Motor is making a strange noise

[Riding.ebike]

Hello there,
I have a 45amp Sabvaton programmable controler, I’ve ran hall angle testing and tired a lot to fix it. The motor makes an odd height pitch sound, it’s almost like the hall sensors are making a noise one by one. I really need help it’s never done this with other stock controllers, is this normal?

 

[amberwolf]

Sounds like it's PWM frequency is low enough to hear, or it's sensorless (see below).

Is it a high-pole-count motor? (lots of magnets in the rotor)

Does the motor run correctly despite the noise?

Is it an FOC controller? If so it might have adjustments available including PWM frequency. If it does not, there's probably nothing you can change about it.

I have a generic controller that makes a constant faint whine with any motor attached to it even when it is not operating the motor. It *only* operates sensorless, even though it has hall wires it doesn't read them. I have had an FOC controller that did this too, though the designer made some firmware changes to it that helped with that a bit, it never completely went away.

In both cases, the sensorless operation means that the controller has to figure out rotor position some other way. In the case of the two controllers I mention above, it generates a high-frequency (audible) signal into the phase wires that reacts with the magnets in the rotor to create feedback the controller can detect over the phase wires to tell where the rotor is, so it can send the correct phase currents at the right times to keep the motor spinning as commanded.