MH's ideal coil and voltage question

[minnie]

  Have you had a gander at the Waterloo induction analogy?
            J.

[partzman]

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

[poynt99]

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

[tinman]

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

[tinman]

  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