Motor, also known as electric motor, is an electromagnetic device that realizes the conversion or transmission of electric energy according to the law of electromagnetic induction. According to the type of working power supply, DC motor: DC power supply is used as the working power supply. It has the characteristics of good speed regulation performance and large starting torque. It is widely used in occasions that require precise speed regulation and large starting torque, such as electric vehicles, cranes, etc. AC motor: It is powered by AC power supply. It has a simple structure, reliable operation and low cost. It can be divided into synchronous motor and asynchronous motor. Asynchronous motor is widely used in industrial production, such as fans, water pumps, etc.; synchronous motor is mainly used in large generators and other occasions.