MH's ideal coil and voltage question

[verpies]

I did not notice the short circuit you drew into your diagram.  I mistook those arrows for measurement points (only glanced, time is short right now).

That could be the root of the misunderstanding with Tinman.  When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".

Surely you do not believe that is the equivalent circuit for an ideal inductor with zero resistance.

I think he does and he is correct. 

Why do you indicate a wire shorting your coil?  You do know that does not represent an ideal inductor don't you?

The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all.  This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.

[verpies]

Question 2--see diagram below.

No.

[tinman]

Indeed the ideal voltage source has no internal resistance nor reactance.
However an ideal inductor has reactance even if it does not have resistance.
Impedance = Resistance + Reactance



This is the reason why a simple Ohm's law i=V/R is not applicable to calculating current in an L circuit, as it totally disregards the reactance (half of the complex impedance).

That's why if an ideal voltage source is connected in series with an ideal inductor, then the current will be impeded by its reactance despite not being impeded by its resistance.

The connection is not just a series connection when there is only two components.
The connection is both series and parallel.
The fact that the ideal voltage source has no internal resistance,and is connected across the ideal inductor,means the inductor is now a loop connection with no resistance to current flow through that now looped inductor. And as we know,a voltage cannot be measured across any two points of a looped(shorted) ideal inductor.

Regardless of the fact that the ideal voltage source can produce a voltage,the fact that the ideal voltage source is now connected across that ideal inductor,means that the current flowing through it is in no way impeded,nor is there any loss to resistance,as the resistance value is 0--and so no power is dissipated.

So now you have a situation where we cannot measure a voltage across any two points of the circuit,and yet at the same time,we are trying to place the very same thing across that circuit that cannot be measured.


Brad

[poynt99]

That could be the root of the misunderstanding with Tinman.  When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".
I think he does and he is correct. 
The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all.  This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.

What are you saying exactly?

That an ideal inductor is one that has a short across its terminals? Please clarify your point.

[partzman]

That could be the root of the misunderstanding with Tinman.  When he writes "shorted inductor" he means "shorted by an ideal wire" not "shorted by an ideal voltage source".
I think he does and he is correct. 
The opposite to a shorted inductor is an "open inductor" and such inductor behaves as if it did not exist at all.  This can be seen when an "open inductor" is subjected to varying magnetic flux. i.e from an approaching permanent magnet.
Most real inductors are somewhere in-between - between the "shorted inductor" and "open inductor" ...closer to the shorted, though.

Verpies,

I disagree here. The coil resistance should be in series with the inductance not in parallel. If this were a multiple winding arrangement, then the reflected resistance/impedance would be in parallel with the referenced winding.

partzman