Speed-torque calculations for induction motors

THERE HAS recently been a renewed interest in the part-winding method of securing reduced starting current with moderate starting torque values for polyphase induction motors in sizes of 50 hp and larger. The most usual scheme is to provide the motor with two identical parallel circuits in the stator winding, and to connect only one of these circuits in each phase to the power supply for starting. After a brief interval, the remaining circuits are connected, and the motor then operates in a normal way.