Abstract:
An apparatus includes multiple brushes (30, 30B, 30A, 30a, 30b) and a commutator (10) that has multiple commutator plates (12, 12A, 12B, 13B) to contact the multiple brushes for commutation in order to convert electrical energy into mechanical energy or vice versa. A brush may include an EMI suppression mechanism (30, 38A, 38B) to reduce random electromagnetic interferences or a filter circuitry (400B) to reduce the overall level of electromagnetic interferences. An EMI suppression mechanism may include a specially designed brush that leverages dielectric properties or mechanical properties of the brush to reduce electromagnetic interferences. An EMI suppression filter circuitry may include an all-capacitor filter circuitry that does not include beads or chokes.
Abstract:
A DC electric motor (10) comprises a rotor (30) rotably attached to a stator (20). The rotor (30) comprises an output shaft (31) and a rotor core (33), and a plurality of winding coils (35) wound on the rotor core (33) and electrically connected to a commutator (34) on the output shaft (31). An insulating sleeve (32) is disposed between the output shaft (31) and rotor core (33), forming a capacitor between the output shaft (31) and rotor core (33), thereby reducing the EMI caused by the fluctuating current in the winding coils (35).