Methods For Servo Drive Maintenance

- Sep 15, 2017-

Maintenance methods for Servo Drive

Servo drive is a controller that use to control the servo motor,its role is similar to the role of the inverter to the ordinary AC motor, part of servo system, mainly use in high-precision positioning system. Generally through three ways: position, speed and torque,to control the servo motor to achieve high-precision transmission system positioning, is high-class product of transmission technology at  current.How to test the servo drive when manintenance? This article describes seven methods of servo drive maintenance.


1, the oscilloscope check the drive current monitoring output,find all is noise, can not read

Cause: The current monitoring output is not isolated from the AC supply (transformer).

Treatment: DC voltmeter can be used to detect.

2, the motor in one direction running faster than the another direction

(1) cause of the malfunction: brushless motor phase is mistaken.

     Remedy: Detect or get the correct phase.

(2) Cause of failure: When no need testing, the test / deviation switch is in the test position.

      Remedy: Make the test / deviation switch in the deviation position.

(3) Cause of failure: The deviation potentiometer position is not correct.

      Remedy: Reset.

3,servo motor stalled

(1) cause of the malfunction: the polarity of the speed feedback is wrong.

     Solution:try following methods.

     A. If possible,make the position feedback polarity switch to another location. (some drives can achieve)

     B. If use the tachometer,refore connect the TACH + and TACH- on the drive .

     C. If use an encoder,refore connect ENC A and ENC B on the drive.

     D. If under HALL speed mode,refore connect the HALL-1 and HALL-3,same with Motor-A and Motor-B

(2) Cause of failure: When encoder speed feedback, the encoder power failure.

      Remedy: Check the connection of the 5V encoder supply. Make sure that the power supply provides enough current. If use 

an external power supply,make sure that the voltage is on the servo drive signal ground.

4.LED lights are green, but servo motor does not run

(1) Cause of failure:Servo motor in one or more directions is prohibited.

      Remedy: Check the + INHIBIT and -INHIBIT ports.

(2) cause of the fault: the command signal is not for servo drive signal ground.

     Solution: Connect the command signal ground to servo drive signal ground.

5.After power on, the driver's LED light does not light

     Cause: The supply voltage is too low, less than the minimum voltage requirements.

     Remedy: Check and add the supply voltage.

6, when the motor turns, LED lights flashing

(1) Cause: HALL phase error.

      Remedy: Check that the motor phase setting switch (60? / 120? ) is correct. Most brushless motors are 120 phase difference.

(2) cause of the malfunction: HALL sensor failure

      Remedy: Detect the voltage of Hall A, Hall B, Hall C when the motor rotates. The voltage value should be between 5VDC and 


7, LED lights always keep red

    Cause: There is a problem.

    Remedy: Over-voltage,under-voltage,short circuit,over-heat,drive disabled,HALL invalid.

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