We've been using a FOC 75/300A from Trampa as a starter motor on a special application. We're using a big outrunner (10 pole pairs) and a AS5047 encoder.
Everything had been going -kinda- well until we started upping the phase Amps (going from 120 to 200, still well within spec) and then all of a sudden the VESC seemed to have "lost" track and produced loud growling noises and shut down.
At restarting, the VESC wouldn't work at all, when I tried to control it through the VESC tool using the UART apply, it would maybe apply a bit of current, just enough to make a small ticking noise then stop...
No amount of motor detection, even applying manually the settings would do... The only way was to reflash the firmware then reidentify the motor and tweak parameters here and there (as before).
Now, this behaviour had already happened on the bench when I had only part of the engine (and thus part of the torque) driven. At one point, I tried with too much of current and it somewhat "lost" sync / track, made loud noises and the only way to have a working VESC was to reflash the firmware.
EXCEPT this time, it won't work as before! No matter how much I reapply the old settings, tweak the observer gain or up the switching frequency (it's a very low inductance motor). Past a certain duty cycle or current, it will completely go crazy and sometimes a super loud hissing noise before shutting down. It will start and run OK up until 7% duty cycle which is already driving the motor past the sensorless RPM point. Going to 8% will make the motor go crazy.
When the VESC loses track, the phase and FOC currents also go berserk...
I sincerely hope somebody have some feedback on this because we're at a loss... It's as if the motor OR the Inverter had been damaged by something but apart from that very brief overcurrent (which was also something that happened before even though we were far from the ABS current limit) and the loud noises, we really haven't touched anything on the motor and Inverter...
Thanks to all of you!