The handling of faults in electric actuators should follow the principle of "safety first, diagnosis first, and graded handling". The following is a systematic solution:
1. Four-step Fault Diagnosis Method
1. Phenomenon Observation
Operation error: Stalling, jittering, abnormal speed
Signal anomaly: Feedback loss, control failure
Environmental abnormalities: overheating, noise, oil leakage
2. Fault Location
Mechanical failure: Gear wear, bearing jamming, valve stem deformation
Electrical faults: Motor burnout, circuit short circuit, contactor sticking together
Control failure: Parameter loss, program error, communication interruption
3. Tool Inspection
Electrical testing: Multimeter measures voltage/current/insulation resistance
Mechanical testing: Using a dial indicator to measure clearance, and using a stethoscope to listen for noise.
Environmental testing: Infrared thermometer measures temperature, hygrometer measures humidity.
4. Cause Analysis
Design defect: Incorrect selection, insufficient protection level
Improper use: Overloading operation, frequent start-stop cycles
Maintenance deficiency: Insufficient lubrication, aging seals
II. Common Fault Resolution Guide
| Fault Type | Typical Symptoms | Handling Steps |
|--|--||
| Motor overload | Excessive current, high temperature |
Cut off the power supply
2. Check the load
3. Measure the insulation resistance of the motor
4. Replace the burned-out windings
| Control signal lost | Actuator does not operate |
Check the PLC/DCS output
2. Test the continuity of the cable
3. Restore control panel parameters
| Gearbox oil leakage | Oil level drops, oil stains on the ground |
Fasten the bolts
2. Replace the sealing ring
3. Check the wear condition of the oil seal
Limit switch failure | Actuator beyond its travel limit
Calibrate the switch position
2. Clean the contacts
3. Replace the damaged switch
| Valve jamming | Actuator torque alarm |
Operating valve
2. Check the curvature of the valve stem
3. Apply lubricating grease
III. Emergency Handling Procedure
1. Immediately cut off power supply: to prevent the expansion of the fault
2. Safety isolation: Hang the "Do Not Close Switch" sign
3. Document the phenomenon: Take photos/record videos, record the fault codes
4. Preliminary Judgment: Determine the type of fault based on experience
5. Grading Treatment:
Simple faults: If there is a loose bolt, deal with it immediately.
Complex faults: If there is a motor failure, contact a professional.
IV. Preventive Maintenance Recommendations
1. Regular lubrication:
Gearbox: Replace the gear oil every 6 months.
Bearings: Add lubricating grease every 3 months.
2. Electrical Inspection:
Measure the insulation resistance of the motor quarterly (≥ 2 MΩ)
Check the capacitors and relays of the control board every year.
3. Environmental Management:
Temperature: Control ≤ 60℃
Humidity: ≤ 85% RH (No condensation)
Protection: Above IP65 standard
4. Operating Procedures:
Avoid frequent starting and stopping (it is recommended that the intervals be ≥ 5 minutes)
Prohibit overloading operation (≤ 90% of rated torque)
V. Case Analysis
Case: The electric actuator of a certain power plant frequently malfunctions.
Fault phenomenon: The actuator gets stuck at the 30% position.
Diagnosis process:
Measuring the motor current: Normal
Inspect the gearbox: It was found that the oil level was too low.
Operating valve: The valve stem is slightly bent.
Handling measures:
Add lubricating oil for gears
Calibrate the straightness of the valve stem
Adjust the position of the limit switch
Result: The fault was eliminated and the operation became stable.
VI. Important Notes
1. Safety first: Perform operations after power outage, and wear protective equipment.
2. Tool Usage: It is strictly prohibited to use non-insulated tools to touch the live components.
3. Spare parts management: Store essential components (such as seals and bearings)
4. Professional Support: For complex faults, contact the manufacturer or professional maintenance personnel.
Through systematic diagnosis and preventive maintenance, the failure rate can be reduced by over 70%. It is recommended to establish a fault database, recording each fault phenomenon, handling measures and results, to accumulate knowledge.