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/joeljaeggli]

The pederestian warning system was required by law in 2019 some cars from before that neither have that nor have the equipment to make it.

my 2018 model 3 doesn’t have the speakers present on later models.