REDUCING ELECTRIC DISCHARGE MACHINING CURRENTS IN ELECTRIC MOTORS

Presented are electric motors and apparatuses thereof for discharging an electric charge buildup on the rotor. In an embodiment, an electric motor apparatus includes a case, a stator arranged within the case, a rotor, a motor shaft extending longitudinally through the rotor to include an axial end, a grounding brush having an outer surface and an elliptical surface, and a spring including one portion maintaining slidable contact with the case and another portion coupled to an outer surface of the brush, the elliptical surface attached to the axial end of the motor shaft for causing a current flow via the brush through the case, which can act as system ground, for discharging an electric charge buildup on the stator due to a parasitic capacitance between the stator and rotor.