Classified by motor speed

(1) Constant speed motors have ordinary cage type, special cage type (deep groove type, double cage type, high starting torque type) and winding type.
(2) Speed regulating motor is a motor equipped with a commutator. Generally, three-phase parallel excited winding rotor motor (rotor control resistance, rotor control excitation) is used.
(3) Variable speed motors include pole-changing motors, single-winding multi-speed motors, special cage motors and slip motors.