Author Topic: MH's ideal coil and voltage question (Read 487950 times)

poynt99 · « **Reply #1095 on:** June 21, 2016, 01:01:57 AM »

Quote from: picowatt on June 20, 2016, 10:15:27 PM

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.

poynt99 · « **Reply #1096 on:** June 21, 2016, 01:08:32 AM »

Quote from: Magluvin on June 21, 2016, 12:12:35 AM

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?

tinman · « **Reply #1097 on:** June 21, 2016, 01:12:38 AM »

Quote from: poynt99 on June 20, 2016, 07:10:30 PM

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

tinman · « **Reply #1098 on:** June 21, 2016, 01:22:46 AM »

Quote from: MileHigh on June 20, 2016, 10:01:29 PM

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

MileHigh · « **Reply #1099 on:** June 21, 2016, 02:03:10 AM »

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.

poynt99 · « **Reply #1100 on:** June 21, 2016, 03:03:07 AM »

Quote from: tinman on June 21, 2016, 01:12:38 AM

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.

Quote

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 X_L=2PIFL, so with a fixed frequency and inductance, the inductive reactance "seen" across the terminals of the ideal inductor is X_L. 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 X_L. 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 X_L). 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?

tinman · « **Reply #1101 on:** June 21, 2016, 06:43:10 AM »

Quote from: poynt99 on June 21, 2016, 03:03:07 AM

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 X_L=2PIFL, so with a fixed frequency and inductance, the inductive reactance "seen" across the terminals of the ideal inductor is X_L. 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 X_L. 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 X_L). 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

hoptoad · « **Reply #1102 on:** June 21, 2016, 06:59:38 AM »

Quote from: tinman on June 21, 2016, 06:43:10 AM

snip...
Am i on the right track here?
Thanks
Brad

In one word, yes.
Cheers

TinselKoala · « **Reply #1103 on:** June 21, 2016, 07:03:05 AM »

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.

Magluvin · « **Reply #1104 on:** June 21, 2016, 07:32:59 AM »

Quote from: poynt99 on June 21, 2016, 01:08:32 AM

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

Magluvin · « **Reply #1105 on:** June 21, 2016, 07:54:57 AM »

Quote from: Magluvin on June 21, 2016, 07:32:59 AM

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

ramset · « **Reply #1106 on:** June 21, 2016, 08:24:00 AM »

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

and stop Kissing the Mirror in the mens room...your crusty drool is making it useless

MileHigh · « **Reply #1107 on:** June 21, 2016, 11:34:50 AM »

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.

Quote

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.

tinman · « **Reply #1108 on:** June 21, 2016, 01:07:41 PM »

author=MileHigh link=topic=16589.msg486769#msg486769 date=1466501690]

Quote

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.

Quote

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.

Quote

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

MileHigh · « **Reply #1109 on:** June 21, 2016, 02:16:32 PM »

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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