The bifilar pancake coil at its resonant frequency

[MileHigh]

On what you quoted me on above, Im just relaying what Tesla says in the pat on electromagnets.  The inductance is ignored by the input and the only current limiting factor over time is the coils resistance. So it was the resistance part that you agreed with me on that the currents through a non inductive resistor has no delay in reaching max current V/R. Soo, if Teslas claim is correct then if we pulse the bifi coil, the only thing the input sees is the resistance and if the current reaches max instantly then what of the magnetic field it generated?  Its a short read. So why not investigate THAT claim? 

You are missing the key point here.  Tesla states in the patent that at the right AC excitation frequency the bifilar coil (or any coil) will appear as a pure resistance.  This is where the coil is modeled as a series LC circuit.  And we know that when you excite a series LC circuit with a pure sine wave that the series LC circuit looks like the wire resistance only because at the right AC excitation frequency the reactance of the inductance and the capacitance cancel each other out.

So if you pulse a bifilar coil, this is not the same as pure sine wave excitation at the resonant frequency, and the "wire resistance only" statement does not apply.

[TinselKoala]

Brad: Your wirewound cement resistor probably has significant inductance too!

[MileHigh]

The use of the words "in theory" suggests that you haven't tested the idea you are contemplating......  you are fishing for ideas before you present your own....LOL....  There is only one way to accomplish this task, and as a requirement one must embrace an alternative form of induction, one which does not result in the inductor's opposition to change mechanism being triggered.

You are not even close and I am not fishing for anything.

I am not going to answer the question either, and would ask those that "know", who are not of the self appointed elite to not answer the question.  A select few of you have been playing with coils, parroting and preaching the gospel for over 30 years. You have no plan, for the near-instant magnetic field generation in a coil, but you'd like us to think you do......If you had a working concept, with your experience, and this knowledge, you could write your own ticket!

Try thinking it out and coming up with an answer instead of looking for trouble.  The point in asking the question is to get you to think, and I think that you are going in that direction which is good.

[Magluvin]

OK, I see what you mean now. It's a good question but difficult to answer experimentally. I'll see what I can do.
But you have to remember that there are different kinds of "non inductive resistors". There are wirewound resistors that use special windings like hairpin bifilar and Ayrton-Perry, whose magnetic fields do exist but cancel in the bulk due to the proximity of the windings carrying currents in opposite directions. There are carbon composition resistors that have no windings at all. There are flat resistors with special partial conductive materials that also have no windings at all.

ok we cool.  I know the test will have to be developed. Im imagining that a pulse train on a normal coil will show the current build delay due to inductance and if Tesla is correct the bifi should show instant or even say a much shorter delay due to inductance. It will be interesting.

Mags

[TinselKoala]

I understand that. But with a bifi, is it different than what you posted above. His pat clearly states differently than you quote above. Like I said, its a very quick read. So lets test his claim. Or is it your opinion that he was terribly mistaken as you have read it already and took note of the claim? Just askin.

Mags

No, I think you are misinterpreting the physical situation. As MH has said, the inductive and capacitive reactances work to cancel at a specific frequency. They still exist! That is, the magnetic field of the coil and the electric field of the capacitance still exist but when combined at the right frequency they make the coil "look like" it has only the ohmic resistance during the AC oscillation. A 'coil for electromagnets' wouldn't be much good if it did not have a magnetic field, would it? And it takes time for a magnetic field to build, it does not happen instantly, except maybe in superconductors ("instantly" still being limited by the speed of light). In the bifilar coil or any coil at its resonant frequency, you have an exchange of energy between the magnetic field and the electric field and if this happens at the right timing, it looks like there is no impedance. But if you could monitor either the magnetic field or the electric field you would still see them growing and shrinking, with each cycle of the stimulating AC current.