Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: MH's ideal coil and voltage question  (Read 477904 times)

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: MH's ideal coil and voltage question
« Reply #570 on: May 19, 2016, 01:59:52 AM »
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

Pirate88179

  • elite_member
  • Hero Member
  • ******
  • Posts: 8366
Re: MH's ideal coil and voltage question
« Reply #571 on: May 19, 2016, 03:03:07 AM »
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

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: MH's ideal coil and voltage question
« Reply #572 on: May 19, 2016, 05:08:47 AM »
I had no idea that Jiffy Pop was not really available anymore.  I am devastated.  I don't know what Fizzies are.

Pirate88179

  • elite_member
  • Hero Member
  • ******
  • Posts: 8366
Re: MH's ideal coil and voltage question
« Reply #573 on: May 19, 2016, 06:01:06 AM »
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

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   

tinman

  • Hero Member
  • *****
  • Posts: 5365
Re: MH's ideal coil and voltage question
« Reply #574 on: May 19, 2016, 06:45:31 AM »
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

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: MH's ideal coil and voltage question
« Reply #575 on: May 19, 2016, 06:55:47 AM »
The waveform is correct.

tinman

  • Hero Member
  • *****
  • Posts: 5365
Re: MH's ideal coil and voltage question
« Reply #576 on: May 19, 2016, 07:14:53 AM »
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
« Last Edit: May 19, 2016, 11:39:39 AM by tinman »

Johan_1955

  • Sr. Member
  • ****
  • Posts: 334
Re: MH's ideal coil and voltage question
« Reply #577 on: May 19, 2016, 10:16:53 AM »
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:

tinman

  • Hero Member
  • *****
  • Posts: 5365
Re: MH's ideal coil and voltage question
« Reply #578 on: May 19, 2016, 12:08:21 PM »
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

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: MH's ideal coil and voltage question
« Reply #579 on: May 19, 2016, 01:41:44 PM »
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.

tinman

  • Hero Member
  • *****
  • Posts: 5365
Re: MH's ideal coil and voltage question
« Reply #580 on: May 19, 2016, 02:40:34 PM »
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.

Quote
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.

Quote
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

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #581 on: May 19, 2016, 03:28:46 PM »
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.

MileHigh

  • Hero Member
  • *****
  • Posts: 7600
Re: MH's ideal coil and voltage question
« Reply #582 on: May 19, 2016, 03:48:59 PM »
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

tinman

  • Hero Member
  • *****
  • Posts: 5365
Re: MH's ideal coil and voltage question
« Reply #583 on: May 19, 2016, 04:01:51 PM »
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

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #584 on: May 19, 2016, 04:10:45 PM »
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).

Quote
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.