Multi-speed motor control

Abstract From the Canadian patent

A motor speed control circuit generates a half cycle waveform and applies the half cycle waveform to the motor at a controlled frequency to achieve, speed reduction in the motor without motor modification. The circuit includes a, rectifier bridge electrically connected to a power source and the motor terminals, a, polarity sensing circuit electrically connected to the power source a , frequency, reducing circuit coupled to the polarity sensing circuit and a bridge enabling circuit, coupled to the frequency reducing circuit and to the rectifier bridge. For example, a, one speed induction motor can effectively operate at two speeds using the circuit.