Electric actuators are core drive equipment in industrial automation control systems, widely used in power, chemical, water conservancy, HVAC, oil & gas transmission and other industries. They drive valves, dampers and other mechanisms to complete on-off and regulating movements, achieving automatic equipment control and precise working condition adjustment. As mechatronics precision devices, electric actuators integrate mechanical transmission, electrical control, sensing and detection structures. During long-term continuous operation, they are susceptible to dust, moisture, vibration, high and low temperatures, which may lead to wear, signal drift, jamming and failure. Standardized maintenance is critical to guarantee stable equipment operation, improve control accuracy, extend service life and reduce downtime losses, and it is also a key part of refined industrial equipment operation and maintenance.

General Principles of Maintenance

Maintenance of electric actuators shall follow the core principles of prevention first, regular inspection, graded maintenance and targeted disposal, and avoid the misconception of prioritizing repair over maintenance. Daily work focuses on cleaning and simple function inspection to identify minor risks in advance. In-depth overhaul, component maintenance and accuracy calibration shall be carried out periodically to prevent major faults at the source. All maintenance operations shall comply with equipment manual specifications. Unauthorized disassembly, mixed use of spare parts and over-parameter commissioning are prohibited. Complete maintenance records shall be kept to form full operation and maintenance files, providing data support for equipment overhaul, replacement and upgrade. In addition, idle equipment shall be started and tested periodically to prevent component rusting, grease solidification and circuit failure caused by moisture.

Graded Regular Maintenance Specifications

According to equipment operating load, working environment and wear law, maintenance of electric actuators is divided into four levels: daily maintenance, quarterly maintenance, semi-annual maintenance and annual maintenance, adapting to different operation and maintenance requirements while balancing economy and reliability.

Daily Routine Maintenance (Daily / Weekly)

Daily maintenance is the foundation of stable equipment operation. No disassembly is required; it mainly includes visual inspection, cleaning and simple function testing, applicable to electric actuators under all operating conditions.

1. Appearance and environment inspection: Check whether the equipment shell is damaged, deformed or corroded; verify the integrity of sealing covers and waterproof gaskets to prevent rainwater, dust and oil from penetrating into the equipment. Check the firmness of the mounting base for looseness, offset and abnormal vibration. Clear sundries around the equipment and keep heat dissipation holes unobstructed to avoid high temperature accumulation which shortens the service life of electrical components.
2. Cable and wiring inspection: Check cable sheaths for damage, aging and cracking. Ensure terminal blocks are free from looseness, oxidation and burning. Junction box sealing shall be intact to avoid hidden dangers such as short circuit, electric leakage and poor contact. The grounding wire shall be firmly connected with grounding resistance meeting industrial standards to ensure electrical safety.
3. Cleaning: Wipe dust and oil stains on the equipment surface with dry soft cloth. Neutral special detergent can be used for slight wiping in heavy dust and oil environments; liquid penetration into the equipment is strictly prohibited. Keep the valve stem and transmission connection parts clean without debris jamming.
4. Simple function test: Perform local start-stop and on-off operation tests. Observe whether the equipment responds normally and runs without abnormal noise, jitter or sticking. Verify the local/remote switch, indicator lights and display screen work properly.

Quarterly Special Maintenance (Every 3 Months)

Special inspection and maintenance for transmission, lubrication, limit and sensing components are carried out to address minor wear, grease degradation and slight accuracy drift.

1. Transmission mechanism inspection: Disassemble and inspect gears, worms, racks and other transmission parts. Clear metal debris generated by wear. Check components for slight wear, deformation and excessive meshing clearance. Minor deviations shall be adjusted in a timely manner, and damaged parts shall be reported for replacement in advance.
2. Lubrication system maintenance: Check the condition of lubricating grease on bearings, gearboxes and valve stem transmission parts. Supplement lubricating grease of the same model if grease dries out, contains impurities or viscosity drops, to ensure smooth transmission and reduce mechanical wear. Grease cleanliness must be controlled; mixing different types of grease is forbidden to prevent grease deterioration and failure.
3. Limit and accuracy calibration: Verify the sensitivity and accuracy of travel limit switches and torque limit switches, adjust trigger positions to avoid false or failed actuation. Perform preliminary calibration of position feedback sensors to correct slight signal drift and ensure accurate on-off positioning.
4. Trial operation of idle equipment: For low-frequency operating equipment, complete full-stroke start-stop operation every 3 to 4 months to prevent valve stem rusting, transmission component jamming and internal circuit moisture.

Semi-annual In-depth Maintenance (Every 6 Months)

Focus on component fastening, insulation test, lubricant replacement and manual mechanism verification to fully detect hidden faults, suitable for high-frequency operation and harsh working conditions.

1. Component fastening: Fully tighten equipment mounting bolts, valve connection bolts and terminal block bolts. Focus on hidden looseness risks under vibration conditions. All fastening bolts shall meet torque requirements to eliminate operation looseness faults.
2. Insulation performance test: Use a megohmmeter to test the insulation resistance of motor windings. Normal insulation resistance shall be higher than 100 MΩ. Investigate moisture and aging problems if the value is lower than 10 MΩ, and shut down for overhaul if lower than 1 MΩ to prevent motor leakage and burnout.
3. Lubricating oil replacement: Completely replace gearbox oil, clean residual waste oil and impurities in the box, and fill with original specified lubricating oil to avoid transmission jamming and accelerated wear caused by oil aging. The oil change cycle can be shortened according to operating load for frequently started equipment.
4. Manual mechanism verification: Test the flexibility of handwheel operation. The manual/electric switching mechanism shall switch smoothly without jamming, and manual control can be performed normally in case of power failure to ensure controllability under emergency conditions.

Annual Comprehensive Overhaul (Once a Year)

Annual maintenance is a full disassembly overhaul covering mechanical, electrical, control and sensing systems to completely eliminate hidden troubles and restore optimal equipment performance.

1. Comprehensive mechanical system overhaul: Disassemble the transmission mechanism and inspect the wear condition of gears, worms, bearings, lead screws and other core components. Replace all parts with excessive wear, deformation and fatigue aging. Adjust transmission clearance to ensure stable operation without abnormal noise or axial movement.
2. In-depth electrical system inspection: Check motor operating status and test motor speed, current and temperature rise. Inspect contactors, relays, circuit boards, capacitors and other electrical components for aging, burning and malfunction. Calibrate zero and full-scale signals of smart actuators (4 mA for 0%, 20 mA for 100%) to completely eliminate signal drift and guarantee regulating accuracy.
3. Sealing and protection overhaul: Replace aged and deformed sealing gaskets and waterproof washers comprehensively, repair equipment protection defects, and improve dustproof, waterproof and anti-corrosion performance for outdoor, humid and corrosive environments.
4. Spare parts replacement: The backup battery for encoders of smart electric actuators is generally replaced every 5 years. Check battery status during annual maintenance and replace when necessary to avoid parameter loss after power failure. Sort out operation and maintenance records, count component wear, and formulate maintenance and spare parts replacement plans for the next year.

Special Maintenance Points for Core Components

Motor Assembly

The motor is the power core; overheating, moisture and overload faults shall be prevented. Monitor motor temperature rise during operation; operating temperature shall not exceed the standard value of the equipment. Long-time overload start-stop is prohibited. Regularly clean dust from motor heat dissipation channels to ensure heat dissipation. Take moisture-proof measures in humid environments and perform insulation test before long-term shutdown to prevent winding short circuit caused by moisture.

Transmission Mechanism

Gears, worms, bearings and other transmission parts are vulnerable components; jamming and wear are main fault causes. Replace lubricating grease periodically and avoid dry friction due to oil shortage. Prevent the equipment from running under full torque for a long time to reduce component fatigue loss. Stop operation immediately if abnormal noise, jamming or stroke deviation occurs. Running with faults is forbidden.

Control and Sensing System

Limit switches, position sensors and control circuit boards directly determine equipment control accuracy and safety. Calibrate limit parameters regularly to avoid over-travel damage to valves and equipment. Keep the inside of control boxes dry and clean to prevent short circuit and abnormal signals caused by dust and oil accumulation. Back up operating parameters of smart actuators regularly to avoid equipment out-of-control due to parameter loss.

Sealing and Protection System

Sealing components determine the equipment protection rating, which needs priority maintenance for outdoor and chemical corrosive working conditions. Inspect shell sealing, junction box sealing and valve stem sealing regularly, and replace damaged parts promptly. Check water seepage risks after rain and in humid weather to prevent damage to internal electrical components from moisture.

Prevention and Handling of Common Faults

Sticking and abnormal noise: Mostly caused by lubrication failure, transmission component wear or debris blockage. Clean transmission parts, replace grease, inspect worn components and adjust transmission clearance.

Incomplete on-off and accuracy deviation: Mainly caused by offset limit switches, sensor signal drift or valve jamming. Re-calibrate limit and signal parameters, clear valve debris and fasten connecting parts.

No action or slow response: Check loose wiring, abnormal power supply, control component failure and motor overload. Fasten wiring, test power supply and replace faulty electrical components.

Electric leakage and abnormal insulation: Usually caused by moisture, cable aging and sealing failure. Dry internal moisture, replace aging cables and repair sealing structure to meet insulation requirements.

Safety and Prohibited Specifications for Maintenance

Cut off power supply and hang warning signs before operation. Live disassembly and overhaul are prohibited. Take safety protection measures for high-altitude and internal equipment operations.

It is forbidden to mix lubricating grease and spare parts of different brands and models, which may lead to equipment failure and accuracy loss.

Unauthorized modification of equipment limit parameters, control programs and wiring is prohibited. Parameter commissioning and disassembly overhaul shall be performed by professional operation and maintenance personnel.

Do not use strong acid or strong alkaline corrosive cleaners for equipment cleaning. Directly flushing the equipment body with water is forbidden to prevent liquid penetration and damage to circuits and mechanical structures.

Conduct no-load and load trial run after maintenance. Confirm the equipment operates normally and parameters are accurate before putting it back into service. Fully record maintenance content, time and component replacement.

Conclusion

Stable operation of electric actuators relies on normalized, standardized and refined maintenance. Graded maintenance, targeted measures and compliant operation can effectively avoid faults such as jamming and out-of-control, greatly improve equipment control accuracy and operational reliability, and significantly extend service life. Under the demand of efficient industrial automation operation and maintenance, implementing the full operation and maintenance process including daily inspection, regular maintenance, fault prediction and file management can reduce equipment maintenance costs and downtime losses, and lay a solid foundation for safe, stable and efficient operation of the whole automation control system.