Speed-Changing Two-Phase Induction Motors, Part II: Phase Modulation Techniques

The phase modulation method of induction motor speed changing with single-winding machines has been extended to two-phase machines. The paper presents theory and design methods and shows for the first time that phase modulated motors can be wound with standard coils of equal turns and pitch. The study also brings out a useful comparison of amplitude and phase modulation techniques. The work is supported by extensive experimental investigations covering numerous pole ratios.