VARISTOR FOR AN ELECTRIC MOTOR

摘要

A varistor comprises an annular ring 32 of varistor material having a heat sink 34 bonded to one face 36. The heat sink includes a plurality of fan blades 38. The varistor is attached to a commutator 24 in a fractional horsepower PMDC motor. The heat sink 34 increases the thermal capacity of the varistor 32 to resist overheating under stall conditions and improves heat dissipation when the motor is running.