High pitched noise in motors

Other Hardware Motors, Mechanics, Power and CNC
1

Hi,

I'm running four Vex motors off of a Vex 7.2V battery (using the Vex battery expander). I'm using the Servo class to control the motors (they behave like continuous rotation servos, so I'm suspecting that's what they are). I notice that even when not moving they are emitting a relatively high pitched whine. (They do move, though.)

Is this normal or should I be worried?

2

I am having a similar problem with a pair of motors but they dont turn, they do alone though.

so maybe we need the same fix?

3

It is likely just the PWM frequency you can hear.

Part numbers / datasheets?