A basic educational video, it explains something I'd read about but not understood: High torque at low rpm - very nice for getting off the line. But at higher rpm, PM motors can generate significant reverse voltage limiting the current. Low reverse EMF at high rpm - the rotor field magnetic fields become an inductive motor by effectively cancelling some of the PM fields. The correct term is "Internal Permanent Magnet Synchronous Reluctance Motor." I knew Toyota had them in their transaxles but did not understand the physics. Bob Wilson
The Toyota papers and "new car features" doc mentioned field-weakening a lot, because it was important for keeping back EMF from exceedimg battery voltage through the IGBT back-diodes. I think this was still in play when coasting in neutral, which explained how several of my experiments didn't blow things up. It also explained why flat-towing a Prius with the inverter power off was a bad idea. _H*
