A NEW PHILOSOPHY FOR SPEED-CHANGE INDUCTION MOTORS

A new concept termed ‘phase shift modification’ for the design of two-speed single-winding three-phase induction motors is discussed. Designs are classified based on the chosen phase-spread on the initial and final pole scales. A method for improving the layer factor on the final-pole connection without affecting the winding factor for the initial pole connection is also presented. Although the concept is illustrated with respect to a 8/10 pole-combination it is equally applicable to any other pole-ratio.