Electromagnets have an extremely wide range of applications in daily life. The electromagnet is an application of the magnetic effect of the current (electromagnetic magnetic), and is closely related to life, such as electromagnetic relays, electromagnetic cranes, magnetic levitation trains and so on. Electromagnets can be divided into two types: DC electromagnets and AC electromagnets. If the electromagnets are divided according to purpose, they can be mainly divided into the following five types: (1) Traction electromagnets—mainly used to pull mechanical devices and open or close various valves to perform automatic control tasks. (2) Lifting electromagnet - used as a lifting device to lift ferromagnetic materials such as steel ingots, steel, and iron sand. (3) Brake electromagnet - mainly used for braking the motor to achieve accurate parking. (4) Electromagnetic systems of automatic appliances - such as electromagnetic relays for electromagnetic relays and contactors, electromagnetic releases for automatic switches, and operating electromagnets. (5) Electromagnets for other uses - such as grinders' electromagnetic chucks and electromagnetic vibrators.