a grounding system for an ac or dc motor or other rotating apparatus employs a conductive brush in resilient contact with a contamination free conductive member removably secured onto a rotating part such as a motor shaft or tachometer shaft . the contacting surface is preferably formed of brass and is shielded from contamination from motor bearings and the like , for reliably shunting the shaft to the frame of the machine so as to avoid high voltage transients across bearings as would otherwise result in bearing damage or destruction .