STARTING CONTROL CIRCUIT FOR AN AC MOTOR

摘要

A starting control circuit is provided for an alternating current motor having a run winding and a start winding and a mechanical rotational output. The motor is powered by an alternating current source. A reference oscillator produces pulses having a reference frequency. A first control circuit is provided for counting the number of reference pulses produced during a predetermined number of cycles of the alternating current source. A sensor is provided for sensing a predetermined amount of rotational movement of the mechanical rotational output of the motor and producing a sensor pulse indicative thereof. A second control circuit is provided for counting the number of reference pulses produced during the time between a predetermined number of sensor pulses and for comparing the counts on the first and second control circuits. The second control circuit assumes first and second output states dependent on the relationship between the first and second output counts. A switch is connected to the second control circuit, the alternating current source and the start winding for connecting and disconnecting the alternating current source and the start winding in response to the output state of the second control circuit.