Drive cooling fan
Common heat-related VFD and servo-drive failure point.
Servo Motor Fault Codes — What They Usually Mean
Servo alarms can be intimidating because the motor, encoder, amplifier, mechanics, and control all interact. In practice, most servo faults fall into five groups: overcurrent, encoder feedback, overtravel/position error, overtemperature, and communication faults.
Common Servo Fault Categories
| Fault Type | Typical Meaning |
|---|---|
| Overcurrent | Axis jam, cable short, amplifier problem |
| Encoder feedback | Lost position, encoder cable fault, battery issue |
| Position deviation | Axis can’t keep up with commanded motion |
| Overtemperature | Motor overloaded or cooling poor |
| Communication | Drive network or amplifier not ready |
Need Replacement Parts?
Before ordering, match the replacement part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
Common Causes Across Brands
- Overcurrent — Mechanical binding, bad motor cable, or short acceleration time.
- Encoder faults — Oil contamination at connector, broken cable, dead battery on absolute systems.
- Position error — Coupling slip, ballscrew drag, overloaded axis.
- Motor overtemp — Excessive duty cycle or fan/cooling failure.
Step-by-Step Fix
- Separate mechanical from electrical — Can the axis move freely by hand or jog slowly?
- Read both control alarm and drive amplifier alarm — They rarely tell the full story alone.
- Inspect encoder and motor cables — They fail more often than the motor itself.
- Check axis load and lubrication — Dry ways and tight ballscrews create servo faults fast.
- Back up parameters before drive replacement.
Common Brands
- Fanuc
- Mitsubishi
- Siemens
- Yaskawa
- Delta
- Panasonic
When to Call a Pro
If a servo axis faults repeatedly under low load or loses home position unexpectedly, get a qualified motion technician involved. Persistent servo alarms can damage machine accuracy long before total failure happens.