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What is the difference between DC servo motor and AC servo motor?

  • classification:Industry
  • author:管理员
  • source:
  • Release time:2020-11-12 09:22:01
  • Visits:69



        The servomotor can control the speed, position accuracy is very accurate, can convert the voltage signal to the torque and speed to drive the control object. The rotor speed of the servomotor is controlled by the input signal and can respond quickly. In the automatic control system, it is used as an actuator with the characteristics of small electromechanical time constant, high linearity and starting voltage, etc. It can convert the received electrical signals into angular displacement or angular velocity output on the motor shaft. It can be divided into DC and AC servo motors. Its main feature is that when the signal voltage is zero, there is no rotation phenomenon, and the rotation speed decreases uniformly with the increase of torque.

      Servo motors are divided into AC servo motors and DC servo motors. What are the pros and cons of each? Now let's introduce it to you.

      A: dc servo motor and AC servo motor in the basic structure of the comparison

      Dc servo motor is similar to DC motor in structure. Motor speed n = E/K1j = (Ua - IaRa)/K1j, type of E for armature counter electromotive force, K is constant, j per pole flux, Ua, Ia for the armature voltage and the armature current, Ra as the armature resistance, change Ua or phi, all can control of dc servo motor speed, but generally adopt the method of control the armature voltage, in the permanent magnet dc servo motors, field winding replaced by * magnets, magnetic flux phi is constant.

      What is the difference between dc servo motor and AC servo motor? How to choose?

      The structure of ac servo motor is similar to that of AC asynchronous motor. There are two excitation windings (Wf) and control windings (WcoWf) with phase space displacement of 90° and electric Angle on the stator, which are connected with constant AC voltage. The ac voltage or phase change applied to Wc can be used to control the motor operation.

Two: dc servo motor and AC servo motor advantages and disadvantages of the comparison

      (1) Advantages and disadvantages of DC servo motor

       Advantages: accurate speed control, hard torque speed characteristics, simple control principle, good linear adjustment characteristics, fast time response, easy to use, cheap price.

       Disadvantages: brush reversal, speed limit, additional resistance, resulting in wear particles (dust-free and explosive environment is not suitable)

       (2) Advantages and disadvantages of AC servo motor

       Advantages: good speed control features, in the whole speed range can achieve smooth control, almost no oscillation, more than 90% of the high efficiency, less heat, high speed control, high accuracy position control accuracy (depending on the encoder), stable operation, good controllability, rapid response, high sensitivity and the characteristics of mechanical properties and adjust the nonlinearity of indicators strictly, etc. Within the rated operation area, it can achieve constant torque, low inertia, low noise, no brush wear, no maintenance (suitable for dust-free and explosive environment).

       Disadvantages: the control is more complex, the drive parameters need to be adjusted on the spot to determine the PID parameters, need more wiring.

       Through the above comparative analysis, we can clearly know the advantages and disadvantages of DC servo motor and AC servo motor. Such analysis can help us know how to choose the motor more accurately, so that our work can reach the ideal state. Zhongsheng technology main products: AC servo motor, new energy vehicle motor, etc.


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