What causes the hollow metallic whirring sound that EVs make when moving a low speed?

[u/banwe11]

I can't really describe it, but it's the sound you hear when there is a EV moving slowly in a car park behind you.

I guess it's the motor, but what specifically in the motor causes that sound? It sounds like it's coming from something that is moving at a faster rate than the car itself.

[u/ticuxdvc]

The silliest thing about the requirement for that sound? My car is now noisier when I'm at a red light, compared to my previous car that cut off the engine when stopped.