Hello,

I am servicing an old electrical engine. There is a red and a yellow wire (which were connected to phase and neutral and the motor was working that way).

After opening the motor I found a third wire which is black and connects to this part that I am holding in my hand. What is it? Could it be the ground wire?

The grey part is pushed down when the axis of the motor is in place and all screws are in place, which lets current flow to the tip of the black wire, whereas as it is now, the grey part is pushed up by the yellowish part which acts as a spring, disconnecting the tip of the black wire.

If that's not the ground wire, maybe I could wire a ground cable to one of the screw hole in the outside shell of the motor?

Thanks for your help!