Multi-speed motor control

Abstract

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 c

Dependencies are inferred from the claim text.