FANUC Series 0i-F / 0i-F Plus alarm SP9012: OVERCURRENT POWER CIRCUIT
SP9012 (OVERCURRENT POWER CIRCUIT) on a FANUC 0i-F means the spindle motor current was abnormally high; the spindle amplifier shows alarm 12. FANUC lists poor motor insulation, a motor-specific parameter that does not match the motor model, and a faulty spindle amplifier.
Diagnose this with AI
Try Free CNC Alarm Diagnostic Upload a keypad photo, the fault history or a parameter export from your FANUC Series 0i-F / 0i-F Plus. InduQT compares the evidence and suggests the next useful checks.
When it happens
- At spindle start or acceleration
- Immediately after a motor, amplifier or parameter change
- Intermittently in wet or coolant-heavy conditions
Likely causes and checks
1Motor or cable insulation breakdown
- Points to it
- Coolant ingress, damaged cable, or alarm worse when wet; may come with SP9003 (DC-link fuse blown).
- Check
- Insulation-test the spindle motor and power cable with them disconnected from the amplifier.
2Spindle parameters do not match the motor
- Points to it
- Started after a motor replacement or parameter reload.
- Check
- Compare the motor-specific spindle parameters with the motor model and the builder’s backup.
3Spindle amplifier fault
- Points to it
- Motor and cable test good and parameters match, but the alarm repeats.
- Check
- Replace the spindle amplifier per FANUC’s remedy, after the motor and parameter checks.
Telling it apart
- SP9022 (SP AMP OVER CURRENT) is an amplifier overload current from heavy acceleration or cutting, rather than an abnormal current spike.
- SP9003 (DC-LINK FUSE IS BROKEN) can follow a motor ground fault; check insulation before replacing the amplifier.
Evidence to collect
- Spindle amplifier display (12 with red LED)
- Insulation test results for motor and cable
- Any recent motor, amplifier or parameter change
- Coolant exposure of the motor and connectors
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