M109Rider
Active Member
My guess is that it's just acoustic noise from the magnetic fields vibrating the stator. I would imagine that minimizing these would be correlated (possibly not 100%) with good efficiency. For the preconditioning, they're presumably altering the field vectors to somehow produce lower efficiency, and it probably produces a bit more vibration as well.
That's extremely hand-wavy, but they have a lot of control over exactly how they excite the windings in these motors, and it does seem that they can produce a fair amount of excess heat with non-optimal waveforms. And those non-optimal waveforms probably produce some heat & noise & vibration.
Interesting. Thanks for the reply.
Since some units whine more than others, I hope that isn’t an indicator that some are more prone to fault down the line as a result.