Common servo motor faults and maintenance methods
Servo motors are motors used in equipment with relatively high requirements for process accuracy, processing efficiency, and work reliability. If faults occur, they need to be repaired in a timely manner to avoid affecting normal operation.
Common servo motor faults include:
1. Motor heating too high or smoking motorThe reason for this type of fault is usually due to excessive load; Two phase operation; Blocked air duct; The ambient temperature increases; Short circuit between phases or turns of stator winding; The voltage of the stator winding grounding power supply is too high or too low.Maintenance method: Reduce the load or choose a large capacity motor; Clean the air duct; Take cooling measures; Check the input power supply voltage with a multimeter and voltmeter.
2. The motor has a live shell phenomenonThe cause of this malfunction may be due to moisture in the winding; Insulation aging; Or the outgoing line is grounded to the junction box shell; The end of the coil touches the end cover.Maintenance method: Dry and replace the winding.
3. Servo motor movementWhen there is movement during feeding, the speed measurement signal is unstable, such as cracks in the encoder; Poor contact of wiring terminals, such as loose screws; When the movement occurs at the moment of reversal between forward and reverse movement, it is generally caused by excessive reverse clearance or servo drive gain in the feed transmission chain.Maintenance method: Adjust the feed transmission chain or reduce the drive gain parameters.
4. Servo motor crawlingThis type of fault mostly occurs during the acceleration stage or low-speed feed, usually due to poor lubrication of the feed transmission chain, low servo system gain, and excessive external load.Maintenance method: Feed transmission chain lubrication; Improve the gain parameters of the servo system; Reduce external loads.
5. Servo motor vibrationWhen the machine tool is running at high speed, vibration may occur and an overcurrent alarm will be triggered.Maintenance method: The vibration problem of the servo motor is generally a speed problem, so it should be solved from the perspective of setting the speed ring to reduce the speed.
6. Servo motor torque reductionWhen the servo motor runs from rated torque to high speed, the torque may suddenly decrease, which is due to the heat dissipation damage of the motor winding and the increase in temperature of the motor at high speed caused by the heating of the mechanical parts.Maintenance method: Adjust the speed, and before using the servo motor correctly, it is necessary to verify the load of the motor.
7. Servo motor does not rotateThere are many reasons why the servo motor does not rotate, and it is necessary to investigate the cause of the fault one by one and carry out maintenance.
Maintenance method:
Check if the CNC system has pulse signal output; Check if the enable signal is connected; Observe whether the input/output status of the system meets the starting conditions of the feed axis through the LCD screen; Confirm that the brake has been turned on for the servo motor with electromagnetic brake; Check for drive failure; Check for servo motor failure; Check if the coupling between the servo motor and ball screw is ineffective or if the key is detached.
What are the precautions for servo motor maintenance?
1. Repairing servo motors requires professionals to be familiar with the structural characteristics and maintenance technical requirements of servo motors.
2. Before maintenance, the site should be cleaned. If disassembly and repair are required, compressed air should be used to blow away the dust on the surface of the servo motor and wipe off any dirt on the surface.
3. In order to further understand the defects in the operation of the servo motor, if conditions permit, inspection and testing can be conducted before disassembly. For this purpose, the servo motor is loaded onto the load changing machine for testing and rotation, and the temperature, sound, vibration, and voltage of each part of the servo motor are checked in detail.
Servo motors are relatively precise instruments and maintenance is not easy. In daily use, it is still important to pay attention to maintenance work, which can extend the service life of servo motors as much as possible and reduce the occurrence of faults.