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Author Topic: MH's ideal coil and voltage question  (Read 119783 times)

Offline Magneticitist

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Re: MH's ideal coil and voltage question
« Reply #30 on: May 09, 2016, 02:35:52 AM »
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?

Free Energy | searching for free energy and discussing free energy

Re: MH's ideal coil and voltage question
« Reply #30 on: May 09, 2016, 02:35:52 AM »

Offline Magluvin

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Re: MH's ideal coil and voltage question
« Reply #31 on: May 09, 2016, 02:40:11 AM »
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


Offline Magneticitist

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Re: MH's ideal coil and voltage question
« Reply #32 on: May 09, 2016, 02:45:36 AM »
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.

Offline Magluvin

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Re: MH's ideal coil and voltage question
« Reply #33 on: May 09, 2016, 03:00:19 AM »
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


Offline Magluvin

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Re: MH's ideal coil and voltage question
« Reply #34 on: May 09, 2016, 03:05:39 AM »
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

Free Energy | searching for free energy and discussing free energy

Re: MH's ideal coil and voltage question
« Reply #34 on: May 09, 2016, 03:05:39 AM »
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Offline poynt99

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Re: MH's ideal coil and voltage question
« Reply #35 on: May 09, 2016, 03:46:05 AM »
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.

Quote
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?

Offline massive

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Re: MH's ideal coil and voltage question
« Reply #36 on: May 09, 2016, 05:37:46 AM »
 
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

Free Energy | searching for free energy and discussing free energy

Re: MH's ideal coil and voltage question
« Reply #36 on: May 09, 2016, 05:37:46 AM »
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Offline allcanadian

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Re: MH's ideal coil and voltage question
« Reply #37 on: May 09, 2016, 06:29:15 AM »
@Magneticitist
Quote
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

Offline tinman

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Re: MH's ideal coil and voltage question
« Reply #38 on: May 09, 2016, 06:31:00 AM »
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

Offline Pirate88179

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Re: MH's ideal coil and voltage question
« Reply #39 on: May 09, 2016, 06:33:50 AM »
T=0 is The Big Bang.

Think about it.  There was no time prior to that event so it had to be 0.

Bill

Free Energy | searching for free energy and discussing free energy

Re: MH's ideal coil and voltage question
« Reply #39 on: May 09, 2016, 06:33:50 AM »
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Offline tinman

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Re: MH's ideal coil and voltage question
« Reply #40 on: May 09, 2016, 06:45:13 AM »
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

Offline tinman

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Re: MH's ideal coil and voltage question
« Reply #41 on: May 09, 2016, 06:49:07 AM »
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


Offline minnie

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Re: MH's ideal coil and voltage question
« Reply #42 on: May 09, 2016, 09:07:38 AM »



   Come on tinman, the answer's in the question.
            John.

Offline Magneticitist

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Re: MH's ideal coil and voltage question
« Reply #43 on: May 09, 2016, 10:08:09 AM »
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.


Offline tinman

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Re: MH's ideal coil and voltage question
« Reply #44 on: May 09, 2016, 10:22:41 AM »


   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

Free Energy | searching for free energy and discussing free energy

Re: MH's ideal coil and voltage question
« Reply #44 on: May 09, 2016, 10:22:41 AM »

 

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