According to function:

1. Generator: Convert mechanical energy into electrical energy.

2. Electric motor: Convert electrical energy into mechanical energy.

3. Transformers, frequency converters, etc.; used to change the voltage, frequency, etc. of electrical energy.

4. Control motor: used as an original component in the automatic control system.

Motors generally use magnetic fields as coupling fields and use electromagnetic induction and electromagnetic force to achieve energy conversion. Therefore, the materials used in motors are as follows:

1. Conductive materials: used in circuit systems in motors. In order to reduce I²R losses, the resistivity of the materials is required to be small. Commonly used materials are copper and copper.

2. Magnetic materials. It is used in the magnetic circuit system in motors. In order to generate a strong magnetic field and reduce iron loss under a certain excitation magnetomotive force, the material is required to have high magnetic permeability and low iron loss coefficient. Commonly used materials are silicon steel sheets, Steel plate, cast steel.

3. Insulating materials: used for electrical isolation between charged bodies and between charged bodies and iron cores. The materials are required to have high dielectric strength and good heat resistance. They can be divided into A, E, B, F, Level 6, such as H and C, has the highest allowable operating temperatures of 105, 120, 130, 155, and 180°C respectively. The life of the insulating material is greatly affected by the operating temperature of the motor. If the temperature exceeds the allowable value when the motor is running, the service life will be shortened.

4. Structural materials: make each part form a whole, support and connect other machinery. The material is required to have good mechanical strength, easy processing and light weight. Cast iron, cast steel, steel plate, aluminum alloy and engineering plastics are commonly used.