MH's ideal coil and voltage question

[verpies]

As we know, there is a potential downside in providing formulas because then you rely on the formulas only without thinking.

Of course. Conceptual understanding should always precede mathematical analysis.

Sadly, often this is not the case.

[poynt99]

So my question remains--what happens to the stored energy (during the 0 volt part of the cycle),when the negative 3 volt part of the cycle start's?
1-MHs theory-->it just disappears--energy is destroyed.
2-it is stored in the ideal voltage source?
3-it is absorbed by the ideal voltage source that cannot dissipate power=stored in the ideal voltage source.

Yes, 3 would be the answer. And you reaffirmed that you can't agree with that.

So to put it simple,how can a component that absorbs energy,but cant dissipate energy,not store that energy?.

You agree that during the period when the voltage source is 0V, it looks essentially like a short across the inductor? Why does the current flatline during this period?

You agree that during the period the voltage source is 4V, the current ramps up? Why does it do that? What would happen if the startng voltage was -4V rather than +4V?

From this you may be able to deduce, at least in concept, what the current does when the voltage source reverses polarity from the initial voltage.

[SeaMonkey]

Miles, your conceptualization of an Ideal Voltage Source
reminds one of the demonstrations of Daniel Pomerleau.

The Sources of electrical energy in his demonstrations
are simply coils of wire;  yet, when Daniel is in communion
with the True Source electrical energy mysteriously appears
and it actually powers whatever devices are connected to
Daniel's coils of wire.

In his (Daniel's) case the Source isn't really a Source but more
akin to a Conduit.  A conduit which conveys the energy from a
real source somewhere outside our physical dimension.

Apparently something has changed in how Ideal Voltage Sources
are taught in today's World.  If, that is, your conceptualization is
characteristic of what is taught these days.

[tinman]

Yes, 3 would be the answer.

3-it is absorbed by the ideal voltage source that cannot dissipate power=stored in the ideal voltage source.
Thank you.So it is stored in the voltage source,and not just disappears as MH say's. But of course,we knew that was a ridiculous statement anyway.

And you reaffirmed that you can't agree with that.

That is correct,and i draw your attention to verpies comment below.
These formulas are accurate only when the inductance (L), exciting voltage (V) and resistance (R) do not vary in time.  If they do, than much more complicated formulas would need to be used.
As at T=5s,the ideal coil loop has a steady DC current flowing through it. At this point in time,there is no induction taking place. At T=5s,a negative 3 volts is placed across the coil. How is the L value of that coil changed when the now negative EMF first has to pull down the existing current flow to a value of 0,before the opposite current flow starts to flow?.

You agree that during the period when the voltage source is 0V, it looks essentially like a short across the inductor? Why does the current flatline during this period?

It flat lines at 2.3 amps because there is no impedance to the current flow during the 0 volt time period,and so it retains that 2.4 amp current flow reached at T=3 seconds. Since both the coil and voltage source are ideal,then no power is dissipated,and so the current flow remains a constant until T=5s.

You agree that during the period the voltage source is 4V, the current ramps up? Why does it do that? What would happen if the startng voltage was -4V rather than +4V?

The current ramps up because the CEMF is reducing,due to the magnetic fields change in time decreasing. If the applied voltage was inverted(negative),then the current would flow in the opposite direction through the current loop.

From this you may be able to deduce, at least in concept, what the current does when the voltage source reverses polarity from the initial voltage.

Yes. It would first have to stop the current flow that already exist in the loop,before it could start to flow in the opposite direction. Being an ideal voltage from an ideal source,it would want to instantly collapse the existing magnetic field around the coil to a non existent state to stop the existing current flow,so as it can start to induce the reversed current flow into that coil.
So what effect dose this have on how the EMF sees the L value of the inductor?.


Brad

[tinman]

If we are to take things as being !normal!,and the inductance value seen by the EMF is not changed due to the existing current flow at T=5 seconds,then i have plotted my current trace below for the entire cycle.

I would first ask that MH say whether it is correct or not,before anyone else says whether or not it is correct.

Brad