With the development of the times, the application of the DC motor will be more, the original use of AC motor in many occasions are replaced by DC motor. Especially after the brushless motor, the production of the DC motor is continuously increasing. Our annual production of various DC motors up to billions of units or more, too many to count the production of DC motor manufacturers. In industry and agriculture, DC motors are also widely used in electrical and automatic control and instrumentation. In the medical field, the use of DC motor is not small, such as medical instruments, surgical instruments. In life, more use, and now even the toothbrush is made of DC motor toothbrush. The application of the DC motor is really too numerous to mention, can be said to be everywhere. Various kinds of DC motors are used in automobile industry, such as fan, wiper, water jet pump and flameout device.