Motor servo motor is also called the implementation, in the automatic control system, is used as the drive power element, is provided by the controller signal into angular displacement or velocity of motor shaft output command.And the precision of servo motor in rotating position is very accurate.
   When the choose and buy must be more need to choose adaptation.
   Motor classification:
   1. A brush motor, low cost, simple structure, big start torque, wide speed range, easy control, need maintenance, but the maintenance is convenient, is the need to replace carbon brush), will produce electromagnetic interference, have certain requirements on the environment.So it can be used in some of the cost control more strictly.
   2. The brushless motor, the advantages of small volume, light weight, the output is big, fast response, high speed, small inertia, the rotation smooth, the characteristics of the torque is stable, easy to implement intelligent action, and motor has a simple maintenance, high efficiency, low operating temperature and the advantages of long service life, widely used in environment is now more commonly used efficient motors.
   3. Synchronous motor: the scope of its power is big, can do a lot of power.Big moment of inertia, high rotational speed is low, and with the increasing power and fast.On the stator two phase space displacement electric Angle 90 ° of Wf excitation winding and control winding WcoWf by constant voltage, the use of applied to the ac voltage on the Wc or phase change, achieve the goal of control motor operation.Ac servo motor with stable operation and good controllability, rapid response, high sensitivity and the characteristics of mechanical properties and regulation of the nonlinearity of indicators strictly (less than 10% ~ 15% and less than 10% ~ 25%), etc.The working principle of the dc servo motor is the same as the general dc motor.Motor speed n is n = E/K1j = (Ua - IaRa)/K1j type E for armature counter electromotive force;K is constant;J per pole flux;Ua, Ia for the armature voltage and armature current;Ra as the armature resistance.Change Ua or phi, all can control of dc servo motor speed, but usually adopt the method of control the armature voltage.In permanent magnet dc servo motors, field winding is replaced with a permanent magnet flux phi is constant.
   4. Synchronous motor: there are three main operation mode of the synchronous motor, which is the machine running generators, motors and compensation.As a generator to run is the most important operation mode of the synchronous motor, as the motor running is another important operation mode of the synchronous motor.The power factor of synchronous motor can be adjusted, without requiring speed, using large-scale synchronous motor can improve the efficiency.In recent years, the small synchronous motor starting to get more application in variable frequency speed regulation system.Synchronous motor can also be connected into power grid as a synchronous condenser.When motor without any mechanical load, by adjusting the flow in the rotor excitation electric power grid from the inductive or capacitive reactive power, to improve the power factor or the purpose of the power grid voltage adjustment.
   5. Asynchronous motor: in the case of not cause misunderstanding or confusion, general induction motor can be said for the asynchronous motor.Ordinary asynchronous motor stator windings to communication network, and the rotor windings without other power supply connection.Therefore, it has simple structure, manufacture, use and maintenance is convenient, reliable operation and quality is small, low cost advantages.Asynchronous motors have higher efficiency and better operation of the work, from no-load to full load within the scope of nearly constant speed operation, the majority of industrial and agricultural production to meet the mechanical transmission requirements.