A wide constant power range vector controlled AC motor drive using winding changeover technique

A high-performance vector-controlled induction-motor drive with a very wide constant power range of 1:10 to 1:30 has been developed for use in spindle drives of machine tools. The motor has two combinations of winding connections, and one of them is selected in accordance with the operating conditions. Using this technique, the gear box in the spindle drives is eliminated. Theoretical analysis and test results are presented.<<ETX>>