End cap assembly and brush box an electric motor

Abstract

A stator assembly of an electric motor includes a lamination stack, a field coil, an end cap having a plastics body fixed to the lamination stack, a brush box made of electrically conducting material, mounted on the plastics body, housing brushes resiliently biased towards the axis of the assembly, and a plurality of electrical conductors in the form of strips of predetermined configuration located on the plastics body for making electrical connections between components of the motor. The electrical conductors include a first conductor extending from the brush box; a second conductor extending from a termination of the field coil and a conducting means, which incorporates an inductance, connects the first and second conductors. The inductance in the connection is altered by altering the inductance of the conducting means. The first conductor is wrapped around the brush box to give a good and reliable electrical connection. The end wall of the brush box is connected by a tongue that can be flexed repeatedly to allow brush replacement without the end wall's breaking off. An impedance, typically a capacitor, that is connected across the power supply of the motor, is clamped on the end cap by a plastics clamping arm.