Daf, remember we talked about the eddy currents affecting the non segmented magnets in the partial load?
This is frequency related. The PWM signals the rotors are 'seeying' are different coming from different controllers. a certain frequency would heat it up quicker than the other. (i know this from my schulze controller) while one motor gets hotter on 9khz, the other has a higher temp on 19khz sampling frequency. This frequency is used to make the PWM signal build up like a signal.
I am convinced that a sinus build up PWM signal would heat up the rotor less than an on/off signal.
The better the signal follows the rotor, the more efficient it will be. If the pulses are 100 percent digital, (on off, 0,1) the magnet would heat up the fastest.
The permanent magnet has resistance to the electric-magnetical signal. Due to this resistance the rotor will spin, but if this signal is 'spastic' the rotor/stator would heat up the fastest.
not only the magnet/stator is responsible for the temperature of the motor, but the controller has got a strong hand in this as well.
A 95 percent efficient motor can run less efficient on the bad controller.
Talk about something impressive;
http://lehner-motoren.com/motordaten...50-6HA.32V.xls
I wondered the same thing that you guys do..
Yes... 94 percent efficiency at allmost 70000 rpm.....
But 94 percent of 6400 watts is 400 watts.. 400 watts in a small motor like the 1950... Captain.. We need cooling..