Structure and working principle of three-phase asynchronous motor

The three-phase asynchronous motor consists of two basic parts: a fixed stator and a rotating rotor. The rotor is installed in the inner cavity of the stator and supported on two end covers by means of bearings.

1. Stator

The stator is generally composed of three parts: the stator core, the stator winding and the frame.

2. Rotor

The rotor generally consists of a rotor core and a rotor winding.

Working Principle:

After the stator winding of the three-phase asynchronous motor is applied with a symmetrical voltage, a rotating air gap magnetic field is generated, and the conductor of the rotor winding cuts the magnetic field to generate an induced electric potential. A rotor current is generated due to the rotor winding being short-circuited. The rotor current interacts with the air gap magnetic field to generate electromagnetic torque, which drives the rotor to rotate. The speed of the motor must be lower than the synchronous speed of the magnetic field, because only then the rotor conductor can induce the potential to generate the rotor current and electromagnetic torque. So the motor is called asynchronous motor, also called induction motor.