DEVELOPMENTS IN POLE CHANGING WINDINGS USING STAR STAR-DELTA SWITCHING

Pole-changing windings using star/star-delta switching for 4:1 and 7:1 pole combinations have been developed. A universal computer program was developed for a straightaway application for any pole combination (close-ratio or wide-ratio). The program can be used by anyone without an elaborate study of the techniques for the design of pole-changing windings. Test results on laboratory size machines wound with the proposed 8/2 and 14/2 pole-changing windings are given to show that they are superior to the earlier designs in all respects. The proposed windings are fully up to the normal industrial standards, and are suitable for crane, hoist and similar wide-speed ratio industrial applications.