An electric motor is a device that converts electrical energy into mechanical energy. Motors are widely used in machinery, metallurgy, petroleum, coal, chemical, aviation, transportation, agriculture and other industries. With the continuous improvement of industrial automation, a variety of control motors are required to be used as components of the automation system. In the automatic control system of artificial satellites, the motor is also indispensable. In addition, in the national defense, culture, education, medical and daily life (modern household electrical appliances industry) motors are more and more widely applied.

　　The role of structure and parts

　　The general motor consists of two parts: the fixed part is called the stator and the rotating part is called the rotor. There are also end covers, fans, shrouds, chassis, junction boxes and so on.

　　The function of the stator is to generate magnetic field and support the motor. The stator of the motor is composed of three parts: stator core, stator winding and frame. The stator winding is embedded in the stator iron core, and the induced electromotive force is generated by the current, so as to realize the electric energy conversion. The main function of the frame is to fix and support the stator core. When the motor is running, the heat generated by the internal loss is transmitted to the engine base through the iron core, and then emitted to the surrounding air by the surface of the machine seat. In order to increase the heat dissipation area, the general motor is designed as a cooling sheet on the outside surface of the frame.

　　The rotor of the motor is composed of rotor core, rotor winding and rotating shaft. The rotor core is also a part of the magnetic circuit of the motor. The role of rotor windings is to induce electromotive force and generate electromagnetic torque through current. The rotating shaft is the main component that supports the weight of the rotor, transfers torque and outputs mechanical power.