When your linear actuator stops working, production halts and deadlines slip. Most actuator failures stem from a handful of common issues you can diagnose and fix with a systematic approach. This saves downtime and gets your equipment back online faster.
Common Failure Modes
Linear actuators fail in predictable ways. Recognizing the symptoms points you to the root cause.
Complete Loss of Movement
The actuator doesn’t respond at all. You’re dealing with an electrical issue. The motor receives no power, or something in the control circuit has failed. This accounts for 30 to 40% of actuator failures.
Motor Hums But Rod Stays Put
You hear the motor running, but the rod doesn’t move. Something has jammed, or internal gears have stripped. The motor draws current and makes noise, but that energy isn’t translating into motion.
Slow or Weak Movement
The actuator works but moves slow or can’t push its rated load. Voltage drops, worn gears, or dry lead screws cause this. You might also see this when the actuator is overloaded.
Overheating and Thermal Shutdown
The actuator gets hot and stops working. A thermal protection circuit might kick in. This happens when you exceed the duty cycle, overload the actuator, or operate it in high temperatures without cooling.
Diagnostic Sequence
Start with the easiest checks and move toward more complex diagnostics.
Visual and Audio Inspection
Before you grab tools, use your senses:
- Check for loose or disconnected wires at terminal blocks
- Look for burnt smell or visible scorch marks
- Inspect for bent or misaligned mounting brackets
- Check if anything blocks the rod’s travel path
Listen to what happens when you apply power. A humming sound means the motor gets power but can’t move. Clicking might indicate a relay cycling or limit switches engaging. Grinding noises point to gear damage or a bent lead screw.
Verify Power Supply
Most industrial linear actuators run on 12V or 24V DC power. Grab a multimeter and check the voltage at the power supply output. Compare what you measure against the actuator’s rated voltage. If you’re getting 10V when you need 12V, that voltage drop causes weak or erratic performance.
Check these items:
- Power supply output matches actuator requirements
- Circuit breakers and fuses haven’t tripped
- Battery voltage if using battery power
- Power supply current rating exceeds actuator’s peak draw
If your actuator draws 20A at full load, your power supply needs to deliver at least 20A. An undersized power supply causes voltage sag under load.
Examine Wiring and Connections
Loose connections cause intermittent failures. Tug on wire connections at both the power supply and actuator ends. If wires pull out, you found your problem.
Check for wire continuity with a multimeter. Broken wires inside insulation aren’t visible, but a continuity test reveals them. Pay attention to wires that move or flex during operation because these fail from fatigue.
Test Control Systems
Actuators that work sometimes but not others often have control system issues. Bypass the controller by connecting the actuator directly to the power supply. If it works now, the controller has failed or has incorrect settings.
Modern actuators with intelligent controls need proper configuration. Verify that communication settings match between the controller and actuator. A single misconfigured parameter can prevent operation.
Inspect Internal Components
If external checks don’t reveal the problem, open the housing. Make sure power is disconnected and locked out first.
Look for these failure points:
- Stripped or broken gear teeth
- Worn motor brushes in brushed DC motors
- Bent or damaged lead screw
- Debris inside the housing
- Corroded electrical connections
Gears wear over time, especially if the actuator has been overloaded. Small metal particles inside the housing indicate gear wear. If you find this, the gearbox needs replacement.
Test Limit Switches
Limit switches prevent the actuator from over-extending or over-retracting. When limit switches fail or get misadjusted, the actuator might stop short of full travel or refuse to move.
Press each limit switch while observing actuator behavior. The switch should click and stop motor operation. If a switch doesn’t click or doesn’t stop the motor, it needs adjustment or replacement. Electrical limits built into modern actuators provide this protection without mechanical switches, eliminating switch failures but requiring proper calibration.
Fixing Overheating Problems
Overheating destroys actuators faster than any other failure mode. Heat degrades lubricants and damages motor windings.
You need to respect the duty cycle rating. If your actuator is rated for 20% duty cycle, that means 2 minutes on and 8 minutes off in every 10-minute period. Operation beyond this generates heat faster than the actuator can dissipate it.
Reduce the load if you can. Heavy loads force the motor to draw more current, which generates more heat. If you need more force, you need a higher capacity model.
Improve cooling by ensuring airflow around the actuator. For high ambient temperatures, select actuators rated for extended ranges. Models that operate from negative 30°C to positive 70°C can handle extreme conditions.
When Professional Support Makes Sense
Some failures require manufacturer intervention. Contact the manufacturer when you encounter:
- Persistent issues despite correct power, wiring, and load conditions
- Need for replacement parts like gearboxes, lead screws, or motor assemblies
- Warranty situations where failure stems from manufacturing defects
- Complex diagnostic needs requiring specialized knowledge
Manufacturers with strong technical support can diagnose problems by discussing symptoms and test results. They can identify configuration issues or provide updates that resolve problems without hardware replacement.
Getting the Right Support
With over 30 years of experience, Aoxiang provides technical support for complex troubleshooting situations. Our engineering team can help diagnose persistent failures and recommend solutions for challenging applications.
We also offer the AOX-L Series, which incorporates electrical limits to prevent overtravel without the use of mechanical switches. IP67 protection is standard, keeping contaminants out in harsh industrial environments. When you need replacement parts or technical guidance, experienced manufacturers can help you resolve issues faster.
For applications requiring system integration, models with Modbus, Profibus, and Hart communication can provide diagnostic data that helps identify problems before they cause failures.
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