a grounding system for an ac or dc motor or other rotating apparatus comprising 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 . a brush housing or holding means positions the brush in juxtaposition with the rotating conductive member and cooperates to substantially enclose the region of contact between the brush and the conductive member . the apparatus defines a cavity for extending the immediate enclosed region of contact between the brush and the conductive member for the purpose of receiving and holding residue produced by the brush as the shaft rotates , thereby preserving a clean room environment in which the motor may be utilized .