Rotating Magnetic Field's and Inductors.

[verpies]

Are you saying you believe the coil is accelerated during both the coil on time and flyback periods?
I would think that once past TDC, it would be tugging the wrong way and decelerate the rotor...

Unless the "flyback period" ends before the TDC.

[verpies]

So what is it that the external alternating magnetic fields do to the coil to reduce the dissipated heat from the coil,

The magnets of the rotor provide some of the magnetic flux, so the coil needs less current to maintain constant flux that penetrates it.  Less current means less input energy and less heating.

You can come to the same conclusion by considering the superposition of the battery EMF and the induced EMF, but I prefer my method of analysis because the maintenance of the constant flux through a shorted coil is its most fundamental behavior...all the currents and induced EMFs stem from it.

...and raise the P/out from that coil.

...electric or mechanical output power ?  Where are your measurements of it?

Anyway, if the recovery period is timed to occur immediately after the TDC then we have Case #3 and the recovery current during this period increases as more current is needed to maintain the flux level that was at TDC.

[verpies]

Kickback always less dude!

[tinman]

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Anyway, if the recovery period is timed to occur immediately after the TDC then we have Case #3 and the recovery current during this period increases as more current is needed to maintain the flux level that was at TDC.

The magnets of the rotor provide some of the magnetic flux, so the coil needs less current to maintain constant flux that penetrates it.  Less current means less input energy and less heating.

This is exactly what i said some pages back,so lets run with this for a bit,and think about what is happening during each cycle. We do know which comes first(the chicken or the egg) in this case,and that is the induced flux into the core from the PM's. We know this because we have alternating fields on the rotor. The coils produced field at the rotor end is north,so the other end of the coil will be of course a south field(we will stick to N&S as it makes it easy). We know that the magnetic domains within the core will align opposite to those in the PM,and so will be aligned the same when the coil has a current flowing through it. So the induced flux in the core from the PM's is now present before the coil switches on. This in turn lowers the P/in needed to raise the flux volume in that core and it's surroundings to the level we had without the rotor-->this we know,as the P/out dose not change,which tells us the field in and around the inductor was the same in both cases. The extra waste heat dissipated by the coil when the rotor is not in play,is due of course to more current flowing through the coil. The extra current flow is due to the fact that it now has to induce the flux into the core as well,where as with the rotor,the flux is already induced !mostly!,and the domains are !mostly! already aligned within the core material. So from this we know work is needed to induce the flux into the core,and align the magnetic domains within that core-->and we also know that this work being done came from the magnets when the rotor is in play. So lets use some example numbers here-that being the power required to spin the rotor,and the reduced power that the magnets on the rotor cause. Lets say it takes 10mW to spin the rotor,but the P/in is reduced by say 50mW's due to the magnets on the rotor inducing the flux into the core--if this was not the case,then the P/in would rise by that 10mW's,and not be reduced by the 50mW's. But it has to be,as we know the magnets are inducing the flux into the core before current starts to flow through the windings.

Now-is useful work being done when the magnets induce this flux into the core?.

.electric or mechanical output power ?  Where are your measurements of it?

As stated many times in this thread,we are looking only at the electrical output,and mechanical is not yet taken into account. The measurements are in the video's.

Brad

[verpies]

This is exactly what i said some pages back,so lets run with this for a bit,...

I think that what you wrote is mostly correct.
I would use the superposition of EMFs method, too, but only outside the ON-period.
During the ON-period, when the coil is connected, I would use its flux freezing principle and superposition of currents.

This video illustrates the flux freezing principle by a coil without resistive losses (a superconducting disc) ...regardless whether gravity pulls or pushes on the coil. Resistive coils do all that, too, ...just for a short time.

...we know the magnets are inducing the flux into the core before current starts to flow through the windings.
Now-is useful work being done when the magnets induce this flux into the core?

Yes, although i would not use the word "inducing" in reference to magnetic flux, since flux is generated or routed.
When the permanent magnet is approaching a soft magnetic core, while current is not allowed to flow in the coil, we have the Case #15 and useful mechanical work is being done during this period and the rotor gains mechanical energy then.