This method of starting a variable-speed induction motor utilizes a speed control of the induction motor by varying the output frequency from a cycloconverter. The method comprises applying an output from the cycloconverter to the secondary winding of the induction motor while the primary winding of the induction motor is short-circuited during the start-up of the motor, applying a voltage lower than the line voltage to the primary winding when the induction motor is operating within an intermediate speed range, and applying the line voltage within a speed region near the rated speed. This method enables speed control over a wide range, and provides a sufficiently large start-up torque for the induction motor.
