Patent ID: 8247944

Claim:
A method for reducing current ripple in a brushed electric motor comprising a stator and a rotor, the stator comprising a brush housing having a plurality of circumferentially spaced brushes disposed about a commutator, each brush having a contact face that is in electrical contact with the commutator, an opposed bias face and a peripheral wall, each brush disposed in a brush pocket having a pocket wall, a base and a bias spring that is configured to apply a contact force to the bias face, thereby urging the contact face into electrical contact with the commutator, comprising: inserting a resilient damper within each said brush pocket and the respective brush disposed within said brush pocket, said resilient damper configured to provide a damping coefficient between said brush pocket and said respective brush, wherein inserting a resilient damper comprises placing said resilient damper in damping contact between the base and the bias face in each brush pocket, placing grease between the peripheral wall of the brushes and the pocket wall in each brush pocket or placing at least two shims in opposing relation and wedged between the peripheral wall and the pocket wall in each brush pocket, or a combination thereof wherein each bias spring comprises a coil spring and inserting a resilient damper in damping contact between the base and the bias face comprises locating the resilient damper within a plurality of coils of the coil spring.