inductance, DCR, or CEMF of that inductor.
Again, consider your black box. Who knows what was put in there? Measuring current will be more informative.
Regardless of whether or not the inductor is ideal, if connected across an ideal Vsource, the voltage across that inductor says nothing with regard to its inductance, DCR, or CEMF...
It does not matter, the question was a discussion of the hypothetical.
Agaiin, when connected across an ideal voltage source however, the voltage across the inductor has little to do with the discussion related to CEMF. One must measure current...
I was considering a simple length of wire as an inductor. We know that changing the geometry of the wire (i.e., winding it into a coil) increases the inductance of that same length and size of wire. If the increased inductance is due to increased flux cutting/coupling, than one might ponder what would happen if it were somehow possible to cause all the magnetic flux to losslessly induce a CEMF into the wire, would that CEMF be equal to the applied EMF, and if so, would current be able to flow thru it. With reference to that, I suggested that an inductor so constructed would possess infinite inductance.
An infinite number of turns would most likely result in an infinite inductance (using an ideal conductor), but then I suspect, upon first thought, that there might also be an infinite amount of loss due to radiated flux.
But these are just hypothetical discussions that are supposed to be somewhat lighthearted and enjoyable.
Your definition of CEMF derailed the train so to speak...
PW
Not sure, but I think that was what Brad was saying a while back, that a straight ideal wire may not even have a field outside the wire itself as the cemf would keep it in check.
Mags
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But that still leads me to wonder, if the ideal voltage source were turned to 0v, like an ideal wire across the coil as described earlier, what keeps the current flowing steady in the coil? What mechanism keeps the electrons moving from atom shell to another atom shell? Does it not take energy to do such? Like why doesnt the field collapse when the source is switched out for an ideal piece of wire? What holds the field in place and not allow it to change, as in collapse? If it is a careful balance of initial emf and cemf, then that same ideal should hold for the explanation of cemf being equal to the input when we first apply the input to the ideal coil, in which there should be no current flow ever. ;) When does that careful balance begin and/or end? ;)
Mags
Poynt already answered this stating that there is no load to dissipate the energy, but let me take a crack at it. I am just going to give you a non-scientific seat-of-my-pants explanation.
Let's use a yo-yo as a flywheel. So the spinning yo-yo had a shot of energy put into it from your arm. Once it is spinning, naturally you don't question the fact that it is spinning. You also know that you can't easily stop it from spinning, it has inertia.
So if you spin up the yo-yo, that's step one. But then in step two, if you want to disturb the yo-yo, it's almost like the yo-yo wants to spin you. It's almost like once you set it going, the yo-yo has a life of its own. There is energy in the yo-yo and it has direction and magnitude. It's hard to mess with that energy.
It's like you applied torque to the yo-yo and if you want to mess with the yo-yo it says "back off" and applies torque right back to you.
Now look at a coil. The current flows through the wire. The wire subtends a magnetic field around the wire into all space. It took energy to create that magnetic field. So that means by definition there is literally a certain number of Joules of energy in each cubic centimeter of space around the coil, and in all 3D space.
When you are right up close to the wire you see the current flowing through the wire, and the energy of the magnetic field in the space surrounding the wire. That energy is real, it means something. The current and the magnetic field are so tightly connected to each other that you can just about treat them as one. That's why most people in electronics only talk about the current flow through the coil, the magnetic field is essentially the same damn thing, so you don't even have to mention the magnetic field.
So let's go back to a close up view of a wire. You see the current flow, and you see the magnetic field wrapped around the wire. But you can also just as easily say this: You see the magnetic field wrapped around the wire and you see the current flow.
What are the implications: They are as follows, and this is a thought experiment: What if you removed the current-carrying wire and instantly replaced it with a brand new wire but with no current flowing through it?
The answer is that the very presence of the magnetic field would demand that current instantly start flowing trough the wire. If there is a magnetic field present there must be current flow, period.
This explains why you get a shock if you cut the power to a 12-volt relay coil with your two fingers across the terminals. You take away the source of the magnetic field, but the magnetic field is there anyways and therefore current simply must flow through the wire.
So going to a superconducting coil, obviously work is expended to create the magnetic field, and the the current flow through the coil, which is the same thing. So when you remove the power source, the magnetic field "takes over" and current must flow through the wire. The current flow and the magnetic field are so intimately connected it's like they are a single entity.
You spin up a heavy flywheel by hand and then if you run out of gas then the flywheel will spin your hand. Just like if you build up a magnetic field by pushing current through a coil and then stop supplying energy, then the magnetic field will "take over" and supply the energy to keep the current flowing through the wire.
Anyway, if you get the sense of how the current flow and the magnetic field are so intimately connected that they are the same thing for all practical intents and purposes, and how energy is stored in the 3D space of the magnetic field, then maybe all of this will make sense.
MileHigh
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Had not looked at this stuff for a long time, but was looking at the element chart. I found that all conductors we typically see only have 1 electron in the outer shells, like gold, silver, copper, etc, and as I went down the line as in other elements that were metals, that outer shell tends to have more electrons in the and they are less conductive. Still looking into that stuff. And it was long ago that I knew this stuff and it wasnt like we spent weeks or months on the subject. Interesting stuff
The last one is interesting. I wonder if it has better conduction than gold?
Mags
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Since the amps/sec is constant, the induced cemf should be steady.
Indeed Poynt.
And this is why i tried so hard at the start of this thread to get you guys to take into account,that the infinite time constant plays a vital roll in MHs question.
If the CEMF is what limits the rise time of current flow,and the value of that CEMF is a constant--》what will be the value of current flow from T=0 throughout time ?.
The current can only rise in value over time if the value of the CEMF falls over time.
Brad
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PW hasn't acknowledged it (or perhaps not read my post), but we are saying the same thing. In short, that the cemf is not the voltage you would measure across the terminals when the inductor is connected to a voltage source, and the actual cemf is effectively shorted out by it.
I don't think you should take issue with the term "voltage drop" when you put your KVL hat on. As you go around the loop there _is_ a tangible, measurable voltage drop as you spiral your way through the coil. Granted, it is not a voltage drop like a voltage drop in a resistor, but it is still a voltage drop. It's all a question of your perspective and your semantic approach to the issue.
I'm not sure why you think I am disagreeing with you on this. Did you misunderstand my posts?
Anyway, although it doesn't make sense to me now, I am going to assume you are correct MH. Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indcur.html) does seem to support you (when R=0, V=Emf), so until someone can prove it wrong, I'll go along with it.
As for the use of "cemf" for resistor voltage drops? Sorry, I'm pretty firm on that one ;)
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PW:
My comment:
"I don't know if you _must_ measure the current. If you know the inductance, and you measure the voltage you at least know the rate of change of the current, but you don't necessarily know the magnitude of the current, unless you know the initial conditions, etc."
Your reply:
"If an inductor is connected across an ideal V source, the voltage measured across that inductor says nothing about the inductance, DCR, or CEMF of that inductor.
Again, consider your black box. Who knows what was put in there? Measuring current will be more informative."
--------------------
If the setup is simple, ideal voltage source, ideal coil, you know the inductance, and you know the initial conditions, aren't you being too dogmatic here?
In the simple setup then the CEMF has to be equal to the ideal voltage source. You know the inductance so you know the current.
Anyway, I am just about all pooped out on this stuff.
MileHigh
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Had not looked at this stuff for a long time, but was looking at the element chart. I found that all conductors we typically see only have 1 electron in the outer shells, like gold, silver, copper, etc, and as I went down the line as in other elements that were metals, that outer shell tends to have more electrons in the and they are less conductive. Still looking into that stuff. And it was long ago that I knew this stuff and it wasnt like we spent weeks or months on the subject. Interesting stuff
The last one is interesting. I wonder if it has better conduction than gold?
Mags
I think we were even taught that in General Science class about the "loose electrons" in the outer shell of the metals. Also I believe the luster or shine to metals comes comes from the outer shell electrons bouncing up and down in response to external EM radiation (light) and re-emitting that radiation.
Can you resize the giant images?
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Not sure, but I think that was what Brad was saying a while back, that a straight ideal wire may not even have a field outside the wire itself as the cemf would keep it in check.
Mags
Indeed.
And the same applies to the ideal coil with the ideal voltage placed across it.
Most all here fell for MHs wrong conclusion that an infinite time constant changes nothing,and a small value of resistance has very little effect on the outcome.
If the time constant is infinite,then the current will rise at a steady rate throughout time. This means that the CEMF that is acting against the induced current is also at a steady state.
So now,what will the induced current value be from T=0 ?.
Brad
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PW hasn't acknowledged it (or perhaps not read my post), but we are saying the same thing. In short, that the cemf is not the voltage you would measure across the terminals when the inductor is connected to a voltage source, and the actual cemf is effectively shorted out by it.
I'm not sure why you think I am disagreeing with you on this. Did you misunderstand my posts?
Anyway, although it doesn't make sense to me now, I am going to assume you are correct MH. Hyperphysics (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indcur.html) does seem to support you (when R=0, V=Emf), so until someone can prove it wrong, I'll go along with it.
As for the use of "cemf" for resistor voltage drops? Sorry, I'm pretty firm on that one ;)
I caved a long time ago on the resistor voltage drops and was just getting too analytical when I did a treatise on it anyway.
At this point I am easy and I am honestly pooped out on the whole thing. Yes, Hyperphysics agrees with me, how about them apples? I am perplexed how we were apparently not on the same page for this particular thing.
Just to toot my horn, from Hyperphysics, if R = 0, and using our terminology, then the applied EMF equals the CEMF. I deserve a t-shirt.
MileHigh
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I caved a long time ago on the resistor voltage drops and was just getting too analytical when I did a treatise on it anyway.
At this point I am easy and I am honestly pooped out on the whole thing. Yes, Hyperphysics agrees with me, how about them apples? I am perplexed how we were apparently not on the same page for this particular thing.
Just to toot my horn, from Hyperphysics, if R = 0, and using our terminology, then the applied EMF equals the CEMF. I deserve a t-shirt.
MileHigh
If R=0, then the current will climb at a steady rate fo all time-right?--no-wrong.
If the flow of current from T=0 is going to rise at a steady state,then the apposing current generated from the CEMF will also rise at a steady state. So what dose that mean for the current induced by the applied voltage?
It's like i said MH , there is a big difference between having a small amount of resistance,and none at all. It is the difference between having a time constant,and not having one.
It is the difference between having a current trace curve over time,and not having one.
It is the difference of having water at 1*C and ice at 0*C
Brad
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Poynt already answered this stating that there is no load to dissipate the energy, but let me take a crack at it. I am just going to give you a non-scientific seat-of-my-pants explanation.
Let's use a yo-yo as a flywheel. So the spinning yo-yo had a shot of energy put into it from your arm. Once it is spinning, naturally you don't question the fact that it is spinning. You also know that you can't easily stop it from spinning, it has inertia.
So if you spin up the yo-yo, that's step one. But then in step two, if you want to disturb the yo-yo, it's almost like the yo-yo wants to spin you. It's almost like once you set it going, the yo-yo has a life of its own. There is energy in the yo-yo and it has direction and magnitude. It's hard to mess with that energy.
It's like you applied torque to the yo-yo and if you want to mess with the yo-yo it says "back off" and applies torque right back to you.
Now look at a coil. The current flows through the wire. The wire subtends a magnetic field around the wire into all space. It took energy to create that magnetic field. So that means by definition there is literally a certain number of Joules of energy in each cubic centimeter of space around the coil, and in all 3D space.
When you are right up close to the wire you see the current flowing through the wire, and the energy of the magnetic field in the space surrounding the wire. That energy is real, it means something. The current and the magnetic field are so tightly connected to each other that you can just about treat them as one. That's why most people in electronics only talk about the current flow through the coil, the magnetic field is essentially the same damn thing, so you don't even have to mention the magnetic field.
So let's go back to a close up view of a wire. You see the current flow, and you see the magnetic field wrapped around the wire. But you can also just as easily say this: You see the magnetic field wrapped around the wire and you see the current flow.
What are the implications: They are as follows, and this is a thought experiment: What if you removed the current-carrying wire and instantly replaced it with a brand new wire but with no current flowing through it?
The answer is that the very presence of the magnetic field would demand that current instantly start flowing trough the wire. If there is a magnetic field present there must be current flow, period.
This explains why you get a shock if you cut the power to a 12-volt relay coil with your two fingers across the terminals. You take away the source of the magnetic field, but the magnetic field is there anyways and therefore current simply must flow through the wire.
So going to a superconducting coil, obviously work is expended to create the magnetic field, and the the current flow through the coil, which is the same thing. So when you remove the power source, the magnetic field "takes over" and current must flow through the wire. The current flow and the magnetic field are so intimately connected it's like they are a single entity.
You spin up a heavy flywheel by hand and then if you run out of gas then the flywheel will spin your hand. Just like if you build up a magnetic field by pushing current through a coil and then stop supplying energy, then the magnetic field will "take over" and supply the energy to keep the current flowing through the wire.
Anyway, if you get the sense of how the current flow and the magnetic field are so intimately connected that they are the same thing for all practical intents and purposes, and how energy is stored in the 3D space of the magnetic field, then maybe all of this will make sense.
MileHigh
Here is what I posted to Poynt yesterday....
"If so, then the ideal conductor doesnt require energy for electrons to be stripped from atoms and move them from atom to atom, jumping shell to shell. I can understand the seeming inertial effects of an inductor on electrons in its conductors, but not inertial effects of moving electrons on their own. This might incur that electrons have mass. And the seeming inertial effects of electrons of the inductor are when the field is collapsing. In this situation there is no field collapse or motion of the fields at all. So what mechanism keeps the electrons flowing in the loop? What energy is 'stored' that keeps the flow going? What form is the energy stored as?"
Mags
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PW:
My comment:
"I don't know if you _must_ measure the current. If you know the inductance, and you measure the voltage you at least know the rate of change of the current, but you don't necessarily know the magnitude of the current, unless you know the initial conditions, etc."
Your reply:
"If an inductor is connected across an ideal V source, the voltage measured across that inductor says nothing about the inductance, DCR, or CEMF of that inductor.
Again, consider your black box. Who knows what was put in there? Measuring current will be more informative."
--------------------
If the setup is simple, ideal voltage source, ideal coil, you know the inductance, and you know the initial conditions, aren't you being too dogmatic here?
In the simple setup then the CEMF has to be equal to the ideal voltage source. You know the inductance so you know the current.
No, I do not believe I am being too dogmatic. I am, however, being quite firm with regard to referring to CEMF, particularly on a thread about inductors, as it is defined regarding inductors.
Sure, one can deduce what effect the inductor's CEMF must be having in the circuit given all the data you list. But the voltage measured across an inductor connected to an ideal voltage source says nothing, directly, with regard to the CEMF. The effects of the inductor's CEMF can only be observed by measuring current.
PW
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I think we were even taught that in General Science class about the "loose electrons" in the outer shell of the metals. Also I believe the luster or shine to metals comes comes from the outer shell electrons bouncing up and down in response to external EM radiation (light) and re-emitting that radiation.
Can you resize the giant images?
Yeah. Thats why I went to look and refresh on that stuff. Hadnt thought on that in many years.
Oh. Man they are big. They seemed so small when I had copied them to post.
Getting into some eats n a shower here. Ill recopy and repost in a little while.
Mags
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If R=0, then the current will climb at a steady rate fo all time-right?--no-wrong.
If the flow of current from T=0 is going to rise at a steady state,then the apposing current generated from the CEMF will also rise at a steady state. So what dose that mean for the current induced by the applied voltage?
It's like i said MH , there is a big difference between having a small amount of resistance,and none at all. It is the difference between having a time constant,and not having one.
It is the difference between having a current trace curve over time,and not having one.
It is the difference of having water at 1*C and ice at 0*C
Brad
I have no clue what you really mean when you talk about "opposing current generated by the CEMF." The CEMF does not generate any current. If R = 0 in an ideal setup the current will rise indefinitely. This has been covered already.
If there is a small amount of resistance vs. no resistance at all, and you evaluate situations where the time frame you are examining is much less than the time constant, then there will be negligible differences in the current for the two setups. This has been covered several times already but I suppose that it did not stick.
This is exhausting, going over the same material over and over.
MileHigh
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Here is what I posted to Poynt yesterday....
"If so, then the ideal conductor doesnt require energy for electrons to be stripped from atoms and move them from atom to atom, jumping shell to shell. I can understand the seeming inertial effects of an inductor on electrons in its conductors, but not inertial effects of moving electrons on their own. This might incur that electrons have mass. And the seeming inertial effects of electrons of the inductor are when the field is collapsing. In this situation there is no field collapse or motion of the fields at all. So what mechanism keeps the electrons flowing in the loop? What energy is 'stored' that keeps the flow going? What form is the energy stored as?"
Mags
As already stated, the energy is physically stored in the magnetic field in the 3D space around the coil. Having a magnetic field in a given volume of space of a certain intensity takes real work. It is magnetically stressed space.
I don't have a real hard core answer for you. Just an observational answer. When you observe a self-contained magnetic field structure in 3D space, say a classic toroidal doughnut shape around a coil, at the heart of that magnetic field structure there must be some circulating electric current. That is what the structure is by definition, there are two components, but they are two parts of a single whole.
Electrons have mass, but the inertia associated with the moving mass is pretty insignificant. However, the moving electron also subtends a magnetic field around itself when it is moving. There is electrical inertia, i.e.; inductance associated with that also. I am willing to bet you that the mechanical inertia and associated mechanical energy of an electron in motion at a given velocity is only a tiny tiny fraction of the electrical inertia and magnetic energy associated with an electron in motion at the same speed. I am making a reasonable guess off the top of my head.
I am pretty sure the magnetic energy associated with an electron in motion is stated in the rationalized unit of the electron-volt. What is the mass of an electron, something like 1/1830th the mass of a proton or neutron?
I am not looking anything up, I am too tired.
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I have no clue what you really mean when you talk about "opposing current generated by the CEMF." The CEMF does not generate any current. If R = 0 in an ideal setup the current will rise indefinitely. This has been covered already.
If there is a small amount of resistance vs. no resistance at all, and you evaluate situations where the time frame you are examining is much less than the time constant, then there will be negligible differences in the current for the two setups. This has been covered several times already but I suppose that it did not stick.
This is exhausting, going over the same material over and over.
MileHigh
No,this has not been covered already.
The CEMF is created by the changing magnetic field,which is due to the increasing current over time,that was induced when the voltage was placed across the inductor
This CEMF creates a current flow that is in the opposite direction to that of which the applied voltage induced. The value of the current flow produce by the CEMF is less than that induced by the applied voltage. It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF. As you can see,the current produced by the CEMF ,is less than that of the induced current by the applied voltage. This means the remaining difference is flowing through the coil at the end of the first time constant. The greatest amount of CEMF is produced at T=0,and so the greatest amount of reverse current is produced. This is why the inductor draws the least amount of current at T=0-because the difference between the revers current from the CEMF,and the induced current from the applied EMF ,is at a minimum.
The CEMFs value,and so the value of reverse current,is dependant on how much the magnetic field is changing over time. As the magnetics field change over time slows,less reverse current is produced,as the CEMF value is less. This is why the current induced by the voltage starts to rise over time.
If the current is going to continue to rise-such as it would in your question,then the magnetic field would continue to increase at a steady rate. If the magnetic fields change in time is a constant (as it would be for your ideal coil),then the CEMF would also be at a steady value-as Poynt has answered.
The magnetic fields rate of change over time in a coil with no resistance,remains at a constant value,and that value is what it was at T=0--the instant the ideal voltage was placed across the ideal coil.
The current value will never increase from what it was as T=0,as the magnetic fields change over time remains at a constant value,and so the self induced EMF also remains at a constant value-->and there for,the reverse current also remains at a constant value.
So,regardless of what you believe, the answer to you question is--the current will not increase any higher than it was at T=0--regardless of the time the voltage is applied to the coil for.
Brad
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I have no clue what you really mean when you talk about "opposing current generated by the CEMF." The CEMF does not generate any current. If R = 0 in an ideal setup the current will rise indefinitely. This has been covered already.
If there is a small amount of resistance vs. no resistance at all, and you evaluate situations where the time frame you are examining is much less than the time constant, then there will be negligible differences in the current for the two setups. This has been covered several times already but I suppose that it did not stick.
This is exhausting, going over the same material over and over.
MileHigh
Ok. Another duh moment for me. Must have been thinking of photons. I dunno.
Hmm. inertia of electrons. I wonder. If we had a crt that was operating where electrons are attracted to the front screen, if we turned on and off the HV, would the electrons already firing toward the screen when the hv is off still make it to the screen. Just thinkin.
And for the say suspended mag field, when we produce a field with coils and such, when we take the input away, the field wants to shrink or collapse. It hard to realize how the field is the supporting part in the continued current flow.
Im off to bed. Think more on it tomorrow.
Mags
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...
The magnetic fields rate of change over time in a coil with no resistance,remains at a constant value,and that value is what it was at T=0--the instant the ideal voltage was placed across the ideal coil.
The current value will never increase from what it was as T=0,as the magnetic fields change over time remains at a constant value,and so the self induced EMF also remains at a constant value-->and there for,the reverse current also remains at a constant value.
So,regardless of what you believe, the answer to you question is--the current will not increase any higher than it was at T=0--regardless of the time the voltage is applied to the coil for.
Tinman,
You should research superconductors a bit.
It's a huge field to weed thru, but there is both normal inductance (L) and kinetic inductance (Lk) associated with superconductors.
The kinetic inductance, Lk allows for operation up to and into the THz region and is exploited in radar components, such as antennas and phase shifters. Lk allows low loss superconducting stripline techniques to be used rather than traditional and bulkier waveguides having more loss.
At lower frequencies where normal inductance applies, an 1800 RPM, 1MW, portable generator was constructed as a power source for a mobile radar system that uses superconductors in the rotor windings to reduce the generator's size.
Thousands of superconducting electromagnets (i.e., inductors) are in use everyday all over the world.
The field of zero resistance electronic components and specialized sensors is also a rapidly growing and heavily investigated field.
And then there is energy transport and storage, the list goes on...
You may argue that man made superconductors do not have a DCR of exactly zero. In some cases that may be true, particularly with respect to high temp SC's. Their resistance can range from 10-9 to 10-18 ohms of directly measured or calculated resistance. However, some low temp SC's, which were believed to be less than 10-28 ohms, the limits of measurement resolution (directly or by proxy), have since been measured by way of some rather unique methods that indicate they do indeed possess zero ohms of resistance.
The point I am making is that zero DCR inductors (and other components) are in use everyday all over the world. If an inductor made from a zero DCR conductor behaved as you propose, surely that would be a commonly known phenomenon by now.
Just food for thought...
PW
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Tinman,
You should research superconductors a bit.
It's a huge field to weed thru, but there is both normal inductance (L) and kinetic inductance (Lk) associated with superconductors.
The kinetic inductance, Lk allows for operation up to and into the THz region and is exploited in radar components, such as antennas and phase shifters. Lk allows low loss superconducting stripline techniques to be used rather than traditional and bulkier waveguides having more loss.
At lower frequencies where normal inductance applies, an 1800 RPM, 1MW, portable generator was constructed as a power source for a mobile radar system that uses superconductors in the rotor windings to reduce the generator's size.
Thousands of superconducting electromagnets (i.e., inductors) are in use everyday all over the world.
The field of zero resistance electronic components and specialized sensors is also a rapidly growing and heavily investigated field.
And then there is energy transport and storage, the list goes on...
You may argue that man made superconductors do not have a DCR of exactly zero. In some cases that may be true, particularly with respect to high temp SC's. Their resistance can range from 10-9 to 10-18 ohms of directly measured or calculated resistance. However, some low temp SC's, which were believed to be less than 10-28 ohms, the limits of measurement resolution (directly or by proxy), have since been measured by way of some rather unique methods that indicate they do indeed possess zero ohms of resistance.
The point I am making is that zero DCR inductors (and other components) are in use everyday all over the world. If an inductor made from a zero DCR conductor behaved as you propose, surely that would be a commonly known phenomenon by now.
Just food for thought...
PW
Ok,so we have our L ,as used to try and answer MHs question.
If the ideal coil is seen as a super conductor,then why was this !K! left out of all the measurements?.
As much as it may seem a waste of time to some,how about we go back to basics(that seem to be not so basic now),and determine a direct answer as to what stops the current flow through an inductor going straight to it's maximum value as soon as the voltage is placed across it.
My understanding is that the self induced EMF(CEMF) creates a current flow that apposes that which created it in the first place. The value of this CEMF is determined by the rate of change in time of the induced magnetic field.
The greatest rate of change in time for the magnetic field ,is at T=0-->the instant a voltage is placed across that coil,as we go from having no magnetic field,to one now existing at that point.
Then as time go's on,the rate of change of the magnetic field in time decreases.
This results in a lower value of this reverse current that is apposing the induced current by the applied voltage,and so the current flow through the inductor rises as the CEMF decreases over time.
Am i correct so far?.
And can we please forget about this ! a resistor creates a CEMF! rubbish.
P.S
I will add to this,that the reason that the resistance !seems! to increase with frequency,is because the magnetic fields change in time increases,and thus creates a larger CEMF in the inductor. What we are really doing,is bringing this overall change in time of the magnetic field,closer to that of the value it was at T=0. If we keep increasing the frequency,and thus increasing the rate of change over time for the magnetic field,we will reach a frequency where none/or very little current will flow through the inductor,as the increase in frequency has brought the rate of change of the magnetic field very close to what it was at T=0.
Brad
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You can accept it or not, but the actual reality is different and NOT covered in any textbook due to lack of need, and basic understanding. 2 other PhD's agree with me, but then quoted me one of Murphy's laws. "Never argue with a fool, people might not know the difference." In the context of this situation, they say I am the fool for expecting someone else's viewpoint to be even close to mine.
We know, the books are running years behind the ICE Tuning-Ateliers, this since years, the tuning Software even more, sorry!
With a Overlay in Exhaust and Inlet of a ICE, its a Serie-Cavity-Resonator, piece of Sheet-Metal called ........ is just a small part of the complete phenomena, what is almost not to catch in language its a understanding / knowing called Resonance, harmony and missing here grotesque!
To talk whit bookies, you have to talk there bookies-slang, other language than "The Haempstead" slang they don't willing understand.
OU is most dominated by RosaGlass-Followers, thinking they are in the lead, but out of compensation, and missing the best out of ........................ because of Dunnig-Kruger with a teacher syndrome!
Building NO.7!
Chemtrails!
Nasa!
Don't think, we do it for you!
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In your standard example of an EMF source driving a resistor in series with an ideal coil then what you MUST look at is the APPLIED EMF ACROSS THE IDEAL COIL, and not the unchanging EMF source before the resistor.
Why is this?
Because as more current flows through the resistor the resistor causes an EMF DROP.
The EMF drop results in a new lower EMF across the ideal coil.
The ideal coil responds to the lower EMF imposed across it with an equal CEMF.
The lower EMF and the lower CEMF MUST BE EQUAL because they are CONNECTED to each other.
I know that I am really just repeating myself, try to understand it this second time.
Yes I understand and tentatively agree - for a theoretical 'Ideal' Inductor this would likely be the case. Although I'm not certain it would be, but I have no real actual knowledge to say it wouldn't. I misread one of your posts and simply didn't see the word 'net' in regard to the applied emf to the inductor. Qe Sera.
The circuit I posted a link to however is a good example of modeling what happens with a real inductor, with the internal resistance separated out and represented as an independent element from the inductor, in order to show the effective response of the inducance and resistance to the applied emf. The purpose of their circuit is to show the variation of the level of cemf and the resistance/inductance/voltage relationship with applied emf.
The circuit they use shows a separate Inductor and series resistor. Any real inductor circuit diagram that is drawn to convey the combined effect of the inductance and internal resistance would be represented the same way. The inductor in series with the (internal) resistance, with the internal resistance depicted externally.
As I see it this applies to real inductors :
snip...There are 2 voltage drops for the inductor, one is the self-induced voltage which is opposite of the source making it a drop, and the other is the resistance of the conductor part of the inductor.So you would have Vdrop1+Vdrop2=Vsource,, which then would have Vdrop1 going down and Vdrop2 staying constant and then when in a steady state condition Vdrop1 is gone leaving only Vdrop2.So as long as there is an R in the inductor the self-induced voltage will be less than the source,, but Vdrop1+Vdrop2 (that would make for the entire inductor and self-inductance) would equal Vsource.
snip...
Which leads back to one of tinmans statements that : 'the emf must be greater than the cemf for current to flow', with my added caveat - 'in a real inductor.'
What will happen in an 'ideal' inductor is great debating material, however, almost all explanations could be considered equally valid simply because the ideal doesn't exist (except possibly - inductors made with superconductors?) and therefore any hypothesis relating to it is (currently) unfalsifiable. But 'ideal' hypothesis do give the brain matter something to chew on.
Cheers
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Cheers
Which leads back to one of tinmans statements that : 'the emf must be greater than the cemf for current to flow', with my added caveat - 'in a real inductor.'
Yes-for real(non ideal) inductors,we know this is true.
What will happen in an 'ideal' inductor is great debating material, however, almost all explanations could be considered equally valid simply because the ideal doesn't exist (except possibly - inductors made with superconductors?) and therefore any hypothesis relating to it is (currently) unfalsifiable. But 'ideal' hypothesis do give the brain matter something to chew on.
Indeed--what will happen?
The question deserved a better look than it go.
Instead of this being a thread to discuss the question as presented,the thread turned into a !!MH must be correct!! thread.
The mere fact that the coil has no resistance was in it self,worthy of a closer look. But it was just discarded,and so we removed the time constant from the equation,and went to plan B to find an answer.
We already know that the CEMF is what stops the current flowing through the coil,from shooting straight up to it's maximum value for that coil.
We also know,and have agreed on,that the current flowing through an ideal coil,with an ideal voltage across it,will rise in a steady state of increase for all time.
This can only mean that the magnetic field is changing at a steady state as well,and there for,the CEMF produced by that magnetic field will also be at a steady state.
So what dose happen from T=0s ?
Well,that is yet to be worked out,but i can tell you that it will not be the answer MH believes it should be,and that is the very reason that i said that i could(and did) provide the answer he wanted to see,but that i did not agree with that answer,or the equation used to get that answer.
The fact that the time constant is infinite,dose not just mean you dismiss it,and move onto another equation to derive at an answer you want to see.
Brad
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Here is what I posted to Poynt yesterday....
"If so, then the ideal conductor doesnt require energy for electrons to be stripped from atoms and move them from atom to atom, jumping shell to shell. I can understand the seeming inertial effects of an inductor on electrons in its conductors, but not inertial effects of moving electrons on their own. This might incur that electrons have mass. And the seeming inertial effects of electrons of the inductor are when the field is collapsing. In this situation there is no field collapse or motion of the fields at all. So what mechanism keeps the electrons flowing in the loop? What energy is 'stored' that keeps the flow going? What form is the energy stored as?"
Mags
The energy in an inductor is stored as the magnetic field.
Dos your question pertain to steady current and when the inductor is shorted?
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Loner
Quote
Take an "Ideal" voltage source, of any value. Connect to "Ideal" switch of SPST design. Connect this to an "Ideal" inductor. I hope I have not lost anyone, yet. This is for the "Minds" eye, as such components don't actually exist. Close to these "Ideals" is of no use in this explanation, just as 0 is 0, not some infinitely small number...
If the switch closes at Time = 0, as was mentioned here by someone, what is the situation that is REALLY happening. ( Common sense applies here, try to stay in the minds eye and remember "Imagination is more important than knowledge" )
At t=0, you have a voltage "appearing" at the leads of the inductor, before current has started to flow, and therefore BEFORE the CEMF has been generated by self inductance.
If someone wishes to argue that the current would "instantaneously" appear, then you wish to state that a current can appear that way in an inductor, which violates the "Laws" of an inductor. You can have it both ways at the quantum level, but not at the macro scale.
THIS is one of the errors in current thinking and math, because as t increases, the current increases. as current increases, it is the "Rate of change", NOT that actual amount, that is producing the CEMF. Again, if the CEMF were EXACTLY equal to the applied EMF, the "Rate of change" would be equal to 0, which then forces the CEMF to also drop. I am ignoring ALL external influences here. We ARE NOT talking about a wave or cyclic event, just the initial magnetic charge from 0. To put it another way, simply try to see HOW a totally empty inductor, with NO field, can produce any CEMF. There IS NONE UNTIL the current flows. It's not even a "Chicken and Egg" idea, it is just the reality.
Are we there yet? I am NOT talking about a large difference, nor could anyone on this forum (I'll wager...) say with absolute certainty WHERE that difference could be measured, Even if you used real circuit components, this Micro difference exists. It is how much of the math could be easily derived, as a figure so low can easily be ignored for any realistic calculation of components or values, but to blatantly state, "It does not exist" is to deny reality and common sense for people like me.
Snip
You can accept it or not, but the actual reality is different and NOT covered in any textbook due to lack of need, and basic understanding. 2 other PhD's agree with me, but then quoted me one of Murphy's laws. "Never argue with a fool, people might not know the difference." In the context of this situation, they say I am the fool for expecting someone else's viewpoint to be even close to mine.
end quote
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It was good to read all your contributions over the years , Thanks for all the work you shared and the level headed mindset
you brought along with it.
Loner has deleted all his posts and his acc't [or it will be shortly]
A sad day indeed.
ChetKremens@Gmail.com
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If not, then what is it,, if yes,, then why?
This part is not covered so well,, so I ask.
I think that is what I ended up saying,, that so long as there is an R in the inductor the CEMF from the inductor will be less than the source EMF
.
Exactly,and the R is the very reason the CEMF is less than the applied EMF,as some energy is lost due to resistive heat from both the applied EMF,and resulting CEMF.
The applied EMF looses some energy to R,and then the self induced EMF(the CEMF) looses some more to R-->this is why there is a value difference between the EMF and CEMF. We see this every day in transformer losses.
Does an ideal inductor have a relaxation time period?
Not sure what you mean there--relaxation period?
If you mean,is there a time delay between the applied voltage and current starting to flow,well we are dealing with propagations that happen at the speed of light,and it only seems like there is a delay between applied voltage and current flow,because the CEMF is creating a current flow in the opposite direction to that of the induced current flow,and so keeps the induced current flow down very low for a short time.
We can watch this all happen in real time--a time period as long as you want it,with a PM DC motor.
You place a voltage across that motor,and let it get up to running speed. We now have the magnetic fields greatest change in time in regards to the rotor windins. As we slow the motor down(place a load on it),we decrease the value of the magnetic fields change in time,as now the rotor windings are passing slower through the PM fields. We also know that the current flow through the rotor windings(coils) will increase when the rotor windings pass through the PMs magnetic fields slower--the change in the magnetic fields in time has decreased-it's the same dam thing. If we were to spin that motor faster than it's maximum unloaded speed,we would get a CEMF that is greater than the applied EMF,and the current would start to flow in the opposite direction. We know this is true,as we already have DC generators. Infact,i am rebuilding such a generator ATM,where it is both a motor,and a generator--see pics below.
We can take an inductor,and simulate a CEMF in that inductor on the bench-no problem at all,and very simple to show and do.
Brad
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Loner has deleted all his posts and his acc't [or it will be shortly]
If you look at his profile, he has 994 posts, so no I don't think he has deleted any of his posts.
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Poynt
please read here
Loner
Quote
I will not "Discuss" this and will probably not receive any reply as I have requested to Stephan that both my accounts and all posts be deleted, so this may not even get posted
Removing posts takes time !!
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No,this has not been covered already.
The CEMF is created by the changing magnetic field,which is due to the increasing current over time,that was induced when the voltage was placed across the inductor
This CEMF creates a current flow that is in the opposite direction to that of which the applied voltage induced. The value of the current flow produce by the CEMF is less than that induced by the applied voltage. It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF. As you can see,the current produced by the CEMF ,is less than that of the induced current by the applied voltage. This means the remaining difference is flowing through the coil at the end of the first time constant. The greatest amount of CEMF is produced at T=0,and so the greatest amount of reverse current is produced. This is why the inductor draws the least amount of current at T=0-because the difference between the revers current from the CEMF,and the induced current from the applied EMF ,is at a minimum.
The CEMFs value,and so the value of reverse current,is dependant on how much the magnetic field is changing over time. As the magnetics field change over time slows,less reverse current is produced,as the CEMF value is less. This is why the current induced by the voltage starts to rise over time.
If the current is going to continue to rise-such as it would in your question,then the magnetic field would continue to increase at a steady rate. If the magnetic fields change in time is a constant (as it would be for your ideal coil),then the CEMF would also be at a steady value-as Poynt has answered.
The magnetic fields rate of change over time in a coil with no resistance,remains at a constant value,and that value is what it was at T=0--the instant the ideal voltage was placed across the ideal coil.
The current value will never increase from what it was as T=0,as the magnetic fields change over time remains at a constant value,and so the self induced EMF also remains at a constant value-->and there for,the reverse current also remains at a constant value.
So,regardless of what you believe, the answer to you question is--the current will not increase any higher than it was at T=0--regardless of the time the voltage is applied to the coil for.
Brad
It's like you have regressed and you are back to some kind of whackadoo "Great Pumpkin" fantasy.
It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF.
So like if the 5th time constant current is 100 amps and the 1st time constant current is 25 amps then the reverse current produced by the CEMF is 75 amps. So does that mean when you first apply the voltage across the coil the current is -75 amps? It's "Attack from Planet Bizarro and the Pumpkin Patch Creatures."
As you can see,the current produced by the CEMF ,is less than that of the induced current by the applied voltage.
I can't see anything. I thought the current was -75 amps at the start.
The greatest amount of CEMF is produced at T=0,and so the greatest amount of reverse current is produced. This is why the inductor draws the least amount of current at T=0-because the difference between the revers current from the CEMF,and the induced current from the applied EMF ,is at a minimum.
I am totally confused. I tried every setting on my secret decoder ring and it's not able to unscramble what you are saying.
The magnetic fields rate of change over time in a coil with no resistance,remains at a constant value,and that value is what it was at T=0--the instant the ideal voltage was placed across the ideal coil.
The current value will never increase from what it was as T=0,as the magnetic fields change over time remains at a constant value,and so the self induced EMF also remains at a constant value-->and there for,the reverse current also remains at a constant value.
It's like you have completely regressed and this entire thread never happened.
Listen, when you apply voltage across a coil, the coil integrates the voltage with respect to time and the result of the integration is current flowing through the coil. It's like pushing on a shopping cart.
If the coil is a real coil then you have to account for the resistance. Then it becomes a slightly more difficult problem. Using standard mathematical techniques you solve for the circuit and you get the standard exponential equation that we all know that with a tiny bit of algebraic rearranging of some variables gives you a nice convenient time constant to work with.
That's all there is too it, a coil integrates on voltage to give you current just like a shopping cart integrates on force to give you velocity. It's just Mother Nature in action.
All of the stuff in your head about "battling currents" is a model that simply does not work. It's crazy talk. It's like something that you found in a pumpkin patch.
MileHigh
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Which leads back to one of tinmans statements that : 'the emf must be greater than the cemf for current to flow', with my added caveat - 'in a real inductor.'
What will happen in an 'ideal' inductor is great debating material, however, almost all explanations could be considered equally valid simply because the ideal doesn't exist (except possibly - inductors made with superconductors?) and therefore any hypothesis relating to it is (currently) unfalsifiable. But 'ideal' hypothesis do give the brain matter something to chew on.
Cheers
This is where switching over to a mechanical analogy can be so useful sometimes.
What is a real shopping cart?
The answer is that it is a shopping cart with friction in the wheel bearings.
What is a close approximation to an ideal shopping cart?
The answer is that you remove the wheels and you replace them with a very flat surface. The new shopping cart now sits on a giant "air table" just like you have for an air hockey game. In other words, the shopping cart is now floating frictionlessly on a cushion of air, just like a hovercraft.
So the question is this: Is it hard to imagine how the "ideal" shopping cart will respond when you push on it?
It's is very wrong to state that "we don't know what would happen if you have an ideal coil." Every time you use an equation for a coil to solve a problem about a circuit, it assumes an ideal coil. We know exactly how an ideal coil will respond. To attach some kind of attribute of "mysticism" to an ideal coil is a major mistake. It's just like some people rejected the idea that a voltage source could be variable in time.
Again, how does an ideal coil respond to a voltage stimulus?
Current(t) = (1/Inductance) * integral [Voltage(t)] dt
That is the real answer, we know this for certain. Any ideas that "we don't know what would happen with a true ideal coil because we can't make one" are false.
MileHigh
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Indeed--what will happen?
The question deserved a better look than it go.
Instead of this being a thread to discuss the question as presented,the thread turned into a !!MH must be correct!! thread.
As you can read in my posting to Hoptoad, it's a big mistake to believe that how a true ideal inductor will respond needs to be investigated further.
It's not a question of me being correct. I am just stating what you will find in any book on electronics or physics. So in effect, you are questioning "the system." More often than not, the system is right, and this is one of those times.
And you can't forget the fact that when people get educated in these matters, they still go through a step by step process where they investigate and test all of these things on the bench so they can see it for themselves in real life. These are not "eggheads in the sky" concepts, these are things that are real and tangible that people test and observe for themselves, as well as learning it in the classroom.
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Poynt
please read here
Loner
Quote
I will not "Discuss" this and will probably not receive any reply as I have requested to Stephan that both my accounts and all posts be deleted, so this may not even get posted
Removing posts takes time !!
I read that, yes.
I will be very surprised if Stefan deletes his posts.
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What was up with the Loner? He suggested quantum and I thought
that was a good idea..
I've enjoyed the analysis of the statement and feel I've learned
something.
John.
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I read that, yes.
I will be very surprised if Stefan deletes his posts.
Poynt
Stefan has always been polite and considerate of members requests ,not certain if he is Bound By Laws or his own moral standards.
But
yes he will delete them if asked By Loner
I have seen it happen many times before.
It takes him some time [apparently time consuming]
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The energy in an inductor is stored as the magnetic field.
Dos your question pertain to steady current and when the inductor is shorted?
Yes. See, I figured it would be the field is where the energy is stored, as is with real inductors. Its the idea that if there is that careful balance between the already induced emf and cemf that holds that balance after the short, as in, the inductor resists changes in current, then that may hold true for when we first apply the input and possibly no current would flow at all. Make sense?
Mags
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I don't really like the thread / forum without Loner.
I think, it is a good way to listen to Professionals with practical Experience.
Perhaps it is better to start a new topic for learning and understanding.
@ Root => Stefan.. Wood you like to insert a new Topic for learning and understanding?
Only my 2 cent in the round.
Love + Peace
3K
Sry for my bad English,
try to become better
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Poynt
Stefan has always been polite and considerate of members requests ,not certain if he is Bound By Laws or his own moral standards.
But
yes he will delete them if asked By Loner
I have seen it happen many times before.
It takes him some time [apparently time consuming]
Don't be surprised if not only will his posts not be erased, but his account may remain intact as well.
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I certainly hope you are right
He is such a good man and has a Bit of a legacy around here .
His experience , perspective , and attitude are really what we need more of ...not less of , his posts never disappointed and were always well thought out and heart felt.
with respect
Chet K
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snip...
The answer is that you remove the wheels and you replace them with a very flat surface. The new shopping cart now sits on a giant "air table" just like you have for an air hockey game. In other words, the shopping cart is now floating frictionlessly on a cushion of air, just like a hovercraft.
snip...
Even a hovercraft will still experience some resistance, however miniscule, from the air it passes through. It will also experience viscosity however miniscule. You can approach zero resistance and zero viscosity but never reach it except in an 'ideal' vacuum. However, in a vacuum, the hovercraft's mode of operation will be negated. Their is no 'ideal' in anything. As I said ,yes, we use ideal equations because they work for real world designing purposes, but the products of our designs will always have a real error margin built in to them however well they approximate the ideal design.
I've agreed with almost everything you've posted on real circuits except for your erroneous assertion that a voltage drop is the same as cemf. I disagree that we can know exactly how an ideal 'anything' will act, because their is no such thing as an ideal in an unideal world.
We can imagine, postulate and use provable math, ignore infinitesimally small values, reach high values of probability and a consensus of agreement - yet we can never 'know' it. We can only know what is real. The whole question of 'ideal' is no different to 'God'. We use all the evidence available to us to argue in favour or against, but will never 'know'. Not being able to know 'ideal' or 'perfection' is not mysticism, its reality.
Cheers
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author=MileHigh link=topic=16589.msg487063#msg487063 date=1466779069]
It's like you have regressed and you are back to some kind of whackadoo "Great Pumpkin" fantasy.
Lol--really ::)
Lets have a look at your next statement.
So like if the 5th time constant current is 100 amps and the 1st time constant current is 25 amps then the reverse current produced by the CEMF is 75 amps. So does that mean when you first apply the voltage across the coil the current is -75 amps? It's "Attack from Planet Bizarro and the Pumpkin Patch Creatures."
I think you had better do a refresher course in time constants,and the % of current at the end of the first time constant will be, of that of the end peak current flow at the fifth time constant-or the steady state current flow
Here is a blunt hint. The current will rise to 63.2% of it's steady state value after the first time constant. So in reference to your 100 amps steady state current flow ,after the first time constant,the current flow will be 63.2 amps.So the reverse current value at the end of the first time constant is 36.8 amps-not 75 amps as you say. God only knows where or how you came up with 25amps after the first time constant. I suspect it was from the same place you found that resistor that generates it's own CEMF :o
I can't see anything. I thought the current was -75 amps at the start.
If you keep coming up with those oddball numbers,derived from you wackadoo mathematics,then yes--you will never see nothing.
I am totally confused. I tried every setting on my secret decoder ring and it's not able to unscramble what you are saying.
It's like you have completely regressed and this entire thread never happened.
Indeed--you totally are.
It's like you have gone from some one with some intelligence,to some one that has defiantly drank to much coolaid. First you bring us the resistor that generates it's own CEMF,and now a new time constant calculation for inductors
If the coil is a real coil then you have to account for the resistance. Then it becomes a slightly more difficult problem. Using standard mathematical techniques you solve for the circuit and you get the standard exponential equation that we all know that with a tiny bit of algebraic rearranging of some variables gives you a nice convenient time constant to work with.
It would seem that you are unable to work with those standard mathematical techniques,and derive the correct % of current flow for each time constant.
That's all there is too it, a coil integrates on voltage to give you current just like a shopping cart integrates on force to give you velocity. It's just Mother Nature in action.
All of the stuff in your head about "battling currents" is a model that simply does not work. It's crazy talk. It's like something that you found in a pumpkin patch.
It is not pumpkin patch talk that dose not work,it is actual fact.
When a voltage is placed across a coil, the current will change quickly from zero. This change creates an expanding magnetic field around the coil, and when this happens,it induces a voltage back into the coil. This self induced voltage is known as back EMF,or CEMF,and creates a current flow in the OPPOSITE direction to the current flow that induced it in the first place. The result of this is that it slows the rate of change of the current that was induced from the voltage being placed across the coil(the impedance). If this initial rate of change were to continue in a linear fashion, the current would reach its maximum or steady state value in 5 time constants,where the time constant is T=L/R seconds.
MH
Every time you try and make me look bad,you only end up making your self look stupid.
Brad
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Even a hovercraft will still experience some resistance, however miniscule, from the air it passes through. It will also experience viscosity however miniscule. You can approach zero resistance and zero viscosity but never reach it except in an 'ideal' vacuum. However, in a vacuum, the hovercraft's mode of operation will be negated. Their is no 'ideal' in anything. As I said ,yes, we use ideal equations because they work for real world designing purposes, but the products of our designs will always have a real error margin built in to them however well they approximate the ideal design.
I've agreed with almost everything you've posted on real circuits except for your erroneous assertion that a voltage drop is the same as cemf. I disagree that we can know exactly how an ideal 'anything' will act, because their is no such thing as an ideal in an unideal world.
We can imagine, postulate and use provable math, ignore infinitesimally small values, reach high values of probability and a consensus of agreement - yet we can never 'know' it. We can only know what is real. The whole question of 'ideal' is no different to 'God'. We use all the evidence available to us to argue in favour or against, but will never 'know'. Not being able to know 'ideal' or 'perfection' is not mysticism, its reality.
Cheers
Yes, but there is no point in talking about the fact that there will be a very small resistance. I already qualify that in my comments. The first paragraph is not necessary.
To make things simpler, I already agreed that it makes sense to not call a voltage drop across a resistor CEMF. I stated that at least TWICE. So why are you and Brad stating that? Why?
We do know how an ideal inductor will work.
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When you first connect a conductor to a source nothing happens instantly,, I read somewhere at one time that this condition is called the relaxation time period and can be calculated.
If you had a long enough wire you could turn it on and then back off before this time period has been reached,, I read a small article on some people who used a large spool of coaxial cable to run this kind of test,, but I would think that the capacitance of that cable would also have an influence on such tests.
What information is propagating and how is it propagating,, has been one of those little niggles I think about from time to time.
Webby
We can switch an inductor on and off fast enough so as no current flows.
The propagation speed would have to be the speed of light-would it not?.
The reason you can see this with a long piece of wire,is because it has resistance and inductance,and so,it has impedance.
Even with a long straight piece of wire,you must form a loop to apply a voltage,and so now you have a single turn coil.
Brad
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Yes, but there is no point in talking about the fact that there will be a very small resistance. I already qualify that in my comments. The first paragraph is not necessary.
To make things simpler, I already agreed that it makes sense to not call a voltage drop across a resistor CEMF. I stated that at least TWICE. So why are you and Brad stating that? Why?
We do know how an ideal inductor will work.
Perhaps you could tell us all,as to why the current dose not shoot straight up to it's steady state value,when a voltage is place across it
What impedes on that current flow?
Brad
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Brad:
I think you had better do a refresher course in time constants,and the % of current at the end of the first time constant will be, of that of the end peak current flow at the fifth time constant-or the steady state current flow
Here is a blunt hint. The current will rise to 63.2% of it's steady state value after the first time constant.
That's a real doozie Brad. Let's see, I probably first learned about a time constant in 1977. Do you really think I don't know what the approximate values are? I was tired and just threw up some arbitrary numbers for illustrative purposes.
So here you are making a complete fool of yourself, a spectacle of yourself, by "pretending" that I don't know the approximate value of the first time constant. That's you cynically being an asshole for all to see.
You are such a little imp, I think you need a good spanking.
I suspect it was from the same place you found that resistor that generates it's own CEMF
Bad little imp boy! You read multiple times how I agreed that it is more appropriate to avoid that term for a resistor. Little imp boy needs another spanking, count down from 200.
First you bring us the resistor that generates it's own CEMF,and now a new time constant calculation for inductors
Now count down from 300.
It would seem that you are unable to work with those standard mathematical techniques,and derive the correct % of current flow for each time constant.
Now count down from 400. That's what you call beet red for being a bad boy.
When a voltage is placed across a coil, the current will change quickly from zero. This change creates an expanding magnetic field around the coil, and when this happens,it induces a voltage back into the coil. This self induced voltage is known as back EMF,or CEMF,and creates a current flow in the OPPOSITE direction to the current flow that induced it in the first place.
No it doesn't create a current flow in the OPPOSITE direction. That is a nonsensical idiotic fantasy that does not happen and you will never find a single stitch of evidence for that. It's a bad-old-days belligerent Brad fantasy.
The EMF source is say a battery, and the CEMF source from the coil looks like another battery. That's two EMF sources facing each other at the same potential and so NO CURRENT FLOWS towards the battery driving the coil. You have about as much electronics common sense as lumpy gravy. Your whackadoo fantasy story is completely and utterly ridiculous and after all the work that was done in this thread you should be embarrassed for regressing once again. Like I have told you, GET SOME ELECTRONICS BOOKS AND LOCK YOURSELF IN A ROOM FOR A MONTH AND READ THEM AND UNDERSTAND THEM.
very time you try and make me look bad,you only end up making your self look stupid.
Anybody can read this thread from the beginning through the end with a doorman's clicker, the type used to count the number of people in the club. Every time you have "a moment" the person can register a click. Seriously, you wouldn't want to know what the count was when they got to this very posting.
MileHigh
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Perhaps you could tell us all,as to why the current dose not shoot straight up to it's steady state value,when a voltage is place across it
What impedes on that current flow?
Brad
*CLICK*
You should not even be asking that question at this point in time.
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Yes, but there is no point in talking about the fact that there will be a very small resistance. I already qualify that in my comments. The first paragraph is not necessary.
To make things simpler, I already agreed that it makes sense to not call a voltage drop across a resistor CEMF. I stated that at least TWICE. So why are you and Brad stating that? Why?
We do know how an ideal inductor will work.
Put simply, we do not 'know' how an ideal inductor will perform, we 'theorize' how it will/should perform and in practice attain good approximations of the theory.
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author=MileHigh link=topic=16589.msg487098#msg487098 date=1466818180]
That's a real doozie Brad. Let's see, I probably first learned about a time constant in 1977. Do you really think I don't know what the approximate values are? I was tired and just threw up some arbitrary numbers for illustrative purposes.
What a whole lot of crap MH.
You threw those numbers up to make my explanation look wrong,but it is right,and you are a lyre.
So here you are making a complete fool of yourself, a spectacle of yourself, by "pretending" that I don't know the approximate value of the first time constant. That's you cynically being an asshole for all to see.
What it shows MH,is how deceitful you can be,in trying to make some one else look wrong.
But once again,i caught you out in your pathetic attempt at doing so.
You are such a little imp, I think you need a good spanking.
Bad little imp boy! You read multiple times how I agreed that it is more appropriate to avoid that term for a resistor. Little imp boy needs another spanking, count down from 200.
Now count down from 300.
Now count down from 400. That's what you call beet red for being a bad boy.
Your pathetic.
You are also no where big enough to give me any sort of spanking--you never have,and never will.
No it doesn't create a current flow in the OPPOSITE direction. That is a nonsensical idiotic fantasy that does not happen and you will never find a single stitch of evidence for that. It's a bad-old-days belligerent Brad fantasy.
Wrong again,as i can show it on my bench--no problem at all.
What you dont get,is that the reverse current flow is subtracted from the induced current flow,and you cannot separate the two,as one subtracts from the other,and all you see is the end resulting value.
The EMF source is say a battery, and the CEMF source from the coil looks like another battery. That's two EMF sources facing each other at the same potential and so NO CURRENT FLOWS towards the battery driving the coil.
And there you go--you just shot your self in the foot again.
You said that the CEMF is always equal and opposite to the EMF,but current will still flow.
Now you have just shown us all that if the CEMF and EMF are the same value,no current will flow lol ;--Good one MH ;)
You have about as much electronics common sense as lumpy gravy. Your whackadoo fantasy story is completely and utterly ridiculous and after all the work that was done in this thread you should be embarrassed for regressing once again. Like I have told you, GET SOME ELECTRONICS BOOKS AND LOCK YOURSELF IN A ROOM FOR A MONTH AND READ THEM AND UNDERSTAND THEM.
My lumpy gravy MH,is the same lumpy gravy that PW,Poynt,Hoptoad,and everyone else here are eating.
Sorry cobba--you have been outvoted on this one.
Anybody can read this thread from the beginning through the end with a doorman's clicker, the type used to count the number of people in the club. Every time you have "a moment" the person can register a click. Seriously, you wouldn't want to know what the count was when they got to this very posting.
I think you had better take a walk back in time MH,and see who has the most clicks against there name-->you win hands down.
We have had all sorts of wackadoo from you in this thread,and the JT thread--the latest being your attempt to discredit what i said about the CEMF current value being the difference between that of the peak current at each time constant,and the steady state current.
I was correct,and you were of in wackadoo land.
Here is what i said--It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF.
Here is your attempt to discredit my claim
Quote: So like if the 5th time constant current is 100 amps and the 1st time constant current is 25 amps then the reverse current produced by the CEMF is 75 amps. So does that mean when you first apply the voltage across the coil the current is -75 amps? It's "Attack from Planet Bizarro and the Pumpkin Patch Creatures."
As you can see,an idiotic attempt to discredit what i said,and the only bizarro comes from you.
You know dam well that if you had of used the correct values for each time constant,what i stated is absolutely true. But no,you had to pluck some incorrect numbers out of your wackadoo head,so as to try and make others believe that i dont know what im talking about--your pathetic.
The correct amounts using your 100 amp steady state current flow.
At the end of the first time constant,the current flowing through the coil will be 63.2 amp's,and the reverse current value from the self induced EMF will be 36.8 amps.
Perhaps PW,Poynt or Hoptoad would like to confirm what i said.
MH-face it--you got caught out again at trying to discredit me,and you had another epic fail-as you do often-->the latest being your CEMF producing resistor.
I was the first to tell you that is crap,and you gave me a mouthful,and said i had no idea what i was talking about. But then Poynt,PW,and Hoptoad had to slap some sense into you,and now you have admitted it was another stupid thing to say.
Keep going MH,your hole is getting deeper by the day.
Brad
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*CLICK*
You should not even be asking that question at this point in time.
Well not from you anyway.
Im fine with the question MH,but it seems you have a little trouble with it.
Im sure all the info you need to catch up,is out there for you to find.
Brad
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This is one of those times when it feels like it is completely and utterly hopeless with you Brad.
And there you go--you just shot your self in the foot again.
You said that the CEMF is always equal and opposite to the EMF,but current will still flow.
Now you have just shown us all that if the CEMF and EMF are the same value,no current will flow lol ;--Good one MH
*CLICK*
No current will flow into the battery due to the CEMF from the coil.
Current will flow due to the battery's EMF being imposed on the coil due to the nature of the coil.
But you are such an electronics simpleton sometimes that some basic critical thinking skills like looking at the situation from both perspectives is beyond your thinking capability. It's just hopeless.
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Well not from you anyway.
Im fine with the question MH,but it seems you have a little trouble with it.
Im sure all the info you need to catch up,is out there for you to find.
Brad
More making a complete fool of yourself, a spectacle of yourself, by "pretending."
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MH,
Tinman defined CEMF as follows:
When a voltage is placed across a coil, the current will change quickly from zero. This change creates an expanding magnetic field around the coil, and when this happens,it induces a voltage back into the coil. This self induced voltage is known as back EMF,or CEMF,and creates a current flow in the OPPOSITE direction to the current flow that induced it in the first place.
Were I grading papers, I would merely have scratched out the words I highlighted in bold above, and replaced "the OPPOSITE direction" with the word "opposition" so that it reads "creates a current flow in _opposition_ to the current flow", just to clarify and be a bit more precise.
If I wanted to nitpick at it a bit further, I might also have circled "CEMF" and wrote "preferred" next to it, and possibly replaced the word "coil" where used with the word "conductor" (unless the question specifically asked about a coil, and not just a generic inductor).
I would also have been tempted to insert "flowing through it" in the first sentence so that it reads "the current _flowing through it_ will change from zero".
However, I would have given full credit for his response, as it demonstrates a basic grasp of the concept.
I know the two of you have been at odds for some time, but the rather demeaning nature of your response seems a bit much.
PW
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No it doesn't create a current flow in the OPPOSITE direction. That is a nonsensical idiotic fantasy that does not happen and you will never find a single stitch of evidence for that. It's a bad-old-days belligerent Brad fantasy.
MileHigh
Quote Poynt post 1310
The point being, the cemf, no matter it's value, will effectively be shorted by the load. But as I explained there is no real consequence, because the resulting induced current does the job of limiting the current.
PW post 1333
By definition, the CEMF will oppose _current_ and in order to see the effects of CEMF (as defined), one must measure current.
PW post 1284
As well, it would seem that any device capable of producing a CEMF exactly equal to an applied EMF would prevent current flow.
Citfta post 1301
The CEMF is generated by the increasing magnetic field of the coil as the current rises. If your claim that the CEMF equals the EMF were true then no current would flow and that means the could NOT BE any CEMF. Sorry, but your argument makes no sense at all. I haven't read all the posts in this thread but it appears you are the only one that believes CEMF can equal EMF.
Poynt post 1218
The higher the inductance, the higher the induced cemf for a given frequency. At some point (either relatively large L or high frequencies) the cemf will equal the applied voltage (or it may be more correct to say the induced current will equal the applied current) and the net resulting current will be minimal.
Post 1208-your reply to me on a question i asked point
And you are still stuck. Surprise surprise. The CEMF is identical to the applied EMF. This was also covered in the thread multiple times.
Thankfully the rest of us here put an end to that rubbish.
Some links for you to study up on CEMF ,and what it is.
http://www.electronics-tutorials.ws/inductor/inductance.html
Quote: Lenz’s Law tells us that an induced emf generates a current in a direction which opposes the change in flux which caused the emf in the first place, the principal of action and reaction.
https://www.nde-ed.org/EducationResources/CommunityCollege/EddyCurrents/Physics/selfinductance.htm
Quote: Lenz's law states that an induced current has a direction such that its magnetic field opposes the change in magnetic field that induced the current. This means that the current induced in a conductor will oppose the change in current that is causing the flux to change.
http://web.mit.edu/viz/EM/visualizations/coursenotes/modules/guide11.pdf
Kirchhoff's Loop Rule Modified for Inductors:
If an inductor is traversed in the direction of the current, the “potential change” is
−L d( / I dt). On the other hand, if the inductor is traversed in the direction opposite of the
current, the “potential change” is +L d( I / dt).
I can post a lot more links to info MH,if you are still stuck.
Brad
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MH,
Tinman defined CEMF as follows:
Were I grading papers, I would merely have scratched out the words I highlighted in bold above, and replaced "the OPPOSITE direction" with the word "opposition" so that it reads "creates a current flow in _opposition_ to the current flow", just to clarify and be a bit more precise.
If I wanted to nitpick at it a bit further, I might also have circled "CEMF" and wrote "preferred" next to it, and possibly replaced the word "coil" where used with the word "conductor" (unless the question specifically asked about a coil, and not just a generic inductor).
I would also have been tempted to insert "flowing through it" in the first sentence so that it reads "the current _flowing through it_ will change from zero".
However, I would have given full credit for his response, as it demonstrates a basic grasp of the concept.
I know the two of you have been at odds for some time, but the rather demeaning nature of your response seems a bit much.
PW
Thank you PW.
I am willing to lean,but i am not willing to let MH make me look like i have no idea as to what is going on here.
I would like to have good standing with those around me,but MH is doing his best to discredit that good standing,and i just cant sit back from that,and i dont believe you,Poynt,or anyone else would either.
Brad.
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PW:
Yes, a coil will produce a CEMF when you connect a battery up to it. And the true definition of CEMF is based on the rate of the changing current flowing through the coil. But you kind of get in to a chicken and egg argument since it is the EMF from the battery itself that causes the changing current in the first place. So is it "allowed" to say that the battery's EMF is the cause of the CEMF, being aware that if it is a real coil they won't be equal?
The bottom line is that it is the battery that causes current to flow into the coil, and any talk about the CEMF causing current to flow into the battery, tangible or hypothetical, is wrong. We are talking about a simple single current loop here.
Brad can talk trash too, so don't always paint me as the "bad guy." Reading his crazy theory was extremely disappointing to me. It is what it is.
There is nothing wrong with making a very strong point sometimes, especially when it would appear almost nothing registered going the polite route for all these years. You won't even tell him in simple terms that he is wrong sometimes, like you are going to faint or something. Even though it is not your style, ultimately it's counter-productive for him. If I didn't scrap with him, he would still be completely lost like he was at the beginning of this thread. Direct talk sometimes has its merits.
In the final end game, if Brad is going to have his crazy theories, live and let live. It's just a chat forum.
MileHigh
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Thank you PW.
I am willing to lean,but i am not willing to let MH make me look like i have no idea as to what is going on here.
I would like to have good standing with those around me,but MH is doing his best to discredit that good standing,and i just cant sit back from that,and i dont believe you,Poynt,or anyone else would either.
Brad.
Fix this statement Brad to show you have an idea:
Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply.
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The bottom line is that the the battery causes current to flow into the coil, and any talk about the CEMF causing current to flow into the battery, tangible or hypothetical, is wrong. We are talking about a simple current loop here.
I do not recall Tinman suggesting that the CEMF was sufficient to actually reverse the flow of current and cause current to flow into the battery. Perhaps I missed that. Although a bit on the loose side where I pointed it out, his definition of CEMF was, for the most part, correct.
Brad can talk trash too, so don't always paint me as the "bad guy." Reading his crazy theory was extremely disappointing to me. It is what it is.
I do not "always paint you as the bad guy". I have always had a great deal of respect for the knowledge you bring to the table. But lately, you have become a bit "crotchety".
When the bulk of a response is just demeaning and derogatory insults, perhaps it is time to take a break.
Surely it is not worth all the emotional investment...
PW
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PW:
Pushing 100 thread pages to get Brad and others to understand how an inductor works and you get this from Brad:
----------------------------------------------------------------
[Part 1 from Brad]
If R=0, then the current will climb at a steady rate fo all time-right?--no-wrong.
If the flow of current from T=0 is going to rise at a steady state,then the apposing current generated from the CEMF will also rise at a steady state. So what dose that mean for the current induced by the applied voltage?
[Part 2 from Brad]
No,this has not been covered already.
The CEMF is created by the changing magnetic field,which is due to the increasing current over time,that was induced when the voltage was placed across the inductor
This CEMF creates a current flow that is in the opposite direction to that of which the applied voltage induced. The value of the current flow produce by the CEMF is less than that induced by the applied voltage. It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF. As you can see,the current produced by the CEMF ,is less than that of the induced current by the applied voltage. This means the remaining difference is flowing through the coil at the end of the first time constant. The greatest amount of CEMF is produced at T=0,and so the greatest amount of reverse current is produced. This is why the inductor draws the least amount of current at T=0-because the difference between the revers current from the CEMF,and the induced current from the applied EMF ,is at a minimum.
The CEMFs value,and so the value of reverse current,is dependant on how much the magnetic field is changing over time. As the magnetics field change over time slows,less reverse current is produced,as the CEMF value is less. This is why the current induced by the voltage starts to rise over time.
If the current is going to continue to rise-such as it would in your question,then the magnetic field would continue to increase at a steady rate. If the magnetic fields change in time is a constant (as it would be for your ideal coil),then the CEMF would also be at a steady value-as Poynt has answered.
The magnetic fields rate of change over time in a coil with no resistance,remains at a constant value,and that value is what it was at T=0--the instant the ideal voltage was placed across the ideal coil.
The current value will never increase from what it was as T=0,as the magnetic fields change over time remains at a constant value,and so the self induced EMF also remains at a constant value-->and there for,the reverse current also remains at a constant value.
So,regardless of what you believe, the answer to you question is--the current will not increase any higher than it was at T=0--regardless of the time the voltage is applied to the coil for.
Brad
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After nearly 100 thread pages and finally answering the famous question as well as all of us responding to hundreds of secondary questions and assuming that Brad finally had a decent grasp of the material, we get the comments above. I can barely comprehend some parts of the prose because it sounds to me like near-gibberish. However, it appears to be pretty clear that he believes that there is a "tangible reverse current" due to the CEMF somewhere in the mix when you connect a battery or EMF source to a coil.
Hence my frustration, and myself and Brad had a little mutual trash talk. I am very tempted to just walk away.
MileHigh
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MH,
I believe the "opposite" current that Tinman is discussing is with reference to the induced voltage that creates opposing currents as per the definition of CEMF. But again, I never read that to mean he believed the CEMF actually reversed the flow sufficiently to "charge the battery" so to speak.
As for the rest of what he is saying, well, that is why I suggested he consider looking into superconductors.
All conductors are inductors, and according to what he is saying, current could not flow through a length of superconducting wire (or at least no more than flows at T=0). So we kinda' know that can't be right.
There is nothing wrong with leading a horse to water, but...
PW
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author=MileHigh link=topic=16589.msg487109#msg487109 date=1466824385]
Yes, a coil will produce a CEMF when you connect a battery up to it. And the true definition of CEMF is based on the rate of the changing current flowing through the coil.
That is correct,and the CEMF is never the same value as the EFM,as you have stated on more than one occasion now that the EMF and CEMF are the same value ,you are wrong when you state that about inductors and motors.'
The bottom line is that it is the battery that causes current to flow into the coil, and any talk about the CEMF causing current to flow into the battery, tangible or hypothetical, is wrong. We are talking about a simple single current loop here.
No, one here has ever stated that current will flow back into a battery--this is a misleading comment by you,and you should retract it.
If you had bothered to take the time to read what i said,you would have seen that the reverse current value(the self induced current) is subtracted from the current induced by the voltage that is placed across the coil.
Brad can talk trash too, so don't always paint me as the "bad guy." Reading his crazy theory was extremely disappointing to me. It is what it is.
If your talking about what we are discussing here,now,about the self induced current,then it is not trash talk--it's just beyond your means of understanding.
There is nothing wrong with making a very strong point sometimes, especially when it would appear almost nothing registered going the polite route for all these years. You won't even tell him in simple terms that he is wrong sometimes, like you are going to faint or something. Even though it is not your style, ultimately it's counter-productive for him. If I didn't scrap with him, he would still be completely lost like he was at the beginning of this thread. Direct talk sometimes has its merits.
The only one here that is lost,is you MH,and that has been made apparent time after time.
You just cant handle the fact that i have been told by the top guys here ,that i am correct,and you are wrong.
In the final end game, if Brad is going to have his crazy theories, live and let live. It's just a chat forum.
The only crazy here,is you MH.
Brad
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MH,
I believe the "opposite" current that Tinman is discussing is with reference to the induced voltage that creates opposing currents as per the definition of CEMF. But again, I never read that to mean he believed the CEMF actually reversed the flow sufficiently to "charge the battery" so to speak.
As for the rest of what he is saying, well, that is why I suggested he consider looking into superconductors.
All conductors are inductors, and according to what he is saying, current could not flow through a length of superconducting wire (or at least no more than flows at T=0). So we kinda' know that can't be right.
There is nothing wrong with leading a horse to water, but...
PW
PW
I have never said that there would be a current flow going back into the battery.
Here is what i said
Quote post 1390-->What you dont get,is that the reverse current flow is subtracted from the induced current flow,and you cannot separate the two,as one subtracts from the other,and all you see is the end resulting value.
MH came up with this !reversed!(self induced current) current flow going back into the battery/power supply,when he tried once again to make me look like a fool,in post 1372-->
So like if the 5th time constant current is 100 amps and the 1st time constant current is 25 amps then the reverse current produced by the CEMF is 75 amps. So does that mean when you first apply the voltage across the coil the current is -75 amps? It's "Attack from Planet Bizarro and the Pumpkin Patch Creatures."
This was his response when i stated that-Quote:The value of the current flow produce by the CEMF is less than that induced by the applied voltage. It you take the peak current value that will be flowing at the 5th time constant,and you subtract from that the peak current value of the first time constant,you are left with the calculated reverse current produced by the CEMF. As you can see,the current produced by the CEMF ,is less than that of the induced current by the applied voltage.
So as you can see,MH plucked this !reverse current flow back into the battery! out from his own blunder on calculating what the current flow would be after 1 time constant,when the steady current flow value after the fifth time constant would have an end value of 100 amp's.
So now you see why these issues keep coming up,and a threads become 100's of pages long.
For me, there are only two outstanding issues and I will mention them again and I will put them in a better sequence this time:
1. MH gets up the learning curve , and clearly demonstrates that he understands what he is doing.
2. MH admits that he is wrong when he stated that my response to what CEMF is,how it creates a current that is in opposition to the induced current,and how it reacts against,or impedes upon the induced current,was incorrect.
Brad
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Quick setup showing the EMF and CEMF in a DC motor in real time,as a load is applied.
https://www.youtube.com/watch?v=SqPur5JUumg
Brad
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Can't really tell from the video. What interests me, is when the consumption goes to zero, and then negative. I experience zeroing of the consumption often...as seen from the meter of my supply, when this happens, it means that my "self-induced voltage" is higher than the applied, but unlike in your demonstration, my machine does not continue to motor strong.
Regards
Where you are saying "induced", the text books say "applied". That being said, the comparison is applied versus self-induced EMF (CEMF), applied versus self-induced current.
Current is not applied to the motor,it is induced by the applied EMF.
This leads me to ask where the energy is coming from that keeps your rotor running strong even after the consumption has gone to zero, because technically it shouldn't be.
Technically you'd be correct ;)
Regarding the inversion of the current, I would like to get into that, however, it would be best if you addressed my noted concerns, you aren't obligated to do so, I am just curious, and am probably one of the only ones who is really listening, to what you are saying and demonstrating "right now".
There are a few following this thread,so i dont think it will be missed lol.
During the video you state "as we increase the load on our motor...", you then adjust the pot. One speculates that the CEMF labeled motor, is functioning as a "generator", the load across it being the pot.
Yes,that is the load motor-(CEMF) motor,but as the self induced current increases past the value of the EMF induced current,then it becomes the motor,and the(EMF) motor becomes the generator,and so the current reverses through the CVR :D
Nothing special happening there ;)
Brad
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Current is applied to the motor, self-induction opposes, via an induced EMF, the build up of the applied current. In this wise, to say that it, the applied current, is "induced" by the applied EMF is inaccurate. Can you demonstrate current being "induced" by the applied EMF, using your present demonstration platform?
What is this thing you are calling "EMF induced current"?
Regards
While the term used may appear confusing, it is correct. You don't get current until a voltage source (EMF) is applied to a load circuit.
So the voltage (EMF) is applied to the load circuit, and this application of the voltage (EMF) to the load circuit induces a current to flow in the load circuit. So yes, the applied current is actually an EMF induced current.
Personally I would call the EMF induced current an applied current or source current, but it's really a semantic issue, which should be clarified by the context of the use of the term.
However, your confusion highlights yet again how everyone needs to be on the same page with terminology.
induce : meaning
ɪnˈdjuːs/verb
1.
succeed in persuading or leading (someone) to do something.
"the pickets induced many workers to stay away"
synonyms:persuade (https://www.google.com.au/search?client=opera&hs=Z07&q=define+persuade&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIHzAA), convince (https://www.google.com.au/search?client=opera&hs=Z07&q=define+convince&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIIDAA), prevail upon, get (https://www.google.com.au/search?client=opera&hs=Z07&q=define+get&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIITAA), make (https://www.google.com.au/search?client=opera&hs=Z07&q=define+make&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIIjAA), prompt (https://www.google.com.au/search?client=opera&hs=Z07&q=define+prompt&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIIzAA), move (https://www.google.com.au/search?client=opera&hs=Z07&q=define+move&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIJDAA), inspire (https://www.google.com.au/search?client=opera&hs=Z07&q=define+inspire&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIJTAA), instigate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+instigate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIJjAA),influence (https://www.google.com.au/search?client=opera&hs=Z07&q=define+influence&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIJzAA), exert influence on, press (https://www.google.com.au/search?client=opera&hs=Z07&q=define+press&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIKDAA), urge (https://www.google.com.au/search?client=opera&hs=Z07&q=define+urge&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIKTAA), incite (https://www.google.com.au/search?client=opera&hs=Z07&q=define+incite&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIKjAA), encourage (https://www.google.com.au/search?client=opera&hs=Z07&q=define+encourage&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIKzAA), impel (https://www.google.com.au/search?client=opera&hs=Z07&q=define+impel&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoILDAA), actuate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+actuate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoILTAA), motivate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+motivate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoILjAA);
2.
bring about or give rise to.
"none of these measures induced a change of policy"
synonyms:bring about, bring on, cause (https://www.google.com.au/search?client=opera&hs=Z07&q=define+cause&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIMzAA), be the cause of, produce (https://www.google.com.au/search?client=opera&hs=Z07&q=define+produce&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoINDAA), effect (https://www.google.com.au/search?client=opera&hs=Z07&q=define+effect&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoINTAA), create (https://www.google.com.au/search?client=opera&hs=Z07&q=define+create&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoINjAA), give rise to,generate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+generate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoINzAA), originate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+originate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIODAA), instigate (https://www.google.com.au/search?client=opera&hs=Z07&q=define+instigate&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIOTAA), engender (https://www.google.com.au/search?client=opera&hs=Z07&q=define+engender&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIOjAA), occasion (https://www.google.com.au/search?client=opera&hs=Z07&q=define+occasion&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIOzAA), set in motion, develop (https://www.google.com.au/search?client=opera&hs=Z07&q=define+develop&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIPDAA), lead to,result in, have as a consequence, have as a result, trigger off, spark off, whip up, stir up, kindle (https://www.google.com.au/search?client=opera&hs=Z07&q=define+kindle&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIPTAA), arouse (https://www.google.com.au/search?client=opera&hs=Z07&q=define+arouse&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIPjAA), rouse (https://www.google.com.au/search?client=opera&hs=Z07&q=define+rouse&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIPzAA), foster (https://www.google.com.au/search?client=opera&hs=Z07&q=define+foster&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIQDAA), promote (https://www.google.com.au/search?client=opera&hs=Z07&q=define+promote&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIQTAA), encourage (https://www.google.com.au/search?client=opera&hs=Z07&q=define+encourage&sa=X&ved=0ahUKEwiA6YKA_8LNAhXLnpQKHWsjCXgQ_SoIQjAA);
Cheers
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Brad:
How about just fixing this comment of yours:
<<< Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply. >>>
Can you do that?
MileHIgh
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Brad:
How about just fixing this comment of yours:
<<< Yea--good one MH--only we do not have a loop,we have a coil attached to a voltage supply. >>>
Can you do that?
MileHIgh
Yes, I do agree, that is a bit of a misnomer by Brad which he should acknowledge. Any load on a power supply of any sort (including a battery) that results in a current flow, be it a single wire or a coil across the terminals will create a full current loop within the supply and load.
Interestingly, a simple resistor connected directly across the battery will have the same voltage readings across it as the battery it is connected to and could be considered in parallel with the battery voltage, but the current from the battery through the resistor back into the battery is considered as taking a series path.
Cheers
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Quick setup showing the EMF and CEMF in a DC motor in real time,as a load is applied.
https://www.youtube.com/watch?v=SqPur5JUumg
Brad
Tinman,
I have always preferred using counter-EMF (CEMF) with regard to inductors and back-EMF (BEMF) with regard to the action of motors. If used interchangeably, one must be sure to indicate which action is being referred to within the context of its usage.
From the following Wiki:
https://en.wikipedia.org/wiki/Counter-electromotive_force
The term back electromotive force, or just back-EMF, is most commonly used to refer to the voltage that occurs in electric motors where there is relative motion between the armature of the motor and the magnetic field from the motor's field magnets, or windings. From Faraday's law, the voltage is proportional to the magnetic field, length of wire in the armature, and the speed of the motor. This effect is not due to the motor's inductance and is a completely separate effect.
PW
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Miles
absolutely lives for the "out of context" examples where the subject matter is self evident and profoundly obvious
but the ambiguity can be greatly enhanced and his EGO even more so if he can take twenty pages or more to show just how important he really is around here.
Miles has indeed formed a semantic EGO loop with several "Impotent feeds" to draw from...
this will truly Loop in perpetuity and most likely many more good Members will "CLICK"
their way out of this Forum [as Miles stamps errr Clicks another X for job well done .
Miles
Quote
"Can't wait to put an end to this once and for all"
oh, and Miles will be holding a spelling class next Tuesday
so we can do a better job on the OU Bench.....
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Like I already said Chet, I think it's really all about you stroking your own ego up and down and up and down to get some good resonant motion going.
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Miles
forgot to mention
I have to cancel on your Thursday night "folding your way to a better OU experimenter"
napkin folding class .
Yes ..
resonance was sooo misunderstood until you came along...
completely changed the way we do things around here...
Sooo helpful and informative !
I am signing up for your "Tying your way to a better OU Bench"
shoelace class for certain....
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Much to your chagrin Mr. Wannabee Ignorance Enforcer, indeed some people now understand what true resonance really is, and they understand what it is not. Resonance is NOT a timing delay device that results in better synchronous timing for a machine at one specific operational frequency. Stomp your feet or bang your head against the wall as much as you want, the truth will not change. I know that the spread of knowledge upsets you, so just go back to your hate and your polishing.
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OFF-Topic+++OT++OT
Hello Together,
i try to understand the ideal coil , ideal source question.
My math skills are very rusty and due to i need a refresh to understand the scientific discussion in this thread.
My question:
What is the meaning of "dA" ?
So far, i be able to remember it is a change of the area like a2*b2 - a1*b1 = Delta A [Rectangle]
What relationship dA is mentioned due to a magnetic field?
What kind of relation is dA in the context of magnetic fields?
Sry for the double question,
my English is not so good.
Try to become better
Thx for your answers.
Love + Peace
3K
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I don't wish to add fuel to any fire here but I do have a logical question. I will refer to the quoted portion below from Wikipedia's Counter-Electromotive Force.
Quote: "The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it. CEMF is the voltage drop in an alternating current (AC) circuit caused by magnetic induction (see Faraday's law of induction, electromagnetic induction, Lenz's Law). For example, the voltage drop across an inductor is due to the induced magnetic field inside the coil.[1][2] The voltage's polarity is at every moment the reverse of the input voltage.[1][3]"
Now I ask this, in a simple circuit with a supply having an inductor connected across it, how can you have CEMF in the inductor that is in opposite polarity to the applied supply voltage as stated above when the supply goes from 0 to some amount at T0 and remains for a period of time? Where is this CEMF hiding? How do I measure it? Or does it really exist in this example?
Curious minds wish to know!
pm
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Going back to my simplified example...
Given:
L=5H
V=+4V
What happens:
At t<0, XL=0
At t=0, XL=infinity, and the current rises from 0A linearly at 0.8A/s.
At t=1, XL=5 Ohms
At t=2, XL=2.5 Ohms
At t=4, XL=1.25 Ohms
i.e. with every doubling of "t", "XL" goes to 1/2 of previous value. XL never reaches 0 Ohms.
At t>0 when IL begins rising, an induced cemf of -4V is produced, based on Vcemf=L x di/dt. The cemf remains steady at -4V as long as di/dt stays at 0.8A/s. This of course occurs simultaneous with the application of 4V and the rise of IL.
The question is, if emf=cemf, would it not makes sense that this result is created through an equalizing process? The amps/s rate ultimately being determined by the applied voltage and the inductance values.
The equalization I refer to comes about via the simultaneous process of an applied emf that wants to drive a current, vs. a reactionary process that wants to lower that current. To me this is very much like a negative feedback mechanism commonly used in linear amplifiers. Your amplifier may have an inherent gain of 1000, but through the application of negative feedback, the gain is reduced to some desired level, such as 100. In the case of our self-inductance, the negative feedback mechanism is the self-induced current and B field, which happens to oppose the B field resulting from the applied voltage. It is not quite an exact analogy, but conceptually similar. It all happens in real time, simultaneously, and only the end result is observable.
Perhaps it comes down to an applied emf, vs. an induced E field. We know the applied emf is 4V, but can we break the induced cemf (equivalent to the E field) down any further? Well, for a multi-turn inductor we can divide the cemf by the number of turns to obtain the induced cemf per turn. To me this would represent the actual value of the E field circulating around the inductor. So if we have a total cemf of 4V, and a 1000-turn coil, the actual induced E field would be 4/1000 = 4mV. This does not sound like much, but with R=0, 4mV could drive a significant current in a single loop, and each loop would carry the same current. I'm sure the induced current can be derived from the E field (or B field) and rate of change.
Some things to perhaps think about anyway. Sorry there are no definitive answers here. Still thinking about this.
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Miles
quote
"They know what resonance really is..."
---------------------------------------------------
Oh goody we can put that in with Electricity , magnetism and gravity then....
I profoundly disagree Miles
the day we truly "Know what resonance is "and how to make it work in all materials for our benefit.
will be a very big day.
as Smokey 2 was teaching you earlier in this thread.
oh yeah
he's another one of your CLICKS
well done... well done Miles ..
I can feel the breeze of you patting yourself on the back from here...
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Chet, you are just being a pain in the ass. Now some people understand a resonating wine glass, or a bell, or a tuning fork. It's just a means to store energy, not create energy. Hate away all you want, your hate will change nothing.
Smokey2 was just a Big Fish story guy, nothing more than that.
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I apologize to the membership for my misguided Zeal.
there are truly good Points... being made here
.....
respectfully
and Back to my Bench
Chet K
PS
for clarity
I am not being "smarmy" here
it is a sincere apology to the members for interrupting useful dialog .
and I hope things can proceed with respect to all "opinions" .
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The equalization I refer to comes about via the simultaneous process of an applied emf that wants to drive a current, vs. a reactionary process that wants to lower that current. To me this is very much like a negative feedback mechanism commonly used in linear amplifiers. Your amplifier may have an inherent gain of 1000, but through the application of negative feedback, the gain is reduced to some desired level, such as 100. In the case of our self-inductance, the negative feedback mechanism is the self-induced current and B field, which happens to oppose the B field resulting from the applied voltage. It is not quite an exact analogy, but conceptually similar. It all happens in real time, simultaneously, and only the end result is observable.
I like where you're going with this...
PW
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It only happens in real time,simultaneously,and only the end result is observable.
Sounds good to me.
John.
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From this perspective I can appreciate whats being suggested, I still don't agree with it, however, an agreement isn't required for appreciation, and I do appreciate the whats being suggested. There are many things that folk in general aren't on the same page on, and that is the real problem.
It is great to see you hear, your work on the Adams motor was an inspiration to me.
Regards
Yes,it dose get confusing,but i am trying to stick to what actually happens when i use terms.
A voltage can exist without current flow,and you do not get current flow until that voltage is applied across the device.
So when you apply a voltage across a coil,a current is induced through that coil. This creates a magnetic field that then self creates the CEMF,and that in turn induces a !counter! current ,that apposes that which induced it in the first place.
But anyway,we all know what is being said ;)
Brad
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Tinman,
I have always preferred using counter-EMF (CEMF) with regard to inductors and back-EMF (BEMF) with regard to the action of motors. If used interchangeably, one must be sure to indicate which action is being referred to within the context of its usage.
From the following Wiki:
https://en.wikipedia.org/wiki/Counter-electromotive_force
PW
PW
I dont see the difference between the two? BackEMF or CounterEMF.
Most everything i read,says the two are one in the same,and mean the same thing-a coil subject to a magnetic field that changes in time.
Quote wiki-The counter-electromotive force (abbreviated counter EMF, or CEMF),[1] also known as the back electromotive force, is the voltage, or electromotive force, that pushes against the current which induces it.
I do realize that the DC motors i used will have the coils(windings) see two changing magnetic fields-one self induced,and one from the PMs,but still,is not the same thing happening,as in,the coils will still be subject to a magnetic field that changes in time?.
What is the outcome between a !Pushing! type DC PM motor,and a !Pulling! type DC PM motor? How dose that effect the terms being used?,and how dose it change the outcome,when both types will work as a generator as well,but each will subject the coils on the rotor to a different PM field.
One must also take care as to !what! PM field the coils are actually subjected to,in regards to the timing of the motor it self. There are a lot of people that dont actually know as to where each !two! coils are,that has the bulk of the current flowing through them,in relation to the two stator magnets(i am using my DC motors as reference,as they are two pole motors-two PMs)
For example here.
1-If we take a simple pulse motor,and we have our inductor producing a !north! field at the rotor end of that inductor,will the inductors CEMF value be changed if we have all the PMs on the rotor with there north field facing out(toward the inductor),so as the motor is a pushing motor,to that if we have all the south fields facing out(toward the inductor),so as the motor is a pulling motor.
We are to assume that the RPM will remain a constant between the two tests.
So what happens now is,one test,the field of the PM will be the same as the induced field,and so opposite that of what the CEMF wants to produce,and one will be the opposite that of the induced field,but the same as what the CEMF wants to produce.
2- Now,if i remove the rotor altogether,and i pulse that inductor with my FG,so as to simulate the switching of the coil to that of when the rotor was in play,will there be any difference in the efficiency or operation of that inductor?
This is something i can do,and have done many times on my bench.
The point being-how much difference do the stator magnets really make to the coils in that DC motor. Have people just decided that it is the stator PMs that are reducing the current flow,due to them(the PMs) being responsible for creating the backEMF,of have they just failed to realize that as the motor increases speed,that the coils are switching faster-much the same as raising the pulse frequency of a pulsed inductor?.
Brad
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Yes, I do agree, that is a bit of a misnomer by Brad which he should acknowledge. Any load on a power supply of any sort (including a battery) that results in a current flow, be it a single wire or a coil across the terminals will create a full current loop within the supply and load.
Interestingly, a simple resistor connected directly across the battery will have the same voltage readings across it as the battery it is connected to and could be considered in parallel with the battery voltage, but the current from the battery through the resistor back into the battery is considered as taking a series path.
Cheers
I already did,in post 1385
Quote: Even with a long straight piece of wire,you must form a loop to apply a voltage,and so now you have a single turn coil.
As we were talking about Kirchhoff's law at the time,i was referring to a single loop,as being one without a power supply attached-as it was in the tests i carried out with Poynt,where the current was induced into that loop by an external electric field that was not physically a part of the loop.
Brad
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PW
I dont see the difference between the two? BackEMF or CounterEMF.
Really?
The CEMF of an inductor causes the current to increase from a minimum after T=0
The BEMF of a motor causes the current to decrease from a maximum after T=0 (as the motor's RPM increases)
PW
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I already did,in post 1385
Quote: Even with a long straight piece of wire,you must form a loop to apply a voltage,and so now you have a single turn coil.
As we were talking about Kirchhoff's law at the time,i was referring to a single loop,as being one without a power supply attached-as it was in the tests i carried out with Poynt,where the current was induced into that loop by an external electric field that was not physically a part of the loop.
Brad
Sorry Brad, I missed that.
Cheers
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The fat lady sings.
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Really?
The CEMF of an inductor causes the current to increase from a minimum after T=0
The BEMF of a motor causes the current to decrease from a maximum after T=0 (as the motor's RPM increases)
PW
Yes,i know that. I stated that in my video.
But what is the difference as far as the mechanism go's?,in that, as the motor speeds up,the magnetic fields change in time increases,and the current decreases.
With the inductor,the fastest rate of change in time for the magnetic field ,is at T=0-the moment a voltage is placed across the inductor.
In both cases,it comes down to the rate of change of the magnetic field in time,only as i stated in my video,this change in time with the motor to that of the inductor is ass about--but the mechanism is still the same.
In saying that,do you know for sure that the PMs in a DC motor have any effect what so ever to the BackEMF value?.
Well we will soon find out,as i can measure this BackEMF value very accurately--i have found a way to do it ;)
Brad
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The fat lady sings.
Does she dance too? :P
Cheers
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Mmm-interesting.
A question for you all.
Regarding the BackEMF in a DC PM motor,such as the ones i am using in the previous video.
Is the bulk of the BackEMF a result of the PMs,or a result of the rising and falling current in the rotor winding's ?
I will await a day or two,before i post my video showing the result's.
MH-->what do you think? :D
Brad
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Mmm-interesting.
A question for you all.
Regarding the BackEMF in a DC PM motor,such as the ones i am using in the previous video.
Is the bulk of the BackEMF a result of the PMs,or a result of the rising and falling current in the rotor winding's ?
I will await a day or two,before i post my video showing the result's.
MH-->what do you think? :D
Brad
display the waveforms on a DSO. use a single coil to pulse... a 5V DC pulse can produce a sharp negative voltage of over 580v. the current as indicated on the DSO can still be positive.
This will have huge implications on the design of Pulse Motors.
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display the waveforms on a DSO. use a single coil to pulse... a 5V DC pulse can produce a sharp negative voltage of over 580v. the current as indicated on the DSO can still be positive.
This will have huge implications on the design of Pulse Motors.
How about you do it instead,and post your results on your own thread.
We all know about inductive kickback-or flyback,and that has nothing to do with the discussion ATM.
What is so great about the voltage inverting across an inductor,when the current flow is interupted?.
Brad
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Going back to my simplified example...
Given:
L=5H
V=+4V
What happens:
At t<0, XL=0
At t=0, XL=infinity, and the current rises from 0A linearly at 0.8A/s.
At t=1, XL=5 Ohms
At t=2, XL=2.5 Ohms
At t=4, XL=1.25 Ohms
i.e. with every doubling of "t", "XL" goes to 1/2 of previous value. XL never reaches 0 Ohms.
At t>0 when IL begins rising, an induced cemf of -4V is produced, based on Vcemf=L x di/dt. The cemf remains steady at -4V as long as di/dt stays at 0.8A/s. This of course occurs simultaneous with the application of 4V and the rise of IL.
The question is, if emf=cemf, would it not makes sense that this result is created through an equalizing process? The amps/s rate ultimately being determined by the applied voltage and the inductance values.
The equalization I refer to comes about via the simultaneous process of an applied emf that wants to drive a current, vs. a reactionary process that wants to lower that current. To me this is very much like a negative feedback mechanism commonly used in linear amplifiers. Your amplifier may have an inherent gain of 1000, but through the application of negative feedback, the gain is reduced to some desired level, such as 100. In the case of our self-inductance, the negative feedback mechanism is the self-induced current and B field, which happens to oppose the B field resulting from the applied voltage. It is not quite an exact analogy, but conceptually similar. It all happens in real time, simultaneously, and only the end result is observable.
Perhaps it comes down to an applied emf, vs. an induced E field. We know the applied emf is 4V, but can we break the induced cemf (equivalent to the E field) down any further? Well, for a multi-turn inductor we can divide the cemf by the number of turns to obtain the induced cemf per turn. To me this would represent the actual value of the E field circulating around the inductor. So if we have a total cemf of 4V, and a 1000-turn coil, the actual induced E field would be 4/1000 = 4mV. This does not sound like much, but with R=0, 4mV could drive a significant current in a single loop, and each loop would carry the same current. I'm sure the induced current can be derived from the E field (or B field) and rate of change.
Some things to perhaps think about anyway. Sorry there are no definitive answers here. Still thinking about this.
and the current rises from 0A linearly at 0.8A/s.
So we have a coil that is ideal--free from resistive losses.
We have a current that is going to follow a straight linear rise at 800mA/s
Our current dose not follow an exponential curve,as it would with a coil that has a resistance value.
This being true,it must also be true that the magnetic fields change it time would remain a constant value to that of the linear current rise,and that value would be the value it was at T=0--the instant the voltage was placed across the coil.
If the magnetic field is increasing/changing in time at a constant value,then the CEMF must also be doing the same. If the CEMF value is the same as the applied EMF,and the coil has no resistance,and cannot dissipate energy,then the reverse current flow must also be the same as the induced current flow.
The only reason we get an exponential current curve,is because real world inductors have a resistance value,and so some of the energy is dissipated as heat,and so the difference between the EMF and CEMF value. But an ideal coil has no resistance,and there for cannot dissipate energy,and so there is no loss associated with the CEMF value as there is in real world coils.
I really hope you have a closer look at this,because as i stated long ago,things are not the same when the coil/inductor is void of resistance.
Brad
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Perhaps consider the following:
a) emf = cemf = the E field times the number of turns.
b) If an inductor has 1000 turns, then the effective cemf to emf ratio is 1/1000.
c) per turn, the cemf is therefore much less than the applied emf.
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Perhaps consider the following:
a) emf = cemf = the E field times the number of turns.
b) If an inductor has 1000 turns, then the effective cemf to emf ratio is 1/1000.
c) per turn, the cemf is therefore much less than the applied emf.
And how can that be,when the EMF also see the same amount of turns.
Also,if this were true,dose this mean an ideal 1 turn coil will have an EMF to CEMF ratio of 1:1,and no current can flow.
I do not think that is right.
If the ratio was 1/1000,then the current would rise much faster.
There is also the fact that,the more turns you have,with the same current flow value,the greater the magnetic field. This results in a greater magnetic field,but the rate of change over time is still a linear constant-along with the induced current.
Are we skipping equal and opposite reactions,even though there is no dissipated power?
Brad
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Mmm-interesting.
A question for you all.
Regarding the BackEMF in a DC PM motor,such as the ones i am using in the previous video.
Is the bulk of the BackEMF a result of the PMs,or a result of the rising and falling current in the rotor winding's ?
I will await a day or two,before i post my video showing the result's.
MH-->what do you think? :D
Brad
I'll venture a guess.
I see 6 separate test conditions.
1. Locked rotor, no PM, no pole pieces.
Armature acts only as an inductor with CEMF, no BEMF, max I determined by RDC
2. Locked rotor, no PM but with pole pieces installed.
Similar to above but with larger inductance, CEMF only, no BEMF, max I determined by RDC
3. Locked rotor, with PM and with pole pieces installed.
As above but with larger inductance or shift in BH curve (saturation), CEMF only, no BEMF, max I determined by RDC
4. Spinning rotor, no PM, no pole pieces (no magnetic or conductive material in proximity to rotor, spun via external means)
Rotor acts as an inductor with modulated inductance and RDC, some noise, CEMF only, no BEMF, max I determined by RDC
5 Spinning rotor, no PM but with pole pieces installed, rotor spins as attraction motor
Rotor still has inductance but those effects are swamped by the BEMF now present. Max I determined by BEMF.
6. Spinning rotor, with PM and pole pieces installed, rotor spins as normal PM motor.
As above, max I determined by BEMF, more torque (or RPM) available for a given BEMF (current draw)
PW
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So we have a coil that is ideal--free from resistive losses.
We have a current that is going to follow a straight linear rise at 800mA/s
Our current dose not follow an exponential curve,as it would with a coil that has a resistance value.
This being true,it must also be true that the magnetic fields change it time would remain a constant value to that of the linear current rise,and that value would be the value it was at T=0--the instant the voltage was placed across the coil.
If the magnetic field is increasing/changing in time at a constant value,then the CEMF must also be doing the same. If the CEMF value is the same as the applied EMF,and the coil has no resistance,and cannot dissipate energy,then the reverse current flow must also be the same as the induced current flow.
The only reason we get an exponential current curve,is because real world inductors have a resistance value,and so some of the energy is dissipated as heat,and so the difference between the EMF and CEMF value. But an ideal coil has no resistance,and there for cannot dissipate energy,and so there is no loss associated with the CEMF value as there is in real world coils.
I really hope you have a closer look at this,because as i stated long ago,things are not the same when the coil/inductor is void of resistance.
Brad
Tinman,
Are you stating that you believe that the only amount of current that can flow thru an inductor with zero DC resistance is the amount of current that flows at T=0?
PW
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I'll venture a guess.
I see 6 separate test conditions.
1. Locked rotor, no PM, no pole pieces.
Armature acts only as an inductor with CEMF, no BEMF, max I determined by RDC
2. Locked rotor, no PM but with pole pieces installed.
Similar to above but with larger inductance, CEMF only, no BEMF, max I determined by RDC
3. Locked rotor, with PM and with pole pieces installed.
As above but with larger inductance or shift in BH curve (saturation), CEMF only, no BEMF, max I determined by RDC
4. Spinning rotor, no PM, no pole pieces (no magnetic or conductive material in proximity to rotor, spun via external means)
Rotor acts as an inductor with modulated inductance and RDC, some noise, CEMF only, no BEMF, max I determined by RDC
5
6.
PW
Only 5 and 6 are applicable for this test.
All we want to know is how much of the current draw reduction is due to the PMs being in place when the motor is spinning.
Spinning rotor, no PM but with pole pieces installed, rotor spins as attraction motor
Rotor still has inductance but those effects are swamped by the BEMF now present. Max I determined by BEMF.
If the PMs are removed,what BackEMF are you referring to ?.
The motor used is the same as the one on the right side of the pic below. When the magnets are removed,so too is the steel cylinder that housed them. The only thing left is the two bolts to hold the Ali bearing carriers together-see pic below.
Spinning rotor, with PM and pole pieces installed, rotor spins as normal PM motor.
As above, max I determined by BEMF, more torque (or RPM) available for a given BEMF (current draw)
So the first thing to do,was find the power draw of the motor free spinning(no load),as in standard trim-motor complete.
The second part of the test was to simply remove the magnets and the steel tube that housed them,so as we are left with the bare rotor. I then spun that rotor by way of the second motor seen in the pic below,at the same RPM(or very close to)as the motor was spinning in the first part of the test. This is so we know that the coils were switching at the same rate as they were in the first part of the test.
I was going to do various RPM test,but we will have to stick with just the one in this test :o
So now this is where it starts to get confusing PW,with you wanting to use BackEMF to denote the generating effects in a DC PM motor,and CEMF for pulsed/AC fed inductors.
You say in answer 5--> Rotor still has inductance but those effects are swamped by the BEMF now present.
If the magnets are now removed,where is this generated BackEMF coming from?
Brad
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Tinman,
Are you stating that you believe that the only amount of current that can flow thru an inductor with zero DC resistance is the amount of current that flows at T=0?
PW
The CEMF induced current is determined by the rate of change of the magnetic field in time--yes?
If as Poynt says,that the current will rise at a steady linear rate of 800mA/s,then it must also be true that the rate of change of the magnetic field in time will also change at that steady linear rate.That being the case,then the value of the CEMF,and there for the self induced current,must also rise at that steady linear rate--the joys of having no exponential current curve--no time constant.
As there is no time constant--the process is infinite,then the determined action/reaction is determined at T=0. The coil is also ideal,and there for dose not dissipate any energy,and so none is lost such as it is in a coil with resistance.
The answer given for MHs question is not correct,as the fact that there is no time constant ,was simply ignored--and it should not have been.
Having no time constant results in a steady linear climb in EMF induced current,and there for must also result in a steady climb in self induced current that is in opposition to that which created it.
Brad
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Only 5 and 6 are applicable for this test.
All we want to know is how much of the current draw reduction is due to the PMs being in place when the motor is spinning.
If the PMs are removed,what BackEMF are you referring to ?.
The motor used is the same as the one on the right side of the pic below. When the magnets are removed,so too is the steel cylinder that housed them. The only thing left is the two bolts to hold the Ali bearing carriers together-see pic below.
Your image looks like my test #4 conditions (although the two bolts remain in proximity to the armature).
The wording of the my test #4 conditions is with regard to elimination of induced eddy currents and their subsequent magnetic field.
Not knowing whether or not you would have pole pieces remaining, test condition #5 is without the PM's but with pole pieces remaining.
It looks as if you are comparing my test conditions #6 with something close to my test #4.
PW
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The CEMF induced current is determined by the rate of change of the magnetic field in time--yes?
If as Poynt says,that the current will rise at a steady linear rate of 800mA/s,then it must also be true that the rate of change of the magnetic field in time will also change at that steady linear rate.That being the case,then the value of the CEMF,and there for the self induced current,must also rise at that steady linear rate--the joys of having no exponential current curve--no time constant.
As there is no time constant--the process is infinite,then the determined action/reaction is determined at T=0. The coil is also ideal,and there for dose not dissipate any energy,and so none is lost such as it is in a coil with resistance.
The answer given for MHs question is not correct,as the fact that there is no time constant ,was simply ignored--and it should not have been.
Having no time constant results in a steady linear climb in EMF induced current,and there for must also result in a steady climb in self induced current that is in opposition to that which created it.
Brad
Again, to be clear, are you stating that you believe that the only amount of current that can flow thru an inductor with zero DC resistance is the amount of current that flows at T=0?
A simple yes or no would be most helpful.
PW
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The CEMF induced current is determined by the rate of change of the magnetic field in time--yes?
If as Poynt says,that the current will rise at a steady linear rate of 800mA/s,then it must also be true that the rate of change of the magnetic field in time will also change at that steady linear rate.That being the case,then the value of the CEMF,and there for the self induced current,must also rise at that steady linear rate--the joys of having no exponential current curve--no time constant.
As long as the current is rising at a steady rate of 0.8A/s, the cemf will be a steady 4V, it will not rise at a steady linear rate.
As there is no time constant--the process is infinite,then the determined action/reaction is determined at T=0. The coil is also ideal,and there for dose not dissipate any energy,and so none is lost such as it is in a coil with resistance.
The answer given for MHs question is not correct,as the fact that there is no time constant ,was simply ignored--and it should not have been.
Having no time constant results in a steady linear climb in EMF induced current,and there for must also result in a steady climb in self induced current that is in opposition to that which created it.
It is very unlikely anyone agrees with you. How are you going to prove this?
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As long as the current is rising at a steady rate of 0.8A/s, the cemf will be a steady 4V, it will not rise at a steady linear rate.
It is very unlikely anyone agrees with you. How are you going to prove this?
Ok -now we are getting somewhere.
If at T=0,4 volts is placed across the coil. The CEMF is also 4 volts as you state the moment current starts to flow.
So the outcome is?.-remembering that we have agreed (with the exception of MH-who seems to have his own ruels)that the CEMF has to be lower than the applied EMF in order for current to flow.
Brad
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Again, to be clear, are you stating that you believe that the only amount of current that can flow thru an inductor with zero DC resistance is the amount of current that flows at T=0?
A simple yes or no would be most helpful.
PW
Going on what has been discused so far,and Poynt has stated that the CEMF value will be 4 volts,then why would current flow if the CEMF value is the same as the applied EMF?
We have all agreed that if the CEMF was the same value as the EMF ,then no current would flow.
So why would this change now?.
It would seem there is a catch 22 situation here,and that is why i say the question deserves a closer look.
Brad
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Sorry, but you sound incredibly stupid. You have been playing with electronics all this time, for years, and you can't understand what a bloody voltage drop is?
MileHigh
\
.
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Ok -now we are getting somewhere.
If at T=0,4 volts is placed across the coil. The CEMF is also 4 volts as you state the moment current starts to flow.
So the outcome is?.-remembering that we have agreed (with the exception of MH-who seems to have his own ruels)that the CEMF has to be lower than the applied EMF in order for current to flow.
Brad
The net outcome is that the current rises at a rate of 0.8A/s.
The details of how this happens don't seem available, and I have been offering a couple of ideas of my own in previous posts.
Ultimately, the inductor acts just like a resistor, but one that changes its value over time as I have previously described in detail. So it exhibits a voltage drop across its terminals, and it acts as a current limiter, albeit a dynamic one.
The mechanism of exactly how the cemf equals the emf while still permitting current flow is still somewhat of a mystery.
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As long as the current is rising at a steady rate of 0.8A/s, the cemf will be a steady 4V, it will not rise at a steady linear rate.
The answer given for MHs question is not correct
It is very unlikely anyone agrees with you. How are you going to prove this?
You and others are going to do it for me ;). I only hope you and others will take the time to read all i have gathered,as i have taken the time to put it altogether. :)
Quote post 1218-Poynt
I think you have the basic concept, yes. Again, the fundamental frequency and the harmonic content influences how the inductor reacts. The higher the inductance, the higher the induced cemf for a given frequency. At some point (either relatively large L or high frequencies) the cemf will equal the applied voltage (or it may be more correct to say the induced current will equal the applied current) and the net resulting current will be minimal.
Quote post 1227-MH
So even though the battery is imposing its voltage on the coil, you need to be able to shift your perspective and go "inside" the coil and realize that the coil is pushing back with the same CEMF. The applied EMF and the CEMF from the coil must add up to zero. Therefore, the CEMF must be equal and opposite to the EMF.
Post 1231--Poynt
The voltage across the coil terminals does not change, it is determined by the voltage source. But the induced cemf is in series opposing with the voltage source Vin, and its value is determined by the frequency of Vin and the inductance L.
So, from this perspective the induced cemf is usually not equal to the applied emf (Vin). It is usually lower.
Then there is this confusing one by MH-post
I think that you are just going to confuse Brad with that diagram because he is going to see the CEMF being opposite the EMF
Then at the bottom of the same post,he say this
If you agree with this, then the CEMF is always equal and opposite to the applied EMF
So im lost with that one,as he says that i will get confused and think that the CEMF is opposite the EMF,and then go's on to say that it is ???
Post 1233--Poynt
I don't think he will assume that. I believe he knows that even though the induced emf (cemf) is opposite in polarity to that of the applied voltage, it will almost always be less, and therefore there will still be a net applied emf and resulting current.
Post 1282--Hoptoad,in reference to my statement--> if the CEMF was equal and opposite to the EMF,then the total voltage across the inductors terminals would be 0v,and no current would flow.
I agree. No potential difference, No current flow.
Post 1284 from PW
As well, it would seem that any device capable of producing a CEMF exactly equal to an applied EMF would prevent current flow.Consider two identical voltage sources connected in parallel (positive to positive, negative to negative). One Vsource represents EMF and the other Vsource represents CEMF. As long as both sources produce identical voltage, there will be no current flow.
Post 1297 from Hoptoad. I am going to post the link in that reply.
https://www.wisc-online.com/learn/career-clusters/stem/ace5903/an-inductor-opposing-a-current-change
You will see,if you follow the test pages,this statement.
Quote: At 1 time constant,the CEMF cannot be sustained,and after the first time constant,the counter voltage reduces by 63%.
As our coil is ideal,we have no time constant,and the counter voltage will remain at a steady 4 volt,s--as you stated Poynt.
Post 1301-Citfta
If your claim that the CEMF equals the EMF were true then no current would flow
Post 1308 from Weby-a link attached
https://books.google.com/books?id=9dsWAAAAQBAJ&pg=PA268&lpg=PA268&dq=Is+a+resistance+a+CEMF?&source=bl&ots=OmxEsMZ6B2&sig=21Hvbdp3lsZo50GzV2t_DlJF7Bc&hl=en&sa=X&ved=0ahUKEwiRq4-Tm77NAhVC9GMKHegBCcgQ6AEIMjAI
A quote from that book regarding a DC motor.
Quote: If the BackEMF is equal to the applied EMF,then no current will flow through that motor. As we know,an increase in BackEMF means a decrease in current draw from the motor--this i showed in my last video very clearly.
Post 1313 by Hoptoad
If the cemf was a steady value, all other factors would also be steady.
Post 1331-Poynt
One is called cemf because that is precisely what it is; i.e. it is a generated voltage in this case. Going around the loop is simply confirming KVL, and it always holds.
Post 1332-Poynt
Since the amps/sec is constant, the induced cemf should be steady.See post 1313 above from Hoptoad
Post 1333 from PW
As I responded to Tinman, if it were somehow possible to cause all the magnetic flux created by a current flowing thru an ideal conductor to be confined to, and cut thru, that conductor in such a way as to make the inductor's CEMF be equal to the EMF, I believe that inductor would have infinite inductance. To avoid the "chicken or egg paradox" in answering whether current could flow thru such an inductor, I stated that I believed that an infinitely small current would flow over an infinitely long period of time.
Post 1359--Loner
Again, if the CEMF were EXACTLY equal to the applied EMF, the "Rate of change" would be equal to 0,
Post 1363-Hoptoad
What will happen in an 'ideal' inductor is great debating material, however, almost all explanations could be considered equally valid simply because the ideal doesn't exist (except possibly - inductors made with superconductors?) and therefore any hypothesis relating to it is (currently) unfalsifiable. But 'ideal' hypothesis do give the brain matter something to chew on.
And post 1446-Poynt
As long as the current is rising at a steady rate of 0.8A/s, the cemf will be a steady 4V,
At T=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts
Post 1450-Poynt
The mechanism of exactly how the cemf equals the emf while still permitting current flow is still somewhat of a mystery.
Do i know what CEMF is?
To quote PW post 1399
Although a bit on the loose side where I pointed it out, his definition of CEMF was, for the most part, correct.
I believe that i have provided enough information by all here,that it is agreed upon,that if the CEMF value is equal to that of the applied EMF,then no current could flow.
It has also been concluded that the CEMF is Equal to the applied voltage at T=0.
In your last post Poynt(quoted above),you state that how the current can flow,when the CEMF value is equal to that of the applied EMF,is still a mystery.
So i ask-how is an accurate and correct answer gained from something yet unknown(the mystery),and also go's against all that most of us here believe to be true-even your self and PW ?.
You ask how am i going to provide proof to back up what i believe?. It would seem to me,that most of you here,are trying to find the proof that go's against all that has been stated in this thread-with the exception of MH,who provided a formula base around inductors/coils that have a resistance value.
I have spent the last 2 1/2 hours gathering all this information throughout this thread,and i only hope it dose not fall on death ears.
Brad
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I am also going to add post 15 from AC
In an ideal voltage source the source Emf would be fixed and an ideal inductor would have virtually no losses. It seems to me no current could flow because the moment a charge tried to moved due to the ideal voltage source Emf the ideal inductor would produce an equal and opposite Cemf to oppose it. Ideally if the source Emf is always instantaneously opposed by the inductors Cemf then nothing can move, a stalemate.
There is also a number of others that believe the same.
Just to make it clear,my first answer was incorrect
Quote: you cannot place an ideal voltage across an ideal inductor.
The reason being,at T=0,when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity. The reason this cannot happen,is because an ideal inductor dose not dissipate any power in the form of heat,due to the fact that it has no resistance or hysteresis loss,as it is an ideal inductor. If an ideal voltage was placed across an ideal inductor(in theory),it would result in an explosion the likes the universe has not seen since the creation of it-the big bang all over again.
It is clear that this is not the outcome,and i retract that answer,but it will remain as a reference as to where i started,and where i am now.
I am happy with my later answer,and until !!proven!! otherwise,remains my answer.
At T=0,no current flows,as the CEMF induced current keeps the EMF induced current in check.
If you happen to find the mechanism that allows current to flow,even though the CEMF is equal to that of the applied EMF Poynt,then we would have learned something together-along with everyone else on this thread.
Brad
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Perhaps we could stand back for a moment and consider the heretical idea of what we have if we remove Cemf from our single inductor analysis!
The formula for Emf is EMF = L*dI/dt and the formula for Cemf is Cemf = -L*dI/dt. Logically as has been stated, if Cemf = Emf then no current will flow in our inductor. But our inductor does exhibit inductance so therefore the Cemf must less than the Emf by a varying amount depending on the magnitude of the inductance. Does anyone have a derivation for this relationship?
OTOH, we can calculate the inductance of an air core single layer solenoid (neglecting fringing) with 𝑳 = 𝝻o × 𝒏^2 × 𝝿 × 𝙍^2 × 𝒍 where 𝒏 = 𝑵/ 𝒍. I used unicode characters to eliminate the confusion between small L for length of coil and I for current. We have no Cemf used here and the inductance is dependent on the coil's physical properties and the permeability of space.
Without the CEMF, we could say however that we have a fixed counter-magneto motive force or Cmmf due to the physical position of each wind to the others. Mmf = N*I and Cmmf = -N*I. The H field around the wire (synonymous with the flux field) is
H = N*I/𝒍 which tends to cancel or buck between adjacent windings and aids on the outside of the windings. As we move our winds closer together, the flux cancellation is greater yielding a higher inductance and as we move the windings farther apart, we have less cancellation resulting in a lower inductance. No Cemf required.
pm
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PM,
Let's not confuse the applied emf with the cemf. The induced cemf is L x di/dt, and it is negative due to Lenz's law. The applied emf is Vin, and is set by the input voltage, not the inductor.
The inductor voltage is often referred to as an induced emf, and that is fine as long as "induced" prefaces "emf". It is easier to just say cemf. The emf in our case is of course referring to the applied emf, or voltage source.
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With a non-ideal inductor, the voltage across the inductor is at a maximum upon t=0. The resistor may as well not be in the circuit at this instant (it could be replaced with a short). This is when the applied emf=cemf, and at this very instant, current begins to flow. Seems to me this is evidence that current can and does flow when the cemf=emf.
The only difference with the ideal inductor of course is that the full cemf is always across the inductor, and so it makes sense that the linear increase of current continues as long as the emf is applied, just as it does for the brief time in the non-ideal case just after t=0.
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Quote from: MileHigh on June 23, 2016, 02:43:33 PM (http://overunity.com/16589/mhs-ideal-coil-and-voltage-question/msg486974/#msg486974)
Sorry, but you sound incredibly stupid. You have been playing with electronics all this time, for years, and you can't understand what a bloody voltage drop is?
MileHigh
That graphic you made is cringe-worthy and nobody wants to touch it. All that you are doing is showing is how foolish or ignorant or stupid you can be. Like I told you, buy yourself a few books on basic electronics and lock yourself in a room for a month and read them and understand them. You definitely deserve the trash talk in this case.
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Just a few thoughts:
1. By stating that we are using an inductor of 5Hy, we have, by definition, stated that the inductor will produce a CEMF of 4 volts when the RATE OF CHANGE of the current flowing thru it is .8 amps per second. Any inductor that does not produce 4 volts of CEMF when the RATE OF CHANGE of the current flowing thru it is .8 amps per second is not, by definition, a 5Hy inductor.
2. When the 5Hy inductor is connected across the 4 volt Vsource, current flows until it reaches a rate of change of .8 amps per second at which time a CEMF of 4 volts is generated. When the inductor's CEMF equals 4 volts, the rate of change of the current flow drops towards zero amps per second. As the current flow's rate of change becomes less than .8 amps per second, the CEMF produced is also less than 4 volts. When the CEMF produced is less than 4 volts, current flow will again increase until it once again reaches a rate of change of .8 amps per second, causing the CEMF to again be 4 volts, which again reduces the rate of change of the current flow toward zero. This action continues for as long as the 4 volts is applied across the inductor.
3. Although the action above is described in a step wise fashion, those familiar with the use of negative feedback in analog circuits will easily visualize the above action as being a smooth, continuous, and self-regulating action that maintains a continuous .8 amps per second of rate of change thru the inductor.
4. Unlike a "normal" inductor, the magnitude of the current flowing thru an ideal inductor having zero DC resistance has no effect upon, that is, produces no deviation from, the as defined .8 amps per second rate of change necessary to generate 4 volts of CEMF (as evidenced by a linear increase in current).
5. With regard to a "normal" inductor that does have resistance, as the magnitude of the current flow changes, the IR related voltage drop produced by that current also changes. That voltage drop does affect, that is, causes the rate of change to deviate from, the as defined .8 amps per second rate of change necessary to generate a CEMF of 4 volts (as evidenced by a deviation from a linear increase in current).
6. Being more so an energy storage and retrieval mechanism, the reactance of an inductor is not a "dissipative" mechanism. Only whereby the inductor deviates from ideal (having resistance, etc.) is any energy stored or retrieved lost to dissipative mechanisms.
PW
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tinman,
how about measuring it? My guess is that you'd have to be quicker than C.
John.
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That graphic you made is cringe-worthy and nobody wants to touch it. All that you are doing is showing is how foolish or ignorant or stupid you can be. Like I told you, buy yourself a few books on basic electronics and lock yourself in a room for a month and read them and understand them. You definitely deserve the trash talk in this case.
I dont care how you wish to word it MH,as i am not bound by incorrect definitions such as it seems the EE world is,nor am i too worried about what you think. When a value drops,to me it means it is now lees than the supply value. If you have a drop in HP from that that is supplied,then you have less than that of what the motor is putting out. We get a drop in HP from the engine to the wheels,due to friction in the drive line-so less out than in as far as HP go's.
The resistor causes no drop in voltage to that being supplied-if the supply can provide the required voltage. So,regardless if that resistor is across the battery or not,there is no drop in voltage-the voltage remains at 2 volts.
Brad
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Just a few thoughts:
1. By stating that we are using an inductor of 5Hy, we have, by definition, stated that the inductor will produce a CEMF of 4 volts when the RATE OF CHANGE of the current flowing thru it is .8 amps per second. Any inductor that does not produce 4 volts of CEMF when the RATE OF CHANGE of the current flowing thru it is .8 amps per second is not, by definition, a 5Hy inductor.
2. When the 5Hy inductor is connected across the 4 volt Vsource, current flows until it reaches a rate of change of .8 amps per second at which time a CEMF of 4 volts is generated. When the inductor's CEMF equals 4 volts, the rate of change of the current flow drops towards zero amps per second. As the current flow's rate of change becomes less than .8 amps per second, the CEMF produced is also less than 4 volts. When the CEMF produced is less than 4 volts, current flow will again increase until it once again reaches a rate of change of .8 amps per second, causing the CEMF to again be 4 volts, which again reduces the rate of change of the current flow toward zero. This action continues for as long as the 4 volts is applied across the inductor.
3. Although the action above is described in a step wise fashion, those familiar with the use of negative feedback in analog circuits will easily visualize the above action as being a smooth, continuous, and self-regulating action that maintains a continuous .8 amps per second of rate of change thru the inductor.
4. Unlike a "normal" inductor, the magnitude of the current flowing thru an ideal inductor having zero DC resistance has no effect upon, that is, produces no deviation from, the as defined .8 amps per second rate of change necessary to generate 4 volts of CEMF (as evidenced by a linear increase in current).
5. With regard to a "normal" inductor that does have resistance, as the magnitude of the current flow changes, the IR related voltage drop produced by that current also changes. That voltage drop does affect, that is, causes the rate of change to deviate from, the as defined .8 amps per second rate of change necessary to generate a CEMF of 4 volts (as evidenced by a deviation from a linear increase in current).
6. Being more so an energy storage and retrieval mechanism, the reactance of an inductor is not a "dissipative" mechanism. Only whereby the inductor deviates from ideal (having resistance, etc.) is any energy stored or retrieved lost to dissipative mechanisms.
PW
PW
I guess that it could be looked at that way,but dose not resolve the fact that current still flows when there is no potential difference.
Also,why is this not true for a DC PM motor-such as the ones used in my video.
If the BackEMF is equal to the applied EMF,then the motor will not draw any current-or current will not flow through that motor. This i have-and can do again more accurately show on my bench.
BackEMF and CEMF are one in the same.
Inductive kickback is BackEMF. We are now saying that the inductive kickback from our ideal coil,will now give back the same amount of energy it took to create it,when the CEMF value is equal to the EMF value across that coil,as we have no I/R losses.
As far as i can work out,if the feedback is going to be the same as the applied,then the net power flowing is 0--we just end up with a tank circuit that keeps self oscillation.
Brad
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Anyway,here is a quick and dirty test i did on the BackEMF value the magnets play a part in,in regards to a DC PM motor.
It was going to be a much more accurate test,but lack of the needed equipment means we only got a !round about! value-you will see why.
https://www.youtube.com/watch?v=-Jf_daUOdy0
Brad
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PW
I guess that it could be looked at that way,but dose not resolve the fact that current still flows when there is no potential difference.
Simply stated, if there is no potential difference, no current flows. If no current flows, there is no CEMF... If there is no CEMF, there is a potential difference. If there is a potential difference, current flows. Ad infinitum...
Think about it a bit. An inductor's CEMF is a self regulating feedback mechanism dependent on the RATE OF CHANGE of the current flowing thru the inductor.
As for the rest, I would never state that an inductor's CEMF, a motor's BEMF, and "inductive kickback" (or flyback) are all identical.
PW
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Hello together,
i think that there is no electric field in the ideal Coil (super conductor coil).
If there where a(n) electric field inside, the current have to go to infinity.
In other words, over a super conductive wire is no voltage drop measurable.
A super conductive coil has N turns to build up the 5 Henry.
P lost= i²*R
I= U/R
If R = 0 also U=0
But this is only my personal assumption.
Love + Peace
3K
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PW:
Pushing 100 thread pages to get Brad and others to understand how an inductor works and you get this from Brad:
----------------------------------------------------------------
[Part 2 from Brad]
The CEMF is created by the changing magnetic field,which is due to the increasing current over time,that was induced when the voltage was placed across the inductor
This CEMF creates a current flow that is in the opposite direction to that of which the applied voltage induced.
-----------------------------------------------------------
However, it appears to be pretty clear that Brad believes that there is a "tangible reverse current" due to the CEMF somewhere in the mix when you connect a battery or EMF source to a coil.
Hence my frustration, and myself and Brad had a little mutual trash talk. I am very tempted to just walk away.
MileHigh
Lenz's law MH
Quote: If an induced current flows, its direction is always such that it will oppose the change which produced it.
Quote: Lenz's law states that when an emf is generated by a change in magnetic flux according to Faraday's Law, the polarity of the induced emf is such, that it produces an current that's magnetic field opposes the change which produces it.
This is something you should know by now MH.
Brad
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That graphic you made is cringe-worthy and nobody wants to touch it. All that you are doing is showing is how foolish or ignorant or stupid you can be. Like I told you, buy yourself a few books on basic electronics and lock yourself in a room for a month and read them and understand them. You definitely deserve the trash talk in this case.
Please feel free to take a DMM,and measure the voltage drop you speak of in a parallel circuit such as depicted in my diagram,and then post your results here,along with a diagram as to how you measured a voltage drop across the resistor.
Also please remember,that a voltage is a value of potential difference between two points,and a voltage is not a voltage drop.
Quote Fundamentals of electricity
Wires carrying current always have inherent resistance, or impedance, to current flow. Voltage drop is defined as the amount of voltage loss that occurs through all or part of a circuit due to impedance.
We could even add your CEMF producing resistor to this,and say that if there was an EMF drop of 2 volts across the resistor,then your equal and opposite CEMF would return that 2 volt's,and so the total loss across the resistor is 0--nothing. And so by your own analogy(the CEMF producing resistor),an equal and opposite reaction happens,and the voltage drop is counter acted,and so,no voltage drop took place.
Aint that a hoot MH--you killed your own claim. ;D
Brad
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I guess that it could be looked at that way,but dose not resolve the fact that current still flows when there is no potential difference.
There is no "potential difference" with a resistor yet current flows.
BackEMF and CEMF are one in the same.
Inductive kickback is BackEMF. We are now saying that the inductive kickback from our ideal coil,will now give back the same amount of energy it took to create it,when the CEMF value is equal to the EMF value across that coil,as we have no I/R losses.
Brad, IK is not the same as cemf or bemf.
As far as i can work out,if the feedback is going to be the same as the applied,then the net power flowing is 0--we just end up with a tank circuit that keeps self oscillation.
With standard feedback in amplifiers, even with 100% feedback the signal passes through at unity gain. Something to think about perhaps.
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There is no "potential difference" with a resistor yet current flows.
If there is no potential difference across a resistor,current will not flow through it--or did i miss something here?
Brad, IK is not the same as cemf or bemf.
IK is BackEMF.
All three are the result of the same action--a magnetic fields change over time,where the value is determined by the !rate! of change over time--among other things.
With standard feedback in amplifiers, even with 100% feedback the signal passes through at unity gain. Something to think about perhaps.
As the coil is ideal,then any energy put into that coil,should be returned,as an ideal coil cannot dissipate energy. So for example,if we put 100 joules of energy into that coil,we should get 100 joules of energy back out of that coil--one way,by IK collection.
Dose that sound right?
Brad
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Some quotes by MarkE
1-That is correct. BEMF resists changes in the current that any applied voltage attempts to drive.
2-Eddy currents induce voltage that opposes the driving voltage. They are about resisting current changes.
3-Generator BEMF is not inductive kickback. But inductive kickback is definitely BEMF.
4-BEMF is very simple: It is the EMF that results from changing magnetic flux crossing perpendicular to a conductor that acts in opposition to the applied voltage across the length of the conductor.
So from what i understand,is IK BackEMF,and BackEMF/CEMF are only set apart as IK is a separate function to that of motor BackEMF and CEMF,but although the function is separate,the function that gave rise to the IK is still the same--a magnetic fields change in time.
Brad
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If there is no potential difference across a resistor,current will not flow through it--or did i miss something here?
I presumed, perhaps incorrectly, that when you referred to "potential difference" you meant the difference between the emf and cemf. Was I wrong? If not, then replace the inductor with a resistor, now you have the same voltage across the voltage source as the resistor, yet current flows.
IK is BackEMF.
All three are the result of the same action--a magnetic fields change over time,where the value is determined by the !rate! of change over time--among other things.
IK generally refers to the terminal voltage when an energized inductor goes open.
As the coil is ideal,then any energy put into that coil,should be returned,as an ideal coil cannot dissipate energy. So for example,if we put 100 joules of energy into that coil,we should get 100 joules of energy back out of that coil--one way,by IK collection.
Dose that sound right?
Sure.
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A good net search reveals all of this...we have been up and down this road for years....whats next....Is this leading up to something? Doesn't feel like it is....
When is the perspective going to change so that folk can begin discussing something that leads to something practical?
Regards
Something is all screwed up Erfinder.
Seems now there is to much debating what is and what is not,and far less time building and research on the bench.
It seems the more you learn,the less things make sense.
Think im going back to the !old days!,and let my bench do the talking.
I dont even know why im here,talking about a situation that dose not exist ???
I went further forward just building and testing,that i ever have discussing that which dose not exist.
Anyway, a few new exciting devices coming up,and a couple that i have already started on-->and one big one hiding in the background,near completion ;)
In saying that,do you know how to cut Tungsten carbide ?
Brad
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Regarding the Emf (applied voltage) equaling the Cemf (induced counter-emf) in an inductor with the analogy of an amplifier with feedback raises some questions IMO. Having designed, built, and manufactured many types of amplifiers with various types of feedback loops thru the years, they all have a common summing point somewhere in the circuitry. This summing point is actually a current node where the input and inverted output voltages are converted to opposing currents in ratios to yield an overall amplifier gain that one desires. The higher the open loop gain, the more accurate the designed gain.
This all seems to fit our Emf=Cemf situation at first glance but I would like to know "where is the summing point" in a single inductor? If it exists it should be able to be shown mathematically.
We know that Emf (applied voltage to a coil) = L*dI/dt as we can easily prove this with experimentation. We can rearrange the formula to solve for any unknown variable with the remaining known factors, so we are again assured this formula is correct.
We also know that Lenz dictates that with an "induced" current, Cemf = -L*dI/dt and this again can be proven experimentally.
What is difficult for me to accept and understand is to say the the Emf=Cemf in a single inductor with a voltage applied for if they are equal mathematically, they cancel mathematically and no current flows. I have to agree with TM on this. I would be happy to see mathematical proof to the contrary.
The current in an inductor is in phase with the applied voltage to the inductor which fits the Emf equation above and this would seem to indicate that the EMF wins in the production of output current over the Cemf. If the two are in a feedback interaction as the amplifier analogy implies, what is the ratio that would produce these results? What magnitudes or Emf and Cemf would have to exist to satisfy the EMF equation? IMO, Cemf would have to equal zero or the equation is invalid!
So, IMO Cemf does not exist in a single inductor but Cmmf does as I posted earlier.
pm
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" In saying that,do you know how to cut Tungsten carbide ? "
Dear Brad.
You can use any Diamond edged cutting disc and plenty of water.
One of those motor powered ceramic tile cutters should do the trick.
Cheers Grum.
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During the course of the rioting more than 1000 oscilloscopes were destroyed.
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Regarding the Emf (applied voltage) equaling the Cemf (induced counter-emf) in an inductor with the analogy of an amplifier with feedback raises some questions IMO. Having designed, built, and manufactured many types of amplifiers with various types of feedback loops thru the years, they all have a common summing point somewhere in the circuitry. This summing point is actually a current node where the input and inverted output voltages are converted to opposing currents in ratios to yield an overall amplifier gain that one desires. The higher the open loop gain, the more accurate the designed gain.
This all seems to fit our Emf=Cemf situation at first glance but I would like to know "where is the summing point" in a single inductor? If it exists it should be able to be shown mathematically.
We know that Emf (applied voltage to a coil) = L*dI/dt as we can easily prove this with experimentation. We can rearrange the formula to solve for any unknown variable with the remaining known factors, so we are again assured this formula is correct.
We also know that Lenz dictates that with an "induced" current, Cemf = -L*dI/dt and this again can be proven experimentally.
What is difficult for me to accept and understand is to say the the Emf=Cemf in a single inductor with a voltage applied for if they are equal mathematically, they cancel mathematically and no current flows. I have to agree with TM on this. I would be happy to see mathematical proof to the contrary.
Partzman,
I would have thought anyone familiar with the concept of negative feedback would realize that my step wise description of the action of an inductor's CEMF was actually a smooth and continuous, self-regulating process.
Looking at slices in time, I could as well describe the action of the feedback resistor of an amplifier, emitter degeneration, or various other electronic, chemical, or mechanical feedback mechanisms in a step wise fashion, even though they may actually be a smooth and continuous process.
Regarding where the "summing junction" is will depend on your measurement reference point. The rate of current change dependent voltage that is the inductor's CEMF, appears across the inductor's terminals and is "summed with" the EMF applied across those terminals.
The two formulae you posted exactly describe the feedback mechanism related to CEMF. As well, both you and Tinman are indeed correct when you state that if the CEMF equals the applied EMF, no current will flow.
However, (in the 4V across 5H example discussed) the only time the CEMF is equal to the applied EMF of 4 volts is when the RATE OF CHANGE of the current flowing thru the inductor is .8 amps per second.
If, for example, the rate of current change were to become even slightly less than .8 amps per second, the generated CEMF would also become less than 4 volts, which would allow the current flow to increase until the .8 amps per second rate of change is again achieved. It is this feedback mechanism that regulates the rate of change of the current flowing thru the inductor to be .8 amps per second.
Although discussed in a rather step-wise manner, like the negative feedback in an amplifier or the degeneration of an emitter, it is a smooth and continuous process.
PW
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It looks as if by what PW is saying that for the 5hy inductor with
4 volts applied what MH is saying is true. Result!!!!
John.
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Partzman,
I would have thought anyone familiar with the concept of negative feedback would realize that my step wise description of the action of an inductor's CEMF was actually a smooth and continuous, self-regulating process.
Looking at slices in time, I could as well describe the action of the feedback resistor of an amplifier, emitter degeneration, or various other electronic, chemical, or mechanical feedback mechanisms in a step wise fashion, even though they may actually be a smooth and continuous process.
Yes I am familiar with the dynamics of negative feedback loops and agree with what you are saying here.
Regarding where the "summing junction" is will depend on your measurement reference point. The rate of current change dependent voltage that is the inductor's CEMF, appears across the inductor's terminals and is "summed with" the EMF applied across those terminals.
This is where I have a problem when we "sum" a positive applied voltage or Emf with any value of - voltage or Cemf other than zero and still maintain the fixed applied Emf. Are we saying that +4 + (-4) = 4?
The two formulae you posted exactly describe the feedback mechanism related to CEMF. As well, both you and Tinman are indeed correct when you state that if the CEMF equals the applied EMF, no current will flow.
However, (in the 4V across 5H example discussed) the only time the CEMF is equal to the applied EMF of 4 volts is when the RATE OF CHANGE of the current flowing thru the inductor is .8 amps per second.
Respectively this seems contradictory to me. How can we have any dI or rate of change of current if Emf=Cemf? Forgive me but I just can not wrap my head around that. If this is true, what mathematical expression will support this condition?
If, for example, the rate of current change were to become even slightly slower than .8 amps per second, the generated CEMF would also become less than 4 volts, which would allow the current flow to increase until the .8 amps per second rate of change is again achieved. It is this feedback mechanism that regulates the rate of change of the current flowing thru the inductor to be .8 amps per second.
Although discussed in a a rather step-wise manner, like the negative feedback in an amplifier or the degeneration of an emitter, it is a smooth and continuous process.
PW
To respond to this, I will repeat my last paragraph of my previous post-
"The current in an inductor is in phase with the applied voltage to the inductor which fits the Emf equation above and this would seem to indicate that the EMF wins in the production of output current over the Cemf. If the two are in a feedback interaction as the amplifier analogy implies, what is the ratio that would produce these results? What magnitudes or Emf and Cemf would have to exist to satisfy the EMF equation? IMO, Cemf would have to equal zero or the equation is invalid!
So, IMO Cemf does not exist in a single inductor but Cmmf does as I posted earlier."
I might add here that IMO the nexus or feedback summing point in a single inductor is at the physical interface between turns involving the bucking or cancellation of the H field or flux field.
pm
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It looks as if by what PW is saying that for the 5hy inductor with
4 volts applied what MH is saying is true. Result!!!!
John.
There was never any dispute that the voltage across the inductor was 4 volts when it was connected across an ideal voltage source of 4 volts.
However, the induced voltage associated with the CEMF of the inductor, as connected, can only be observed indirectly by measuring its effect on the current flowing thru the inductor and noting that the current increases at a specific rate.
The dispute was more so with regard to also referring to the voltage across a resistor as CEMF. Although I understand what MH was saying, I believe "CEMF" should be used only as defined with regard to inductors.
PW
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Yes I am familiar with the dynamics of negative feedback loops and agree with what you are saying here.
This is where I have a problem when we "sum" a positive applied voltage or Emf with any value of - voltage or Cemf other than zero and still maintain the fixed applied Emf. Are we saying that +4 + (-4) = 4?
Respectively this seems contradictory to me. How can we have any dI or rate of change of current if Emf=Cemf? Forgive me but I just can not wrap my head around that. If this is true, what mathematical expression will support this condition?
To respond to this, I will repeat my last paragraph of my previous post-
"The current in an inductor is in phase with the applied voltage to the inductor which fits the Emf equation above and this would seem to indicate that the EMF wins in the production of output current over the Cemf. If the two are in a feedback interaction as the amplifier analogy implies, what is the ratio that would produce these results? What magnitudes or Emf and Cemf would have to exist to satisfy the EMF equation? IMO, Cemf would have to equal zero or the equation is invalid!
So, IMO Cemf does not exist in a single inductor but Cmmf does as I posted earlier."
I might add here that IMO the nexus or feedback summing point in a single inductor is at the physical interface between turns involving the bucking or cancellation of the H field or flux field.
pm
My apologies Partzman, but I have done about the best I can to describe CEMF in terms of being a rate of current change dependent feedback mechanism.
Perhaps someone else can do better, I'll just be repeating myself...
PW
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PW understood when I mentioned negative feedback, that it was a similar process, not a process reflecting exactly what happens in an amplifier. I even stated that it was "similar". PW got it, others apparently took it literally, current summing nodes and all.
CEMF appears to behave as a negative feedback process. How is the nfg applied? It is applied via reverse induction caused by the circulating E field, which drives the inductor current in a direction opposing the current caused by the applied Vin.
And yes, it does appear that current can and does flow when the cemf=Vin.
Current flows if the inductor is replaced with a resistor. I think we all agree with that. The voltage across the resistor is a voltage drop. It is both a voltage drop and an induced emf in the case of the inductor however. The two values happen to be the same. It is not the induced emf that is driving the opposing current though. Simple proof supporting this is if the inductor was replaced with a 4V supply, there would be no current flow, period. The mechanism limiting the current therefore must be via an induced opposing current. The feedback mechanism is via the magnetic and electric fields, which relate directly to the current in the inductor. The two are inter-linked. If the current rises, the B field rises.
Clearly cemf is not the most suitable term for this scenario, it only confuses the issue. Even the official definitions don't make sense; "Increasing current in a coil of wire will generate a counter emf (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html#c2) which opposes the current." How does an emf oppose a current? An emf can only oppose another emf. Unless we are misinterpreting what "they" are saying. Opposing may not mean what many of us first and may still be assuming; that oppose as to actively "DRIVE" the circuit. Perhaps what they really mean is that the voltages oppose, just as the case with a voltage source and a resistor; i.e. it is a "passive" voltage drop only. The end result of the inductor's behaviour is that it behaves exactly like a dynamic resistor.
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The end result of the inductor's behaviour is that it behaves exactly like a dynamic resistor.
I am a bit uncomfortable with this statement.
The CEMF is a generated effect due to induction. A better visualization for the inductor's CEMF might be as a variable voltage source in series with a conductor. The voltage of the variable voltage source is constantly adjusted as necessary to maintain the .8 amps per second rate of change to the current flowing thru the conductor (with regard MH's applied 4 volts and 5H inductor).
PW
(Added: I am uncomfortable with the use of "dynamic resistor" as it seems to imply a dissipative mechanism)
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The end result of the inductor's behaviour is that it behaves exactly like a dynamic resistor.
I think we have to leave resistors of any kind out of this,as there is no such thing as an ideal resistor.
If a resistor did not dissipate energy,then it would have a resistive value of 0 ohms,and so,you have no resistor.
A resistor has no inductance,dose not store energy,and has resistance.
An ideal coil has inductance,dose store energy,and has no resistance.
The applied EMF see's the number of turns in the coil. The CEMF also see's the same number of turns in the coil.
As soon as the EMF induced current starts to flow,an equal and opposite CEMF produced current will start to flow,due to the fact that there are no losses associated to R.
The only reason the self induced current is of a lesser value to that of the EMF induced current in a real world inductor,is due to the losses associated to R in that inductor.
Brad
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I think we have to leave resistors of any kind out of this,as there is no such thing as an ideal resistor.
If a resistor did not dissipate energy,then it would have a resistive value of 0 ohms,and so,you have no resistor.
A resistor has no inductance,dose not store energy,and has resistance.
An ideal coil has inductance,dose store energy,and has no resistance.
The applied EMF see's the number of turns in the coil. The CEMF also see's the same number of turns in the coil.
As soon as the EMF induced current starts to flow,an equal and opposite CEMF produced current will start to flow,due to the fact that there are no losses associated to R.
Only when the RATE OF CHANGE of the current flowing thru the inductor equals .8 amps per second will the CEMF be equal to the applied EMF (with regard to the 4V applied to 5H). For an ideal inductor, it does not matter if the actual current flowing is 1 amp or 1000 amps. It is the RATE OF CHANGE that determines the CEMF.
The only reason the self induced current is of a lesser value to that of the EMF induced current in a real world inductor,is due to the losses associated to R in that inductor.
The resistance of a real world inductor is a source of error that causes the inductor's rate of change of the current flowing thru it to deviate from ideal (linear) and also limits the maximum current that can flow thru the inductor.
The formula for calculating the CEMF of an ideal inductor does not use or require a resistance.
PW
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I am a bit uncomfortable with this statement.
The CEMF is a generated effect due to induction. A better visualization for the inductor's CEMF might be as a variable voltage source in series with a conductor. The voltage of the variable voltage source is constantly adjusted as necessary to maintain the .8 amps per second rate of change to the current flowing thru the conductor (with regard MH's applied 4 volts and 5H inductor).
PW
(Added: I am uncomfortable with the use of "dynamic resistor" as it seems to imply a dissipative mechanism)
Yes,
I should have qualified that with the fact that from the current profile perspective it acts just like a resistor that changes with time. But of course it would dissipate energy while the inductor does not.
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The instant 4V is applied to the inductor, the cemf goes to -4V and current begins to flow.
In the case of an ideal inductor there is no trade-off with a resistor, therefore the cemf remains constant (and equal to Vin) as does the rate of rise of the current.
Are we all in agreement?
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The instant 4V is applied to the inductor, the cemf goes to -4V and current begins to flow.
In the case of an ideal inductor there is no trade-off with a resistor, therefore the cemf remains constant (and equal to Vin) as does the rate of rise of the current.
Are we all in agreement?
If we are measuring across the inductor such that we see +4 volts, I would say that when the +4 volts is applied across the inductor, current begins to flow and as soon as the rate of change of that current flow reaches .8 amps per second, the inductor's CEMF also becomes +4 volts (not -4 volts).
PW
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I disagree PW.
The instant current begins to flow and rise, it is already rising at 0.8A/s (there is no gradual or "reaching" rise in current to the level of 0.8A/s). But we may be saying the same thing.
As far as the polarity of the cemf, yes it is the same as Vin.
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The instant 4V is applied to the inductor, the cemf goes to -4V and current begins to flow.
In the case of an ideal inductor there is no trade-off with a resistor, therefore the cemf remains constant (and equal to Vin) as does the rate of rise of the current.
Are we all in agreement?
I think we are going around in circles here.
The question tryi g to be answered here,is how can it be,that the CEMF value,and the EMF value can be the same,but current still flows?.
What i thi k is being forgotten here is-there is no R value for the ideal coil,and there for,no loss or reduction in current value that is induced by the CEMF.
The very same holds true for the EMF induced current.
So,lets think about this.
If there was no CEMF,and there for no self induced current that apposes that which created it,and no resistance-as our coil is ideal,then when the 4 volts is placed across the coil,the current would rise instantly,to an infinite amount.
So now ,ask your self this-->what value would the self induced current have to be to limit an infinite amount of current flow?
You might think that was a stupid thing to ask,but this can be answered correctly and accurately with any real world inductor,at any point in time. But simply removing the coils winding resistance,throws a spanner in the works.
The reason that the self induced current value is always less than the EMF induced current in real world inductors,is because of the conducting wires resistance.
You take that resistance away,then there is no way any of the self induced currents energy can be dissipated,and there for it is equal and opposite to that which created it.
It is an assumption that the current is going to rise at .8 amps a second,because as you stated Poynt-the EMF and CEMF values are the same, and the mechanism that allows current to flow,is yet unknown.
How was a definitive current value given,when unknows exist?.
Brad
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I disagree PW.
The instant current begins to flow and rise, it is already rising at 0.8A/s (there is no gradual or "reaching" rise in current to the level of 0.8A/s). But we may be saying the same thing.
As far as the polarity of the cemf, yes it is the same as Vin.
I was just trying to clarify that the CEMF did not exist prior to, or reach 4 volts, until the rate of change was .8 amps per second, which for all practical intents and purposes, can be considered instantaneous.
Any rate of change faster or slower than .8 amps per second would generate a CEMF that is more than of less than 4 volts.
PW
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I think we are going around in circles here.
The question tryi g to be answered here,is how can it be,that the CEMF value,and the EMF value can be the same,but current still flows?.
Technically speaking, current would not flow if the CEMF and EMF were exactly equal. But then what would the rate of change of the current be? Zero volts per second, so no CEMF would be generated. With no CEMF, current would again flow until it reached .8 amps per second, at which time the CEMF would again equal the EMF, and the cycle would repeat. But it does not happen in this step-wise fashion, it is a smooth feedback type process where the CEMF is maintained as equal to the level of the applied EMF (or at the least, very, very close to it, if that helps with the visualization) so that the rate of change is .8 amps per second.
What i thi k is being forgotten here is-there is no R value for the ideal coil,and there for,no loss or reduction in current value that is induced by the CEMF.
The very same holds true for the EMF induced current.
No, the R value is not being forgotten, it just does not come into play with regard to the CEMF. The CEMF is an induced voltage. The CEMF equals 4 volts when the RATE OF CHANGE of the current flow is .8 amps per second (4V applied to 5H). Do not confuse the CEMF, which is a mechanism that determines the rate at which energy can be stored, with the actual amount of energy that is stored. And do not forget that the inductor is storing energy.
So,lets think about this.
If there was no CEMF,and there for no self induced current that apposes that which created it,and no resistance-as our coil is ideal,then when the 4 volts is placed across the coil,the current would rise instantly,to an infinite amount.
So now ,ask your self this-->what value would the self induced current have to be to limit an infinite amount of current flow?
As soon as the RATE OF CHANGE reached .8 amps per second, 4 volts of CEMF would be generated and effectively regulate/limit the rate of the current's rise to that .8 amps per second.
You might think that was a stupid thing to ask,but this can be answered correctly and accurately with any real world inductor,at any point in time. But simply removing the coils winding resistance,throws a spanner in the works.
The reason that the self induced current value is always less than the EMF induced current in real world inductors,is because of the conducting wires resistance.
You take that resistance away,then there is no way any of the self induced currents energy can be dissipated,and there for it is equal and opposite to that which created it.
You are wrong. Faraday says nothing about a required resistance or required dissipation. Resistance does not enter into it. If the rate of change of the current flowing thru the 5H inductor is .8 amps per second, the generated CEMF will be 4 volts. If the rate of change is less than .8 amps per second, the generated CEMF will also be less than 4 volts. And do not forget that with regard to an ideal inductor, we are not dissipating energy, we are storing/retrieving energy.
It is an assumption that the current is going to rise at .8 amps a second,because as you stated Poynt-the EMF and CEMF values are the same, and the mechanism that allows current to flow,is yet unknown.
How was a definitive current value given,when unknows exist?.
Brad
Consider reading this whole Wiki, but from the Wiki:
https://en.wikipedia.org/wiki/Inductor
So inductance is also a measure of the amount of electromotive force (voltage) generated for a given rate of change of current. For example, an inductor with an inductance of 1 henry produces an EMF of 1 volt when the current through the inductor changes at the rate of 1 ampere per second. This is usually taken to be the constitutive relation (defining equation) of the inductor.
PW
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Technically speaking, current would not flow if the CEMF and EMF were exactly equal. But then what would the rate of change of the current be? Zero volts per second, so no CEMF would be generated. With no CEMF, current would again flow until it reached .8 amps per second, at which time the CEMF would again equal the EMF, and the cycle would repeat. But it does not happen in this step-wise fashion, it is a smooth feedback type process where the CEMF is maintained as equal to the level of the applied EMF (or at the least, very, very close to it, if that helps with the visualization) so that the rate of change is .8 amps per second.
No, the R value is not being forgotten, it just does not come into play with regard to the CEMF. The CEMF is an induced voltage. The CEMF equals 4 volts when the RATE OF CHANGE of the current flow is .8 amps per second (4V applied to 5H). Do not confuse the CEMF, which is a mechanism that determines the rate at which energy can be stored, with the actual amount of energy that is stored. And do not forget that the inductor is storing energy.
As soon as the RATE OF CHANGE reached .8 amps per second, 4 volts of CEMF would be generated and effectively regulate/limit the rate of the current's rise to that .8 amps per second.
You are wrong. Faraday says nothing about a required resistance or required dissipation. Resistance does not enter into it. If the rate of change of the current flowing thru the 5H inductor is .8 amps per second, the generated CEMF will be 4 volts. If the rate of change is less than .8 amps per second, the generated CEMF will also be less than 4 volts.
Consider reading this whole Wiki, but from the Wiki:
https://en.wikipedia.org/wiki/Inductor
PW
The assumption is still being made , that the current value will continue to rise at 8 amps per second.
You seem to keep missi g the point i am making,and one that Poynt hast stated is yet to be understood.
At T=1 second,the EMF and CEMF are the same value. If at this point the current continues to rise,then it must be stated as to why the self induced current is of a lesser value than that of the EMF induced current,to allow current to continue to flow, when there is no potential difference across the coil
It would seem to me that making a claim to have a definitive answer,is very premature, when the mechanism is not yet known as to why the self induced current should be less than that of the EMF induced current.
Brad
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The assumption is still being made , that the current value will continue to rise at 8 amps per second.
You seem to keep missi g the point i am making,and one that Poynt hast stated is yet to be understood.
At T=1 second,the EMF and CEMF are the same value. If at this point the current continues to rise,then it must be stated as to why the self induced current is of a lesser value than that of the EMF induced current,to allow current to continue to flow, when there is no potential difference across the coil
It would seem to me that making a claim to have a definitive answer,is very premature, when the mechanism is not yet known as to why the self induced current should be less than that of the EMF induced current.
Brad
The CEMF is only less than the applied EMF of 4 volts when the rate of change of the current flowing thru the 5H inductor is less than .8 amps per second. At .8 amps per second the CEMF would equal the applied EMF. The generated CEMF is what limits the rate at which the current can rise to .8 amps per second.
It is not an assumption, it is the how and why inductors work like they do. Have you read the Wiki? Perhaps that will help.
I do not know how to explain the action of the inductor's CEMF any better than I already have several times now.
PW
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The CEMF is only less than the applied EMF of 4 volts when the rate of change of the current flowing the the 5H inductor is less than .8 amps per second. At .8 amps per second the CEMF would equal the applied EMF. The generated CEMF is what limits the rate at which the current can rise to .8 amps per second.
It is not an assumption, it is the how and why inductors work like they do. Have you read the Wiki? Perhaps that will help.
I do not know how to explain the action of the inductor's CEMF any better than I already have several times now.
PW
PW
You are still missing the point,and you have not yet explained why current would continue to rise when there is no potential different across the coil.
I understand that in order to have a CEMF valje equal to that of the applliex EMF value,that the current must rise at .8 amps per second.
The point is,the current is rising at that rate from T=0-not just from T=1s
So,as soon as that 4 volts is placed across that inductor,a CEMF of 4 volts exist..From the moment of connection,there is no potential difference across that coil,and so the only way a current could flow,is if the self induced current is of a lower value than that of the EMF induced current.
So-i am asking why the self induced current is a lesser value than the EMF induced current,so as current can flow.
I might also add that Faraday never had a means to determine the outcome of the stated question this thread is about..
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PW
You are still missing the point,and you have not yet explained why current would continue to rise when there is no potential different across the coil.
I am not missing the point. Current would not continue to flow if there was no potential difference, but then there would also cease to be any CEMF, so current would again increase until the rate of change was .8 amps per second and the CEMF was again equal to the EMF. Repeat continuously... But it does not happen in this step wise manner, it is a smooth analog feedback mechanism.
I understand that in order to have a CEMF valje equal to that of the applliex EMF value,that the current must rise at .8 amps per second.
The point is,the current is rising at that rate from T=0-not just from T=1s
So,as soon as that 4 volts is placed across that inductor,a CEMF of 4 volts exist..
A CEMF of 4 volts will exist as soon as the rate of change of .8 amps per second is achieved
From the moment of connection,there is no potential difference across that coil,and so the only way a current could flow,is if the self induced current is of a lower value than that of the EMF induced current.
Just prior to the connection there is no CEMF. As soon as the EMF is applied current begins to flow and as soon as the rate of change of .8 amps per second is reached, a CEMF of 4 volts is generated.
So-i am asking why the self induced current is a lesser value than the EMF induced current,so as current can flow.
I might also add that Faraday never had a means to determine the outcome of the stated question this thread is about..
This rate of change and CEMF thing, as well as Faraday and Lenz, is all wrapped up in the very definition and quantification of an inductor. So yes, it does refer to the question asked.
Perhaps this will help:
Consider two ideal voltage sources connected in parallel. If both are set to output 4 volts (EMF=CEMF), no current will flow.
How much less than 4 volts would one of the supplies have to be to allow an infinite amount of current to flow?
Consider what would happen if the voltage of one supply is set to be even an infinitesimal amount less than 4 volts.
So, to regulate the current flow so that it is increasing at exactly .8 amps per second, how far from 4 volts would you ever be?
If you are familiar with negative feedback mechanisms, the action of an inductor's CEMF as a regulator of the current's rate of change should be fairly easy to grasp. If not, after all this, I doubt i would have the patience to explain emitter degeneration or the like. I know you are capable of understanding this, and I am at a loss as to why you do not.
Please read my posts again where I describe the action of the CEMF in a step-wise fashion. The part you appear to be having difficulty grasping is the smooth continuous action of the CEMF as a feedback mechanism that maintains the .8 amps per second rate of change.
Consider the CEMF to "hover" between the 4 volt value and just below it if you must to help visualize the feedback mechanism. Once you can grasp it that way, it will be easier to see the smooth continuous action.
Being able to understand this as a feedback mechanism will be useful in other areas of electronics as well...
PW
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author=picowatt link=topic=16589.msg487380#msg487380 date=1467185200]
I am not missing the point. Current would not continue to flow if there was no potential difference, but then there would also cease to be any CEMF, so current would again increase until the rate of change was .8 amps per second and the CEMF was again equal to the EMF. Repeat continuously... But it does not happen in this step wise manner, it is a smooth analog feedback mechanism.
So,as the CEMF is equal to the applied EMF at the instant the voltage is placed across the resistor,then the outcome is what?-->how have you decided that the EMF wins over the CEMF,when both forces are the same(if we are to stick with voltage as being a force),and acting in opposition.
So thats all im asking--how have you decided that the current can flow,when there is no potential difference?.
A CEMF of 4 volts will exist as soon as the rate of change of .8 amps per second is achieved
Just prior to the connection there is no CEMF. As soon as the EMF is applied current begins to flow and as soon as the rate of change of .8 amps per second is reached, a CEMF of 4 volts is generated.
PW
The rate of change to the value of .8 amps per second is instant--there is no waiting for this rate of change value to reach .8 amps per second--it is there as soon as there is an EMF--a voltage placed across the inductor.
Quote Poynt: The instant 4V is applied to the inductor, the cemf goes to -4V and current begins to flow.
That statement by point makes no sense when you read it.
We have no potential difference,but current begins to flow ???
This rate of change and CEMF thing, as well as Faraday and Lenz, is all wrapped up in the very definition and quantification of an inductor. So yes, it does refer to the question asked.
So which one(Lenz or Faraday) placed an ideal voltage across an ideal coil of 5H,to quantify there law stands with ideal coils/inductors.
Why dose every circuit model of a circuit that includes an inductor,have a series resistor associated with it?.
Perhaps this will help:
Consider two ideal voltage sources connected in parallel. If both are set to output 4 volts (EMF=CEMF), no current will flow.
How much less than 4 volts would one of the supplies have to be to allow an infinite amount of current to flow?
Ah,ok.
Well the difference would only have to be minute--> i dont have enough time to place that many 0's before the decimal point,and even then,we would be no where near as low as we needed to be,before the current flow would no longer be an infinite amount.
When you start to talk about infinite amount's,there is no !just a bit less!--math simply cannot deal with divisions,subtraction,additions or fractions of infinite--there simply is no such math.
It's like asking how long it will take to walk around a circle,and reach the end,where there is no end to a continuous loop.
If you are familiar with negative feedback mechanisms, the action of an inductor's CEMF as a regulator of the current's rate of change should be fairly easy to grasp. If not, after all this, I doubt i would have the patience to explain emitter degeneration or the like. I know you are capable of understanding this, and I am at a loss as to why you do not.
I have no problem with that ,when dealing with real world devices that dissipate energy.
The problem comes when ideals are involved,and where we have a coil that dose not,and cannot dissipate energy.
Please read my posts again where I describe the action of the CEMF in a step-wise fashion. The part you appear to be having difficulty grasping is the smooth continuous action of the CEMF as a feedback mechanism that maintains the .8 amps per second rate of change.
No
The part i have a problem with,is how you have come to the conclusion that the EMF wins over the CEMF in this smooth transition step function ,when there is no potential difference.
Here is how i am seeing it.
A water pump has a coiled hose attached to it. Both the pump and hose are ideal.
The pump has a pressure switch that cuts the power to the pump when the pressure reaches 8psi in the hose. The hose now has one end blocked off,and so the pump will stop as soon as the pressure in the hose reaches that which the pump will supply. Every time the pump tries to raise the pressure in the hose,the hose pushes back with just as much pressure,and so no water flows.
We can adjust that pressure switch as much as we want,and as fine as we want,but no water will ever flow--equal and opposite action/reaction.
Consider the CEMF to "hover" between the 4 volt value and just below it if you must to help visualize the feedback mechanism. Once you can grasp it that way, it will be easier to see the smooth continuous action.
Im simply not going to drop a value to just below it's value,so as something fits with what the books say--that's just no me. I do not bend rules to make things work.
With a non ideal coil,i have no problem with the current rising,as the CEMF value cannot be, and is not the same as that of the applied EMF,as we have a current rise that has an exponential curve,and this curve starts at T=0. And this is why i said that the resistance of the coils windings are the reason that the CEMF is a slightly lower value than the applied EMF. Even that !minute !amount will start a chain reaction when winding resistance is involved,and so the current can flow,due to the coils ability to dissipate energy. But that just is not the case when talking ideals--that is why they are ideal.
On the bench,using non ideal motors,i can show that when the BackEMF equals the EMF,no current will flow. I can do this because i can externally control the amount of BackEMF produced by the motor.
Perhaps we could find the answer using real world inductor's
Lets say we take a 1:1 transformer--any size and value.
We pulse each side of that transformer with the same voltage across each winding continuously.
Now,we know that even though the two coils/windings have the same voltage placed across them,the two coils will still allow a current to flow--why?
One last thing.
What polarity is this CEMF as far as to that of the polarity of the supplied voltage.
A silly question you may think,but draw it out,and see what you see.
Poynt was right--it makes no sense.
Brad
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Perhaps OT
But if there a inductor is in the circuit, maybe the Kirchhoff Rule is not the correct way.
Kirchhoff's Loop Rule Is For The Birds
https://youtu.be/LzT_YZ0xCFY?list=PLyQSN7X0ro2314mKyUiOILaOC2hk6Pc3j
8.02x - Lect 16 - Electromagnetic Induction, Faraday's Law, Lenz Law, SUPER DEMO
https://youtu.be/nGQbA2jwkWI?t=33m12s
Hope this is helpful,
at the moment i am totally brain twisted.
Love and Peace
3K
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Technically speaking, current would not flow if the CEMF and EMF were exactly equal. But then what would the rate of change of the current be? Zero volts per second, so no CEMF would be generated. With no CEMF, current would again flow until it reached .8 amps per second, at which time the CEMF would again equal the EMF, and the cycle would repeat. But it does not happen in this step-wise fashion, it is a smooth feedback type process where the CEMF is maintained as equal to the level of the applied EMF (or at the least, very, very close to it, if that helps with the visualization) so that the rate of change is .8 amps per second.
No, the R value is not being forgotten, it just does not come into play with regard to the CEMF. The CEMF is an induced voltage. The CEMF equals 4 volts when the RATE OF CHANGE of the current flow is .8 amps per second (4V applied to 5H). Do not confuse the CEMF, which is a mechanism that determines the rate at which energy can be stored, with the actual amount of energy that is stored. And do not forget that the inductor is storing energy.
As soon as the RATE OF CHANGE reached .8 amps per second, 4 volts of CEMF would be generated and effectively regulate/limit the rate of the current's rise to that .8 amps per second.
You are wrong. Faraday says nothing about a required resistance or required dissipation. Resistance does not enter into it. If the rate of change of the current flowing thru the 5H inductor is .8 amps per second, the generated CEMF will be 4 volts. If the rate of change is less than .8 amps per second, the generated CEMF will also be less than 4 volts. And do not forget that with regard to an ideal inductor, we are not dissipating energy, we are storing/retrieving energy.
PW
;) :)
Makes perfect sense.
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With a non ideal coil,i have no problem with the current rising,as the CEMF value cannot be, and is not the same as that of the applied EMF,as we have a current rise that has an exponential curve,and this curve starts at T=0. And this is why i said that the resistance of the coils windings are the reason that the CEMF is a slightly lower value than the applied EMF. Even that !minute !amount will start a chain reaction when winding resistance is involved,and so the current can flow,due to the coils ability to dissipate energy. But that just is not the case when talking ideals--that is why they are ideal.
I've already stated this and I know it did not register, so here it is again:
With a non-ideal inductor, the instant Vin is applied, all the voltage appears across the inductance, and nothing across the resistance (assuming a lumped inductance and resistance model), therefore Vin=cemf, and lo and behold, current still begins to flow. In fact this is the moment the A/s is the highest rate!
Now, what happens if we were able to make R smaller and smaller?
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;) :)
Makes perfect sense.
I do not know if Tinman is actually unable to grasp the concept of a negative feedback mechanism or if he is just being contrary to adhere to his belief that an inductor with zero resistance cannot function as an inductor (in spite of the large number of zero resistance inductors in use daily throughout the world).
PW
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Time to sharpen up your measurement skills tinman!
If photons can go say 30,000,000,000. centimetres
in a second it's going to take some doing.
J.
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I do not know if Tinman is actually unable to grasp the concept of a negative feedback mechanism or if he is just being contrary to adhere to his belief that an inductor with zero resistance cannot function as an inductor (in spite of the large number of zero resistance inductors in use daily throughout the world).
PW
Why do you wish to single me out PW,when there are more that believe what i believe,than there is those who believe what you believe on this thread.
It would seem that yourself,Poynt,and MH are the three that stand alone on this belief that current can flow when the EMF and CEMF are of the same value--the rest of us seem to be of the opinion that when the EMF and CEMF are of the same value,that no current will flow.
You also forget the fact that these !0! resistance inductors have stored energy applied to them in order to make them super conductors.
So no-we do not have !room! temperature super conductors,or ideal coils/inductors that do not dissipate energy--this is a fact,and for you to bring this into the discussion,only diverts traffic in the wrong direction.
The answer is always avoided by way of introducing real world configurations that dissipate power/energy--such as your feed back system.
A quote from my dad's book
Because no one has been able to discover fundamental realistic answers to explain phenomenal events like these, scientists have resorted to using strange speculative theories and extremely complicated mathematics in an attempt to perfect their otherwise imperfect scientific theoretical models.
And to quote Poynt
Even the official definitions don't make sense; "Increasing current in a coil of wire will generate a counter emf which opposes the current." How does an emf oppose a current?
It really comes down to this,the EE guys are always right,and need no such test to prove they are,and the rest of us are wrong--it's that simple.
I thank you for your time PW--and all,but my journey to find those who can see past the known is complete.
Brad
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Why do you wish to single me out PW,when there are more that believe what i believe,than there is those who believe what you believe on this thread.
It would seem that yourself,Poynt,and MH are the three that stand alone on this belief that current can flow when the EMF and CEMF are of the same value--the rest of us seem to be of the opinion that when the EMF and CEMF are of the same value,that no current will flow.
I have repeatedly stated that current will not flow if the EMF and CEMF are equal. That is the basis for how an inductor limits the rate of change. I truly wonder if I would have as much difficulty explaining any other negative feedback mechanism to you, or as I stated, if you are just being contrary for the sake of argument.
You also forget the fact that these !0! resistance inductors have stored energy applied to them in order to make them super conductors.
So no-we do not have !room! temperature super conductors,or ideal coils/inductors that do not dissipate energy--this is a fact,and for you to bring this into the discussion,only diverts traffic in the wrong direction.
Zero resistance inductors are in use daily all over the world. The fact that they must be cooled is not relevant to the discussion. As energy is stored or retrieved using those zero resistance inductors, none of that energy is dissipated as heat. It is the flow of heat towards the superconductor from the outside environment that must be dealt with.
The answer is always avoided by way of introducing real world configurations that dissipate power/energy--such as your feed back system.
A quote from my dad's book
And to quote Poynt
It really comes down to this,the EE guys are always right,and need no such test to prove they are,and the rest of us are wrong--it's that simple.
I thank you for your time PW--and all,but my journey to find those who can see past the known is complete.
Brad
So are you saying that you believe the "EE guys", as you put it, have not heavily investigated zero resistance inductors, that is, tested and proved, that as the resistance is removed from an inductor it behaves more and more like an ideal inductor? The study of the properties of devices made from superconductors is a very large field of research.
PW
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The tinman doesn't seem to believe in theoretical guys.
I watched this thing on YouTube.
"Harold Black and the invention of the negative feedback amplifier"
He had the idea,got it down on paper and his colleague built it.
It's men like those who have given us all these marvellous
communication devices.
J.
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It really comes down to this,the EE guys are always right,and need no such test to prove they are,and the rest of us are wrong--it's that simple.
Brad
I asked you a couple of times to give a concrete example of where the CEMF must be less than the EMF for current to flow using a simple example with a coil and voltage source with actual numbers and you refused. You can't actually put substance to your beliefs.
So, we often hear, "This is what I believe but I can't really explain it and I cannot give you a concrete example illustrating my theory with numbers." And that is just plain bogus. Here is a classic example, "Repeatedly shorting a coil gives extra energy." The thread name is , "Shorting coil gives back more power."
With respect to the discussion, there is more than one way to skin a cat and so different ways of explaining the whole EMF/CEMF business have been explored. Then there is the pure reality of doing tests on your bench. And within that reality you must have the full conscious realization that within the real coil on your bench, there is actually an ideal coil, and that ideal coil is functioning exactly like the EE equations state it should function like. Saying, "I only deal with real stuff on my bench" is almost a strange thing to say because the exponential response of the real coil comes directly from the ideal coil that is the basis for the real coil.
I suppose what I am really saying is that if you take the top five old wives' tales that you see on the forums and actually demand that people put substance to those tales and show that they are REAL, you end up coming up goose eggs.
And it's bizarre when you look at somebody on YouTube like TheOldScientist. He uses all the cliches and the old wives' tales all the time in his presentations, but when it comes to the nitty-gritty, and you really look for substance in what he is saying and demonstrating, he comes up short. And he has fantastic test equipment! The other guy that comes to mind is that Quanta Magnetics guy, talk about empty calories.
And you fell into the trap (or the trance) yourself when it came to graphene supercapacitors. In one of your clips you make this claim, something like your home-brew capacitor is 10,000 Farads - but you make no attempt to measure it. Just like my "buddy" RMS. All that you have to do is do a few test runs with a few different resistors to discharge your graphene capacitor and measure the time constant and then crunch the numbers to give you a capacitance value - and you don't. I could smell that your claimed capacitance was grossly exaggerated.
MileHigh
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I asked you a couple of times to give a concrete example of where the CEMF must be less than the EMF for current to flow using a simple example with a coil and voltage source with actual numbers and you refused. You can't actually put substance to your beliefs.
[snip]
MileHigh
Actually MH doesn't every scope shot of an inductor with a voltage applied across it's terminals generating a linear current rise give proof that Emf = L*dI/dt or rearranging di = Emf*dt/L? Where is the evidence of Cemf? So, anyone adhering to the notion that Emf = Cemf in a single inductor has the burden of proof IMO to show by experiment or math derivation that it exists.
By definition, Cemf is opposite to Emf. The current increase in the above example is in phase with the applied Emf and follows Faraday's law without Lenz. How do we justify any amount of negative Cemf to be added to the Emf and still adhere to Faraday's law? I am willing to change my view if and when I see something convincing.
pm
Edit
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Been thinking a bit on the emf=cemf as in if there would be current flow of an ideal inductor when input is supplied.
One conclusion as to how cemf could be always less than emf is probably distance. Distance from one winding to all others. Some are adjacent and some a couple or several or more wire thicknesses away from each other. Emf through the inductors windings, as in each winding will create its own field, and those fields are weaker the further they are from their origin. Like if we apply current to a length of wire, the field around that wire is stronger close to the wire and weaker the further out from the wire we go. So if we placed another length of wire next to the wire to be powered up, the further that second wire is from the powered wire, the less effect the field will have on the second wire. I can see that as an issue in thinking that current would not flow in ideal wires and inductors.
And even in a single wire, the fields of the moving electrons have distance from other moving electrons, and the field from one to another is weaker than closer to the point of origin.
Dont know if that sounds right for sure. Just came up with it this morning at work.
So with that, I can say that ideal wires and inductors can flow current most likely and I can agree that cemf is most likely always in some way less than the emf.
Mags
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PW
I have repeatedly stated that current will not flow if the EMF and CEMF are equal.
And you have repeatedly stated that the EMF and CEMF are equal,but current will still flow.
or as I stated, if you are just being contrary for the sake of argument.
This is always how it is always seen--an EE says this is how it is,and anyone that disagrees with them,is the one who is doing the arguing. It could just as easy be seen to be the other way around.
That is the basis for how an inductor limits the rate of change. I truly wonder if I would have as much difficulty explaining any other negative feedback mechanism to you,
If the negative feedback is slightly lower,then yes,i can see how that would work. But as we are dealing with an ideal coil,and none of that negative feedback energy is dissipated,then i see a balance--such as i have tried many times now to explain. The mere fact that current would continue to flow through this coil,if the coil was bridged,and became an ideal loop,shows that there is no losses in any way shape or form--not even to the magnetic field.
It also tells us that we would get back every bit of energy that went into that coil,when we open that loop,and collect the stored energy.
So are you saying that you believe the "EE guys", as you put it, have not heavily investigated zero resistance inductors, that is, tested and proved, that as the resistance is removed from an inductor it behaves more and more like an ideal inductor? The study of the properties of devices made from superconductors is a very large field of research.
If you can point me in the direction of such tests,then i would be happy to read the results.
Below is a couple of diagrams.
Do we have diagram A showing the correct relationship of the CEMF to that of the EMF polarity,or diagram B showing the correct relationship between the CEMF and EMF polarities ?.
Brad
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I've already stated this and I know it did not register, so here it is again:
With a non-ideal inductor, the instant Vin is applied, all the voltage appears across the inductance, and nothing across the resistance (assuming a lumped inductance and resistance model), therefore Vin=cemf, and lo and behold, current still begins to flow. In fact this is the moment the A/s is the highest rate!
Now, what happens if we were able to make R smaller and smaller?
The above is germane to the argument, yet no comments.
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author=MileHigh link=topic=16589.msg487413#msg487413 date=1467212939]
I asked you a couple of times to give a concrete example of where the CEMF must be less than the EMF for current to flow using a simple example with a coil and voltage source with actual numbers and you refused. You can't actually put substance to your beliefs.
Well Mr resonance,i have done this by way of showing that when the BackEMF in a DC PM motor equals the applied EMF,then no current flows,and no BackEMF voltage can be measured--the same applies for every other electronic component. Show me just one other component that will allow for current flow,when there is no potential difference across it's terminals.
So, we often hear, "This is what I believe but I can't really explain it and I cannot give you a concrete example illustrating my theory with numbers." And that is just plain bogus. Here is a classic example, "Repeatedly shorting a coil gives extra energy." The thread name is , "Shorting coil gives back more power."
And you know this is bogus by experimentation MH?
Quote:Additional phenomenon has also been discovered in atomic physics and has created a lot of confusion and speculation about how the atom fundamentally works. An example of this atomic phenomenon is based on the fact that all atoms are considered to have orbiting electrons, which in theory should radiate electromagnetic energy as they orbit the positive nucleus. This theoretical loss of un-replenished radiated electromagnetic energy should result in the negative electron eventually spiralling inwards and collapsing into the positive nucleus. But in reality this loss of radiated energy is not observed as happening. Scientists are still unclear as to why this is so.
With respect to the discussion, there is more than one way to skin a cat and so different ways of explaining the whole EMF/CEMF business have been explored. Then there is the pure reality of doing tests on your bench. And within that reality you must have the full conscious realization that within the real coil on your bench, there is actually an ideal coil, and that ideal coil is functioning exactly like the EE equations state it should function like. Saying, "I only deal with real stuff on my bench" is almost a strange thing to say because the exponential response of the real coil comes directly from the ideal coil that is the basis for the real coil.
It is funny to watch you tried to compare real and ideal as one in the same,where one will dissipate energy,and the other will not. All your electrical models which include inductors,have a series resistor,and that is to show that there is a resistance associated with real world inductors. It also clearly shows there will be losses associated with that inductor.
Perhaps you would like to have a go at the diagrams below--which is correct?
Brad
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Actually MH doesn't every scope shot of an inductor with a voltage applied across it's terminals generating a linear current rise give proof that Emf = L*dI/dt or rearranging di = Emf*dt/L? Where is the evidence of Cemf? So, anyone adhering to the notion that Emf = Cemf in a single inductor has the burden of proof IMO to show by experiment or math derivation that it exists.
By definition, Cemf is opposite to Emf. The current increase in the above example is in phase with the applied Emf and follows Faraday's law without Lenz. How do we justify any amount of negative Cemf to be added to the Emf and still adhere to Faraday's law? I am willing to change my view if and when I see something convincing.
pm
Edit
Faradays own Faraday disk generator dosnt even follow his own law.
Here we have no rate of change in time between the magnetic field and conductor,but current still flows. We can have the magnets stationary to the rotating conductor,or we can have them spining with the conductor--it makes no difference.
But im sure there has been some tweaking to the laws to account for this--as they often do.
Brad
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But as we are dealing with an ideal coil,and none of that negative feedback energy is dissipated
You are correct, it is not dissipated. That which cannot be dissipated is either stored in, or retrieved from, the magnetic field. It is what inductors do using and obeying the laws of inductance...
We are going on what, 130 years or so of modern man investigating, defining, and verifying the operation of inductors? All manner of wire types, geometries, resistance and capacitance, use at frequencies into the THz region, study of inductance in the realm of nano-length conductors, inductors using zero resistance conductors, and all manner of core types have been investigated over those years.
PW
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The above is germane to the argument, yet no comments.
This seems to go against what we discussed before Poynt.
We agreed that the CEMF is what limits the current,and stops it from going straight to its steady state value. A voltage appears across a resistor as soon as it is placed across that resistor. The only reason the current value is far less than that steady state value at T=0,is because we have the added series resistance generated by the CEMF ,that is added to the coils winding resistance. We know this to be true,because if there was no CEMF(as we discussed),then the current would go straight up to the steady state value.
Brad
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You are correct, it is not dissipated. That which cannot be dissipated is either stored in, or retrieved from, the magnetic field. It is what inductors do using and obeying the laws of inductance...
We are going on what, 130 years or so of modern man investigating, defining, and verifying the operation of inductors? All manner of wire types, geometries, resistance and capacitance, use at frequencies into the THz region, study of inductance in the realm of nano-length conductors, inductors using zero resistance conductors, and all manner of core types have been investigated over those years.
PW
Point taken.
So your answer for the below would be?
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Tinman,
Regarding your diagrams, when the 4 volts is applied to a 5H inductor, as soon as the rate of change of the current flowing thru the inductor reaches .8 amps per second, the generated CEMF would be as in drawing "A".
PW
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author=MileHigh link=topic=16589.msg487413#msg487413 date=1467212939]
Well Mr resonance,i have done this by way of showing that when the BackEMF in a DC PM motor equals the applied EMF,then no current flows,and no BackEMF voltage can be measured--the same applies for every other electronic component. Show me just one other component that will allow for current flow,when there is no potential difference across it's terminals.
Brad
I specifically asked you in no uncertain terms to give an example with a coil, not with a motor. This same thing has happened before, this is the second time we are doing this. A spinning motor is a different kind of thing with a different model that is more complex. The principle difference that comes to mind is that the spinning rotor is an active generator of CEMF and is more akin to a battery than a coil.
So you bait and switch instead of giving a simple, tangible example of CEMF needing to be less than the EMF in a coil for current to flow, because you can't.
Personally, I am not overly interested in this discussion. There are two equations that relate the current and voltage for a coil. No matter how you want to model it, the two equations hold true. And they have their direct analogies in the real life physical world and nobody questions them.
MileHigh
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Tinman,
Regarding your diagrams, when the 4 volts is applied to a 5H inductor, as soon as the rate of change of the current flowing thru the inductor reaches .8 amps per second, the generated CEMF would be as in drawing "A".
PW
OK so you are saying that the Cemf is equal to the Emf in polarity and magnitude during the time the inductor current is ramping at the calculated magnitude according to Faraday's Emf law? IOW, could we say that the Cemf by definition does not exist during this normal operation of the coil? I can also assume that you are saying that an amount of Cemf is present during the extremely brief wavefront activity when the fields are in the process of reaching their stable levels from T0 and then reduces to zero after the stable induction current is reached. No feedback correction is considered after this point.
If yes, then I could accept this as this fits the experimental results excluding any analysis of the wavefront or initial start. Experiments could then be run that would carefully examine the various voltages and currents and even possibly the fields during the startup wavefront activity which should yield any evidence of both Emf and Cemf interaction.
pm
Edit
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OK so you are saying that the Cemf is equal to the Emf in polarity and magnitude during the time the inductor current is ramping at the calculated magnitude according to Faraday's Emf law? IOW, could we say that the Cemf by definition does not exist during this normal operation of the coil?
Absolutely not!
If you were to replace the inductor with another voltage source producing an equivalent CEMF of 4 volts, the only way you would be able to measure that there are two 4 volt sources connected in parallel would be to measure the current flowing thru the circuit. In the case of using two voltage sources, we know the second source is 4 volts when the current flow is zero. In the case of the 5H inductor, we know the CEMF is 4 volts when we see a rate of change of .8 amps per second happening to the measured current.
I can also assume that you are saying that an amount of Cemf is present during the extremely brief wavefront activity when the fields are in the process of reaching their stable levels from T0 and then reduces to zero after the stable induction current is reached. No feedback correction is considered after this point.
The CEMF of 4 volts is generated when, and as soon as, the rate of change of the current flow thru the inductor is .8 amps per second.
If yes, then I could accept this as this fits the experimental results excluding any analysis of the wavefront or initial start. Experiments could then be run that would carefully examine the various voltages and currents and even possibly the fields during the startup wavefront activity which should yield any evidence of both Emf and Cemf interaction.
pm
The evidence of the interaction of EMF and CEMF is via the measured .8 amps per second rate of change to the current flowing thru the circuit. It is the induced CEMF that prevents the rate of change from being faster or slower than the .8amps per second rate, exactly as defined for a 5H inductor with 4 volts applied across it.
PW
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This seems to go against what we discussed before Poynt.
We agreed that the CEMF is what limits the current,and stops it from going straight to its steady state value.
Yes.
A voltage appears across a resistor as soon as it is placed across that resistor.
If, as in my example, we have a lumped resistor/inductor model (see below), the voltage across the resistor compared to the voltage across the inductance at t=0 will be very small, depending on the L/R ratio.
At this point the inductor's cemf and the applied Vin will be equal. Yet current begins to flow. Eventually due to the R, the A/s will taper off and the current will settle at I(max).
Now once again, what happens as we make R smaller and smaller?
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When R reduced to zero with ideal inductor current will
increase to an infinite amount in an infinite time??
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When R reduced to zero with ideal inductor current will
increase to an infinite amount in an infinite time??
Assuming 4 volts across 5H, when R is reduced to zero, current will rise towards an infinite amount at the rate of .8 amps per second...
PW
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Can you have a current flowing without a voltage difference in space?
John.
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Actually MH doesn't every scope shot of an inductor with a voltage applied across it's terminals generating a linear current rise give proof that Emf = L*dI/dt or rearranging di = Emf*dt/L? Where is the evidence of Cemf? So, anyone adhering to the notion that Emf = Cemf in a single inductor has the burden of proof IMO to show by experiment or math derivation that it exists.
By definition, Cemf is opposite to Emf. The current increase in the above example is in phase with the applied Emf and follows Faraday's law without Lenz. How do we justify any amount of negative Cemf to be added to the Emf and still adhere to Faraday's law? I am willing to change my view if and when I see something convincing.
pm
Edit
This is really just to acknowledge your comments. You have a very good understanding of things and I just don't have the fire in my belly to get into it. I made a few comments but I am more of a passive observer at this point.
MileHigh
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I didn't ask what happens when R=0, I asked what happens as R is made smaller and smaller.
The journey can be as enlightening as the destination.
Does everyone acknowledge that at t=0 VL>>>VR and that VL=Vin?
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Absolutely not!
If you were to replace the inductor with another voltage source producing an equivalent CEMF of 4 volts, the only way you would be able to measure that there are two 4 volt sources connected in parallel would be to measure the current flowing thru the circuit. In the case of using two voltage sources, we know the second source is 4 volts when the current flow is zero. In the case of the 5H inductor, we know the CEMF is 4 volts when we see a rate of change of .8 amps per second happening to the measured current.
The CEMF of 4 volts is generated when, and as soon as, the rate of change of the current flow thru the inductor is .8 amps per second.
I don't mean to be a PITA and I know you must be frustrated along with some others with my insistence, but I don't think we are that far apart in our reasoning! For example, when I refer to a Cemf of zero at a dI = .8 amps/sec, my mental equivalent model is a series connected Emf and Cemf where yours is parallel connected. The end result is the same in the fact that the Cemf is basically neutral during normal operation.
I think the parallel model requirement of producing a positive Cemf to match the source Emf with a positive induced current is problematic as compared to the series model Cemf operating around zero especially if one agrees that Cemf controls dI/dt.
The evidence of the interaction of EMF and CEMF is via the measured .8 amps per second rate of change to the current flowing thru the circuit. It is the induced CEMF that prevents the rate of change from being faster or slower than the .8amps per second rate, exactly as defined for a 5H inductor with 4 volts applied across it.
PW
At this point in time, I still have a problem with Cemf determining dI/dt in an inductor because I can't derive an equation to support this but I'm not the greatest mathematician. I can find support however for field interactions with physical dependencies for determining inductance.
pm
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Now once again, what happens as we make R smaller and smaller?
As you make R smaller,the exponential current curve will become a more linear/straight line.
As long as there is a winding resistance,there will still be a curve.
This curve shows that as from T=0 the CEMF induced current value is not the same as that of the EMF induced current,and current will start to flow.
We place a voltage across the coil,and the current from that EMF is set to a maximum value when there is winding resistance. The self induced CEMF(if it actually exists)creates a current that is in opposition to that which the EMF induced,but is not as great,as it to now must obey ohms law,and that current is also limited to a maximum value due to winding resistance,and so we have a loss plus a loss,and there for the self induced current value can never be the same as the EMF induced current value,and so current flows.
When you take away winding resistance,there is no loss in either the EMF induced current value,nor the CEMF induced current value--they are equal and opposite.
Brad
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MileHigh
I specifically asked you in no uncertain terms to give an example with a coil, not with a motor. This same thing has happened before, this is the second time we are doing this. A spinning motor is a different kind of thing with a different model that is more complex. The principle difference that comes to mind is that the spinning rotor is an active generator of CEMF and is more akin to a battery than a coil.
First off,i dont really care to much for demands from some one that dose nothing him self when asked. If you think i am here to bow to your commands,then you have a big shock coming your way.
Second-BackEMF and CEMF are produced by the very same mechanism-the rate of change of the magnetic field imposed on a conductor--in both cases,a coil.
An ideal DC PM motor would not draw any current--that is a fact,and i can show this on the bench with a real world motor--even the value of the BackEMF being identical to the EMF the moment the motor draws no current.
So you bait and switch instead of giving a simple, tangible example of CEMF needing to be less than the EMF in a coil for current to flow, because you can't.
You physically show me the CEMF value being equal to that of the EMF value,then i may consider your request.
It is the value of the CEMF induced current that must be less to allow current to flow,and the self induced current can only be less that the EMF induced current,if there is winding resistance.
Personally, I am not overly interested in this discussion. There are two equations that relate the current and voltage for a coil. No matter how you want to model it, the two equations hold true. And they have their direct analogies in the real life physical world and nobody questions them.
Thats a lye,as there is more people on this thread that has questioned them,than there is people that actually believe they hold.
Like it or not,thats the truth.
Brad
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I think the parallel model requirement of producing a positive Cemf to match the source Emf with a positive induced current is problematic as compared to the series model Cemf operating around zero especially if one agrees that Cemf controls dI/dt.
At this point in time, I still have a problem with Cemf determining dI/dt in an inductor because I can't derive an equation to support this but I'm not the greatest mathematician. I can find support however for field interactions with physical dependencies for determining inductance.
pm
Because there is not one.
Once again,we see nothing more than an assumption based on what is said to be true,but with no experimental data to back it up. Non ideal equations being used to derive an answer for an ideal coil.
The fact remains with all components-no current will flow if there is no potential difference.
At T=0,there is no potential difference between the EMF and CEMF value--apparently,but current still flows because the book says it will.
If we look at the diagram below,we have the CEMF and EMF marked accordingly.
In the second diagram,we have a cap that has the same voltage across it as the battery--no current will flow.
In order to get that current to flow,we must remove some of the stored energy in that cap,or we must have a leaky cap in order for a small set value of current to keep flowing.
The very same must apply for the coil. Once the CEMF value is the same as the EMF value,no current will flow until we either remove some of the stored energy,or the coil can dissipate some energy. In this case,neither happens,as the coil is ideal.
So my question was-and still is,where is this loss that creates an imbalance,so as current can continue to flow?
Brad
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Brad:
Okay, so you are copping out yet again and you refuse to provide an example of CEMF being less than EMF for an EMF source driving a coil - because you can't. Instead, you try useless misdirection.
It is the value of the CEMF induced current that must be less to allow current to flow,and the self induced current can only be less that the EMF induced current,if there is winding resistance.
Why don't you back up your claim and plot the "CEMF induced current" and the regular EMF induced current on a graph. Also plot the net current. Try doing that for a real inductor and an ideal inductor. I have a feeling you might start getting cold feet and confused when you actually try putting your claims down on paper in graphical form.
You hit another doozy and it's also a double whammy. "Lye" is a strongly alkaline solution, especially of potassium hydroxide, used for washing or cleansing. When I say "nobody questions them" I am talking about the physical world real life analogies.
MileHigh
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Brad:
You hit another doozy and it's also a double whammy. "Lye" is a strongly alkaline solution, especially of potassium hydroxide, used for washing or cleansing. When I say "nobody questions them" I am talking about the physical world real life analogies.
MileHigh
Lol-your greatest victory is on a typo? lol
Okay, so you are copping out yet again and you refuse to provide an example of CEMF being less than EMF for an EMF source driving a coil - because you can't. Instead, you try useless misdirection.
Like i said MH,you show me that you can measure the value of the CEMF,and i will show you that the CEMF induced current must be less than that of the EMF induced current,in order for there to be a current flow.fq
Why don't you back up your claim and plot the "CEMF induced current" and the regular EMF induced current on a graph. Also plot the net current. Try doing that for a real inductor and an ideal inductor. I have a feeling you might start getting cold feet and confused when you actually try putting your claims down on paper in graphical form.
I have a feeling that you only know what you read,and have no idea to actually what is what.
What is the difference in how a BackEMf is produced to that of a CEMF,as far as the mechanism that creates both?.
Brad
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I'm not sure that it was a typo.
Like i said MH,you show me that you can measure the value of the CEMF,and i will show you that the CEMF induced current must be less than that of the EMF induced current,in order for there to be a current flow.fq
Here is the chicken and egg argument split into two.
With the 5 Henry ideal inductor, if you connect it across a programmable current source that outputs a linear ramp of current at 0.8 amps per second, you will measure 4 volts of CEMF across the inductor.
With the 5 Henry ideal inductor, if you connect it across a 4-volt DC voltage source then you will measure a linear ramp of current at 0.8 amps per second. Some people will say that is CEMF, but I view it as clamping 4 volts across the inductor and pushing current through it and overcoming the electrical inertia of the coil.
In a way, it's neither here or there, or chicken or egg, because you still have the same increasing current, and the same voltage across the coil.
Now, are you going to give your own example where the CEMF must allegedly be less than the EMF for current to flow or are you just going to say it without offering any substance to back up your claim?
You are non-responsive on my reasonable request for you to make a current vs. time graph for the "CEMF current" and the EMF current and the net current to back up your claim.
I think I see a pattern here. You like to put forth your own pie-in-the-sky theories that you are pretty damn sure are true, but when you are asked to offer some substance to your claims then you are a man of 1000 excuses.
I challenge you to back up your claim and graph the two currents and the net current for both a real inductor and an ideal inductor. Let's see if the Tinmanese makes sense or if it is just gobbledygook.
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I'm not sure that it was a typo.
Here is the chicken and egg argument split into two.
With the 5 Henry ideal inductor, if you connect it across a programmable current source that outputs a linear ramp of current at 0.8 amps per second, you will measure 4 volts of CEMF across the inductor.
With the 5 Henry ideal inductor, if you connect it across a 4-volt DC voltage source then you will measure a linear ramp of current at 0.8 amps per second. Some people will say that is CEMF, but I view it as clamping 4 volts across the inductor and pushing current through it and overcoming the electrical inertia of the coil.
In a way, it's neither here or there, or chicken or egg, because you still have the same increasing current, and the same voltage across the coil.
Now, are you going to give your own example where the CEMF must allegedly be less than the EMF for current to flow or are you just going to say it without offering any substance to back up your claim?
You are non-responsive on my reasonable request for you to make a current vs. time graph for the "CEMF current" and the EMF current and the net current to back up your claim.
I think I see a pattern here. You like to put forth your own pie-in-the-sky theories that you are pretty damn sure are true, but when you are asked to offer some substance to your claims then you are a man of 1000 excuses.
I challenge you to back up your claim and graph the two currents and the net current for both a real inductor and an ideal inductor. Let's see if the Tinmanese makes sense or if it is just gobbledygook.
So once again,it is the same old same old
A continuous claim that the CEMF is equal to the EMF,but current still flows,with no explanation as to how. Why is one electromotive force equal and opposite to another electromotive force,but a direction of current flow can be obtained.
Time and time again,i have asked where is the imbalance that allows current to flow,and time and time again,all i get is--when .8 amps of current is flowing through the 5h coil,we get a CEMF value of 4 volts.
Everything that has been said,is to fit this !! .8 amps a second!! must flow through a 5H coil,with no reason as to how it can be, when the CEMF value is equal to that of the EMF.
No one yet has defined as to where the loss is,and if the CEMF value is equal to that of the EMF value,then there must be a loss for current to flow-->where is this loss-->where is this reaction that is not equal to the action that created it?,when there is no energy dissipation from the system.
PW states some sort of feed back system that has a smooth transition. All well and good,but why is the feed back less than that which was fed into the system in the first place.
Everything keeps going around in a circle to fit this !!must be .8 amps a second for a 5H coil !!,-because that's whats in the books.
So ,for the last time-->where is the loss in this !!feed back!! system,that allows an offset,to allow current to flow?.
Brad
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I challenge you to back up your claim and graph the two currents and the net current for both a real inductor and an ideal inductor. Let's see if the Tinmanese makes sense or if it is just gobbledygook.
I challenge you MH,to measure and show us all here,the CEMF value in real time.
After you have done that,you send me an ideal coil,and i will carry out the experiment ;)
It will not be done using only numbers supplied by those that had no ideal coils to make such claims that there would be no difference between ideal and non ideal.
Brad
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What would it take to get rid of the magnetic field from a conductor carrying current?
Wind your conductor around a speaker magnet,and see how you go with that ?.
Will it have an inductance value at all?. ;)
Brad
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I challenge you MH,to measure and show us all here,the CEMF value in real time.
After you have done that,you send me an ideal coil,and i will carry out the experiment ;)
It will not be done using only numbers supplied by those that had no ideal coils to make such claims that there would be no difference between ideal and non ideal.
Brad
You are back to your nonsense. "Do A then I'll do B." It's pure crap, it's evasive and it's cowardice. It's an immature ridiculous diversion. You are also back to whining that "ideal coils don't exist" for something like the tenth time.
You are making this bizarre claim about two currents flowing in opposite directions, so I am asking you to plot them on a graph and show what you really mean and you are back to doing another dancing chicken. Remember you said something bizarre about the CEMF current being based on the EMF current level at the fifth time constant minus the EMF current level at the first time constant? Who knows what you are really going on about. Make a bloody graph to explain your amazing vision.
Just produce the graph to put substance to your alleged claim and stop hopping on one foot and scratching your belly in a diversionary dancing chicken dance. Just be real.
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author=MileHigh link=topic=16589.msg487470#msg487470 date=1467263078]
You are back to your nonsense. "Do A then I'll do B." It's pure crap, it's evasive and it's cowardice.
Dont call me a coward you piece of crap.
It is always the same--i do all the bench work,and you do nothing but dribble out commands--->go fall of a cliff prawn.
Your weak,and your a fraud.
You have never answered one of my challenges,and so i call you out as being a fake-->all your smarts come's from the internet,and you have none of your own.
It's an immature ridiculous diversion. You are also back to whining that "ideal coils don't exist" for something like the tenth time.
And once again we see you duck.weave,and dodge any challenge that is presented to you--you always have,since the day you joined this forum.
You are making this bizarre claim about two currents flowing in opposite directions, so I am asking you to plot them on a graph and show what you really mean and you are back to doing another dancing chicken.
Lol-sorry MH,that i have already done,and my paper was graded by PW--he gave me an A :D
Perhaps you go argue with him lol.
Remember you said something bizarre about the CEMF current being based on the EMF current level at the fifth time constant minus the EMF current level at the first time constant? Who knows what you are really going on about. Make a bloody graph to explain your amazing vision.
Ah yes.
That is when you had a big booboo,and screwed up the value of current at the end of the first time constant lol.
Now from what i can remember,it went something like this
Quote: So if at the end of the fith time constant,we had a steady current flow of 100 amps,and at the end of the first time constant,we had a flow of 25 amp's,this means we have minus 75 amps. LMAO.
Wait a minute--i'll be back ;)
Look-i found it ;)
Quote: So like if the 5th time constant current is 100 amps and the 1st time constant current is 25 amps then the reverse current produced by the CEMF is 75 amps. So does that mean when you first apply the voltage across the coil the current is -75 amps? It's "Attack from Planet Bizarro and the Pumpkin Patch Creatures.
Please pay careful attention to the highlighted lol.
Then you went on to say to PW,that Brad thinks there is current flowing back into the battery lol-->and this was all bought about by your self--you confused your self when you came up with that !way out to lunch! mumbo jumbo ,time constant values above lol.
If you had of done it right-as i pointed out to you after that disaster time constant calculation you did above,then you would have not confused yourself for the next 5 pages of the thread ;)
At the end of the first time constant,the current flow value would have been 63.2 amp's--not 25 amps as you stated lol. That means that the CEMF induced currents value would have been 36.8 amp's,and not 75 amp's as you posted.
So Miles,if you didnt make such a screw up way back then,you would have understood that what i said is true.
Just produce the graph to put substance to your alleged claim and stop hopping on one foot and scratching your belly in a diversionary dancing chicken dance. Just be real.
After that screw up of yours MH,there is no point in you looking at anything,and i think your time constant calculations confirm what i say about your smarts coming from the internet,and not what you actually poses ;)
You up for that JT build off challenge yet?
Brad
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As one reduces the resistance what happens to the exponential curve?
J.
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As one reduces the resistance what happens to the exponential curve?
J.
It starts to straighten out to a more linear incline-as far as time is concerned.
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poynt is after something.
At time 0. VL = Vin,
He wants to show us something, come on men, what is it?
John.
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So what I am hearing is that the current plot for a non-ideal 5H inductor (Red is R=1) is correct, but for the ideal inductor (Green is R=1p) it is not correct. Did I get that right?
One thing; can we agree that a 5H inductor with 1p Ohm of resistance is close enough to ideal? That is the Green trace. If not, why?
Notice how the two current plots track almost perfectly for the first 0.2s? Yet some say the ideal plot is incorrect.
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It starts to straighten out to a more linear incline-as far as time is concerned.
So what happens when we finally reach R=0?
Is there some paradigm shift that occurs and the world blows up, or does the trace just become perfectly straight?
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Let's look at tau once again:
For an R=1p Ohm and L=5H, tau=L/R, 5/1p = 158 thousand years.
I think in our 3 second time frame, that green current trace can be considered pretty damn straight, and thus close to ideal.
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I can't see anything wrong,it is exactly what I would expect.
PW. seems to suggest that for an ideal inductor.
John.
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Perhaps we have a solution for the Emf = Cemf issue using some basics.
Refer to the image below. Now picture a bar magnet approaching the coil from the left with it’s north pole facing the coil. From Lenz we know an Emf will be produced in the coil that opposes the approaching PM with the polarities as shown. I think on this we can all agree. Note that the current flow is conventional.
Now the question is, does this induced Emf produced coil current produce a Cemf to itself? IMO, no as there is no evidence to support this.
IOW, the induced Emf produced across the windings of the coil produces a current in the coil to oppose the approaching PM field yet it does not produce another Cemf to oppose itself.
Notice the polarity of the Emf. It is the same as would be required by a fixed voltage source to produce the same current and magnetic flux polarity. So, logically we can remove the PM and replace the Emf with a fixed voltage supply and produce the same end results without any Cemf.
So I guess we can say that the Emf = Cemf because they are always the same, Emf is Cemf in this example so one could also simply say that Emf = dI * L/dt. No feedback required.
OK, now you can blow this all apart!
pm
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Who'd a thought a poxy coil of wire could cause so much controversy.
John.
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Perhaps we have a solution for the Emf = Cemf issue using some basics.
Refer to the image below. Now picture a bar magnet approaching the coil from the left with it’s north pole facing the coil. From Lenz we know an Emf will be produced in the coil that opposes the approaching PM with the polarities as shown. I think on this we can all agree. Note that the current flow is conventional.
Now the question is, does this induced Emf produced coil current produce a Cemf to itself? IMO, no as there is no evidence to support this.
IOW, the induced Emf produced across the windings of the coil produces a current in the coil to oppose the approaching PM field yet it does not produce another Cemf to oppose itself.
Notice the polarity of the Emf. It is the same as would be required by a fixed voltage source to produce the same current and magnetic flux polarity. So, logically we can remove the PM and replace the Emf with a fixed voltage supply and produce the same end results without any Cemf.
So I guess we can say that the Emf = Cemf because they are always the same, Emf is Cemf in this example so one could also simply say that Emf = dI * L/dt. No feedback required.
OK, now you can blow this all apart!
pm
And so-- a magnet will remain floating above a superconductor motionless.
The equal and opposite remains when resistance is completely removed.
For every action,there is an equal and opposite reaction when there is no energy dissipation.
Brad
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Who'd a thought a poxy coil of wire could cause so much controversy.
John.
Now that we can agree on John.
Enough time wasted on something that will never be tried and tested--well,not by any of us anyway :)
Brad
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Brad:
You are a coward. You offer up your own "theories" and then when you are asked to provide examples of your theories in action you chicken out. You chicken out because in fact you can't illustrate a simple example of CEMF being less than the EMF with a coil. You chicken out because in fact you can't draw a graph showing the mechanism for "CEMF current" in opposition to EMF current for an ideal coil and a real coil.
You talk the talk but when asked to walk the walk you are a coward.
I can suspect that if you went to try to graph the two opposing currents you would quickly realize that it doesn't work. That would mean you would have to admit that your theory that you have stated repeatedly is wrong, it's nonsense. That would mean that you are wrong. That would lead to you having a nervous breakdown so the only "escape" is you laughably saying, "I will do it but you have to do something first." It's just one big Brad sizzling brain fry.
You're the weakling, you're the fraud.
Please pay careful attention to the highlighted lol.
And that's just you being a pure jackass. I just used some numbers for illustrative purposes. Do you understand that term, "illustrative purposes?" That's just another case where something is explained to you and any normal person would just accept it and move on. But you shamelessly repeat nonsense like that over and over thinking that you are "scoring points" when what you are really doing is looking like an idiot and digging yourself into a hole.
And let's not forget Brad, that the well of your mistakes and gaffes and misunderstandings is so deep and so plentiful and so full of material, that it's a bloody Saudi Arabia of idiocy. If I milked the well like you will repeat nonsense about me over and over, we would need a separate thread just for that. Repeat every mistake and gaffe and misunderstanding you made back to you 20 times and we would end up with a thread that is 500 pages long.
You up for that JT build off challenge yet?
Another vain idiotic feign at misdirection. You know that I am not interested and you know I have no equipment. Every time you say something stupid a bell rings somewhere.
Enough time wasted on something that will never be tried and tested--well,not by any of us anyway
Sure, your sizzling brain learned more in the past three months than you learned in six years worth of staring at spinning pulse motors spin. Why don't you just smash your oscilloscope, it's a waste of time.
You are a coward.
MileHigh
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Perhaps we have a solution for the Emf = Cemf issue using some basics.
Refer to the image below. Now picture a bar magnet approaching the coil from the left with it’s north pole facing the coil. From Lenz we know an Emf will be produced in the coil that opposes the approaching PM with the polarities as shown. I think on this we can all agree. Note that the current flow is conventional.
Now the question is, does this induced Emf produced coil current produce a Cemf to itself? IMO, no as there is no evidence to support this.
As long as the induced emf results in a current flow, wouldn't there will be an associated cemf? I think yes.
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Awaiting your responses Brad.
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As long as the induced emf results in a current flow, wouldn't there will be an associated cemf? I think yes.
That's what I'm a thinkin'
John.
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As long as the induced emf results in a current flow, wouldn't there will be an associated cemf? I think yes.
So we have another Cemf (Cemf2) produced by the current in the coil that is generated by the original Cemf from the approaching PM? If we have two Cemfs produced by the approaching PM, what is the phase of Cemf2 in relation to the original Cemf? IMO, either phase of Cemf2 is problematic in that either attraction or repulsion is increased in regards to the PM.
This is the crux of the issue IMO.
pm
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So we have another Cemf (Cemf2) produced by the current in the coil that is generated by the original Cemf from the approaching PM? If we have two Cemfs produced by the approaching PM, what is the phase of Cemf2 in relation to the original Cemf? IMO, either phase of Cemf2 is problematic in that either attraction or repulsion is increased in regards to the PM.
This is the crux of the issue IMO.
pm
Do you not agree that a changing inductor current results in a changing B field around the inductor? If so, then would self-induction not be present?
It seems to me that regardless how the emf is produced (either by applied voltage or induced magnetically), there would be a corresponding self-induced cemf.
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Do you not agree that a changing inductor current results in a changing B field around the inductor?
Yes I agree.
If so, then would self-induction not be present?
Yes.
It seems to me that regardless how the emf is produced (either by applied voltage or induced magnetically), there would be a corresponding self-induced cemf.
It would seem so and I have no problem with magnetically induced Emf or Cemf. I fail to see a justified Cemf with applied Emf for reasons I've covered in my example in the previous post and because of this view, I also do not hold to an Emf/Cemf feedback control loop with an applied Emf.
In order to support my opinion, I plan to attempt to define the self inductance of a single loop utilizing current and flux but my math skills being what they are, it is going to take some time if in fact I can do it at all.
I have attached an older Bureau of Standards document on the self inductance of single loop turns for the reading pleasure of anyone interested.
pm
Edit
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Awaiting your responses Brad.
It is ironic that you are using the sim to try and prove what some believe !may! happen,when that sim has been programmed to show exactly what it has been told to show ;D
Did you expect the sim to have a mind of it's own?,or will it simply follow the rules it has be given?.
Did the people that wrote the program for the sim have an ideal inductor to test,so as they could write the program and parameters of that sim to suit the inductors reaction's,or was it written based around the very same !laws! that are being discussed here on this thread?.
Brad
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author=MileHigh link=topic=16589.msg487498#msg487498 date=1467306568]
You are a coward. You offer up your own "theories" and then when you are asked to provide examples of your theories in action you chicken out. You chicken out because in fact you can't illustrate a simple example of CEMF being less than the EMF with a coil. You chicken out because in fact you can't draw a graph showing the mechanism for "CEMF current" in opposition to EMF current for an ideal coil and a real coil.
You mean like--if at the end of the first time constant,the EMF induced current is 25 amp's,then the CEMF current will be 75 amp's,and we can charge a battery for free? ;D
You talk the talk but when asked to walk the walk you are a coward.
You mean somethink like the most efficient JT circuit?
Are you taking me up on my challenge then MH--so as your not seen to just talk the talk ;)
I can suspect that if you went to try to graph the two opposing currents you would quickly realize that it doesn't work. That would mean you would have to admit that your theory that you have stated repeatedly is wrong, it's nonsense. That would mean that you are wrong. That would lead to you having a nervous breakdown so the only "escape" is you laughably saying, "I will do it but you have to do something first." It's just one big Brad sizzling brain fry.
Like i said MH,send me the ideal 5H coil,and we'll get started--or do i have to use an imaginary one?. ::)
You're the weakling, you're the fraud
.
JT,pulse motor,or rotoverter MH?--your choice
And that's just you being a pure jackass. I just used some numbers for illustrative purposes. Do you understand that term, "illustrative purposes?" That's just another case where something is explained to you and any normal person would just accept it and move on. But you shamelessly repeat nonsense like that over and over thinking that you are "scoring points" when what you are really doing is looking like an idiot and digging yourself into a hole.
You used those numbers to try and make my statement look stupid,and you continued to use those numbers to try and tell PW that i think there would be current flowing back into the battery---i can go and get those posts if you like,but you know you said that.
You also know that if you had of used correct ratio's,then my statement makes perfect sense,and that would have made you look like the jackass--as you do now.
And let's not forget Brad, that the well of your mistakes and gaffes and misunderstandings is so deep and so plentiful and so full of material, that it's a bloody Saudi Arabia of idiocy. If I milked the well like you will repeat nonsense about me over and over, we would need a separate thread just for that. Repeat every mistake and gaffe and misunderstanding you made back to you 20 times and we would end up with a thread that is 500 pages long.
I think you would find,that most of the thread would be full of your mistakes,as i keep proving you wrong with many of your idiotic comments and claims--like the most efficient JT circuit.
Another vain idiotic feign at misdirection. You know that I am not interested and you know I have no equipment. Every time you say something stupid a bell rings somewhere.
So says the book worm :D
Sure, your sizzling brain learned more in the past three months than you learned in six years worth of staring at spinning pulse motors spin. Why don't you just smash your oscilloscope, it's a waste of time.
You are a coward.
Why do that ?. Do you think it is producing it's own CEMF,and screwing up the measurements?.
Brad
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Brad:
So you are still a coward. You are afraid to illustrate your "theories" with concrete examples. Instead, we get some mindless diversionary trash talk revolving around the usual "you don't do experiments" nonsense.
You mean like--if at the end of the first time constant,the EMF induced current is 25 amp's,then the CEMF current will be 75 amp's,and we can charge a battery for free?
Make a graph of current vs. time for the alleged "CEMF current" and the EMF induced current and show the world what you mean.
Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
Are you taking me up on my challenge then MH--so as your not seen to just talk the talk
And once again we see you duck.weave,and dodge any challenge that is presented to you--you always have,since the day you joined this forum.
How about this Brad: Straight to your face, NO, the answer is NO. For the tenth time, I don't have any equipment. Pound that in to your frying brain. Does that sound like "ducking, weaving and dodging" to you?
Like i said MH,send me the ideal 5H coil,and we'll get started--or do i have to use an imaginary one?
You have to use an imaginary real coil, and you have to use an imaginary ideal coil. Draw a set of graphs showing current vs. time for the "CEMF current" and the EMF current for both types of coil to back up the statements that you have made multiple times. Illustrate your proposition using your intellect only.
Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
You used those numbers to try and make my statement look stupid.
You also know that if you had of used correct ratio's,then my statement makes perfect sense,and that would have made you look like the jackass
No, I used those numbers for illustrative purposes only and it was late at night and I was very tired. You are talking paranoid delusions.
Right now your statement looks totally stupid, it doesn't make sense at all. You don't need the illustrative numbers I made up to create that impression. Correct ratios won't make any difference. Draw up two graphs to back up your own statements to prove me wrong.
One more time for good measure: Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
So says the book worm
This "book worm" could whip your ass on a bench any day of the week with one arm tied behind my back and blindfolded, even though I haven't been on a bench in 25 years. You say crazy things like there is no voltage drop across a resistor, or a battery across a coil doesn't constitute a current loop. I would spin circles around you and leave you dizzy.
What's so annoying is that you are a fraud just like some YouTube free energy pitch man is a fraud. You have the same M.O. but you aren't asking for money. But you play the same game of evasion and deflection and do whatever ass-backwards-bending you have to do to save your fragile ego. There is basically no difference between you stalling and deflecting when asked to graph the current vs. time to illustrate your "theory" and asking John Rohner to measure power-out vs. power-in on his fake Papp engine. Neither will ever happen and in both cases it's a form of fraud, one is for money, and one is pure intellectual fraud to save your fragile ego.
If you admitted that you were wrong you would probably have a nervous breakdown.
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Brad:
You can hate me all you want, but what I hate is intellectual dishonesty. Look at your response to the sim that Poynt made, you just talked useless trash talk about the inner workings of the sim itself, which of course you haven't the slightest clue about at all. That way you avoid actually talking about the real subject matter - the results of the sim as it relates to Poynt's interesting question.
I get the feeling that you were the type of kid that when playing checkers with your friend, if you were losing then you just hit the board with your hand and sent the pieces flying and ruined the game. Better to ruin the game and act like a bully than actually lose and being seen as losing. That's the vibe I am getting from you.
Look what your belligerent attitude has gotten you. Endless frustration when trying to discuss things with you, and obviously your attitude hurt you as you grew up. You were too self-assured and too "smart" to learn things willingly, somehow you always "knew better." You definitely "knew better" when it came to language and now you are reaping the results of what you sewed. And here is the real kicker when it comes to that sensitive issue: The information age started 22 years ago, time flies. 22 years ago you may have come to the realization that the written word was going to be more important than ever. People would be submitting work reports online, your peers and your bosses would be reading them. Everybody started using email. One would think that you would have woken up in 1994 and said to yourself, "I need to kick myself in the butt and finally fix my spelling and diction issues because it is now going to be more important than ever." You were a fully grown man 22 years ago. But that didn't happen.
MileHigh
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snip...
How about this Brad: Straight to your face, NO, the answer is NO. For the tenth time, I don't have any equipment. Pound that in to your frying brain. Does that sound like "ducking, weaving and dodging" to you?
snip...
Well unless you consider $10.00 multi meters as equipment, I don't have any equipment either. Hasn't stopped me from making numerous JT's. Perhaps you don't have any hands either?
So, you haven't got any accurate equipment.? That only prevents you from making accurate measurements, it doesn't prevent you from making things. Surely you've got friends who have equipment to test your 'product' when the need arises. Or are technically minded and equipped friends also absent from your life?
You talk a great talk, but don't walk the walk. That's what sets you apart from people with great minds like TinselKoala who does both.
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So I guess we can say that the Emf = Cemf because they are always the same, Emf is Cemf in this example so one could also simply say that Emf = dI * L/dt. No feedback required.
It would seem so and I have no problem with magnetically induced Emf or Cemf. I fail to see a justified Cemf with applied Emf for reasons I've covered in my example in the previous post and because of this view, I also do not hold to an Emf/Cemf feedback control loop with an applied Emf.
When 4 volts is applied to a 5H inductor, current will rise at .8 amps per second. But why does that happen? Why does current only rise at .8 amps per second? What is regulating or limiting the current's rate of change so that current does not increase at a faster or slower rate?
Consider this:
EMF=dI*L/dt tells us WHAT happens. CEMF=dI*L/dt tells us WHY it happens.
PW
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Well unless you consider $10.00 multi meters as equipment, I don't have any equipment either. Hasn't stopped me from making numerous JT's. Perhaps you don't have any hands either?
So, you haven't got any accurate equipment.? That only prevents you from making accurate measurements, it doesn't prevent you from making things. Surely you've got friends who have equipment to test your 'product' when the need arises. Or are technically minded and equipped friends also absent from your life?
You talk a great talk, but don't walk the walk. That's what sets you apart from people with great minds like TinselKoala who does both.
To look at a LED being lit by a single battery? Wow. I did that in 1976 with an LM3909. I have no interest in playing with a scope, deal with it.
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To look at a LED being lit by a single battery? Wow. I did that in 1976 with an LM3909. I have no interest in playing with a scope, deal with it.
There's nothing to deal with. I readily acknowledge that you can not and will not walk the walk.
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Walking the walk is about being able to put forth a proposition and then back it up with reasoning and logic that you articulate on this forum with arguments and examples that can be explained with various diagrams and schematics. Likewise you can build and test something. That's the kind of thing that takes place around here, technical discussions and schematics and diagrams along with people building and testing things. Both approaches are equally valid ways of "walking the walk." So I can easily walk the walk when I want to, but I am never going to build a pulse motor or a Joule Thief. Meanwhile, the electronic devices that I did design might still be sitting in oil, gas, and hydro power plant control rooms all around the world.
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snip...
Meanwhile, the electronic devices that I did design might still be sitting in oil, gas, and hydro power plant control rooms all around the world.
They might be, but we'll never know will we. We just have to accept your claims at face value.
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It is ironic that you are using the sim to try and prove what some believe !may! happen,when that sim has been programmed to show exactly what it has been told to show ;D
Did you expect the sim to have a mind of it's own?,or will it simply follow the rules it has be given?.
Did the people that wrote the program for the sim have an ideal inductor to test,so as they could write the program and parameters of that sim to suit the inductors reaction's,or was it written based around the very same !laws! that are being discussed here on this thread?.
Brad
Do I take it then that you are also in disagreement with the sim's current trace for R=1 Ohm?
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They might be, but we'll never know will we. We just have to accept your claims at face value.
I suppose you will.
http://www.ti.com/product/tms34010
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I suppose you will.
http://www.ti.com/product/tms34010 (http://www.ti.com/product/tms34010)
Yes, I can see your name all over the site. /s
However I would be more inclined to believe you built this, given your Handle name
https://en.wikipedia.org/wiki/List_of_highest_bridges#/media/File:SiduheBridge.jpg (https://en.wikipedia.org/wiki/List_of_highest_bridges#/media/File:SiduheBridge.jpg)
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Do I take it then that you are also in disagreement with the sim's current trace for R=1 Ohm?
The 1 ohm test is fine-nothing wrong there.
Brad
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I suppose you will.
http://www.ti.com/product/tms34010
With raster graphics-raster?
You should point out there spelling mistakes MH-it could lead ti dire consequences :D :D
Maybe it's a word i just have never heard of.
Being that you cannot determine which little JT circuit would be more efficient ,i find it hard to believe you could accomplish anything like the link presents.
Perhaps some pics of some of your builds from days past would be good to see.
Brad
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Then why do you say the 1p Ohm trace is wrong?
Or, if you're not saying that, are you saying that it is not close enough to ideal? If so, why?
Is the first 3 seconds of a 158 thousand year time constant not close enough to a perfect straight line for you?
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Brad:
So you are still a coward. You are afraid to illustrate your "theories" with concrete examples. Instead, we get some mindless diversionary trash talk revolving around the usual "you don't do experiments" nonsense.
Make a graph of current vs. time for the alleged "CEMF current" and the EMF induced current and show the world what you mean.
Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
How about this Brad: Straight to your face, NO, the answer is NO. For the tenth time, I don't have any equipment. Pound that in to your frying brain. Does that sound like "ducking, weaving and dodging" to you?
You have to use an imaginary real coil, and you have to use an imaginary ideal coil. Draw a set of graphs showing current vs. time for the "CEMF current" and the EMF current for both types of coil to back up the statements that you have made multiple times. Illustrate your proposition using your intellect only.
Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
No, I used those numbers for illustrative purposes only and it was late at night and I was very tired. You are talking paranoid delusions.
Right now your statement looks totally stupid, it doesn't make sense at all. You don't need the illustrative numbers I made up to create that impression. Correct ratios won't make any difference. Draw up two graphs to back up your own statements to prove me wrong.
One more time for good measure: Oh, you won't do that? Then that means your proposition is a fail, your theory is junk, a mistake. You are just too afraid to admit that. You are a coward. You are weak. You are a fraud.
This "book worm" could whip your ass on a bench any day of the week with one arm tied behind my back and blindfolded, even though I haven't been on a bench in 25 years. You say crazy things like there is no voltage drop across a resistor, or a battery across a coil doesn't constitute a current loop. I would spin circles around you and leave you dizzy.
What's so annoying is that you are a fraud just like some YouTube free energy pitch man is a fraud. You have the same M.O. but you aren't asking for money. But you play the same game of evasion and deflection and do whatever ass-backwards-bending you have to do to save your fragile ego. There is basically no difference between you stalling and deflecting when asked to graph the current vs. time to illustrate your "theory" and asking John Rohner to measure power-out vs. power-in on his fake Papp engine. Neither will ever happen and in both cases it's a form of fraud, one is for money, and one is pure intellectual fraud to save your fragile ego.
If you admitted that you were wrong you would probably have a nervous breakdown.
You could whip my ass on the bench any day?
Good-lets do it then.
JT,pulse motor, or rotoverter ?--im ready for you to back up your claim.
While we are at it MH, how is the current able to flow when there is no potential difference?
Lets forget about current flowing through the coil,-tell us how current flows through the wires from the source,when the voltage across the coil is also the same value as the voltage across the source.
I bet iknow what your answer will be,and the reason as to why you have not stated said answer earlier on--but we will see.
Brad
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Brad:
So, you are never going to make a graph to back up your whackadoo "dual current" theory. Surprise surprise.
For what it's worth, I count about 12 spelling, punctuation, and style mistakes in your posting #1570.
Being that you cannot determine which little JT circuit would be more efficient.
I actually responded to that issue in a moderate amount of detail but it passed right through you like you weren't even there. Yes I could easily whip your ass on the bench, and that has been established beyond a shadow of a doubt, but it's likely that I will never go on a bench again.
Lets forget about current flowing through the coil,-tell us how current flows through the wires from the source,when the voltage across the coil is also the same value as the voltage across the source.
I don't really know what you are talking about, and I am not really following the discussion. Now, if you can actually formulate a proper question and not have it be the usual half-assed mangling of the English language and I can actually understand you without having to rely on a secret decoder ring, then I might try answering.
MileHigh
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With raster graphics-raster?
snip...
Brad
Raster graphics is common pixel graphics. Most digital photos are based on raster graphics, which is why a high pixel count camera represents a higher resolution picture, and the raw raster image stored on a disk is usually quite large. Most cameras offer the .jpg or other algorithms to automatically downsize the stored photos bit space for smaller files, but with some loss of initial data.
Vector graphics are more common with drawing programs, and usually have a much smaller file size footprint.
These days computers are so fast, with a lot of memory and high speed processors, the time taken to render an image to a file or to screen is negligible, but decades ago, a raw raster image could take a while to render to screen if it was a very large image, and a vector image could take a while as well, if it was sufficiently complex.
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Brad:
So, you are never going to make a graph to back up your whackadoo "dual current" theory. Surprise surprise.
For what it's worth, I count about 12 spelling, punctuation, and style mistakes in your posting #1570.
I actually responded to that issue in a moderate amount of detail but it passed right through you like you weren't even there. Yes I could easily whip your ass on the bench, and that has been established beyond a shadow of a doubt, but it's likely that I will never go on a bench again.
I don't really know what you are talking about, and I am not really following the discussion. Now, if you can actually formulate a proper question and not have it be the usual half-assed mangling of the English language and I can actually understand you without having to rely on a secret decoder ring, then I might try answering.
MileHigh
Odd how it is only you that ever has trouble understanding what i write-mmm?
So-you make the claim that you could whip my butt on the bench, but refuse to back it up.
I have seen your effort at building a simple electromagnet,and it looked like some one had a bad day with the reel on there fishing rod,so i think im safe there-on the bench.
Could you please post again-in detail as to how the current will flow without a potential difference between coil an source.
Thanks
Brad
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Then why do you say the 1p Ohm trace is wrong?
Or, if you're not saying that, are you saying that it is not close enough to ideal? If so, why?
Is the first 3 seconds of a 158 thousand year time constant not close enough to a perfect straight line for you?
As i said-at what point were actual real world measurements substituted for math that just followed the trend of those actual measurement taken?.
If we look at what nature shows us,we can go from a liquid to a solid when we go from a value of 1 down to 0. So we know drastic changes are indeed possible in one small change-one value less,and we went from a liquid to a solid.
I am remaining undecided until such time that some one can give a solid reason as to how current can flow from a source to the coil,when that coil has the same voltage across it-->apparently
Brad.
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Everybody has trouble understanding what you write, because sometimes the way you write is extremely odd.
some one had a bad day with the reel on there fishing rod
Grok this: They're going to get their rose petals and fishing rod over there.
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Everybody has trouble understanding what you write, because sometimes the way you write is extremely odd.
Or it could be just the fact that Australians do not always word things the same way as other countries-->did that ever cross your mind?
I mean,words can have different meanings.
E.G Complete and finished--seem the same-yea
If you have finished a project,it is now complete.
Or in your case MH,it ,makes you feel !complete! to argue with others here on this forum,but if you took me on in a build off,you would be !finished! :D
Could you please post again-in detail as to how the current will flow without a potential difference between coil an source.
Brad
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No, it has absolutely nothing to do with the way Australians speak English and everything to do with your own personal problems with language. Don't play straw man. There is never going to be a build-off of anything, so fantasize away.
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As i said-at what point were actual real world measurements substituted for math that just followed the trend of those actual measurement taken?.
If we look at what nature shows us,we can go from a liquid to a solid when we go from a value of 1 down to 0. So we know drastic changes are indeed possible in one small change-one value less,and we went from a liquid to a solid.
I am remaining undecided until such time that some one can give a solid reason as to how current can flow from a source to the coil,when that coil has the same voltage across it-->apparently
Brad.
So the 1 Ohm current trace is ok with you, you have no problem with that. But you can't (or won't) see the progression to 1p Ohm and the associated trace and make a mental connection?
Nor will you conclude or acknowledge from that data that a 158 thousand year time constant in a 3 second time frame (the first 3s) can be considered an ideal straight line for the current trace?
Is there anyone else here that also can't or won't make the connection? Are there others that remain "undecided" and or unconvinced?
Anyone else feel that the simulation is only correct for the 1 Ohm trace, but not the 1p Ohm trace? Anyone care to give an explanation why one is correct, while the other is not? I am curious to see the logic here, because this doe not make any sense at all. Are we cherry picking the results of the simulation so that it is only correct when it is in alignment with our own preconceptions (or perhaps misconceptions)? Is that good science? I think not.
I am using the simulation program within the limits of its capabilities, so I fail to see why the results are being scrutinized, especially when one result is considered ok, while the other (tweak to R value) is not.
Please enlighten me, as this is becoming discouraging.
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Could you please post again-in detail as to how the current will flow without a potential difference between coil an source.
PW has explained in detail how/why the current is limited and that the cemf=Vin.
It is a step-wise process that does not happen in steps; it is an instantaneous process. It can be understood however by breaking it into steps as he has posted a few times already.
A lot of time and effort by some here is essentially wasted when the offered explanations are not even challenged on a technical level. I did not see any attempt to analyse and/or debate from a technical perspective PW's descriptions of the process. And the same has been done to a number of my own posts as well. It seems that the explanations are rejected or dismissed out of hand and the same question repeated, indicating to me that either the explanation was not understood, or not agreed to. That is fine, but out of respect, if it is not understood, ask for clarification, if it is not agreed to, explain in technical terms, why.
In summary, it is a self-regulating process facilitated by negative feedback caused by self-induction and Lenz's law.
How does a governor work an a small engine? Similar in concept, but the process with the inductor begins as soon as current flows. The regulation is achieved via the self-induction process and the fact that more current produces more cemf, so it regulates itself to a fixed rate of A/s.
The inductor "produces" a cemf equal to Vin because all the input voltage is always fully across the inductor; there is no resistor to trade off the voltage with. From the simulations, even the 1 Ohm case clearly shows that all the input voltage is across the inductance for the fist part of the trace, and that has not been acknowledged by you either, and this is KEY. It crushes the argument that current can not flow if the cemf equals Vin.
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No, it has absolutely nothing to do with the way Australians speak English and everything to do with your own personal problems with language. Don't play straw man. There is never going to be a build-off of anything, so fantasize away.
I have no problem with the way i speak MH,nor dose anyone else.
It seems that you are the only one with the problem here--another failed attempt at misdirection from the question.
Could you please post again-in detail as to how the current will flow without a potential difference between coil an source.
Brad
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In summary, it is a self-regulating process facilitated by negative feedback caused by self-induction and Lenz's law.
PW has explained in detail how/why the current is limited and that the cemf=Vin.
I was asking MH for his answer.
It is a step-wise process that does not happen in steps; it is an instantaneous process. It can be understood however by breaking it into steps as he has posted a few times already.
A lot of time and effort by some here is essentially wasted when the offered explanations are not even challenged on a technical level. I did not see any attempt to analyse and/or debate from a technical perspective PW's descriptions of the process. And the same has been done to a number of my own posts as well. It seems that the explanations are rejected or dismissed out of hand and the same question repeated, indicating to me that either the explanation was not understood, or not agreed to. That is fine, but out of respect, if it is not understood, ask for clarification, if it is not agreed to, explain in technical terms, why.
I have ask a number of times now,where is the loss?--why is the negative feedback less than that that caused the negative feedback?
So i have ask for clarification a number of times now,and have received no answer.
I will take it that you have misses !on a number of occasions! that i have indeed requested clarification.
How does a governor work an a small engine? Similar in concept, but the process with the inductor begins as soon as current flows. The regulation is achieved via the self-induction process and the fact that more current produces more cemf, so it regulates itself to a fixed rate of A/s.
A good point.
A governor works by regulating the RPM at which an engine will run. It will not allow the RPM to double every second,unlike the current value dose !apparently! in our ideal coil.
If the governor was set to kick in at the point at which the engine crank started revolving,then the engine would not revolve at all. If there was a non ideal governor,and there was some loss in that governing system,then the engine crank will rotate.
So i will ask once again--where is the loss in the negative feed back system?.
The inductor "produces" a cemf equal to Vin because all the input voltage is always fully across the inductor; there is no resistor to trade off the voltage with. From the simulations, even the 1 Ohm case clearly shows that all the input voltage is across the inductance for the fist part of the trace, and that has not been acknowledged by you either, and this is KEY. It crushes the argument that current can not flow if the cemf equals Vin.
And so,the question remains--where is the loss?
Also,are you saying that there is no voltage drop across the series resistor at T=0/s ?
If this is the case,then it should not matter as to what value resistor we use as our series resistor,in order to see the CEMF value--we should see no voltage drop across the resistor at T=0/s-->time of connection--correct?.
Brad
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I was asking MH for his answer.
I have ask a number of times now,where is the loss?--why is the negative feedback less than that that caused the negative feedback?
Asking this question indicates that you do not understand the explanation.
There is no loss; cemf=Vin at all times with the ideal inductor.
A governor works by regulating the RPM at which an engine will run. It will not allow the RPM to double every second,unlike the current value dose !apparently! in our ideal coil.
If the governor was set to kick in at the point at which the engine crank started revolving,then the engine would not revolve at all. If there was a non ideal governor,and there was some loss in that governing system,then the engine crank will rotate.
I see RPM as the voltage and torque as the current. The governor I would be referring to (more or less equal to the inductor current limiting process) would limit torque not voltage. So it would be like an centrifugal clutch that could adjust itself to produce a constant rise in torque.
Also,are you saying that there is no voltage drop across the series resistor at T=0/s ?
If this is the case,then it should not matter as to what value resistor we use as our series resistor,in order to see the CEMF value--we should see no voltage drop across the resistor at T=0/s-->time of connection--correct?.
Brad
For a non-ideal inductor, that is correct. At the instant Vin is connected, unless R is large relative to the L value, the resistor will have very little voltage across it compared to the inductance. So for normal non-ideal inductors, this holds true. You can confirm this on your bench to a certain degree. Obviously real inductors already have a series resistance, but you will have to introduce another so you can measure the voltages across each when the connection is made.
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When 4 volts is applied to a 5H inductor, current will rise at .8 amps per second. But why does that happen? Why does current only rise at .8 amps per second? What is regulating or limiting the current's rate of change so that current does not increase at a faster or slower rate?
Consider this:
EMF=dI*L/dt tells us WHAT happens. CEMF=dI*L/dt tells us WHY it happens.
PW
I assume you have a typo above since by definition, Cemf = -dI*L/dt.
We have a stalemate here between me, yourself, Poynt, and others because at present, I have seen no physical or mathematical evidence to convince me otherwise including your explanation above. I guess that is my problem!
So, in order to not be a burden, I will no longer post on the subject unless I can prove my point at least mathematically.
pm
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I assume you have a typo above since by definition, Cemf = -dI*L/dt.
We have a stalemate here between me, yourself, Poynt, and others because at present, I have seen no physical or mathematical evidence to convince me otherwise including your explanation above. I guess that is my problem!
So, in order to not be a burden, I will no longer post on the subject unless I can prove my point at least mathematically.
pm
Consider two voltage sources connected in parallel. One Vsource represents the applied EMF, the other Vsource represents the inductor's generated CEMF. The first Vsource, representing EMF, is set to output +4 volts.
What voltage must the second Vsource be set to output in order for their to be no current flow?
PW
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I see RPM as the voltage and torque as the current. The governor I would be referring to (more or less equal to the inductor current limiting process) would limit torque not voltage. So it would be like an centrifugal clutch that could adjust itself to produce a constant rise in torque.
OK,i think you had better leave out trying to link this to engine RPM and torque,as none of that makes sense. A centrifugal clutch can only deliver the same amount of torque as the engine,and that torque is determined by the RPM torque range of the engine,where the RPM is limited by the governor. This is the very same as the voltage being able to increase or decrease the amount of current that flows over time,where the system has resistance.
There is no loss; cemf=Vin at all times with the ideal inductor
.
OK,this is where i do not understand.
If there is no loss !somewhere! ,then how dose current flow if we have equal and opposite?
For a non-ideal inductor, that is correct. At the instant Vin is connected, unless R is large relative to the L value, the resistor will have very little voltage across it compared to the inductance. So for normal non-ideal inductors, this holds true. You can confirm this on your bench to a certain degree. Obviously real inductors already have a series resistance, but you will have to introduce another so you can measure the voltages across each when the connection is made.
Very little is enough for a potential difference,and there for,enough for current to start to flow.
I tried a few inductors tonight,and in each case,i got a 600mV difference between the EMF and CEMF values--see scope shot below of 500mH inductor.
The yellow trace is the EMF,and the blue trace is across the inductor.
The winding resistance value is 1.2 ohms.
Asking this question indicates that you do not understand the explanation.
No i dont.
If the negative feed back value is equal to that induced,then why would there be a net current flow in one direction?
Im seeing this as an AC type deal,where the reverse current value is the same as the forward current value--as there are no losses.
Brad
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Consider two voltage sources connected in parallel. One Vsource represents the applied EMF, the other Vsource represents the inductor's generated CEMF. The first Vsource, representing EMF, is set to output +4 volts.
What voltage must the second Vsource be set to output in order for their to be no current flow?
PW
+4 volts
Brad
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I think, there is a request to explain the the asymmetry of V.. Source and V ... Induced. If there is Vs=Vi ,it seem to be no asymmetry. :o
But whats about the payload for Vi ?
Vi can only exist due to the changing magnetic field, for that we need current that changes every time unit.
so what is the result ?
Love + Peace
3K
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I was asking MH for his answer.
I have ask a number of times now,where is the loss?--why is the negative feedback less than that that caused the negative feedback?
So i have ask for clarification a number of times now,and have received no answer.
I will take it that you have misses !on a number of occasions! that i have indeed requested clarification.
So is your issue ONLY with regard to inductors having no resistance, or do you not agree with or understand the concept of an inductor's CEMF as the feedback mechanism that limits the current flow's rate of change with regard to ANY inductor?
PW
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So is your issue ONLY with regard to inductors having no resistance, or do you not agree with or understand the concept of an inductor's CEMF as the feedback mechanism that limits the current flow's rate of change with regard to ANY inductor?
PW
OK,well this seems so hard to make any clearer.
If the CEMF voltage is the same as the EMFs voltage,then where is the loss that allows current to flow,when there is no potential difference between the inductor and source.
Here is the thing. If the CEMF voltage is the same as the V/in,then you have just converted all(100%) of the applied EMFs induced current into CEMF. We now have your two batteries hooked in parallel that have the same voltage--but current still flows. You talk about negative feed back,and this feed back is of the same value,but current still flows--so where is the loss on the negative side(the CEMF side) that allows current to flow with no potential difference.
This is about the fifth or sixth time i have asked,and never get an answer.
From all my test,the CEMF is lower than the EMF by over 1/2 a volt,when 12 volts is applied to that inductor. I am yet to see anyone here making claims that the CEMF is equal to the EMF,actually show it to be the same--my results show it is not,and so current can flow.
Blue is voltage across inductor,yellow is supply voltage.
Brad
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OK,well this seems so hard to make any clearer.
It would make it much clearer if you would just answer my question as posed. As in when I asked if your issue was only with regard to zero R inductors or all inductors...
If the CEMF voltage is the same as the EMFs voltage,then where is the loss that allows current to flow,when there is no potential difference between the inductor and source.
Here is the thing. If the CEMF voltage is the same as the V/in,then you have just converted all(100%) of the applied EMFs induced current into CEMF.
This is not correct. CEMF is only generated by a changing magnetic field and it is only the portion of that changing magnetic field that cuts the conductor at right angles that induces a voltage back into the conductor.
We now have your two batteries hooked in parallel that have the same voltage--but current still flows. You talk about negative feed back,and this feed back is of the same value,but current still flows--so where is the loss on the negative side(the CEMF side) that allows current to flow with no potential difference.
This is about the fifth or sixth time i have asked,and never get an answer.
Again, in order to help you understand this, I have asked if your issue regarding this is only with regard to zero R inductors, or if it is more so that you are having an issue understanding the CEMF's regulating effect with regard to all inductors.
From all my test,the CEMF is lower than the EMF by over 1/2 a volt,when 12 volts is applied to that inductor. I am yet to see anyone here making claims that the CEMF is equal to the EMF,actually show it to be the same--my results show it is not,and so current can flow.
Blue is voltage across inductor,yellow is supply voltage.
You're going to have to provide more info for me to make any sense of your scope shot.
If you are connecting an inductor directly across a Vsupply, how can the supply voltage and the voltage measured across the inductor not be equal? A schematic or description of your test set up would be helpful...
PW
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The magnitude of Vsourse and Vinduced are the same.
But Vsource is a static source, Vind is a dynamic source.
For my assumption, this is the unsymmetrical between the both magnitudes.
The difference is how to get the magnitude. Maybe is is the time between first and second action.
With the equation I(t) = (Us / L) *t we cant describe the difference.
0.8 A/s = 4V/5Henry. For this equation we get at t=0 no difference,
so that Vs = Vi. But we also know that without a changing current 0.8A/s we wont get the -4V.
So Vs is not equal Vi, but the Magnitude (Skalar) is equal.
L+P 3K
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Consider two voltage sources connected in parallel. One Vsource represents the applied EMF, the other Vsource represents the inductor's generated CEMF. The first Vsource, representing EMF, is set to output +4 volts.
What voltage must the second Vsource be set to output in order for their to be no current flow?
PW
Even though I said I would not post until I could show evidence contrary to your beliefs, I will play along.
The second Vsource or Cemf must be +4v of course. And the point is .......?
pm
Edit: PW or anybody, please give an equivalent circuit or model of the Emf/Cemf interaction in a single inductor driven from an Emf source. Or a math derivation would be OK but not just the same repeat of Emf = Cemf please.
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Even though I said I would not post until I could show evidence contrary to your beliefs, I will play along.
The second Vsource or Cemf must be +4v of course. And the point is .......?
pm
Edit: PW or anybody, please give an equivalent circuit or model of the Emf/Cemf interaction in a single inductor driven from an Emf source. Or a math derivation would be OK but not just the same repeat of Emf = Cemf please.
The point is that there is no minus sign where you indicated.
Everyone seems to be in agreement that no current will flow when the EMF=CEMF.
1. When the current flowing thru a 5H inductor is changing at the rate of .8 amps per second, a CEMF of 4 volts is generated (CEMF=dI*L/dt).
2. If the applied EMF is 4 also volts, current flow will cease as soon as the CEMF reaches 4 volts because at that point the CEMF equals the applied EMF (CEMF=EMF).
3. However, as the current flow begins to cease, so does the rate of change, causing the CEMF to be less than 4 volts.
4. When the CEMF is less than 4 volts, that is, when the CEMF<EMF, current will again flow until the rate of change again reaches .8 amps per second and the CEMF again equals 4 volts.
Return to step 2 above (continuous loop)
And again, although described in a stepwise fashion, it is a smooth and continuous process similar to the many instances of negative feedback used in all manner of electronic circuits.
It is this process that limits, or regulates, the current flow's rate of change.
PW
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The point is that there is no minus sign where you indicated.
Everyone seems to be in agreement that no current will flow when the EMF=CEMF.
No current flow in what? Could you be specific as you reference Emf=Cemf below in your feedback correction example below when dI=.8A/S.
1. When the current flowing thru a 5H inductor is changing at the rate of .8 amps per second, a CEMF of 4 volts is generated (CEMF=dI*L/dt).
Well I guess that I'm the only one who disagrees so I will try to explain why! Why are you taking liberty to change Cemf=-dI*L/dt to Cemf=dI*L/dt? Are you throwing the Lenz factor away? If yes, why and how? If not, then when you state that Emf = Cemf, to me you are saying to me that dI*L/dt=-dI*L/dt. Do I not understand the terminology?
2. If the applied EMF is 4 also volts, current flow will cease as soon as the CEMF reaches 4 volts because at that point the CEMF equals the applied EMF (CEMF=EMF).
Now I'm really confused by the above statement because you and others hold to the idea that Emf = Cemf during normal inductor current so again, what current will cease to flow?
3. However, as the current flow begins to cease, so does the rate of change, causing the CEMF to be less than 4 volts.
OK, let's look at what could cause the current in the inductor to decrease even slightly during any given dt. A), the Emf could drop but so would the assumed Cemf so we still follow the EMF law. B), the inductance could change due to self heating (neglecting any change in the DC resistance) creating a slight physical movement so this could really be ignored, but this too would follow the Emf law. So what does that leave but C), the initial instant that the Emf is applied when supposedly the Emf/Cemf feedback loop corrects until we experience dI=Emf*dt/L.
4. When the CEMF is less than 4 volts, that is, when the CEMF<EMF, current will again flow until the rate the change again reaches .8 amps per second and the CEMF again equals 4 volts.
Again, apart from any outside influence such as an approaching magnet or any material that would change the permeability, what would cause the required feedback adjustment above other than the instant of applied Emf?
Return to step 2 above (continuous loop)
And again, although described in a stepwise fashion, it is a smooth and continuous process similar to the many instances of negative feedback used in all manner of electronic circuits.
PW
Well, I can't seem to get past step 1. :-[ Believe me, I understand what you are trying to explain, I just don't agree with it for the above and previously stated reasons.
IMO, your thought model is flawed but I just can't prove it at this point in time.
pm
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The point is that there is no minus sign where you indicated.
Everyone seems to be in agreement that no current will flow when the EMF=CEMF.
1. When the current flowing thru a 5H inductor is changing at the rate of .8 amps per second, a CEMF of 4 volts is generated (CEMF=dI*L/dt).
2. If the applied EMF is 4 also volts, current flow will cease as soon as the CEMF reaches 4 volts because at that point the CEMF equals the applied EMF (CEMF=EMF).
3. However, as the current flow begins to cease, so does the rate of change, causing the CEMF to be less than 4 volts.
4. When the CEMF is less than 4 volts, that is, when the CEMF<EMF, current will again flow until the rate of change again reaches .8 amps per second and the CEMF again equals 4 volts.
Return to step 2 above (continuous loop)
And again, although described in a stepwise fashion, it is a smooth and continuous process similar to the many instances of negative feedback used in all manner of electronic circuits.
It is this process that limits, or regulates, the current flow's rate of change.
PW
Are we talking about cemf of the inductor or an applied cemf equal to the applied emf?
When we first apply 4v emf, how can cemf be equal to the emf? What happened to create the initial cemf? Did some current flow in the beginning due to emf in order for the cemf to develop in the first place? I mean, I can understand that at T0 that the 4v can be read across the inductor leads, but Im not sure it is due to cemf created by induction unless some initial emf current must have happened in order for cemf to develop in the first place.
Im kinda betting on cemf to be in some form, no matter how small the difference, to be always less than the emf.
Mags
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Are we talking about cemf of the inductor or an applied cemf equal to the applied emf?
When we first apply 4v emf, how can cemf be equal to the emf? What happened to create the initial cemf? Did some current flow in the beginning due to emf in order for the cemf to develop in the first place? I mean, I can understand that at T0 that the 4v can be read across the inductor leads, but Im not sure it is due to cemf created by induction unless some initial emf current must have happened in order for cemf to develop in the first place.
Im kinda betting on cemf to be in some form, no matter how small the difference, to be always less than the emf.
Mags
All thru this thread we have been discussing the 4 volts applied across the inductor from an ideal Vsource ,as being the applied EMF, or just EMF. The EMF is the fixed potential of 4 volts applied to the inductor at T=0.
CEMF refers to the voltage induced in the inductor's windings as the current flowing thru the inductor changes at a speciific rate.
PW
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Has everyone at least read the Wiki?
https://en.wikipedia.org/wiki/Inductor
PW
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All thru this thread we have been discussing the 4 volts applied across the inductor from an ideal Vsource ,as being the applied EMF, or just EMF. The EMF is the fixed potential of 4 volts applied to the inductor at T=0.
CEMF refers to the voltage induced in the inductor's windings as the current flowing thru the inductor changes at a speciific rate.
PW
Well, that is not what I asked. Anyway...
I do know about the 4v, as I did mention that in my post..
When we say "...cemf refers to the voltage induced in the inductors windings......" , I look at it a bit differently..
Say we apply the input and current begins to rise. I, instead of seeing the cemf as an actual reverse voltage potential against the input, I see all of that happening in the magnetic realm where the fields are at odds with each other 'from winding to winding' which determines the current flow, rather than thinking that 2 emf's are actually in opposition in the wound conductor.
Mags
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The point is that there is no minus sign where you indicated.
Everyone seems to be in agreement that no current will flow when the EMF=CEMF.
1. When the current flowing thru a 5H inductor is changing at the rate of .8 amps per second, a CEMF of 4 volts is generated (CEMF=dI*L/dt).
2. If the applied EMF is 4 also volts, current flow will cease as soon as the CEMF reaches 4 volts because at that point the CEMF equals the applied EMF (CEMF=EMF).
3. However, as the current flow begins to cease, so does the rate of change, causing the CEMF to be less than 4 volts.
4. When the CEMF is less than 4 volts, that is, when the CEMF<EMF, current will again flow until the rate of change again reaches .8 amps per second and the CEMF again equals 4 volts.
Return to step 2 above (continuous loop)
And again, although described in a stepwise fashion, it is a smooth and continuous process similar to the many instances of negative feedback used in all manner of electronic circuits.
It is this process that limits, or regulates, the current flow's rate of change.
PW
I have highlighted 3 because-->
Being that the coil is ideal,there is no rate of change-change-->the rate of change remains a constant,regardless of the applied voltage value,because the time constant is infinite.
Every time the EMF tries to make a change,the CEMF makes the very same change at an instant--your feed back system.
So the very moment an EMF is applied(the force is applied),the CEMF pushes back with the same force--when you push against a concrete wall,the wall will push back with the same force you applied to it,and there is no motion.
Then there is this-->the equal and opposite to your feed back system.
If the EMF is 4 volt's,and the CEMF is 4 volt's,the only way current can start to flow again,is if either the EMF voltage rises above 4 volts,or the CEMF voltage drops below 4 volt's. In your feed back system,one of these two has to happen in order for current to flow.
As the voltage is ideal,then we can assume that it will not drop below that value. This leaves only the CEMF voltage value. As our rate of change is constant-as our coil is ideal,and free from resistance,i ask !once again!,where is the loss that allows the current to flow?-->how is the CEMFs value reduced when the rate of change is a constant,and the applied voltage is ideal,and will not change from that 4 volts-regardless of load.
So i am asking you(with regards to the original MH question),where is the loss that allows current to flow,if the CEMF value is always that of the !!ideal!! voltages value of 4 volts,and where there is no rate of change in time of the magnetic field.
We have all agreed that the applied 4 vots-our EMF is a constant,and will not change unless we change it. You (and some others) have also clearly stated that you believe that the CEMF is always going to be equal to that of the applied voltage,as there is no rate of change to the magnetic field in our ideal inductor.
So,in order for current to flow through our ideal inductor,the CEMF !must! be lower than the applied !ideal! EMF.
It would seem to me PW,that you are using this !feed back! stuff,so as it aligns with current mathematics,and not looking at the situation as it is.
The circuit in regards to the scope shot,is as below.
It would seem to me that the actual value of the CEMF value at T=0(moment EMF is placed across the inductor),would be 11.6 volts,if the average between the EMF and CEMF is 12.2 volts--the blue trace.
I will have to set up a more robust circuit to confirm this,but it is clear that the CEMF is of a lesser value than the applied EMF.
Brad
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@MH
Could you please post again-in detail as to how the current will flow without a potential difference between coil an source.
This is all i have from you-post 1365
Quote:-->a coil integrates on voltage to give you current just like a shopping cart integrates on force to give you velocity. It's just Mother Nature in action.
All of the stuff in your head about "battling currents" is a model that simply does not work. It's crazy talk. It's like something that you found in a pumpkin patch.
Brad
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Tinman,
First, in your scope shot and schematic you are not measuring the CEMF. The difference you are seeing between channels is the Vdrop across R1. You are in effect measuring current.
The CEMF and EMF across the inductor are equal and the only way you can observe the CEMF is by its effect on current flow.
Second, once again I do not know if you are having problems with seeing the inductor's CEMF as a feedback mechanism in ALL inductors or only with regard to inductors of zero resistance. Please let me know if it is one or the other or both.
If your problem is only with regard to zero R inductors, then perhaps an inductor with .1R should be discussed.
PW
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Tinman,
PW
First, in your scope shot and schematic you are not measuring the CEMF. The difference you are seeing between channels is the Vdrop across R1. You are in effect measuring current.
The voltage being measured is the instantaneous voltage-Vmax.
If the CEMF was equal to the EMF at T=0,then there should be no current flow,so why would there be a voltage drop across the resistor at T=0
Remember,we are reading the maximum voltage values on each channel,and so this is the voltage at T=0.
The CEMF and EMF across the inductor are equal and the only way you can observe the CEMF is by its effect on current flow.
I disagree.
If the CEMF and EMF are equal at T=0,then there should be no current flow at that time,and there for there should be no voltage drop across the resistor.
Second, once again I do not know if you are having problems with seeing the inductor's CEMF as a feedback mechanism in ALL inductors or only with regard to inductors of zero resistance. Please let me know if it is one or the other or both.
If your problem is only with regard to zero R inductors, then perhaps an inductor with .1R should be discussed.
The difference between the EMF and CEMF i am seeing,can only be due to the coils winding resistance. As we have no winding resistance in an ideal coil,then i would agree that the CEMF is equal to the EMF--and there we have our problem.
This feed back system you talk about,must have a loss in the negative feed back in order for it to no be the same that induced it in the first place. At T=0,every change that the EMF tried to make to the current flow,the CEMF would counteract this change with 100% efficiency-and so no change takes place. As you you have said that the drop in voltage in my scope shot is due to current flow,and that is the two instantaneous voltage value's,then current could only flow instantly if the instantaneous CEMF value was less than that of the applied EMF. As i stated,i believe this to be true when the coil has winding resistance.
I am yet to see(as partzman said),anything that confirms that the CEMF is equal to the applied EMF at T=0. So far,i have seen the opposite.
Brad
Brad
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The voltage being measured is the instantaneous voltage-Vmax.
If the CEMF was equal to the EMF at T=0,then there should be no current flow,so why would there be a voltage drop across the resistor at T=0
Remember,we are reading the maximum voltage values on each channel,and so this is the voltage at T=0.
Your input square wave looks rather soft, but all in all what I am seeing in your scope shot is very little, if any, current flow at T=0 as evidenced by there being little drop (difference between channels) at that time. However, it is hard to see any detail at your scope settings and as I said, your input waveform looks soft. But, all in all, I see very little current flow at T=0 with current rising at T>0.
I disagree.
If the CEMF and EMF are equal at T=0,then there should be no current flow at that time,and there for there should be no voltage drop across the resistor.
From what I see in your scope shot, there is no Vdrop across the resistor at T=0, so no current is flowing at T=0. However, you should consider using a stiffer Vsource for your input waveform for this type of testing. The CEMF=EMF when the current flow reaches the appropriate rate of change.
The difference between the EMF and CEMF i am seeing,can only be due to the coils winding resistance.
How are you "seeing" a difference between the EMF and CEMF when nothing in your test setup will allow you to see that?
The drop across R1 can be used to calculate the rate the current is changing, which can act as a proxy to allow you to see the results of the CEMF. The CEMF and EMF however are both contained in the scope channel that is directly across the inductor.
However, if you believe your two scope channels are measuring EMF and CEMF and if you believe that difference is due to winding resistance, that should be a piece of cake to prove or disprove by using R1's value and the DCR of the coil. But if the observed drop it is due to the DCR of the coil as you say, why is the current waveform shaped like it is?
As we have no winding resistance in an ideal coil,then i would agree that the CEMF is equal to the EMF--and there we have our problem.
This feed back system you talk about,must have a loss in the negative feed back in order for it to no be the same that induced it in the first place.
No dissipation is required. But if that is where you are getting hung up, then as .99 attempted to do, perhaps steering the discussion towards an inductor with some amount of resistance would be helpful.
At T=0,every change that the EMF tried to make to the current flow,the CEMF would counteract this change with 100% efficiency-and so no change takes place. As you you have said that the drop in voltage in my scope shot is due to current flow,and that is the two instantaneous voltage value's,then current could only flow instantly if the instantaneous CEMF value was less than that of the applied EMF. As i stated,i believe this to be true when the coil has winding resistance.
I am unable to follow this. Your scope shot appears to show no current current flow at T=0 and then the expected increase in current at T>0
I am yet to see(as partzman said),anything that confirms that the CEMF is equal to the applied EMF at T=0. So far,i have seen the opposite.
I have repeatedly stated that immediately following T=0, and as soon as the rate of change reaches .8amps per second, the CEMF becomes equal the EMF. This can appear as being instantaneous as .99 stated, but I am more comfortable with the wording "as soon as the rate of change reaches .8 amps per second" the CEMF=EMF. This need only happen in a very very short period of time and involve only a minuscule amount of current flow, but again, as I see it, the CEMF will not equal the EMF until the appropriate rate of change is achieved. With 4 volts applied to 5H, that is .8 amps per second That is what the time tested formulae tell us.
PW
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author=picowatt link=topic=16589.msg487598#msg487598 date=1467430986]
How are you "seeing" a difference between the EMF and CEMF when nothing in your test setup will allow you to see that?
The test setup allows exactly that,and now allows us to see the effects of the electric field and capacitance of the windings at work,before current starts to flow.
Your input square wave looks rather soft, but all in all what I am seeing in your scope shot is very little, if any, current flow at T=0 as evidenced by there being little drop (difference between channels) at that time. However, it is hard to see any detail at your scope settings and as I said, your input waveform looks soft. But, all in all, I see very little current flow at T=0 with current rising at T>0.
From what I see in your scope shot, there is no Vdrop across the resistor at T=0, so no current is flowing at T=0. However, you should consider using a stiffer Vsource for your input waveform for this type of testing. The CEMF=EMF when the current flow reaches the appropriate rate of change.
The input is fine,and the square wave is also very defined-as you will see in the scope shot below.
We can reduce the time per division to 50 microseconds,and clearly see when current starts to flow--remember,this is at a low frequency of 10 Hz.
At the very point current starts to flow,both the V/in and V across the inductor should be exactly the same. There should be no voltage drop across the resistor until current starts to flow,so the test setup is valid to see the voltage across the inductor before current starts to flow.
Below is a scope shot with the time base now at 50uS per division.
We can clearly see that the voltage is a vertical rise,and so the square wave being delivered is quite clean. We can also see clearly when current starts to flow,as both trace values begin to fall. We can also see that the transition between no current flowing,and current starting to flow is very clean and definitive. If the CEMF was the same as the applied EMF,then we should see the blue trace start to fall from the same maximum value that the yellow trace reaches--that being our EMF.
But as we can clearly see,the voltage across the inductor is not that of the supply voltage before current starts to flow,and we know we do not get a voltage drop across a resistor until such time as current starts to flow through that resistor. So why is the voltage across the inductor less than the applied voltage at T=0--the very moment current starts to flow?.
Brad
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author=picowatt link=topic=16589.msg487598#msg487598 date=1467430986]
The test setup allows exactly that,and now allows us to see the effects of the electric field and capacitance of the windings at work,before current starts to flow.
Your "test setup" is measuring the current using R1 as a CSR.
The input is fine,and the square wave is also very defined-as you will see in the scope shot below.
Your previous scope capture clearly showed that your input "square" wave had a large amount of tilt.
We can reduce the time per division to 50 microseconds,and clearly see when current starts to flow--remember,this is at a low frequency of 10 Hz.
As we previously discussed, the frequency content of your squarish waveform with a fast rising edge is well beyond the 10Hz repetition rate of the waveform. Take a look using your scope's FFT function...
At the very point current starts to flow,both the V/in and V across the inductor should be exactly the same. There should be no voltage drop across the resistor until current starts to flow,so the test setup is valid to see the voltage across the inductor before current starts to flow.
Yes, the CH1 and CH2 levels should be similar at T=0 (there should be little current flow hence less drop across your CSR), unless, of course, your series R and your inductor's capacitance are producing an RC related error. What is the value of the resistor you are using? What is the capacitance of the inductor?
Below is a scope shot with the time base now at 50uS per division.
We can clearly see that the voltage is a vertical rise,and so the square wave being delivered is quite clean. We can also see clearly when current starts to flow,as both trace values begin to fall. We can also see that the transition between no current flowing,and current starting to flow is very clean and definitive. If the CEMF was the same as the applied EMF,then we should see the blue trace start to fall from the same maximum value that the yellow trace reaches--that being our EMF.
But as we can clearly see,the voltage across the inductor is not that of the supply voltage before current starts to flow,and we know we do not get a voltage drop across a resistor until such time as current starts to flow through that resistor. So why is the voltage across the inductor less than the applied voltage at T=0--the very moment current starts to flow?.
The difference between peak levels is much greater in this capture than in the previous. What else besides the time base has been changed?
Without knowing more details about your test setup, I am going to guess that you are using an inductor with a rather large parasitic capacitance. That would account for current flow at T=0. You can also see signs of ringing on the voltage across the inductor.
If you want to pursue these kinds of tests, we could discuss improvements to your test setup.
PW
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11.3
Energy Stored in Magnetic Fields
Since an inductor in a circuit serves to oppose any change in
the current through it, work must be done by an external source such as a
battery in order to establish a current in the inductor. From the work
-energy theorem, we conclude that energy can be stored in an
inductor. The role played by an inductor in the magnetic case is analogous to that of a
capacitor in the electric case.
The power, or rate at which an external emf extε
works to overcome the self-induced emf Lε and pass current
I in the inductor is ..... => read more at page 10 of the pdf
http://web.mit.edu/viz/EM/visualizations/coursenotes/modules/guide11.pdf
Love + Peace
3K :o
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An ideal inductor would not behave like a capacitor?
John.
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Below are two models showing the relationship between Emf, Cemf, and an inductor. One is the current model that PW, Poynt, MH, and others are promoting and the remaining is my proposal which simply relocates the Cemf source to be in series rather than in parallel with the inductor.
The notations require some explanation and are as follows:
A) Definitions for Emf and Cemf.*
B) Equation for di.
C) Value of Cemf when di reaches it's stable value in A/s for any given inductor.
D) Description of the negative feedback correction for di.
Where there is a question mark, it simply means that I have either not seen or understood any answer given regarding these aspects of the current model. If answers are given, the blanks will be filled.
* Notice I am using the same definition for Cemf as the current model which is a mathematical fudge to make the feedback loop work in my model conceptually. True Cemf opposes or is opposite the change in di so should contain a negative on one side or the other of the equation.
So, the model I propose differs from the current model mostly in the definition of Cemf. Cemf does not equal Emf but rather equals zero when an inductor reaches it's calculated di. This seems to verify what is seen experimentally which also satisfies Faraday's equation and is easier to understand IMO.
pm
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Below are two models showing the relationship between Emf, Cemf, and an inductor. One is the current model that PW, Poynt, MH, and others are promoting and the remaining is my proposal which simply relocates the Cemf source to be in series rather than in parallel with the inductor.
The model that you "propose" is the model we have been discussing and "promoting" all along...
However, your notation for "C" should read "When di=.8A/s, Cemf=4 volts"
PW
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The model that you "propose" is the model we have been discussing and "promoting" all along...
However, your notation for "C" should read "When di=.8A/s, Cemf=4 volts"
PW
No, what you state above is correct for your model but not mine. My notation is correct. That is the big difference between the two models.
pm
Edit: I will add that your model's feedback node is at Emf and mine is at zero.
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No, what you state above is correct for your model but not mine. My notation is correct. That is the big difference between the two models.
pm
Edit: I will add that your model's feedback node is at Emf and mine is at zero.
I am unaware of anyone claiming or discussing that the CEMF is in parallel with di as you depict it in your left hand drawing. Your right hand model is what has been discussed all along.
The only apparent difference in your model seems to be that in "C)", you state that when di=.8A/s the CEMF=0.
Now think about that a minute. How can a di of .8A/s result in a CEMF that equals zero volts? Anytime current is changing in a condutor, there is also a changing magnetic field and a subsequently induced non-zero CEMF.
If CEMF=0 when di=8A/s, then your formula for CEMF in "A)" must also be incorrect.
Perhaps, for discussion, you could post two identical versions of your "proposed" model side by side but with one stating:
C) When di=.8A/s, Cemf=4 volts
With that correction, the model depicts what I and others have been discussing.
Thanks...
PW
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I am unaware of anyone claiming or discussing that the CEMF is in parallel with di as you depict it in your left hand drawing. Your right hand model is what has been discussed all along.
That is correct in the fact that when I have asked for a model or math derivation, none was given. However with the statement that Emf=Cemf when di = .8A/s, the parallel model with L as shown has to be assumed for any di to flow thru L. Please diagram schematically how this would be accomplished otherwise.
The only apparent difference in your model seems to be that in "C)", you state that when di=.8A/s the CEMF=0.
My model is correctly noted and defined and "C)" is correct as compared to yours. Please explain how your position of Emf=Cemf when di=.8A/s fits in my series connected model.
Now think about that a minute. How can a di of .8A/s equal zero volts? Anytime current is changing in a condutor, there is also a changing magnetic field and a subsequently induced non-zero CEMF.
I didn't say that. What I did say in B) is that di=(Emf-Cemf)*dt/L implying that Cemf=0. I don't have a problem with that as I use Cemf for feedback correction only and follow Faraday's law as I stated in B).
I will say here that I have somewhat conceded with this model that Emf/Cemf feedback is required to achieve the .8A/s di in this example which I am not absolutely convinced is the case. Even my own model needs the math fudge to make this happen so something is still wrong here but that is another subject
If CEMF=0 when di=8A/s, then your formula for CEMF in "A)" must also be incorrect.
You are right because in the Cemf in "A" is missing the minus sign. I don't see a problem with Cemf=0 due to di=Emf*dt/L using conventional current flow. Are you saying that Cemf is inherent in Faraday's original derivation of this formula?
Perhaps, for discussion, you could post the two identical models side by side but with one stating:
C) When di=.8A/s, Cemf=4 volts
With that correction, the model depicts what I and others have been discussing.
Thanks...
PW
I'm sorry PW but I can't seem to justify changing C) to what you state because it makes no electrical sense in the series connected configuration. However, I am certainly open to see how this can be logically achieved.
pm
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Where is MMF covered in the conversation in regards to EMF?
https://en.wikipedia.org/wiki/Magnetomotive_force
https://en.wikipedia.org/wiki/Electromotive_force
Since the conversion is from EMF into MMF within the inductor,, don't you think that it would make sense to view things in the correct sequence?
With ZERO resistance in the ideal inductor there is no mechanism to produce a counter EMF, only the conversion into MMF.
Now think about what happens when the EMF is no longer supplied,, the MMF will continue to keep the current flowing unchanged unless and until current can no longer flow unimpeded.
Open the circuit and you introduce an infinite resistance which provides for an infinite EMF, close the circuit with a zero resistance and there is no change, close the circuit with a resistance and the EMF will then manifest as it is converting the MMF in a relationship with the resistance.
This is all covered by the older formulas.
Convenience can lead to misunderstandings.
Good points and I agree.
pm
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That is correct in the fact that when I have asked for a model or math derivation, none was given. However with the statement that Emf=Cemf when di = .8A/s, the parallel model with L as shown has to be assumed for any di to flow thru L. Please diagram schematically how this would be accomplished otherwise.
I have no idea where you are getting the CEMF in parallel idea from. The schematic of the model I and others have been discussing is exactly as you have drawn it in your right hand drawing.
My model is correctly noted and defined and "C)" is correct as compared to yours. Please explain how your position of Emf=Cemf when di=.8A/s fits in my series connected model.
That is exactly what I have been trying to do.
I didn't say that. What I did say in B) is that di=(Emf-Cemf)*dt/L implying that Cemf=0. I don't have a problem with that as I use Cemf for feedback correction only and follow Faraday's law as I stated in B).
In your version of "C)", you clearly state that when di=.8A/s, the CEMF=0. That is incorrect. The CEMF can only equal zero when di=0. When di=.8A/s the CEMF=4volts.
Your formula in "B)", states that when EMF=CEMF, di=0, which is correct and explains why the rate of change cannot exceed or be less than .8A/s.
With the correction to "C)" so that it reads "C) When di=.8A/s, CEMF=4volts", everything else in your notations are exactly as I have been stating and di is maintained at .8A/s.
I will say here that I have somewhat conceded with this model that Emf/Cemf feedback is required to achieve the .8A/s di in this example which I am not absolutely convinced is the case. Even my own model needs the math fudge to make this happen so something is still wrong here but that is another subject
You are right because in the Cemf in "A" is missing the minus sign. I don't see a problem with Cemf=0 due to di=Emf*dt/L using conventional current flow. Are you saying that Cemf is inherent in Faraday's original derivation of this formula?
I'm sorry PW but I can't seem to justify changing C) to what you state because it makes no electrical sense in the series connected configuration. However, I am certainly open to see how this can be logically achieved.
pm
I think you are under the impression that just because EMF=CEMF all current flow ceases. What ceases is rate of change. Being an ideal inductor, the Vsource depicted as the generator of CEMF has zero resistance.
In the step wise discussion of the feedback mechanism, when CEMF=EMF, di equals zero and any current flowing prior to EMF=CEMF continues to flow, it just does not increase or decrease.
However, CEMF can only equal EMF when di=.8A/s. It is this equality that regulates di to .8A/s.
Again, other than your statement in "C)", I agree with everything else stated in your notations. With that one correction to "C)", the feedback mechanism that regulates di works just as described.
PW
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What is the speed at which the inductor is responding?
If virtual photons are involved, they would be considered as
mass-less I presume and would "propagate??" at C.
Just tryin' to get an idea of what's goin' on.
Thank you men,
John.
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What is the speed at which the inductor is responding?
That is an interesting question - especially in the near field case.
I don't know of an experiment that measures the near field propagation of magnetic field, but I do know of an experiment measuring the electric propagation speed.
http://www.pandualism.com/c/coulomb_experiment.html
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That is an interesting question - especially in the near field case.
I don't know of an experiment that measures the near field propagation of magnetic field, but I do know of an experiment measuring the electric propagation speed.
http://www.pandualism.com/c/coulomb_experiment.html
When looking very closely(very narrow time divisions on the scope),i see current rising along with the voltage at T=0,and then the current drop's back down to 0,and then rises again from 0 to follow our exponential curve. So this is either the voltage is instantaneous across the inductor,and these little ceramic resistors have some sort of lag time,or current flows instantly due to winding capacitance,and then drops back to 0 when that capacitor is full,and then current starts to flow ?.
Not to sure on that one,but something is happening before current flow starts due to induction.
I will whip up a quick video to show you guys what i am seeing,and maybe one of you know what is going on?.
Brad
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I am unaware of anyone claiming or discussing that the CEMF is in parallel with di as you depict it in your left hand drawing. Your right hand model is what has been discussed all along.
Thanks...
PW
OK,now i am confused.
I thought you said back in post 1511 ,that it was the left modle we were using,and was correct.
Quote: Regarding your diagrams, when the 4 volts is applied to a 5H inductor, as soon as the rate of change of the current flowing thru the inductor reaches .8 amps per second, the generated CEMF would be as in drawing "A".
I dont see the difference between my drawing A,and Partzman's left drawing?
Brad
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When looking very closely(very narrow time divisions on the scope),i see current rising along with the voltage at T=0,and then the current drop's back down to 0,and then rises again from 0 to follow our exponential curve. So this is either the voltage is instantaneous across the inductor,and these little ceramic resistors have some sort of lag time,or current flows instantly due to winding capacitance,and then drops back to 0 when that capacitor is full,and then current starts to flow ?.
Not to sure on that one,but something is happening before current flow starts due to induction.
I will whip up a quick video to show you guys what i am seeing,and maybe one of you know what is going on?.
Brad
That first current rise is most likely the capacitance of the coil taking on current neglecting the impedance. Like Tesla says about the bifi coils, that the capacitance of the coils charges up upon input as if the inductance is non existent, and the only opposition to the charge up is the coils resistance. A single winding coil has a very tiny capacitance compared to a bifi, but enough to see what you are seeing. ;)
Mags
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OK,now i am confused.
I thought you said back in post 1511 ,that it was the left modle we were using,and was correct.
Quote: Regarding your diagrams, when the 4 volts is applied to a 5H inductor, as soon as the rate of change of the current flowing thru the inductor reaches .8 amps per second, the generated CEMF would be as in drawing "A".
I dont see the difference between my drawing A,and Partzman's left drawing?
Brad
Regarding your two drawings, I believe we were debating the correct polarity of the CEMF at the time, and my answer regarding that was and is that the topmost drawing is correct with regard to the CEMF polarity when di=.8A/s. As well, your drawings do not indicate the CEMF Vsource, it was assumed to be internal to the inductor you drew and that the +/- indicators for CEMF were just indicated measurement points with regard to the polarity debate.
Somewhere buried back in the noise I stated that the best model of an inductor was a conductor in series with a variable Vsource (all conductors being an inductor, and using a conductor removes the redundancy of having an "inductor" inside an "inductor model").
I believe there has been confusion caused by the discussion of CEMF polarity, which was debated for some time using parallel connected Vsources and the like.
The model I have been discussing all along is Partzman's "inductor in series with a Vsource" model, his right most model. If he were to make the change to his notation "C)" as I indicated, it would describe exactly what I have been trying to portray. Faraday, Lenz, the math, and the negative feedback mechanism, all work as discussed given that one change to his drawing notes.
PW
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That first current rise is most likely the capacitance of the coil taking on current neglecting the impedance. Like Tesla says about the bifi coils, that the capacitance of the coils charges up upon input as if the inductance is non existent, and the only opposition to the charge up is the coils resistance. A single winding coil has a very tiny capacitance compared to a bifi, but enough to see what you are seeing. ;)
Mags
And furthermore, if an ideal inductor does not have capacitance, how will that figure into what comes first, the chicken or the egg? ;)
Mags
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And furthermore, if an ideal inductor does not have capacitance, how will that figure into what comes first, the chicken or the egg? ;)
Mags
Yes Mag's
At the moment of placing a voltage across the inductor,both the current and voltage rise together--for a very short period of time.
As far as i can make out.i would agree with you,in that the capacitance of the windings is being charged first--but you have to narrow the time divisions on the scope right down to see this brief rise in current from T=0.
And yes-How will having no winding capacitance effect the outcome?
The thing is now,we know there is going to be a difference between an ideal coil,and a non ideal coil.
Brad
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Somewhere buried back in the noise I stated that the best model of an inductor was a conductor in series with a variable Vsource (all conductors being an inductor, and using a conductor removes the redundancy of having an "inductor" inside an "inductor model").
I believe there has been confusion caused by the discussion of CEMF polarity, which was debated for some time using parallel connected Vsources and the like.
PW
Regarding your two drawings, I believe we were debating the correct polarity of the CEMF at the time, and my answer regarding that was and is that the topmost drawing is correct with regard to the CEMF polarity when di=.8A/s. As well, your drawings do not indicate the CEMF Vsource, it was assumed to be internal to the inductor you drew and that the +/- indicators for CEMF were just indicated measurement points with regard to the polarity debate.
Yes-correct on both accounts.
So dose that not resemble Partzman's drawing on the left?
The model I have been discussing all along is Partzman's "inductor in series with a Vsource" model, his right most model. If he were to make the change to his notation "C)" as I indicated, it would describe exactly what I have been trying to portray. Faraday, Lenz, the math, and the negative feedback mechanism, all work as discussed given that one change to his drawing notes.
This discussion is about whether or not that is correct,and so what would be the point in just changing "C") to the value you believe is correct. If we did that,then why would we be having this discussion?. If we are simply to believe what some one else is telling us,then we might as well have no discussions at all,and just be one of the sheep in the flock,following the leader.
The whole idea of this forum,is to question everything,and believe nothing until shown absolute proof.
An example of this is the belief that current lag's voltage with an inductor,when today i find-when you look close enough,that there is an initial current draw that rises at the same time as the voltage. As Mags and myself think,we believe this is the capacitance of the windings being charged.
One would think that the same would apply for a capacitor,where it is thought that current leads voltage. But what dose it take before current can flow?-->is not an electric field needed between the plates,before current will flow?. If so,would that not mean that a voltage must first appear across the plates,before current could flow?.
Anyway-food for thought.
Brad
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Regarding your two drawings, I believe we were debating the correct polarity of the CEMF at the time, and my answer regarding that was and is that the topmost drawing is correct with regard to the CEMF polarity when di=.8A/s. As well, your drawings do not indicate the CEMF Vsource, it was assumed to be internal to the inductor you drew and that the +/- indicators for CEMF were just indicated measurement points with regard to the polarity debate.
Somewhere buried back in the noise I stated that the best model of an inductor was a conductor in series with a variable Vsource (all conductors being an inductor, and using a conductor removes the redundancy of having an "inductor" inside an "inductor model").
I believe there has been confusion caused by the discussion of CEMF polarity, which was debated for some time using parallel connected Vsources and the like.
The model I have been discussing all along is Partzman's "inductor in series with a Vsource" model, his right most model. If he were to make the change to his notation "C)" as I indicated, it would describe exactly what I have been trying to portray. Faraday, Lenz, the math, and the negative feedback mechanism, all work as discussed given that one change to his drawing notes.
PW
I have family here for the July 4 celebration so it is difficult to find time to respond at the moment.
OK, below is the corrected model as you have requested. Do you see a problem? When Emf = Cemf and di = .8A/s, how is di supplied and maintained? This model is flawed as well IMO.
I have a new model to present time permitting but for now just some food for thought. Since Emf = L*di/dt and -Cemf = L*di/dt, we would be mathematically correct to say Emf = -Cemf. Note that this is |Emf| = |Cemf| not Emf = Cemf as you have been stating. Big difference!
pm
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I have family here for the July 4 celebration so it is difficult to find time to respond at the moment.
OK, below is the corrected model as you have requested. Do you see a problem? When Emf = Cemf and di = .8A/s, how is di supplied and maintained?
No, I do not see a problem. I see an inherent negative feedback mechanism and the reason di is limited to and maintained at precisely .8A/s.
Consider what happens upon application of the 4 volt EMF. Current begins to flow thru the inductor and...
1. As di reaches a rate of change equal to .8A/s, the CEMF becomes equal to 4 volts.
2. As per "B)" in the drawing, as the CEMF becomes equal to the EMF, di also reduces towards zero.
3. But if di becomes less than .8A/s, the CEMF also becomes less than 4 volts which allows di to increase.
4. Return to number 1 above (loop forever)
Although described above in a rather step-wise fashion, it is, in reality, a smooth and continuous process and a classic example of a negative feedback loop.
Thanks for taking the time to post the drawings. By all means, enjoy the 4th!
PW
Added:
Also note that I believe it more appropriate for L2 to be replaced with a simple conductor (wire). Having an inductor inside a "model" of an inductor is redundant and could lead to confusion.
I would replace L2 with a wire and then place a dotted line box surrounding both the CEMF Vsource and the wire with di indicated. The entire dotted line box would then be labeled as L2.
(I would also label the value for CEMF1 as Xv or Xv1 because the only time the CEMF=4volts is when di=.8A/s)
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Being that the coil is ideal,there is no rate of change-change-->the rate of change remains a constant,regardless of the applied voltage value,because the time constant is infinite.
Huh? The rate of change, i.e. A/s is directly proportional to the applied Vin. The higher Vin, the higher is the A/s. If Vin remains constant, so does the current A/s.
As the voltage is ideal,then we can assume that it will not drop below that value. This leaves only the CEMF voltage value. As our rate of change is constant-as our coil is ideal,and free from resistance,i ask !once again!,where is the loss that allows the current to flow?-->how is the CEMFs value reduced when the rate of change is a constant,and the applied voltage is ideal,and will not change from that 4 volts-regardless of load.
So i am asking you(with regards to the original MH question),where is the loss that allows current to flow,if the CEMF value is always that of the !!ideal!! voltages value of 4 volts,and where there is no rate of change in time of the magnetic field.
We have all agreed that the applied 4 vots-our EMF is a constant,and will not change unless we change it. You (and some others) have also clearly stated that you believe that the CEMF is always going to be equal to that of the applied voltage,as there is no rate of change to the magnetic field in our ideal inductor.
So,in order for current to flow through our ideal inductor,the CEMF !must! be lower than the applied !ideal! EMF.
It would seem to me PW,that you are using this !feed back! stuff,so as it aligns with current mathematics,and not looking at the situation as it is.
The circuit in regards to the scope shot,is as below.
It would seem to me that the actual value of the CEMF value at T=0(moment EMF is placed across the inductor),would be 11.6 volts,if the average between the EMF and CEMF is 12.2 volts--the blue trace.
I will have to set up a more robust circuit to confirm this,but it is clear that the CEMF is of a lesser value than the applied EMF.
Brad
To correctly measure the voltages in your circuit, you need to make two separate measurements as noted on the annotation on your diagram. The resistor measurement requires a CH1-CH2 MATH function, while the inductor voltage is simply CH2. Most, if not all the voltage at the instant Vin is applied, should appear across the inductor. What is the value of your R and L?
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It's a job for me to believe this keeps going on and on.
It seems that scientists know the magnetic moment of an electron
to be -9284.764 X 10 to the minus 27 with an accuracy of
7.6 parts in 10 to the minus 13.
I presume people have been looking at these things for a century
and a half so in my mind there's just one right answer.
John.
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I found this a bit of fun.
YouTube "5,000 amp transformer" by photonicinduction.
John.
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An ideal inductor sitting at rest, is essentially an ideal piece of wire. So when an ideal emf is placed across it, the current wants to instantly jump to infinity, right at t=0.
Due to the self-induced cemf however (the negative feedback), current is limited to rise at 0.8A/s (in our case with 4V and 5H).
There are two reasons the induced cemf = the applied emf:
1) The obvious reason is that the ideal voltage source is holding the inductor terminal voltage at 4V.
2) The not so obvious reason is due to the self-induction feedback process trying to be explained here.
To explain further, try thinking about the process right from the very beginning. As I said above, the moment Vin is applied, the current will try to instantly go to infinity. We know however that simultaneously, the inductor is self-inducing an opposing emf which is going to cause the current to increase at a set rate determined by Vin and L. This is the feedback mechanism that makes an inductor what it is. The inductor doesn't limit current, it limits the change in current. Any change in current is reflected in a corresponding opposing emf, which opposes the applied emf. In the case when R=0, the emf and cemf are always equal. The cemf settles or equalizes to the same value as the applied emf.
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An ideal inductor sitting at rest, is essentially an ideal piece of wire. So when an ideal emf is placed across it, the current wants to instantly jump to infinity, right at t=0.
Due to the self-induced cemf however (the negative feedback), current is limited to rise at 0.8A/s (in our case with 4V and 5H).
There are two reasons the induced cemf = the applied emf:
1) The obvious reason is that the ideal voltage source is holding the inductor terminal voltage at 4V.
2) The not so obvious reason is due to the self-induction feedback process trying to be explained here.
To explain further, try thinking about the process right from the very beginning. As I said above, the moment Vin is applied, the current will try to instantly go to infinity. We know however that simultaneously, the inductor is self-inducing an opposing emf which is going to cause the current to increase at a set rate determined by Vin and L. This is the feedback mechanism that makes an inductor what it is. The inductor doesn't limit current, it limits the change in current. Any change in current is reflected in a corresponding opposing emf, which opposes the applied emf. In the case when R=0, the emf and cemf are always equal. The cemf settles or equalizes to the same value as the applied emf.
.99,
I know I have just about exhausted every way I know how to explain the "rate of change" regulating mechanism of an inductor. Perhaps the very concept of negative feedback needs to be explained.
Do you see anything in my last post to Partzman that I could word better to get the point across or make it more clear?
PW
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.99,
I know I have just about exhausted every way I know how to explain the "rate of change" regulating mechanism of an inductor. Perhaps the very concept of negative feedback needs to be explained.
Do you see anything in my last post to Partzman that I could word better to get the point across or make it more clear?
PW
Absolutely not, your explanation and wording makes perfect sense to me.
I do however see the dilemma some may have when trying to get their heads around emf=cemf and current being able to flow. But again, I will refer them to a resistor across a voltage source. The two voltages are identical (i.e. KVL holds), yet current flows. I will also refer them to the fact that upon connection, ALL the voltage is across the inductance, in both real and ideal inductors, yet current begins to flow.
There may be a more scientific explanation to all this, I am just too dumb to muster it.
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Absolutely not, your explanation and wording makes perfect sense to me.
I do however see the dilemma some may have when trying to get their heads around emf=cemf and current being able to flow. But again, I will refer them to a resistor across a voltage source. The two voltages are identical (i.e. KVL holds), yet current flows. I will also refer them to the fact that upon connection, ALL the voltage is across the inductance, in both real and ideal inductors, yet current begins to flow.
There may be a more scientific explanation to all this, I am just too dumb to muster it.
Perhaps more like "too frustrated"...
I am hoping Partzman will eventually "get it" and then perhaps he will be able to explain it better to those that don't.
We shall see...
PW
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No, I do not see a problem. I see an inherent negative feedback mechanism and the reason di is limited to and maintained at precisely .8A/s.
Consider what happens upon application of the 4 volt EMF. Current begins to flow thru the inductor and...
1. As di reaches a rate of change equal to .8A/s, the CEMF becomes equal to 4 volts.
2. As per "B)" in the drawing, as the CEMF becomes equal to the EMF, di also reduces towards zero.
3. But if di becomes less than .8A/s, the CEMF also becomes less than 4 volts which allows di to increase.
4. Return to number 1 above (loop forever)
Although described above in a rather step-wise fashion, it is, in reality, a smooth and continuous process and a classic example of a negative feedback loop.
Thanks for taking the time to post the drawings. By all means, enjoy the 4th!
PW
Added:
Also note that I believe it more appropriate for L2 to be replaced with a simple conductor (wire). Having an inductor inside a "model" of an inductor is redundant and could lead to confusion.
I would replace L2 with a wire and then place a dotted line box surrounding both the CEMF Vsource and the wire with di indicated. The entire dotted line box would then be labeled as L2.
(I would also label the value for CEMF1 as Xv or Xv1 because the only time the CEMF=4volts is when di=.8A/s)
I don't have the time to comment on the above except to say that you still have a math fudge with your definition of Cemf=L*di/dt in order for your model to work.
So, I've attached a new model that may satisfy all requirements. No time to go into detail but I think it is self explanatory.
pm
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But then, perhaps not...
Partzman,
There was no "math fudge" needed, everything worked perfectly just as it was.
As for your new model that apparently requires 3 separate types of EMF, you've completely lost me...
Your notation "D", in particular, is most confusing.
PW
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An ideal inductor sitting at rest, is essentially an ideal piece of wire. So when an ideal emf is placed across it, the current wants to instantly jump to infinity, right at t=0.
Due to the self-induced cemf however (the negative feedback), current is limited to rise at 0.8A/s (in our case with 4V and 5H).
There are two reasons the induced cemf = the applied emf:
1) The obvious reason is that the ideal voltage source is holding the inductor terminal voltage at 4V.
2) The not so obvious reason is due to the self-induction feedback process trying to be explained here.
To explain further, try thinking about the process right from the very beginning. As I said above, the moment Vin is applied, the current will try to instantly go to infinity. We know however that simultaneously, the inductor is self-inducing an opposing emf which is going to cause the current to increase at a set rate determined by Vin and L. This is the feedback mechanism that makes an inductor what it is. The inductor doesn't limit current, it limits the change in current. Any change in current is reflected in a corresponding opposing emf, which opposes the applied emf. In the case when R=0, the emf and cemf are always equal. The cemf settles or equalizes to the same value as the applied emf.
And so in a real coil,the CEMF dose not equal the EMF,due to the resistance value of the windings-as i said some time back.
If CEMF did equal the EMF in a real coil,then why not the same feed back as an ideal coil free from winding resistance?.
We know that in a real coil,the current is not limited,and will rise to the steady state value,and so the CEMF cannot be equal to the EMF.
Brad
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And so in a real coil,the CEMF dose not equal the EMF,due to the resistance value of the windings-as i said some time back.
Yes, with a real coil at t=0 the cemf=emf, and yet, current flows. I've mentioned this a number of times now.
If CEMF did equal the EMF in a real coil,then why not the same feed back as an ideal coil free from winding resistance?.
There is feedback as well with real coils. You can see the current is rising at 0.8A/s for the first 200ms when R=1 Ohm. After this point the voltage begins to trade off with the resistor until finally ALL the voltage is across the R. It started out with ALL the voltage across the L. Do you wish me to repost the sim result showing the 1 Ohm trace tracking the 1p Ohm trace for the first 200ms?
We know that in a real coil,the current is not limited,and will rise to the steady state value,and so the CEMF cannot be equal to the EMF.
I'm not sure how you came to that conclusion, but it is wrong. What do you mean the current is not limited? Of course it is; in fact it is limited in two different ways: 1) a maximum of 0.8A/s current rate of rise, 2) a maximum current of Vin/R.
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Yes, with a real coil at t=0 the cemf=emf, and yet, current flows. I've mentioned this a number of times now.
There is feedback as well with real coils. You can see the current is rising at 0.8A/s for the first 200ms when R=1 Ohm. After this point the voltage begins to trade off with the resistor until finally ALL the voltage is across the R. It started out with ALL the voltage across the L. Do you wish me to repost the sim result showing the 1 Ohm trace tracking the 1p Ohm trace for the first 200ms?
I'm not sure how you came to that conclusion, but it is wrong. What do you mean the current is not limited? Of course it is; in fact it is limited in two different ways: 1) a maximum of 0.8A/s current rate of rise, 2) a maximum current of Vin/R.
As i said, the CEMF cannot be equal to the EMF like it is with the ideal coil.
What i ment by current flow not being limited,was to that like the ideal coil,where the current is !apparently! limited to 800mA /second. As the winding resistance increases,our current trace follows a greater curve.
If you look close enough at the current,you will see that it first rises right along side the voltage,when the V is placed across the coil. I (and Mags) suspect this to be because of the parasitic capacitance of a real coil.
This being the case,then at T=0,the CEMF is not equal to the EMF, because if it was,then there would be no current flow at T=0.
At vox T=0, a voltage is placed across the inductor.
At the very same time,a current rises to a certain value,where this value will depend on the value of winding capacitance-and so dose the time period for this brief current flow.
The current will fall to 0, once the capacitance has been charged.
Shortly after that,the current will rise ,and track it's exponential curve path.
That is what i have found so far in my tests.
Brad
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As i said, the CEMF cannot be equal to the EMF like it is with the ideal coil.
And as I said, yes it is equal with a real coil too, at t=0.
What i ment by current flow not being limited,was to that like the ideal coil,where the current is !apparently! limited to 800mA /second. As the winding resistance increases,our current trace follows a greater curve.
BOTH the ideal and real coils will be restricted to 0.8A/s maximum rate of current rise if they are 5H inductors, and free of parasitic capacitance. It is interesting that you refer to the ideal coil as being limited, when in fact the real coil is more limited because it hits a maximum current and its rate of rise decreases over time, whereas the ideal coil does not.
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Here is the real coil (R=1 Ohm) voltage tradeoff traces.
At t=0 ALL the voltage is across the inductance, and 0V across the resistor. That is, at t=0, cemf=emf. And yet, current flows.
After 30s or so the inductance ends up with 0V, and the resistance 4V across them; they have traded places.
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But then, perhaps not...
Partzman,
There was no "math fudge" needed, everything worked perfectly just as it was.
As for your new model that apparently requires 3 separate types of EMF, you've completely lost me...
Your notation "D", in particular, is most confusing.
PW
This model was an attempt to make sense of the Emf/Cemf feed back loop and D) represents said attempt. Do not be confused by your thought that I don't understand what you are saying because I understand completely, I just don't agree! I knew that my new model was not correct when I created the two Emf sources.
So, in another approach to resolve the matter, I propose we attempt to simulate the inductor that is, not use the internal inductor model(s) in any given simulator, but break it down into functional components as Webby suggests.
LtSpice is my preference and it's toolbox includes arbitrary behavioral voltage and current sources plus voltage dependent current sources , current dependent voltage sources, etc, so all we need to do is basically establish the model and the math.
I see no reason why this should not be doable and it would be a great teaching tool.
I have attached a schematic that shows the general circuit we wish to simulate and what I believe to be your equivalent model, but I would like you to confirm or indicate any changes that should be made so we can proceed. I am still working on my own equivalent model and will post it as soon as it is complete enough for criticism.
pm
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Here is the real coil (R=1 Ohm) voltage tradeoff traces.
At t=0 ALL the voltage is across the inductance, and 0V across the resistor. That is, at t=0, cemf=emf. And yet, current flows.
After 30s or so the inductance ends up with 0V, and the resistance 4V across them; they have traded places.
Either your sim dose not represent an accurate description of what happens at T=0,or you are not looking closely enough.
At T=0,the current will rise with the voltage until such time as the capacitance of the windings has been charged. depending on capacitance value,the current will !after a short time! return to a 0 value,and then begin it's rise over time.
At T=0,the CEMF dose not equal the EMF,as at T=0, the current tracks vertical with the voltage,and then drops back to a 0 value. The time span is very narrow,but it is at and after T=0.
Brad
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This model was an attempt to make sense of the Emf/Cemf feed back loop and D) represents said attempt. Do not be confused by your thought that I don't understand what you are saying because I understand completely, I just don't agree! I knew that my new model was not correct when I created the two Emf sources.
So, in another approach to resolve the matter, I propose we attempt to simulate the inductor that is, not use the internal inductor model(s) in any given simulator, but break it down into functional components as Webby suggests.
LtSpice is my preference and it's toolbox includes arbitrary behavioral voltage and current sources plus voltage dependent current sources , current dependent voltage sources, etc, so all we need to do is basically establish the model and the math.
I see no reason why this should not be doable and it would be a great teaching tool.
I have attached a schematic that shows the general circuit we wish to simulate and what I believe to be your equivalent model, but I would like you to confirm or indicate any changes that should be made so we can proceed. I am still working on my own equivalent model and will post it as soon as it is complete enough for criticism.
pm
Pm
Do you have a scope,or access to one?
Brad
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This model was an attempt to make sense of the Emf/Cemf feed back loop and D) represents said attempt. Do not be confused by your thought that I don't understand what you are saying because I understand completely, I just don't agree! I knew that my new model was not correct when I created the two Emf sources.
So, in another approach to resolve the matter, I propose we attempt to simulate the inductor that is, not use the internal inductor model(s) in any given simulator, but break it down into functional components as Webby suggests.
LtSpice is my preference and it's toolbox includes arbitrary behavioral voltage and current sources plus voltage dependent current sources , current dependent voltage sources, etc, so all we need to do is basically establish the model and the math.
I see no reason why this should not be doable and it would be a great teaching tool.
I have attached a schematic that shows the general circuit we wish to simulate and what I believe to be your equivalent model, but I would like you to confirm or indicate any changes that should be made so we can proceed. I am still working on my own equivalent model and will post it as soon as it is complete enough for criticism.
pm
Partzman,
Under the "PW Model", the notation should read Cemf=L*di/dt and that is what you would have to simulate.
For a 5H inductor, you will have to sense the current flowing thru the circuit and continuously adjust the CEMF voltage source so that the rate of change (di) is maintained at .8A/s.
In other words, you will have to simulate a rate of change dependent negative feedback loop.
I am not sure how you would go about detecting di, but once you have a way to do so, something like "if di<.8A/s decrease CEMF" and "if di>.8A/s increase CEMF" comes to mind.
Perhaps .99 could offer some suggestions regarding this...
PW
ADDED:
Just thinking out loud...
If you can program an arbitrary current source so that it rises at a rate of .8A/s, it could be used as a reference current, Iref. The applied EMF and Iref would be started simultaneously. The current flowing thru the model would be detected, hereinafter, Idet. You could then use the difference between Iref and Idet to generate an error signal to control the value of the CEMF Vsource using a comparator or the like. In the real world of negative feedback, damping would also need to be dealt with...
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Either your sim dose not represent an accurate description of what happens at T=0,or you are not looking closely enough.
At T=0,the current will rise with the voltage until such time as the capacitance of the windings has been charged. depending on capacitance value,the current will !after a short time! return to a 0 value,and then begin it's rise over time.
At T=0,the CEMF dose not equal the EMF,as at T=0, the current tracks vertical with the voltage,and then drops back to a 0 value. The time span is very narrow,but it is at and after T=0.
Brad
No, the sim is indicating the results it should be. I did clearly specify that these results are for an inductor that is free from parasitic capacitance. I guess you missed that.
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I've got a little question, those of you who are experts will probably be able to
give an answer.
I've found from experience,whatever you're doing, if the formula you're using
isn't suitable your job goes wrong.
Question "Do people who design circuits use the accepted laws and do they
work out right?"
Obviously unidealness of components has to be accounted for.
Thank you John.
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Partzman,
Under the "PW Model", the notation should read Cemf=L*di/dt and that is what you would have to simulate.
For a 5H inductor, you will have to sense the current flowing thru the circuit and continuously adjust the CEMF voltage source so that the rate of change (di) is maintained at .8A/s.
In other words, you will have to simulate a rate of change dependent negative feedback loop.
I am not sure how you would go about detecting di, but once you have a way to do so, something like "if di<.8A/s decrease CEMF" and "if di>.8A/s increase CEMF" comes to mind.
Perhaps .99 could offer some suggestions regarding this...
PW
I was thinking of suggesting/doing this yesterday, but changed my mind. I've been down this road before and the work effort is not worth it. It will only be met with skepticism and will be readily dismissed as invalid.
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I was thinking of suggesting/doing this yesterday, but changed my mind. I've been down this road before and the work effort is not worth it. It will only be met with skepticism and will be readily dismissed as invalid.
.99,
I added the following to my post you referenced:
Just thinking out loud...
If you can program an arbitrary current source so that it rises at a rate of .8A/s, it could be used as a reference current, Iref. The applied EMF and Iref would be started simultaneously. The current flowing thru the model would be detected, hereinafter, Idet. You could then use the difference between Iref and Idet to generate an error signal to control the value of the CEMF Vsource using a comparator or the like. In the real world of negative feedback, damping would also need to be dealt with...
If Partzman wants to attempt this, do you have any better or simpler suggestions as to how he might to go about it?
PW
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.99,
I added the following to my post you referenced:
If Partzman wants to attempt this, do you have any better or simpler suggestions as to how he might to go about it?
PW
These two references (I prefer the approach with the green schematics (pspice), last page):
Should not be difficult.
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Pm
Do you have a scope,or access to one?
Brad
I have a very well equipped bench including a Tek MDO3034 scope with math and FFT capability. What do you have in mind?
pm
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PW and Poynt,
I still have family visiting so I have glanced thru the posts quickly and will have to follow up later as time permits. I am willing to give the sim a go.
pm
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These two references (I prefer the approach with the green schematics (pspice), last page):
Should not be difficult.
Do you seriously believe that many will accept, or even recognize, those models as being similar to the model being discussed?
I was looking for something much simpler and easily recognized as the actual model at hand. How about this:
A fixed Vsource set to 4V is used for the applied EMF and a voltage controlled Vsource is used for for the CEMF. The CEMF Vsource is selected so that 1 volt on the control input equals 1 volt on the CEMF Vsource output.
For a di reference current, Iref, an ideal 5H inductor is simultaneously connected to a second fixed Vsource of 4 volts and the current measured thru that inductor is used as Iref. The current flowing thru the model is detected, Idet, and a comparator function is used to generate an error voltage to control the CEMF's Vsource.
I think most people would be able to recognize this as being similar to the inductor model and the CEMF voltage can be measured directly, or by proxy, via the 1V:1V CV input.
I would be most concerned with how to control damping/ stabilizing the loop. Your thoughts regarding that, and this concept in general, would be most appreciated.
PW
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Do you seriously believe that many will accept, or even recognize, those models as being similar to the model being discussed?
No, I do not. That is why I changed my mind about doing it, as I mentioned. But with all due respect what you are proposing is pointless as well, in my opinion, because it won't be accepted, especially since you are proposing to use an ideal inductor as part of the model (this in itself is part of the contention).
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No, I do not. That is why I changed my mind about doing it, as I mentioned. But with all due respect what you are proposing is pointless as well, in my opinion, because it won't be accepted, especially since you are proposing to use an ideal inductor as part of the model (this in itself is part of the contention).
You are probably correct. What I proposed would, however, allow the voltage of the CEMF to be investigated when di=.8A/s.
Even if the 5H inductor used as an Iref source were replaced with a programmed current source as I originally suggested, there would likely be those that would not accept that either.
Even with all the electronic design examples in use by everyone everyday, it often seems as if some believe the field of electronics to be just another conspiracy theory...
PW
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No, the sim is indicating the results it should be. I did clearly specify that these results are for an inductor that is free from parasitic capacitance. I guess you missed that.
I guess i must have,as i have taken the 1 ohm resistor as the circuit model that represents the winding resistance,and as such,assumed we were now dealing with a non ideal inductor in one of your two examples.
As we have been talking about the CEMF difference between ideal and non ideal being the same at T=0,i thought i would point out that it is not the same,for the very reason you just listed-the ideal coil will have no parasitic capacitance,and the non ideal one will.
So this relates to what i said,that the CEMF with reference to a non ideal coil,is not equal to the EMF,due to the capacitance of the windings.
When a coil is hit with a pulse,and then the circuit becomes open,and the coil ring's down--is this not showing that there is capacitance within the coil?--it's own tank circuit?.
I only ask so as to work out how this would make things different in regards to the ideal coil that has no capacitance.
Brad
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I have a very well equipped bench including a Tek MDO3034 scope with math and FFT capability. What do you have in mind?
pm
I am just wanting to confirm what i am seeing on my bench.
Do you have a large value inductor ?--or ,what is the largest value one you have,as the larger the value,the easier it will be to see what i am seeing.
I will get some scope shot's and a circuit up tonight after work,as it was a tad cold over here last night,and the work shop is too far away from the heater :D
Brad
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If anyone has a series connected bifi coil, the initial input current charging the capacitance will be more visible as the capacitance is greater.
Mags
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Brad,
What you are describing might be core saturation. With parasitic capacitance you will have a short sharp spike of current right at connection, then the current rise will resume as per normal from a low value.
What type of inductor are you using? Voltage? DC resistance? Resistor value? Inductance?
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I guess i must have,as i have taken the 1 ohm resistor as the circuit model that represents the winding resistance,and as such,assumed we were now dealing with a non ideal inductor in one of your two examples.
Yes, that is the non-ideal inductor without any capacitance, just like we've been discussing the last couple of weeks.
As we have been talking about the CEMF difference between ideal and non ideal being the same at T=0,i thought i would point out that it is not the same,for the very reason you just listed-the ideal coil will have no parasitic capacitance,and the non ideal one will.
As up until now we have not discussed parasitic capacitance (or at least I don't recall it), the point being made was that the two are equivalent at t=0. Now that your real-world inductor measurement is indicating some artifact, this may not be the case with your inductor. If you tell me what you used, I may be able to try it myself.
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Brad,
What you are describing might be core saturation. With parasitic capacitance you will have a short sharp spike of current right at connection, then the current rise will resume as per normal from a low value.
What type of inductor are you using? Voltage? DC resistance? Resistor value? Inductance?
Yes,that is what i see-a sharp rise in current ,where the current traces the voltages virtical rise across the inductor.-both current and voltage trace track virtical on scope,unless i narrow the time devisions right down,at which point the voltage trace is not vertical,but starts to slope--so even the voltage takes some time to rise across the inductor,but we are now looking at Pico seconds in time with a 480 mH inductor.
I am using the primary side of a large MOT,as that is the largest in L value i have-short of pulling my welder apart.
The circuit is just the circuit model for an inductor, where the R is being used as the CVR.
Value of the CVR dosnt seem to make any difference,other than a reduction in voltage across it of course,as we decrease the R value of the CVR.
I must say,it is getting hard to know what we are discussing at anyone point in time here now.
I must have missed the bit on looking at a real coil that has no parasitic capacitance,which of course means it is not a real coil.
So ATM, i am looking at a real coil-with it's parasitic capacitance,so as to see what we have ,that we would not have in an ideal coil.
To me,this makes sense,and from there we can work out if the ideal coil would act the same as a real coil at T=0. So far,it would seem not,because at T=0 with an ideal coil,there would be no insthant current to charge the parasitic capacitance,such as we have with a real coil. I would also suspect that the parasitic capacitance value would increase with the increase of windings-such as that guitar picup you were talking about some time back.
I will try and get those scope shots up tonight.
P.S-the coil/inductor has a resistance value of 1.7 ohms,and is being pulsed with a square wave from my FG,with 10% duty cycle. I also have a diode on the positive input,and the CVR is on the negative side of the inductor,due to my common ground issue between scope and FG.
Brad
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OK,the scope shots below.
In the first picture,we have the 470mH inductor,and circuit attached.
In the top scope shot,we see the current trace as expected.
In the bottom scope shot of that same picture,we have decreased the time base P/D,and we now see at T=0,the current trace track the voltage trace,and then settle back down to a 0 value. After a short time,it then starts to show the current trace seen in top pic.
At T=0,the winding capacitance seems to charge first.
In the second pic,i have swapped over to a 540mH inductor,but with a much higher winding resistance value--> lots more turns of smaller gauge wire. Looking at the two scope shot's,it would seem that although the inductance value is greater,so is the winding capacitance,and so at T=0,once again we see the current trace track the voltage trace,and for a short time,the current actually leads the voltage. This would mean a clear indication of capacitance being charged.
And once again,we see the current value return to 0,once the capacitance is charged.
My point is this.
At T=0,with regard to a real world inductor,the CEMF is not equal to the EMF,due to capacitance charging. This means that the ideal coil will react differently to that of a real world coil that has parasitic capacitance.
At higher frequencies,this parasitic capacitance would greatly alter the CEMF to EMF ratio
The frequency used in these tests was 10 Hz,with a 10% duty cycle.
Brad
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So what do you suppose your traces would look like if we could somehow first remove the capacitance, then the resistance?
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So what do you suppose your traces would look like if we could somehow first remove the capacitance, then the resistance?
I do not know,nor do i have the means to find out.
My point is this--
We would assume that we would not see this with an ideal coil,and we know we do have this situation with a non ideal coil,and so the two will not act in the same manor.
As far as i can see from bench tests,the CEMF dose not equal the EMF at T=0 ,with real world inductors--am i incorrect in saying that?,and if so,what is the initial current spike at T=0,if it is not the charging of coil capacitance ?.
Brad
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I do not know,nor do i have the means to find out.
You have the ability to think and ponder, correct? Perhaps you could use your knowledge to surmise what the traces may look like? For example, would there be anything to "charge" if there were no capacitance? If not, then would that current bump be present?
My point is this--
We would assume that we would not see this with an ideal coil,and we know we do have this situation with a non ideal coil,and so the two will not act in the same manor.
As far as i can see from bench tests,the CEMF dose not equal the EMF at T=0 ,with real world inductors--am i incorrect in saying that?,and if so,what is the initial current spike at T=0,if it is not the charging of coil capacitance ?.
Your point is understood and accepted. However, it seems you are missing the forest for the trees (http://www.dictionary.com/browse/can-t-see-the-forest-for-the-trees).
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author=poynt99 link=topic=16589.msg487809#msg487809 date=1467724879]
You have the ability to think and ponder, correct? Perhaps you could use your knowledge to surmise what the traces may look like? For example, would there be anything to "charge" if there were no capacitance? If not, then would that current bump be present?
One could speculate that there would be no bump due to the charging of capacitance with an ideal coil.
But one would also wonder as to how that may effect the outcome of the results.
If we remove one part of a system,then it may just make the outcome a whole lot different than thought.
Your point is understood and accepted. However, it seems you are missing the forest for the trees
An interesting saying,as without the tree's,there is no forest. ;)
I know what your saying Poynt,and chances are you are right. But one thing has become of this so far,and that is,for the first time,i have seen the capacitance being charged in an inductor.
I would rather look at things far more closely, and observe everything that is taking place,rather than just look at the forest from afar.
Better to be amongst the trees i think,that way we see all that exist in the forest :D
Brad
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One could speculate that there would be no bump due to the charging of capacitance with an ideal coil.
But one would also wonder as to how that may effect the outcome of the results.
If we remove one part of a system,then it may just make the outcome a whole lot different than thought.
One can also use their knowledge gained from prior experience to confidently predict certain outcomes.
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My point is this.
At T=0,with regard to a real world inductor,the CEMF is not equal to the EMF,due to capacitance charging. This means that the ideal coil will react differently to that of a real world coil that has parasitic capacitance.
I think that you are making up one of your "ruel's" but unfortunately it doesn't make any sense. Even if you add a parasitic capacitance in parallel with an inductor model that consists of an ideal inductor with added wire resistance only, the CEMF will still be equal to the EMF. You have to think these things through.
once again we see the current trace track the voltage trace,and for a short time,the current actually leads the voltage. This would mean a clear indication of capacitance being charged.
It does look like a capacitance being charged but you typically only talk about current leading the voltage in a case where the excitation is a repeating sine wave. You can even extend the concept and apply this for things like say a repeating square wave. But you are not in that territory at all. You are really just looking at the response to a single pulse and therefore you are misapplying the concept of current leading or lagging the voltage. It does not apply when you look at the response to a pulse.
Beyond that, you are simply leading yourself down a garden path. When you look at the scope shot the current does not "actually lead the voltage." All that you are seeing is that part of the current waveform is higher than the voltage waveform on the scope capture. You could easily change the gain settings on the scope and then the "current actually leading the voltage" would go away. One more time, you have to think these things through.
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Pursuant to simulating an inductance, I have some questions and comments.
In our ideal inductor of 5H, it is stated that Emf = Cemf when di = .8A/s. Can we then say di = Emf-Cemf?
It is interesting to read Wiki's definition of Counter-electromotive force and I quote in part "For example, the voltage drop across an inductor is due to the induced magnetic field inside the coil.[1][2] The voltage's polarity is at every moment the reverse of the input voltage.[1][3]" Is this not contradictory?
pm
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Pursuant to simulating an inductance, I have some questions and comments.
If you are going to try to simulate the PW model, you must simulate Cemf=L*di/dt
In our ideal inductor of 5H, it is stated that Emf = Cemf when di = .8A/s. Can we then say di = Emf-Cemf?
No...
But again, do you at least understand this negative feedback loop? If the problem is one of expression, that can be dealt with. But it does not materially change the model or its action, just the way of looking at it.
1. When CEMF<EMF, di increases.
2. As di=.8A/s, CEMF=EMF.
3. However, if CEMF=EMF, di<.8A/s
4. If di<.8A/s, CEMF<EMF
5. Loop to 1
What is it you are trying to do? "Understand" the feedback mechanism or just "describe" it mathematically in a form you can agree with?
It would help if I knew what you disagree with or do not understand.
If it is your desire to express the CEMF as a negative voltage, that can be done, but it was hoped that as I described it, the concept of the induced CEMF being a negative feedback mechanism would be readily understood.
It is interesting to read Wiki's definition of Counter-electromotive force and I quote in part "For example, the voltage drop across an inductor is due to the induced magnetic field inside the coil.[1][2] The voltage's polarity is at every moment the reverse of the input voltage.[1][3]" Is this not contradictory?
pm
Contradictory to what? In the model, are not the positive terminals of both the EMF and CEMF facing each other? That is, the polarity of the CEMF is such that it "is at every moment the reverse of the input voltage".
If you want to see the CEMF as a negative voltage, measure around the loop KVL style...
I have work related chores to attend to and have little time right now. But please do let me know whether it is the entire concept of CEMF being a negative feedback mechanism that is troubling you or just the desire to mathematically express the CEMF as a negative voltage.
PW
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If you are going to try to simulate the PW model, you must simulate Cemf=L*di/dt
No...
But again, do you at least understand this negative feedback loop? If the problem is one of expression, that can be dealt with. But it does not materially change the model or its action, just the way of looking at it.
1. When CEMF<EMF, di increases.
2. As di=.8A/s, CEMF=EMF.
3. However, if CEMF=EMF, di<.8A/s
4. If di<.8A/s, CEMF<EMF
5. Loop to 1
What is it you are trying to do? "Understand" the feedback mechanism or just "describe" it mathematically in a form you can agree with?
It would help if I knew what you disagree with or do not understand.
Well, I must admit that at this time, I do not believe I can simulate the PW model. I do understand the feedback loop but what you are saying in essence is that the function of inductance is dependent on the applied voltage and Cemf feedback. If so I disagree. I think the feedback is an effect that is the result of a deeper cause and that is flux interaction between windings with said flux generated by the current flowing in the wire due to the applied voltage source. Everything else follows this IMO.
Surely in 3) above you meant to say "if CEMF>EMF, di<.8A/s".
If it is your desire to express the CEMF as a negative voltage, that can be done, but it was hoped that as I described it, the concept of the induced CEMF being a negative feedback mechanism would be readily understood.
Contradictory to what? In the model, are not the positive terminals of both the EMF and CEMF facing each other? That is, the polarity of the CEMF is such that it "is at every moment the reverse of the input voltage".
If you want to see the CEMF as a negative voltage, measure around the loop KVL style...
I don't wish the Cemf to be negative or positive. I am/was trying to generate a single expression (if possible) to simplify the simulation.
I still find the Wiki wording confusing, sorry!
I have work related chores to attend to and have little time right now. But please do let me know whether it is the entire concept of CEMF being a negative feedback mechanism that is troubling you or just the desire to mathematically express the CEMF as a negative voltage.
PW
I understand what you are stating and your description of the feedback mechanism. I do have a problem with it being the controlling factor of inductance as I stated earlier. So, I don't think I can really contribute anything useful to the matter from this point forward and my comments may be confusing without any substance to back them up.
Best to all.
pm
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Well, I must admit that at this time, I do not believe I can simulate the PW model. I do understand the feedback loop but what you are saying in essence is that the function of inductance is dependent on the applied voltage and Cemf feedback. If so I disagree. I think the feedback is an effect that is the result of a deeper cause and that is flux interaction between windings with said flux generated by the current flowing in the wire due to the applied voltage source. Everything else follows this IMO.
Surely in 3) above you meant to say "if CEMF>EMF, di<.8A/s".
Actually no.
If CEMF<EMF, di increases. Consider CEMF=0, at which time the full 4 volts is applied across the conductor and current rises rapidly. Even if CEMF=3.99volts, current would rise very rapidly (both the EMF and CEMF sources are considered ideal in the discussion)
If CEMF=EMF, current does not rise so di<.8A/s. (technically, di=0 would be true if CEMF=EMF. However, this condition also causes the CEMF<EMF, so I would not state di=0 when CEMF=EMF in an isolated statement. It is an unstable term in the feedback loop and would be confusing to state outside of that loop)
If the CEMF>EMF, the CEMF would tend to reverse the flow of current and the rate of change, di, would go negative as the current flow would be decreasing.
Due to the feedback mechanism, di is "trapped" at precisely .8A/s and cannot be greater or lesser than that amount. Any attempt by di to be greater or lesser than .8A/s will affect the CEMF such that di is forced to return to .8A/s.
We know, by the very definition of the Henry (1A/s thru 1H produces an EMF of 1volt that opposes the current that induced it) that the 5H inductor will generate a an EMF of 4 volts when .8A/s is flowing thru it.
That induced EMF will oppose the direction of the current flow that induced it, hence it is referred to as a CEMF. In all the models proposed, including yours, the CEMF polarity has been consistent, with the + terminals of the two representative sources facing each other.
I don't wish the Cemf to be negative or positive. I am/was trying to generate a single expression (if possible) to simplify the simulation.
I still find the Wiki wording confusing, sorry!
I understand what you are stating and your description of the feedback mechanism. I do have a problem with it being the controlling factor of inductance as I stated earlier. So, I don't think I can really contribute anything useful to the matter from this point forward and my comments may be confusing without any substance to back them up.
Best to all.
pm
I had hoped that if you read my proposals for a simple simulation using either an arbitrary current source or another 5H inductor for a .8A/s current reference, that perhaps the action of the CEMF might become more clear.
Even if you do not intend to attempt a simulation, perhaps if you scratched out the proposed simulation circuit on paper it would help...
PW
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Well, I must admit that at this time, I do not believe I can simulate the PW model. I do understand the feedback loop but what you are saying in essence is that the function of inductance is dependent on the applied voltage and Cemf feedback. If so I disagree. I think the feedback is an effect that is the result of a deeper cause and that is flux interaction between windings with said flux generated by the current flowing in the wire due to the applied voltage source. Everything else follows this IMO.
Surely in 3) above you meant to say "if CEMF>EMF, di<.8A/s".
I don't wish the Cemf to be negative or positive. I am/was trying to generate a single expression (if possible) to simplify the simulation.
I still find the Wiki wording confusing, sorry!
I understand what you are stating and your description of the feedback mechanism. I do have a problem with it being the controlling factor of inductance as I stated earlier. So, I don't think I can really contribute anything useful to the matter from this point forward and my comments may be confusing without any substance to back them up.
Best to all.
pm
I believe that what wiki is saying,is that the polarity of the CEMF voltage will cause a current to flow in the opposite direction to that of the source,and so there for,the polarity is opposite to that of the EMF,even though the polarity is the same ::)
The confusion for me is,PW keeps assuming that the EMF will produce a current of 800mA/second,an so some how the CEMF induced current is less than this 800mA.
In a real world inductor,we have first a current flow induced from the EMF to charge the capacitance of the coil,and so at this point (T=0),the CEMF is not equal to the EMF,as a magnetic field is yet to be produced that creates the CEMF. Once capacitance is charged,the current drops back down to a 0 value,and then current starts to flow that produces the magnetic field that induces the CEMF.
So with a real coil,we have a small time delay between applied EMF ,and produced CEMF. This is enough time to create an offset between the EMF induced current,and the CEMF induced current.
With an ideal coil,we get no such offset,as there is no parasitic capacitance,and so to me,there is an instant reaction to any current that tries to flow as a result of the applied EMF,by the CEMF.
So i am still stuck as to how PW still insists that the EMF will win out in this battle,and produce a current flow greater than that of the CEMF induced current.
If at T=0,the EMF induced current flow value is 800mA/second,and at that very same instant the CEMFs induced current flow is also 800mA/second,then you have no current flow.
The very instant current tries to flow in one direction,it is counteracted against by a current trying to flow in the other direction,so how was it decided that the EMF induced current would win in this battle?,as it would seem to me that every action is met with an equal and opposite reaction.
Ideal or not,the current rise time could not be faster than the speed of light,and so the EMF induced current would have to start of with a value at !lets say for example! 1mA,and so at that very time,the CEMF induced current would also have to be 1mA. We know this current variation in time exist,as it has been denoted as rising at 800mA/second,and so that is less than 1mA per microsecond.
So why are we looking at the result at the 1 second mark?,why not at the instant of connection?.
Brad
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@Tinman,
Here's a quote from you:
"I believe that what wiki is saying,is that the polarity of the CEMF voltage will cause a current to flow in the opposite direction to that of the source,and so there for,the polarity is opposite to that of the EMF,even though the polarity is the same ::)"
This is the point I tried to make to you on Luc's moderated thread that got me 86'd off this website!
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I'm returning to some cool audio design.
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I'm returning to some cool audio design.
What are you makin'?
Perhaps it will have a tone control circuit using, as is often done, a simulated inductor circuit, i.e., a "gyrator" circuit...
After all this, I can't imagine having to explain that one...
PW
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Haha,
I refreshed my memory about gyrators the other day as another idea to perhaps help elucidate on the inductor discussion here, but I soon came to my senses ;)
Breaking new ground with a guitar amplifier design. MOSFETs rather than tubes. :) Could use your help with a few advanced questions if you wouldn't mind.
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Haha,
I refreshed my memory about gyrators the other day as another idea to perhaps help elucidate on the inductor discussion here, but I soon came to my senses ;)
Breaking new ground with a guitar amplifier design. MOSFETs rather than tubes. :) Could use your help with a few advanced questions if you wouldn't mind.
.99,
I always wanted to try switching out the outputs in the larger bass and guitar amps with MOSFET's. 6L6/6550?.
I love analog audio design, I miss the old discrete stuff, like Flickinger, API and Sphere consoles, etc (with the Sphere Eclipse C with their SPA62 discrete opamps and passive EQ circuits sounding the best in my opinion). I also miss discrete analog tape recorders like the Ampex 440 and MM1200 series. But the current 2" tape prices and availability, wow... Anyway, those were the days.
As for your project, you could ask but I am now on page 28 and counting of a document for a client and I have not even gotten to inserting graphs or images, and it was expected over a week ago.
So, the timing could not be worse.
There is just never enough fun...
PW
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It has to be an Old School gyrator, see attached. If the gyrator is post-1950 then it is suspect and could have been corrupted by the PTB.
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Poynt and PW:
I am assuming that the Holy Grail would be to market an audio amp with modern components but with a warm tube sound. If the two of you could work some magic and it was truly indistinguishable from a tube amp sound then the sky is the limit!!!!!
Also Poynt, are you familiar with the famous Rolling Stones mobile studio? Well it's found a permanent home in Calgary!!!
http://www.cbc.ca/news/canada/calgary/national-music-centre-restoring-mobile-studio-used-by-rolling-stones-1.3005483 (http://www.cbc.ca/news/canada/calgary/national-music-centre-restoring-mobile-studio-used-by-rolling-stones-1.3005483)
MileHigh
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It has to be an Old School gyrator, see attached. If the gyrator is post-1950 then it is suspect and could have been corrupted by the PTB.
"Gyrator" does tend to conjure the image of someone with cool dance moves more so than an electronic circuit...
PW
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Poynt and PW:
I am assuming that the Holy Grail would be to market an audio amp with modern components but with a warm tube sound. If the two of you could work some magic and it was truly indistinguishable from a tube amp sound then the sky is the limit!!!!!
Also Poynt, are you familiar with the famous Rolling Stones mobile studio? Well it's found a permanent home in Calgary!!!
http://www.cbc.ca/news/canada/calgary/national-music-centre-restoring-mobile-studio-used-by-rolling-stones-1.3005483 (http://www.cbc.ca/news/canada/calgary/national-music-centre-restoring-mobile-studio-used-by-rolling-stones-1.3005483)
MileHigh
Not familiar with the Helios console, but the multi-track appears to be an M79 by 3M. Not the worst sounding machine out there, but I was never a fan of the isoloop tape path. Azimuth always seemed a bit wiggly and I always thought head wear was a bit high. But still, it had a discrete audio path (and pesky relays).
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.99,
Do you have an amp in mind to mod, or are you starting from scratch?
PW
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PW:
Were you a buddy of the late George Martin? lol
Here is a news clip where you see the guts in some detail:
https://www.youtube.com/watch?v=k4_BUIM7gY0
Perhaps Poynt will make the next Sticky Fingers or Abbey Road in it!
MileHigh
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PW:
Were you a buddy of the late George Martin? lol
Here is a news clip where you see the guts in some detail:
https://www.youtube.com/watch?v=k4_BUIM7gY0
Perhaps Poynt will make the next Sticky Fingers or Abbey Road in it!
MileHigh
Cool video, nice closeup of the isoloop...
I can assure you from experience, the razor blades were only used for cutting tape...
PW
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;D ;D ;D
Such shiny white front teeth.
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Imagine two opposite electrodes of a coil each end connected to one of the two poles of a battery positive and negative; Now, if we disconnect the negative side rapidly, the magnetic field collapses, the voltage polarity reverses and the electro motive force flows into the positive side of the battery like two batteries in series one with a higher voltage.
Disconnecting the positive side of the coil would cause a collapse of the magnetic field and a flow of BEMF into the negative side of the power battery. One direction has to be the opposite of the original current flow!
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So with a real coil,we have a small time delay between applied EMF ,and produced CEMF. This is enough time to create an offset between the EMF induced current,and the CEMF induced current.
No instantaneous reactions exist in a quantized world
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The confusion for me is,PW keeps assuming that the EMF will produce a current of 800mA/second,an so some how the CEMF induced current is less than this 800mA.
One last time:
Before the _fixed_ 4volt EMF is applied to the 5H inductor, there is no CEMF being generated so CEMF=0
At T=0, the 4volt EMF is applied to the inductor and current rapidly rises:
1. As di reaches .8A/s, CEMF = EMF
2 If CEMF = EMF, di < .8A/s
3. If di < .8A/s, CEMF < EMF
4. If CEMF < EMF, di increases (return to #1, loop forever)
Read thru the loop (1-4) ten times or so, perhaps it will come in to focus... This is an example of a negative feedback loop.
(A negative feedback loop is a common concept in electronics and there are probably a hundred, if not many more, negative feedback loops operating in the electronic circuits you use daily. Although many people think of gain setting when they think of negative feedback, the most common and numerous circuits throughout your house that use negative feedback are most likely current sources.)
As far as how much current flows at T=0, it does not really matter. If one electron flows at T=0, then 1 picosecond later, a current flow of something just shy of 5 million electrons would be equivalent to .8A/s and that would cause the CEMF to be equal to 4 volts. (5 million electrons flowing being equal to .8 picoamperes or thereabouts, I'm tired so...)
It is the rate of change, not the absolute amount of current, that determines the CEMF Start out with as many electrons in as narrow a slice of time as desired, but when from time slice to time slice the current rises (changes) at the equivalent rate of .8A/s, the generated CEMF will be 4 volts.
Remember, we are discussing inductance, ideal inductance, so please don't add the effects of a resistor and capacitor to the circuit being discussed. That comes later.
PW
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One last time:
Before the _fixed_ 4volt EMF is applied to the 5H inductor, there is no CEMF being generated so CEMF=0
At T=0, the 4volt EMF is applied to the inductor and current rapidly rises:
1. As di reaches .8A/s, CEMF = EMF
2 If CEMF = EMF, di < .8A/s
3. If di < .8A/s, CEMF < EMF
4. If CEMF < EMF, di increases (return to #1, loop forever)
Read thru the loop (1-4) ten times or so, perhaps it will come in to focus... This is an example of a negative feedback loop.
(A negative feedback loop is a common concept in electronics and there are probably a hundred, if not many more, negative feedback loops operating in the electronic circuits you use daily. Although many people think of gain setting when they think of negative feedback, the most common and numerous circuits throughout your house that use negative feedback are most likely current sources.)
As far as how much current flows at T=0, it does not really matter. If one electron flows at T=0, then 1 picosecond later, a current flow of something just shy of 5 million electrons would be equivalent to .8A/s and that would cause the CEMF to be equal to 4 volts. (5 million electrons flowing being equal to .8 picoamperes or thereabouts, I'm tired so...)
It is the rate of change, not the absolute amount of current, that determines the CEMF Start out with as many electrons in as narrow a slice of time as desired, but when from time slice to time slice the current rises (changes) at the equivalent rate of .8A/s, the generated CEMF will be 4 volts.
PW
PW
If the coil is ideal,then the CEMF should always equal that of the EMF,by way of the induced currents by both-correct.
So this being the case, at T=0,there would have to be a current rise,and that rise in current value must start from 0. Through the transition to 800ma?second,it must first produce a current value much less than that--it must start from a value of 0. As soon as a current rise started taking place,due to the EMF(before the maximum value of 800ma/second),it would induce a CEMF that results in producing a current that is in opposition to that of the EMF induced current.
Why dose this feed back loop of yours only start at a value of 800mA,when the starting value is only slightly above 0 shortly after T=0.
My hope with the scope shots i showed,was to show that we need to look at things a lot further down in the time domain,and in this case,with the ideal coil,we must look at speeds near the speed of light.
The coil is ideal,and so the time reference must also be ideal,in that we look at what happens at exactly T=0,and shortly after.
At T=0,we could just as easly say that the CEMF induced current equaled that of the EMF induced current as soon as 1mA of current started to flow,and your negative feed back started from there. Now your current is limited to 1mA/second right from the start.
The voltage really has nothing to do with the current flow in an ideal coil,as that rise must start from a value of 0,regardless of the voltage placed across it.
Remember, we are discussing inductance, ideal inductance, so please don't add the effects of a resistor and capacitor to the circuit being discussed. That comes later.
Those scope shot's were indeed important at this point in time,as it shows what we will not have with an ideal inductor. We will have no charging of capacitance,or any associated losses due to parasitic capacitance or resistance.
What we have with an ideal coil,is instant action/reaction,as there are no losses,as an ideal coil dose not dissipate energy--we have your ideal inductance,at ideal speed.
Why is it we are starting at 800mA/second current flow,when we know that the EMF induced current must start from a value of 0,and rise to a value of 800mA ?. There is no such thing as going from 0 to 800mA instantly,there is a time limit to that rise to 800mA,and regardless of how short that time period is,it starts from a value of 0.
If our coil is indeed ideal,and we have ideal inductance,then as soon as a minute amount of current starts to flow,a magnetic field will rise with it,and as soon as a magnetic field starts to build,so dose the self induced current that apposes that which created it.
So it is just as correct to say that as soon as 1mA of current flows as a result of the applied EMF,then a CEMF induced current of 1mA will start to appose that which created it.
Voltage has no meaning here when dealing with an ideal coil,as even with the smallest value of voltage place across that coil,the current will still start from a 0 value,and rise to an infinite value-but it must transition from a value of 0 amps.
Even the speed of light has a limit,and as far as i am aware,this is the speed at which current can flow through any wire,and so we just cant go from 0 amps of current flow,straight up to 800mA/second--your negative feed back loop would start as soon as current started to flow,and so your current would be limited to that of the initial value at T=0,which would be minute,and no where near 800mA.
Brad
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Good grief Brad. I just read your post above, and you have completely missed the boat here mate!
800mA/s is a rate of rise! It is not an absolute value as you are saying. A rate of rise is SLOPE! From left at t=0, A=0, to the right at t=3, A=2.4A. What is the slope of the trace from left to right? THAT is what 0.8A/s means.
Therefore, even at t=1ms and say there is 1mA of current flowing, STILL IT IS RISING AT A RATE OF 800mA/s!!!!!!!!
So once again, as soon as current begins to flow, it is rising at a rate of 800mA/s.
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Good grief Brad. I just read your post above, and you have completely missed the boat here mate!
800mA/s is a rate of rise! It is not an absolute value as you are saying. A rate of rise is SLOPE! From left at t=0, A=0, to the right at t=3, A=2.4A. What is the slope of the trace from left to right? THAT is what 0.8A/s means.
Therefore, even at t=1ms and say there is 1mA of current flowing, STILL IT IS RISING AT A RATE OF 800mA/s!!!!!!!!
So once again, as soon as current begins to flow, it is rising at a rate of 800mA/s.
No Poynt,i dont think i have missed the boat at all.
Let me ask you this,and in an ideal way.
We have two identical rocket engines strapped to two identical carts. Each rocket engine can produce 1000LBs of thrust. The two are put nose to nose,and they are fired up. Every time rocket engine 1 is throttled up to produce an extra 100 LBs of thrust,rocket engine number 2 also matches that increase in thrust. At no point in time will rocket engine number 1 move rocket engine number 2,as long as rocket engine number 2 matches the thrust of rocket engine number 1--it is a stale mate,and no motion takes place.
We have two current sources here ,not just one. The ideal coils CEMFs induced current will match the current that is induced by the EMF,as there are no losses.
This can only mean that every time the EMF induced current tried to make a change in value,the CEMF induced current would counteract that very current that induced it in the first place,and it would do this ideally.
I am still yet to see it explained as to how rocket engine number 1 exceeds the thrust of rocket engine number tow,so as there is a net gain by rocket engine number 1--this is of course in regards to the EMFs induced current being greater than the CEMFs induced counter courrent,so as a net gain of current flow can be had.
You and PW keep saying that because the current will rise at 800mA/second-->but who says it will. This is what this whole discussion is about--who says the current will rise at that rate?
You and PW seem to keep referring to something that is being refuted,to validate your claim.
If the EMFs induced current is x amount,then the CEMFs reverse induced current is also x amount. This happens as soon as current starts to flow as a result of the voltage being placed across the coil. Your self and PW come up with 800mA a second,even though there is an equal and opposite reverse current being produced by the CEMF.
What i see ,is a very very high frequency oscillation happening here,where the net result is 0--that is how i see the negative feed back thing happening.
This is what i see in an ideal situation-->below
This is how i see the feed back system,only billions of times faster--no net gain in either direction.
https://www.youtube.com/watch?v=0LnbyjOyEQ8
Brad
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PW
If the coil is ideal,then the CEMF should always equal that of the EMF,by way of the induced currents by both-correct.
The CEMF will equal to the the EMF (4 volts) when di=.8A/s
So this being the case, at T=0,there would have to be a current rise,and that rise in current value must start from 0. Through the transition to 800ma?second,it must first produce a current value much less than that--it must start from a value of 0. As soon as a current rise started taking place,due to the EMF(before the maximum value of 800ma/second),it would induce a CEMF that results in producing a current that is in opposition to that of the EMF induced current.
Why dose this feed back loop of yours only start at a value of 800mA,when the starting value is only slightly above 0 shortly after T=0.
The inductor does start producing a CEMF as soon as any current flows, but "this feed back loop" does not begin to limit the rise in current until the rate of change reaches .8A/s. This can, however, be considered a rather instantaneous process that happens as soon as current flows.
My hope with the scope shots i showed,was to show that we need to look at things a lot further down in the time domain,and in this case,with the ideal coil,we must look at speeds near the speed of light.
The coil is ideal,and so the time reference must also be ideal,in that we look at what happens at exactly T=0,and shortly after.
At T=0,we could just as easly say that the CEMF induced current equaled that of the EMF induced current as soon as 1mA of current started to flow,and your negative feed back started from there. Now your current is limited to 1mA/second right from the start.
The CEMF has nothing to do with the _amount_ of current flowing thru the inductor. The CEMF is determined only by the current's _rate of change_.
The 5H inductor's CEMF equals the applied 4 volt EMF when the rate of change of the current flowing thru the inductor is equal to .8A/s. It has absolutely nothing to do with the _amount_ of current flowing thru the inductor, and it does not matter how small your time slices are, the rate of change will be limited to .8A/s.
Using ideal components, the flow of current would be considered instantaneous and therefore achieving a rate of change of .8A/s would also be instantaneous.
The voltage really has nothing to do with the current flow in an ideal coil,as that rise must start from a value of 0,regardless of the voltage placed across it.
That is correct, however, the voltage has everything to do with the rate of change of the current flowing thru the inductor. If 5 volts were placed across the 5H inductor, it would take a rate of change of 1A/s to achieve a CEMF equal to 5 volts, so the rate of change would be limited to 1A/s.
Those scope shot's were indeed important at this point in time,as it shows what we will not have with an ideal inductor. We will have no charging of capacitance,or any associated losses due to parasitic capacitance or resistance.
What we have with an ideal coil,is instant action/reaction,as there are no losses,as an ideal coil dose not dissipate energy--we have your ideal inductance,at ideal speed.
Why is it we are starting at 800mA/second current flow,when we know that the EMF induced current must start from a value of 0,and rise to a value of 800mA ?. There is no such thing as going from 0 to 800mA instantly,there is a time limit to that rise to 800mA,and regardless of how short that time period is,it starts from a value of 0.
You are beginning to lose me over these repeated "starting at 800ma/s" comments. That number is the rate of change that the current will be limited to. 800 femtoamps per picosecond is the same as .8A/s.
Remember, although I have described it in a rather step wise fashion, it is a smooth and continuous process. Consider the time intervals between the steps as being infinitely small or the entire loop as happening infinitely fast. When described in the step-wise fashion, it is like like looking at the events in extreme slow motion.
If our coil is indeed ideal,and we have ideal inductance,then as soon as a minute amount of current starts to flow,a magnetic field will rise with it,and as soon as a magnetic field starts to build,so dose the self induced current that apposes that which created it.
Correct, and that current will be limited to a rate of change of .8A/s.
So it is just as correct to say that as soon as 1mA of current flows as a result of the applied EMF,then a CEMF induced current of 1mA will start to appose that which created it.
Again, the amount of current you wish to consider is of no matter. Only the current's rate of change induces a CEMF and the rate of change will be limited to .8A/s because that is when the CEMF equals 4volts.
Voltage has no meaning here when dealing with an ideal coil,as even with the smallest value of voltage place across that coil,the current will still start from a 0 value,and rise to an infinite value-but it must transition from a value of 0 amps.
Even the speed of light has a limit,and as far as i am aware,this is the speed at which current can flow through any wire,and so we just cant go from 0 amps of current flow,straight up to 800mA/second--your negative feed back loop would start as soon as current started to flow,and so your current would be limited to that of the initial value at T=0,which would be minute,and no where near 800mA.
The voltage applied to the inductor, and the inductance value of the inductor, determine the rate of change the current will achieve.
Again, you seem to be confusing a rate of .8A/s as having to do with some particular amount of current, which it does not. 800ma/s is a rate of change and says nothing about the actual amount of current flowing.
PW
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No Poynt,i dont think i have missed the boat at all.
The concept of "rate of rise" seems to be a difficult one to grasp. Clearly it is not understood, based on your post.
As long as the rate of current rise is 0.8A/s, the cemf will equal the emf, and the rate of rise of 0.8A/s will happen the instant current begins to flow. Therefore, cemf=emf starting from t=0.
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Has anyone here read Miles Mathis? Here is a quote from his paper "Alternating Current and Inductance".
"This also explains inductance. The whole idea of inductance is something they invented because theydon't have a real charge field. Without inductance, they can't explain why current moves in AC, as above, so they come up with inductance as the explanation. The textbook definition of inductance is a voltage produced by a changing current. That is odd beyond odd, since they previously defined current as produced by voltage. So they are telling you that voltage causes current, and changing current causes voltage. I think you can see they have gone circular. The effect cannot cause the cause.
Once you have a real charge field creating your field of initial potentials—both electric and magnetic—you don't need inductance. Mutual inductance is easily explained because the ambient charge field links all local charge fields. And self-inductance is just a ghost. Once you understand how the field really works, you don't need it. It isn't inductance that is the cause of energy transfers, it is the charge field.
All this goes back to initial confusion by Faraday, which has persisted to this day. Faraday didn't recognize the existence of a real charge field, composed of real particles like photons. Nobody at the time did. Therefore, when he saw these effects being produced, he couldn't show a direct cause. Instead of being created or produced, they had to be induced. Something that is induced is produced indirectly, by unknown means. Think of the difference between deduction and induction in philosophy.
Deduction is supposed to be a straight line of logical cause and effect, while induction can be much less rigorous. It is much the same here. The word induction was not chosen by accident. It was a sort of admission that no mechanics could be pointed to. Faraday then created some lines of potential or force, but they were back-engineered from the motions. No kinematics was involved, and Faraday admitted it. How could he not? While it is not surprising that Faraday did what he did at the time, it is quite surprising we have improved on it so little in almost two centuries. We now have mountains of data pointing directly at a real charge field composed of real particles, but we still teach electrical engineering based on these old outdated ideas. It would be like medical schools still teaching leechcraft."
pm
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No Poynt,i dont think i have missed the boat at all.
Let me ask you this,and in an ideal way.
We have two identical rocket engines strapped to two identical carts. Each rocket engine can produce 1000LBs of thrust. The two are put nose to nose,and they are fired up. Every time rocket engine 1 is throttled up to produce an extra 100 LBs of thrust,rocket engine number 2 also matches that increase in thrust. At no point in time will rocket engine number 1 move rocket engine number 2,as long as rocket engine number 2 matches the thrust of rocket engine number 1--it is a stale mate,and no motion takes place.
For this analogy to work, lets tie the carts together so they act as a single cart and lets point the rocket engines' thrusts away from each other so they oppose. Engine #1 has a fixed and continuous thrust (EMF). Engine #2 has an identical thrust that can be turned on or off (CEMF). A sensor and control mechanism is used to determine the acceleration (rate of change) of the cart in the direction determined by engine #1's thrust. We have set the desired acceleration rate to 800 feet per second .
Engine #1 fires and the cart accelerates.
1. When the cart's acceleration reaches 800 feet per second, engine #2 fires
2. When engine #2 fires, the cart's acceleration decreases
3. When the cart's acceleration becomes less than 800 feet per second, engine #2 is cutoff
4. When engine #2 is cutoff, the cart's acceleration increases (return to 1, loop forever)
Again, this is a step wise description. If engine #2 could respond instantaneously, and the time between steps were made infinitely small, there would be a smooth and continuous acceleration of the cart at a rate of 800 feet per second in the desired direction.
PW
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Gyrator-capacitor modeling of inductors and transformers can yield quite accurate simulations of complex electromagnetic devices. I've attached a simulation of a co-planar 3-winding transformer with gaps that has complex couplings and leakage inductances.
In some ways, the application of gyrators for magnetic problems are easier to understand with their magnetic and electric equivalencies.
pm
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Gyrator-capacitor modeling of inductors and transformers can yield quite accurate simulations of complex electromagnetic devices. I've attached a simulation of a co-planar 3-winding transformer with gaps that has complex couplings and leakage inductances.
In some ways, the application of gyrators for magnetic problems are easier to understand with their magnetic and electric equivalencies.
pm
Partzman,
My only experience with gyrators is with respect to fixed and variable Q simulated inductors built using opamps, resistors, and capacitors as used in analog circuits.
Using them to simulate transformer design is, well, "tip of my hat to you" stuff!
Looks very interesting...
PW
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Partzman,
My only experience with gyrators is with respect to fixed and variable Q simulated inductors built using opamps, resistors, and capacitors as used in analog circuits.
Using them to simulate transformer design is, well, "tip of my hat to you" stuff!
Looks very interesting...
PW
Thank you PW.
Off topic but many years ago I designed and marketed a digital tuner for pianos, stringed instruments, etc, that used a very high Q gyrator/capacitance simulated inductor in series resonance that allowed measuring over three octaves with one setting. This created an electronic capability of "stretch tuning" the overtones of a stringed instrument in the same manner as a skilled professional tuner. The accuracy was 1 cent with 100 cents/semitone.
Also off topic but I read the comments about solid state vs tubes so I assume some here are pickers and/or audiophiles. I researched the differences nearly fifty years ago as best one could with a single channel kit scope, and determined the main difference was the output impedance or damping factors. I found tube outputs to be soft or poorly regulated with the changes in speaker impedance over a given frequency range, where s/s was highly regulated with high damping factors. By using a combo of negative voltage and current feedback in a s/s bipolar power amp, one can approach the ideal tube type output impedance tracking which yields the fat, warm tube sound. Other factors played a role as well like depletion mode j-fets in preamps, passive tone networks, and phasing the output so the attack transients from a string pushed the cone forward, etc.
With today's mosfet power devices and engineering tools, some really good sounding amps could be built.
pm
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Also off topic but I read the comments about solid state vs tubes so I assume some here are pickers and/or audiophiles. I researched the differences nearly fifty years ago as best one could with a single channel kit scope, and determined the main difference was the output impedance or damping factors. I found tube outputs to be soft or poorly regulated with the changes in speaker impedance over a given frequency range, where s/s was highly regulated with high damping factors. By using a combo of negative voltage and current feedback in a s/s bipolar power amp, one can approach the ideal tube type output impedance tracking which yields the fat, warm tube sound. Other factors played a role as well like depletion mode j-fets in preamps, passive tone networks, and phasing the output so the attack transients from a string pushed the cone forward, etc.
;)
Aren't all JFETs depletion mode?
I prefer enhancement mode MOSFETs for my pre-amp designs, hi-fi and guitar/bass.
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Is it sort of near field coupling, or am I barking up the wrong tree?
John.
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For this analogy to work, lets tie the carts together so they act as a single cart and lets point the rocket engines' thrusts away from each other so they oppose. Engine #1 has a fixed and continuous thrust (EMF). Engine #2 has an identical thrust that can be turned on or off (CEMF). A sensor and control mechanism is used to determine the acceleration (rate of change) of the cart in the direction determined by engine #1's thrust. We have set the desired acceleration rate to 800 feet per second .
Engine #1 fires and the cart accelerates.
1. When the cart's acceleration reaches 800 feet per second, engine #2 fires
2. When engine #2 fires, the cart's acceleration decreases
3. When the cart's acceleration becomes less than 800 feet per second, engine #2 is cutoff
4. When engine #2 is cutoff, the cart's acceleration increases (return to 1, loop forever)
Again, this is a step wise description. If engine #2 could respond instantaneously, and the time between steps were made infinitely small, there would be a smooth and continuous acceleration of the cart at a rate of 800 feet per second in the desired direction.
PW
And there is the problem PW.
Engine 2s thrust dose not just start only when engine 1 has reached a point of acceleration of 800 feet per second,nor dose engine 2s thrust simply switch off when engine 1s acceleration drops below 800 feet per second. Engine 2s thrust matches that of engine 1 at every instant,and so there is no motion between the two.
I see the same thing with the EMF induced current,and the CEMF induced counter current,where every change made by the forward current is counteracted by the CEMF induced reverse current.
Why dose this action/reaction have to start only when a rate of change has reached a level of 800mA per second?
The value in question here,is the 800mA per second,and it seems that your self and Poynt keep using this very value to justify the value in question it self.
This feed back system i believe should represent a situation where if you push against a concrete wall,the concrete wall will push back just as hard at the very same time,and the net result is no motion. The way i see you explaining thing's,is that some how,the person is able to move the concrete wall,even though the concrete wall is pushing back just as hard.
The ideal coil becomes a power source it self in this case,and it matches that which was induced into it,only with opposition.
Anyway,i am going to leave it at that,as i dont think it is going to go anywhere,when the value in question is being used to confirm the value in question,when the conversation is about that very value it self.
Brad
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And there is the problem PW.
Engine 2s thrust dose not just start only when engine 1 has reached a point of acceleration of 800 feet per second,nor dose engine 2s thrust simply switch off when engine 1s acceleration drops below 800 feet per second.
First, its an analogy, but as I have modified it, it is a very close to describing the action of an inductor. It has the same negative feedback and just like the inductor, and the step wise description has no CEMF, or counter thrust. until the rate of change reaches the desired rate. As stated over and over, it is only being _described_ to you in a step wise fashion. It is actually a smooth and continuous process. As stated in the analogy, try to envision those steps being separated by an infinitely small amount of time and engine #2 having instantaneous response.
Engine 2s thrust matches that of engine 1 at every instant,and so there is no motion between the two.
When does this happen, in either the analogy or the inductor?
If the two thrusts are equal, acceleration decreases. If acceleration is less than 800f/s, engine#2 fires again.
This is the same as what happens when CEMF=EMF which causes the current flows rate of change to decrease. But when the rate of change is less than .8A/s, the CEMF is no longer equal to the EMF so the rate of change again increases. The rocket engine analogy is a very good example of a similar feedback mechanism.
I see the same thing with the EMF induced current,and the CEMF induced counter current,where every change made by the forward current is counteracted by the CEMF induced reverse current.
You are not working with an inductor. You are working with an inductor in series with a reaistor with a capacitor connected across the two.
Why dose this action/reaction have to start only when a rate of change has reached a level of 800mA per second?
It does not "only start" when the .8A/s is reached. .8A/s is the rate of change that produces a CEMF of 4 volts in a 5H inductor. It is the rate of change that current is limited to when 4 volts is placed across a 5H inductor.
The value in question here,is the 800mA per second,and it seems that your self and Poynt keep using this very value to justify the value in question it self.
Seems like the there is much more "in question"..
Perhaps if you were to study the basic units of the Volt, Ampere, Ohm, Farad, and Henry, this would be more clear to you.
The definition of a Henry specifies what value the generated CEMF will be for a given value of inductance with a given rate of change of current flowing thru that inductance (actually, it is with regard to the rate of change of the magnetic flux. However, in an inductor, the current flowing thru it creates the magnetic field and the rate of change of the current flow is also the same as the rate of change of the magnetic field created by that current flow).
One Henry will generate a CEMF of 1 volt when the current flowing thru it is changing at 1A/s.
A 5H inductor will generate a CEMF of 4 volts when di=.8A/s.
A 5H inductor will generate a CEMF of 5volts when di=1A/s. So, if a 5H inductor is connected across a 5 volt source, current flow thru the inductor will rise at 1A/s.
Put 10volts across a 5H inductor and current will rise at 2A/s, because a 5H inductor with current rising at 2A/s will generate a CEMF of 10Volts.
The CEMF is what limits the current flow's rate of change, and the CEMF is well defined for a given inductance and rate of change.
It is somewhat similar to the defined relationship of 1 volt across 1ohm causing 1amp to flow.
This feed back system i believe should represent a situation where if you push against a concrete wall,the concrete wall will push back just as hard at the very same time,and the net result is no motion. The way i see you explaining thing's,is that some how,the person is able to move the concrete wall,even though the concrete wall is pushing back just as hard.
I am not explaining it that way...
It pushes back only as hard as necessary to limit the rate of change to .8A/s.
Perhaps you are just not familiar with negative feedback. The rocket engine analogy was a very good example of a negative feedback loop. As I have stated over and over, although described in a step wise fashion, it is a smooth and continuous process.
The ideal coil becomes a power source it self in this case,and it matches that which was induced into it,only with opposition.
And that opposition only allows the inductor's current to change at a rate of .8A/s (4V across 5H)
Anyway,i am going to leave it at that,as i dont think it is going to go anywhere,when the value in question is being used to confirm the value in question,when the conversation is about that very value it self.
It is indeed obvious that it is not going anywhere...
Regarding the "value" you are so concerned with, perhaps time spent studying the definitions of the most basic units used in electronics would be of help (Volt, Amp, Ohm, Farad, and Henry).
PW
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The feedback system,, well that would have an oscillation,, an extremely small amplitude and high frequency sure,, but an oscillation anyway, and as such invalidates the results.
It is clear that many can not get their heads around negative feedback. There would be no oscillation, at any frequency or amplitude.
Imagine a centrifugal clutch. In a way it can be thought of as a rpm regulator. At a certain rpm, the clutch, due to the centrifugal force engages, and if we anchor the axle so that it can not move, this is obviously going to cause drag on the motor. The harder the motor tries to turn the axle, the more the clutch engages (if the rpm increases), etc. There is no oscillation there.
It is a very similar case with the inductor and the feedback mechanism, except that process begins the instant even minute currents begin to flow. It is an instantaneous reaction that limits the rate of rise. Can you see that the current would rise very quickly upon connection? Can you also see that the cemf would be induced instantly in conjunction with that current?
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And what does any of that have to do with the present discussion?
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Take two identical batteries,call on EMF,the other CEMF. Put a resistor across
battery EMF,current flows,now introduce battery CEMF, nothing changes,current
still flows.
It has to be the rate of change that makes the whole thing tick.
John.
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;)
Aren't all JFETs depletion mode?
Yes they are, but it might be an interesting experiment to see what oscillations might exist at the threshold of forward conduction in the pn gate to source junction!
I prefer enhancement mode MOSFETs for my pre-amp designs, hi-fi and guitar/bass.
Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range. The jfets used back when had a Vds of ~30v so the signal swings were puny compared to say a 12AX7A or 7025.
I'm sure you are familiar with Crown's technology of using a split power supply in the output section where the load is connected between the center tap of the supplies and ground, and the + and - terminals are driven by complimentary bipolars or mosfets. IOW, the entire high voltage/current supply swings at the audio rate. Unaware of Crown back then, I developed the same technology that I sat on for years before building a company around the idea. The design symmetry allowed easy implementation of current and voltage feedback plus control points for prevention of saturation, soft start, quiescent bias, etc.
pm
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Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range.
Dynamic range? In a guitar amplifier? Surely you jest...
Back in the day when audiophiles were trying to reconcile the difference between tubes and solid state, or trying to discern the difference between two amplifier's with similar THD but having a different "sound", listening to the attributes of various tone arms and cartridges, and then later on doing A-B comparisons between analog and early digital, guitar players were doing the "crank 'em all up to 10" maneuver on Marshalls and the like.
Have you ever looked at the waveforms coming out of a Marshall while it's cranking away at ear deafening levels?
Besides clipping just about every stage in the Marshall and saturating the OT, at the levels being played, feedback from the microphonics generated as tubes were rattled to the brink and even the guitar itself, were all contained within an electronic and acoustic feedback loop that was part of a very loud "harmonic generator" or guitar "sound generator".
And if you happened to have a very loud guitar "sound generator" ("amplifier" being a misnomer...) that just did not generate enough harmonics, or was not "edgey" or "fuzzy" enough for you, no worries, all manner of pedals could fix ya' up.
To the woe of every frustrated sound man trying to get a decent live mix and having to deal with stage wash from the axes bleedin' into everything, the words "can you turn it down a bit?" were repeated as if a mantra.
So, with tongue in cheek, and no offense intended toward any guitar players out there, amplifying the sound of the "guitar" has rarely been the desired intention of a guitar "amplifier", but rather it is to use that guitar in the feedback loop of an ear deafeningly loud guitar "sound generator" capable of producing all manner of harmonics.
My apologies to all, I digress...
PW
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Dynamic range? In a guitar amplifier? Surely you jest...
For audio "Hi-Fi", yes of course. For the "clean" channel of a guitar or bass amp, yes to a degree.
So, with tongue in cheek, and no offense intended toward any guitar players out there, amplifying the sound of the "guitar" has rarely been the desired intention of a guitar "amplifier", but rather it is to use that guitar in the feedback loop of an ear deafeningly loud guitar "sound generator" capable of producing all manner of harmonics.
The amp is certainly 50% of the guitarist's "tone".
Pre/Pwr tubes and OPT's are obsolete, as I hope to prove in the near future.
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Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range. The jfets used back when had a Vds of ~30v so the signal swings were puny compared to say a 12AX7A or 7025.
I will be designing around a +18V supply for the preamp stages, and +24v (to start) for the output amplifier.
Output amp will be a full bridge switching type, hence the need for only 24V. CFB will be implemented to achieve an Ro of about 5R.
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For audio "Hi-Fi", yes of course. For the "clean" channel of a guitar or bass amp, yes to a degree.
The amp is certainly 50% of the guitarist's "tone".
Pre/Pwr tubes and OPT's are obsolete, as I hope to prove in the near future.
I hope you appreciated the somewhat sarcastic humor from the standpoint of a sound man. Been there done that...
I am, however, curious. How do you intend to "prove" the obsolescence of Pre/Pwr tubes and OPT's?
Subjective listening tests or the use of a more "measured" approach?
PW
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I will be designing around a +18V supply for the preamp stages, and +24v (to start) for the output amplifier.
Output amp will be a full bridge switching type, hence the need for only 24V. CFB will be implemented to achieve an Ro of about 5R.
Switching amplifier? All I can think of in response to that is "yuck".
But then, as I said, guitar "amplifiers" were never really meant to be "amplifiers".
Just giving you a hard time...
PW
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Dynamic range? In a guitar amplifier? Surely you jest...
PW
;D No not really! My goal was to manufacture the most "musical" instrument amplifiers I could in both solid state and tube. The brand name was Spectra and at one point Gibson wanted us to manufacture our amplifiers exclusively for them to market with their guitar line which was not financially feasible for us at the time. Later sold the business to Dean Markley and it took him less than two years to run it into the ground. End of story.
pm
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;D No not really! My goal was to manufacture the most "musical" instrument amplifiers I could in both solid state and tube. The brand name was Spectra and at one point Gibson wanted us to manufacture our amplifiers exclusively for them to market with their guitar line which was not financially feasible for us at the time. Later sold the business to Dean Markley and it took him less than two years to run it into the ground. End of story.
pm
Interesting...
Were the Spectra series amps by DM your designs or did DM just use the name?
And "JMF" would be ...?
PW
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I hope you appreciated the somewhat sarcastic humor from the standpoint of a sound man. Been there done that...
I am, however, curious. How do you intend to "prove" the obsolescence of Pre/Pwr tubes and OPT's?
Subjective listening tests or the use of a more "measured" approach?
PW
I did appreciate the humor. I especially liked the comment from the sound man "Could you turn it down a little?" Lol.
Proof will be in the pudding; the tone and "feel". But it will just as easily be proved via the scope. I can already duplicate the wave shaping and Ro from just about any class A triode stage using a 12AX7 etc. Most designers have missed the boat when trying to duplicate the breakup of tube circuits. Also, I can operate the MOSFETs in either pentode or triode mode. So I'm at the point I can take any existing tube guitar amp and replicate it using MOSFETs etc.
FETs (all types) already make better tubes than tubes do. Get your mind around that one. ;)
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Switching amplifier? All I can think of in response to that is "yuck".
But then, as I said, guitar "amplifiers" were never really meant to be "amplifiers".
Just giving you a hard time...
PW
Yes, "digital" amp. I know it sounds revolting, but have you heard any hi-fi "digital" amps yet? I have a couple and they are pretty damn good.
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Sorry to hear about the amp line PM.
SS Marshalls are not so good. Perhaps yours was better.
Dean Markley still sells amps (http://www.deanmarkley.com/amplifiers). I've never heard one live, nor on YT. Must check them out.
btw, they have many or all of the Spectra guitar amp schematics online here (http://www.deanmarkley.com/Info/LegacyAmps/Docs.shtml).
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And "JMF" would be ...?
PW
Those would be Jon's initials.
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The DM CD-60 sounds pretty damn sweet. 8)
https://www.youtube.com/watch?v=hsgMYbr1zVw
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The DM CD-60 sounds pretty damn sweet. 8)
https://www.youtube.com/watch?v=hsgMYbr1zVw
Thanks Poynt!
Our tube series was 30T, 60T, and 120T and ended up relabeled and repackaged as the DM CD series with a few minor changes. The solid state models were treated in a similar fashion plus many models were dropped. JMF was vertically integrated in that we had our own tool and die shop to make tooling for the metal fabrication shop, complete pcb fabrication including cnc drilling with PTH and gold plating lines, transformer winding, wood working, and of course assembly lines plus wave soldering, etc. We did everything in-house except injection molding in an effort to control quality.
As time went on, DM's people lost control of some of the processes which was the beginning of the end. I have lost track of where his amps are built today.
Sorry to take this thread so far off course!
pm
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The amplifiers are now made in China of course.
In this interview (http://www.examiner.com/article/the-dean-markley-interview-i-try-to-make-products-that-touch-people-s-souls) Markley says he designed the CD60 around 1985.
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Looks as if tinman has given up!!!
John.