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. For arriving at these designs, a universal computer program has been developed, for a straightaway application for any pole combination (close-ratio or wide-ratio). The program has the merit that it can be applied by anyone without an elaborate study of the too many techniques presented in the literature for the design of pole-changing windings during the last two and half decades. Test results on laboratory size machines wound with the proposed 8/2 and 14/2 pole-changing windings are found superior to the earlier designs in all respects. The proposed windings are fully upto the normal industrial standards, and are suitable for crane, hoist and other similar wide-speed ratio industrial applications.