Design of phase-change 2-speed windings for induction motors, using pole-amplitude modulation techniques

Pole-amplitude/modulation is a well known technique for obtaining two speeds from an induction motor with a single stator winding. In PAM windings, pole changing is achieved by reversing coils. It has been shown that pole changing can also be achieved in a 3-phase motor by connecting coils to a different phase. Combining this principle with a technique devised for the design of PAM windings leads to the development of 2-speed windings with low harmonic content and high winding factors.