A motor is a device that converts electrical energy into mechanical energy. Electric motors are widely used in machinery, metallurgy, petroleum, coal, chemistry, aviation, transportation, agriculture and other industries. With the improvement of industrial automation level from time to time, various control motors are required to be used as the components of the automation system. In the automatic control system of artificial satellites, the motors are also indispensable. In addition, in national defense, culture, education, medical treatment and daily life (in the modern household appliance industry) electric motor is also more and more widely used.

　　Structure and local action

　　The common motor is mainly composed of two parts: the fixed part is called the stator and the rotating part is called the rotor. In addition, there are end cover, fan, housing, housing, junction box, and so on.

　　The stator is used to generate magnetic fields and to provide mechanical support for the motor. The stator of the motor consists of three parts: stator dead center, stator winding and frame. The stator windings are embedded in the stator dead heart, and the induction electromotive force is generated when the electric current is applied to complete the electrical energy conversion. The role of the stand is mainly to fix and support the stator dead center. When the motor is running, the heat due to internal loss is transmitted through the dead center of the motor to the stand, which is then distributed to the surrounding air. In order to increase the heat dissipation area, the common motor is designed as heat dissipation sheet on the surface of the base.

　　The rotor of motor is composed of rotor dead center, rotor winding and rotor shaft. Rotor dead center is also used as a part of the motor magnetic circuit. The action of rotor winding is induction electromotive force. The rotating shaft is the main part to support the weight of the rotor, transmit the torque and output the mechanical power.