Internally shunting grounding brush assembly with a spiral brush

A grounding brush assembly for an electric machine, the electric machine including a rotatable shaft rotatable about a central axis and having an inner circumferential surface defining a hollow bore, an outer housing, at least one bearing rotatably coupling the shaft with the housing, and a fixed shaft extending through the bore of the rotatable shaft and being electrically grounded, the grounding brush assembly comprising:

• a conductive base member having a centerline coaxially alignable with the central axis and including a generally cylindrical body having a first axial end, an opposing second axial end, an outer circumferential surface and an inner circumferential surface defining a bore sized to receive a portion of the fixed shaft;
• and
• a conductive brush coupled with the base member and formed as a spiral extending circumferentially at least one revolution about the centerline of the conductive base member, the conductive brush including a plurality of conductive fibers extending radially outwardly from the outer surface of the base member and axially along and circumferentially about the centerline, each conductive fiber having an inner radial end coupled with the base member and an outer radial end engageable with the inner circumferential surface of the rotatable shaft such that at least one conductive path extends from the rotatable shaft, through the brush and the base member, and to the fixed shaft.