Three-speed single-winding squirrel-cage induction motors

A 2-speed single-winding squirrel-cage induction motor, with only six terminals and of excellent rating and performance, has been described in several previous papers. The same principles have now been extended to give a 3-speed motor of comparable quality. Only twelve terminals and reasonably simple control gear are required for three speeds. Almost any speed combination can be obtained, the example given in the paper being a motor for 6/8/10 poles, particularly suitable for fan or pump drives.