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FANUC Controller
Servo/Axis · Advanced · 30-90 minutes
Fanuc Alarm SV0003 - Z-Axis Servo Overload
SV0003 indicates the Z-axis servo amplifier has detected continuous overcurrent or torque demand exceeding the motor's rated capacity. This commonly occurs when the counterbalance (gas spring or hydraulic cylinder) has lost pressure, forcing the servo motor to support the full weight of the Z-axis head. Mechanical binding, incorrect servo parameters, or amplifier faults can also trigger this alarm.
SV0003
Fanuc Alarm SV0003 - Z-Axis Servo Overload
Servo Overload 3
Motor or drive overload condition. The servo overload 3 has exceeded its rated current capacity and may be at risk of thermal damage.
Root Cause Summary
SV0003 indicates the Z-axis servo amplifier has detected continuous overcurrent or torque demand exceeding the motor's rated capacity. This commonly occurs when the counterbalance (gas spring or hydraulic cylinder) has lost pressure, forcing the servo motor to support the full weight of the Z-axis head. Mechanical binding, incorrect servo parameters, or amplifier faults can also trigger this alarm.
Safety
- Head may drop if counterbalance fails
- Use caution
Causes and Fixes
- 1
Navigate to DIAGNOSIS > SERVO > CURRENT/LOAD screen and monitor Z-axis load percentage during manual jogging up and down. Normal counterbalanced systems show 20-40% load. Readings consistently above 60-80% indicate counterbalance loss.
- 2
Check parameter 2020 (Z-axis gravity compensation value) and parameter 1815 (torque limit). If torque limit is set too low (below 80%), temporary increase to 100% may prevent alarm but does not fix root cause.
Increasing torque limit without fixing counterbalance will accelerate motor wear and potential thermal damage.
- 3
Inspect counterbalance cylinder for nitrogen pressure (typically 120-180 bar when cold). Check for visible oil leakage at seals. Re-pressurize or replace cylinder assembly per OEM specifications.
Machine head will drop rapidly if counterbalance is disconnected. Use mechanical supports before servicing.
- 4
After counterbalance service, verify Z-axis load balance by accessing DIAGNOSIS > SERVO screen and confirming load reads near 0% when axis is stationary mid-travel. Adjust parameter 2020 in 1% increments if necessary.
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Always verify with your machine manual or a certified technician before performing service procedures.