What are the common servo motor faults and maintenance methods? What are the precautions for servo motor maintenance

During the use of servo motors, if the usage method is improper or maintenance is not paid attention to, various faults are inevitable, such as excessive motor temperature rise, motor shell electrification, servo motor movement, servo motor crawling, motor vibration, torque reduction, motor non rotation, etc., which need to be investigated and repaired one by one. When repairing servo motors, it is also important to note that they should be repaired by professionals. Before repairing, the site should be cleaned and inspected and tested.

1、 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 there is a malfunction, it needs to be repaired in a timely manner to avoid affecting normal operation. Common servo motor failures include:

1. Motor overheating or smoking motor

The reason for this type of malfunction is generally due to excessive load; Two-phase operation; Air duct blockage; An increase in ambient temperature; Short circuit between phases or turns of stator winding; Grounding of stator winding; The power supply voltage is too high or too low.

Maintenance method: Reduce the load or choose a large capacity electric motor; Clean the air duct; Take cooling measures; Use a multimeter and voltmeter to check the input power supply voltage.

2. The motor has a charged shell phenomenon

The reason for this malfunction may be that the winding is damp; Insulation aging; Or connect the lead wire to the grounding of the junction box casing; The coil end touches the end cap.

Repair method: Dry and replace the winding.

3. Servo motor movement

During feed, there may be movement and unstable speed measurement signals, 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 motion, it is generally caused by the reverse clearance of the feed transmission chain or excessive servo drive gain.

Repair method: Adjust the feed transmission chain or reduce the drive gain parameter.

4. Servo motor crawling

This type of malfunction mostly occurs during the acceleration stage or low-speed feed, usually due to poor lubrication of the feed transmission chain, low gain of the servo system, and excessive external load.

Repair method: Lubrication of feed transmission chain; Improve the gain parameters of the servo system; Reduce external load.

5. Servo motor vibration

When the machine tool is running at high speed, vibration may occur, which will trigger an overcurrent alarm.

Repair method: The vibration problem of servo motors generally belongs to the speed problem, so it should be solved from the perspective of setting the speed loop to reduce the speed.

6. Servo motor torque reduction

When the servo motor runs from rated torque to high speed, the torque may suddenly decrease due to heat dissipation damage to the motor winding and mechanical part heating. At high speed, the temperature rise of the motor increases.

Repair method: Adjust the speed. In addition, before using the servo motor correctly, it is necessary to verify the load of the motor.

7. The servo motor is not rotating

There are many reasons why servo motors do not rotate, and it is necessary to investigate and repair each fault one by one.

Repair 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 of the servo motor with electromagnetic brake has been turned on; Check for driver malfunction; Check for servo motor faults; Check if the coupling between the servo motor and ball screw is malfunctioning or if the key is disconnected.

2、 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 maintenance are required, compressed air should be used to blow off the dust on the surface of the servo motor and wipe off the dirt on the surface.

3. In order to further understand the defects in the operation of servo motors, if conditions permit, inspection and testing can be conducted before disassembly. For this purpose, the servo motor is loaded onto the load 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 that are not easy to maintain. Therefore, it is important to pay attention to proper maintenance during normal use to prolong the service life of servo motors and reduce the occurrence of malfunctions.