The centrifugal mechanism determines the speed at which the stationary electrical switch actuates. The centrifugal mechanism is composed of a conical spring disk mounted to a bracket which is press-fit onto the motor shaft. Weights are attached to the spring disk and centrifugal force causes the spring to snap. This moves the spool on the centrifugal mechanism away from the stationary switch as the motor achieves approximately 75% of its normal running speed.