How to maintain the servo motor driver

Servo driver, also known as servo motor driver, is a part of servo system. In the process of use, it is inevitable that some faults will occur, such as the driver's LED light is not on, the LED light is flashing, the motor runs faster in one direction than the other, and the motor stalls. , so it is necessary to ask maintenance personnel to check the maintenance. In order to reduce the failure rate of servo driver, attention should be paid to the maintenance of servo motor driver, including standardizing the use and maintenance environment. Let's take a look at the fault and maintenance of servo drive. A, servo driver fault and maintenance treatment

Servo driver is a kind of controller used to control servo motor, and its function is similar to that of frequency converter to ordinary AC motor. As a precision equipment, some faults will inevitably occur in the process of use. Common faults and maintenance methods are as follows:

1. When the motor rotates, the LED light flashes.

(1) Cause of failure: Hall phase error. Treatment: Check whether the motor phase setting switch is correct.

(2) Cause of failure: Hall sensor failure. Processing method: detect the voltages of HallA, HallB and HallC when the motor rotates. The voltage value should be between 5v DC and 0.

2. The 2.LED light is green, but the motor does not move.

(1) Cause of failure: The motor in one or more directions is prohibited from running. Solution: Check the +INHIBIT and _INHIBIT ports.

(2) Cause of failure: The command signal is not grounded to the drive signal. Solution: Connect the command signal ground and the driver signal ground.

3. The LED light stays red all the time.

Causes of failure: overvoltage, undervoltage, short circuit, overheating, drive prohibition, invalid hall, etc. Solution: Check one by one to find out the fault location, and then carry out maintenance.

4. After electrifying, the LED light of the driver does not light up.

Cause of failure: the power supply voltage is too low, which is lower than the minimum voltage requirement. Solution: Check and raise the power supply voltage.

The motor runs faster in one direction than in the other.

(1) Cause of failure: phase error of brushless motor. Processing method: detect or find out the correct phase.

(2) Cause of failure: When not used for testing, the test/deviation switch is in the test position. Solution: Turn the test/deviation switch to the deviation position.

(3) Cause of failure: The position of deviation potentiometer is incorrect. Solution: Reset.

6, motor stall

(1) Cause of failure: wrong polarity of speed feedback. Solution: If possible, turn the position feedback polarity switch to another position; If a tachometer is used, switch TACH+ and TACH-on the drive; If an encoder is used, switch ENCA and ENCB on the driver such as Hall speed mode, switch Hall-1 and Hall -3 on the driver, and then switch motor -A and motor-B..

(2) Cause of failure: When the encoder speed is fed back, the encoder power supply loses power. Solution: Check the power supply connected to the 5V encoder. Ensure that the power supply can provide enough current. If an external power supply is used, make sure that the voltage is the signal of the driver.

7. When the oscilloscope checks the current monitoring output of the driver, it is found that it is all noise and cannot be read.

Cause of failure: The output terminal of current monitoring is not isolated from AC power supply (transformer). Treatment method: DC voltmeter can be used for detection and observation.

8. When the servo motor rotates at high speed, the motor deviation counter overflows.

(1) Cause of failure: The motor deviation counter overflowed during high-speed rotation. Solution: Check whether the motor power cable and encoder cable are connected correctly and whether the cables are damaged.

(2) Cause of failure: When a long command pulse is input, the motor deviation counter overflows. Solution: If the gain setting is too large, manually adjust the gain again or use the automatic gain adjustment function; Extend the acceleration and deceleration time; If the load is too heavy, it is necessary to re-select a motor with larger capacity or reduce the load, and install a transmission mechanism such as a reducer to improve the load capacity.

(3) Cause of failure: The motor deviation counter overflowed during operation. Treatment method: increase the set value of overflow level of deviation counter; Slow down the rotation speed; Extend the acceleration and deceleration time; If the load is too heavy, it is necessary to re-select a motor with larger capacity or reduce the load, and install a transmission mechanism such as a reducer to improve the load capacity.

Second, how to maintain the servo motor driver

Servo driver is a part of servo system, which is mainly used in high-precision positioning system. In order to prolong its service life and reduce the failure rate, it is necessary to pay attention to the maintenance of servo drivers:

1, maintaining the service environment of the servo driver.

For the use environment of the system, factors such as temperature, humidity, dust, vibration and input voltage should be considered. Regularly clean the cooling and ventilation system of CNC equipment. Regularly check whether the cooling fan on the numerical control device works normally. According to the environmental conditions of the workshop, it should be inspected and cleaned once every six months or once every quarter.

2, the correct use of servo driver

The use and setting of servo motor driver should be operated according to the correct use method.

3, fault timely maintenance.

The structure of servo driver is basically the same as that of frequency converter, which consists of switching power supply, protection circuit, PWM wave isolation driver and three-phase inverter bridge. After the fault occurs, all components should be inspected in time to find out the cause of the fault and carry out maintenance.