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## Alarm 416 Definition
Fanuc alarm 416 is servo motor overheat. The motor thermistor has detected temperature above the threshold (typically 120-150°C depending on motor model).
## Immediate Actions
1. Stop production immediately
2. Do NOT restart until motor has cooled (minimum 30 minutes)
3. Check motor surface temperature with infrared thermometer
4. Check cooling fan operation
## Root Cause Analysis
### Duty Cycle Too High
The most common cause on servo presses: the motion profile demands too much continuous torque.
Check: Download drive data log and look at motor current over time. If current is consistently above 80% of rated, the motor is undersized or the cycle is too demanding.
Fix: Reduce SPM, add dwell time between strokes, or upgrade to larger motor.
### Cooling System Failure
- Check cooling fan on motor (should spin freely, no noise)
- Check air filter on drive cabinet (clean if blocked)
- Check ambient temperature in press area (should be below 40°C)
- For liquid-cooled motors: check coolant flow rate and temperature
### Thermistor False Alarm
If motor is cool to touch but alarm 416 triggers:
- Check thermistor resistance (should be 100-120 ohm at 25°C for most Fanuc motors)
- Check thermistor wiring for damage or loose connection
- Parameter 2165 controls thermistor alarm threshold — verify it has not been changed
## Prevention
Monitor motor temperature trend in the drive data. If temperature is rising session over session, address cooling before alarm occurs.