1: servo motor servo motor is widely used in various control systems, can be input voltage signal is converted to a motor shaft mechanical output, drag the control element, so as to achieve the purpose of control. Servo motor with AC and DC component, the first servo motor is a general DC motor, the control precision is not high, the use of general DC motor servo motor. The present DC servo motor structurally, small power DC motor, the excitation by armature control and field control, but usually the armature control. 2: stepper motor stepper motor is mainly used in NC machine tool manufacturing field, the stepping motor does not require A / D conversion, can be directly digital pulse signals into angular displacement, so it has been considered to be the most ideal NC machine tool components. In addition to the application of NC machine tool, the stepper motor can also be used on other machines, such as automatic feeding machine motor, as universal floppy drive motor, but also can be used in printers and plotters. 3: torque motor torque motor with low speed and high torque characteristics. General in the textile industry often use AC torque motor, the working principle and structure and single phase asynchronous motor with the same. 4: Switched Reluctance Motor SRM switched reluctance motor is a new type of motor, the structure is extremely simple and rugged, low cost, speed control performance, is the traditional motor control strong competitor, has great market potential. 5: brushless DC motor brushless DC motor mechanical characteristic and regulation characteristics of good linearity, wide speed range, long service life, convenient maintenance and low noise, not because of the brush and causes a series of problems, so the motor in the control system has great application. 6: DC motor has good speed, easy to start, to load the advantages of starting, so now the application of DC motor is still widespread, especially in the SCR after DC power supply. 7: asynchronous motor asynchronous motor has the advantages of simple structure, convenient manufacture, use and maintenance, quality and reliable operation of small, low cost. Induction motors are widely used in driving machine, water pump, blower, compressor, lifting hoisting equipment, mining machinery, light industrial machinery, agricultural and sideline products processing machinery production machinery as well as most workers and peasants household appliances and medical equipment etc.. In the household appliances more applications, such as fans, refrigerators, air-conditioning, such as vacuum cleaners. 8: synchronous motor synchronous motor mainly used for large-scale machinery, such as blowers, pumps, compressors, ball mill, rolling mill as well as small, miniature equipment or a control element. One phase of a three-phase synchronous motor is the main. In addition, still can be adjustable camera use, to the grid inductive or capacitive reactive power.