Power adjusting ring for e.g. adjustment of carbon brushes of reversible electric motor of drilling machine, has mating contacts arranged as switching contacts such that fixed contacts exert force against both sides of mating contacts

摘要

The ring (3) has a carrier pivotally supported at a base, and fixed contacts arranged at the base and electrically connected with field windings of an electric motor (2). The fixed contacts cooperate with switching contacts in selective contact of carbon brushes of the motor by pivoting the carrier. The fixed contacts are formed as U-shape curved contact arms. Mating contacts are arranged as the switching contacts such that the fixed contacts exert force against both sides of the mating contacts. The fixed and switching contacts are coated with a noble metal.