[e*clipse]

Originally Posted by thingstodo

Sorry - I do that to everyone!

No worries! It's making me think. LOL!

The stator or stationary part of the MGR should be similar to an induction motor - coils with inductance and resistance the adds up (vectors) to impedance? The rotor is magnets so the fields are not induced .. simpler and no weird magnetic coupling ...

That's how I understand it. Physically, the stators are identical.

OK - got it. I was wondering where the 4 pairs of poles and such came from ... my mistake ... assumptions!

So you only get current from applied voltage minus BEMF, right?

Yes - that's what demands the high voltages.

For AC, peak to peak is your bus voltage. One phase (or 2) connected to + and one phase (or 2) connected to -. RMS is peak / 1.414

Ok,actually this question applies to any 3 phase motor: The ORNL test said that the BEMF was averaged line to Neutral for the three phases. Assuming a wye connected motor (the MGR is wye connected) how do you find the neutral? I've looked for a common connection point, and can't find it, even when I took the motor apart. Also, if it is line to neutral, isn't that just the Vdrop of one phase??
Now I'm REALLY confusing myself, because this obviously won't work. I mean, at 13,000 rpm, they say the line-to-neutral RMS voltage is 475V. But - the motor runs with 650VDC applied at the bus. If a bus voltage of 650V is used, then 650/1.414 = 459.7Vrms I mean 459.7Vrms < 475Vrms.

**Edit** Is this where field weakening comes into play, effectively reducing the field strength of the rotor field and thus reducing the BEMF?

Yes. 4.375 ohms at what phase angle? https://en.wikipedia.org/wiki/LC_circuit

It gets messy

Good point - and I'm confused already without throwing a capacitor into the mix. It does show the value of a low impedance bus capacitor for the motor.

There is an increase in impedance due to frequency, and it also changes phase angle

There is a decrease in the effective voltage due to BEMF

So I guess the answer is .. BOTH

I am not going to take a shot at the magnetic circuit effects - switched reluctance design and effects seem to me to be more of a black art than actual engineering and science.

Believe it or not, I'm actually starting to get a handle on this - I really appreciate your help! I guess if I can start asking dumb questions, at least I have that level of understading.