DC tachogenerator is widely used in manufacturing industry, which is used to measure rotating speed and workpiece position, and monitor motion parameters in production process. It plays an important role in CNC machine tools, printing equipment, pharmaceutical equipment and other industries. In the field of transportation, DC tachogenerator can be used to monitor the speed of vehicles and ensure the safe driving of drivers. On the railway, the wheel speed sensor uses DC tachometer generator to measure the speed and position of the train to ensure the safety and accuracy of the train. Ac tachogenerator is mainly used in scientific experiments and national defense industry. In the laboratories of physics, chemistry and other disciplines, AC tachogenerator is widely used to make laboratory motors to show the mutual transformation between electrical energy and mechanical energy. In the precision automatic control technology of national defense industry and scientific research, AC tachogenerator also plays an important role in realizing precision measurement and control. These application fields need high-precision and reliable tachogenerator to meet specific requirements.