Common faults and maintenance methods of electric actuators
one. Indicator light failure 1. Fault phenomenon: After the electric actuator is powered on, it is found that the power indicator light is not on, the servo release board has no feedback, and the signal does not act. Fault judgment and maintenance process: Since the power indicator light is not on, first check whether the fuse tube is open. After checking that the fuse tube is in good condition and comprehensive fault phenomena, it can be inferred that the fault may occur in the power supply part of the servo release board, and then check the power indicator light. Use a multimeter to detect and find that the indicator light is open circuit, replace the indicator light and troubleshoot. Conclusion: The open circuit of the power indicator light will cause the entire servo board to not work. 2. Fault phenomenon: (found during debugging) After the actuator of the electric actuator is powered on, the signal can be turned on, but it cannot be turned off. Fault judgment and maintenance process: first check the feedback circuit carefully to confirm that the feedback signal is faultless. When the ON signal is given, the ON indicator light is on, indicating that the ON is normal. Check the off indicator light, use a multimeter to detect and find that the off indicator light is open circuit, replace it and remove the fault. Conclusion: The thyristor does not act when the off and on indicators are off (open circuit). two. Resistor capacitor 1. Fault phenomenon: After the electric actuator is powered on, given a signal (eg 75%), the actuator will fully open to the end, and then return to the specified position (75%). Fault judgment and maintenance process: According to the above fault phenomenon, it is first necessary to judge whether there is a problem with the servo release board and the actuator. Remove the servo release board from the actuator, directly connect the power line to the terminals X5/1 and X5/4, the actuator moves in the closing direction, connect the power line to the terminals X5/1 and X5/2, the actuator Open direction action, if the actuator does not act normally, it means that the fault is on the actuator. Use a multimeter to test that the motor winding is normal, and then test the resistance on both sides of the capacitor to find an open circuit, replace it and remove the fault. Conclusion: When encountering the above fault phenomenon, first determine which part of the fault occurs, and finally determine the root cause. 2. Fault phenomenon: After the actuator is energized, the close signal (4mA) is given to the actuator first fully open and then fully closed. Fault judgment and maintenance process: First remove the servo release board, directly energize the actuator to find that the original fault still exists, check the resistance, the resistance value of the resistance is normal, indicating that the resistance is no problem, check the motor winding, and find that the resistance value is normal, and the motor is no problem. From this fault, it is inferred that the capacitor may be damaged, and the capacitor should be replaced again to eliminate the fault. Conclusion: Resistors and capacitors are the first suspects when this problem occurs. 3. Others 1. Fault phenomenon: As long as AC220V power supply is sent to the site, the protection switch will act immediately (trip) and the actuator servo release insurance has been burned. Fault judgment and maintenance process: First, use a multimeter to detect the motor winding on the actuator, and find that the resistance of the motor winding tends to zero, indicating that the motor is short-circuited, and then detect the resistance at both ends of the brake, and the resistance tends to infinity, indicating that the brake is broken. Normally it should be around 1.45K. The final solution is to replace the new brake and motor, install the fuse of the servo release board, re-adjust it, and resume normal operation. Conclusion: This situation should be due to the fact that the motor was locked to death after the brake was broken, and the motor was not found in time, which caused the motor to block and transfer heat for a long time, and the work eventually caused the insulation damage between the phases of the motor. 2. Fault phenomenon: The action direction of the actuator is not controlled by the input signal. Judgment and maintenance process: First, check that the two current limiting resistors and phase-shifting capacitors are not abnormal. Use a multimeter to check the winding resistance of the motor. It is found that the resistance value of the motor is 1.45MΩ (and changes from time to time), indicating that the motor winding is wrong. The final solution was to replace the motor. 3. Fault phenomenon: The action direction of the actuator is not controlled by the servo release board. Fault judgment and maintenance process: First, let the user use a multimeter to detect the two current limiting resistors, phase-shift capacitors and the winding resistance of the motor. The user's inspection results are consistent with the final data provided by us. The three factors that affect the steering of the actuator are ① the winding of the motor itself, ② the current limiting resistor, and ③ the phase-shifting capacitor. Apart from these three factors, there is no other possibility.