A three-phase asynchronous motor consists of a stator and a rotor.
Stator is a fixed part of motor, which is used to generate rotating magnetic field. It is mainly composed of stator core, stator winding and base.
The rotor is the rotating part of the motor, which consists of rotor core, rotor winding and rotating shaft. Its function is to obtain rotating torque under the action of rotating magnetic field. Rotor is divided into squirrel-cage rotor and wound rotor according to its different structures.
The squirrel-cage rotor is installed in the rotor core slot with copper bars, and end rings are welded at both ends, which looks like a squirrel cage. Small and medium-sized rotors generally adopt cast aluminum.
The winding of a wound rotor is similar to that of a stator. Three-phase windings are connected in a star shape, and three terminal wires are connected to three copper slip rings installed on the rotating shaft and connected to an external circuit through a set of brushes.
Squirrel cage motor has simple structure and low price. Wound motor has complex structure and high price.