Motor hums When not in use

Not sure what is going on. When motor isn’t in use it has a low pitch hum, as soon as it triggers it works fine and the hum goes away until it stops moving again. I have checked the wires and nothing seems to be loose. Any Suggestions would be great.

When the controller is on the motors are receiving power even when they are not moving.
This is to lock the motors in place so they do not move and loose position.
This may be the source of the hum.
Unless it is exceptionally loud, it is probably not anything to worry about.

There are three things that can affect this.

One is the $1 parameter in grbl. For the X-carve it should be set to 255 ($1=255). This keeps the motors on all the time.

The other thing is the current limit. If your current limit setting is close to the bottom or top of the current range for the motor you can have the motors “sing”.

The last one is the load on the motor. If the load is to high for the current limit setting to move then you can get noise from you motor.

Thanks for the quick response. This is a great forum.