LOW VOLT POWER CIRCUIT
Fanuc · Series 0i-D/0i Mate-D Maintenance
What does SP9051 mean?
This Fanuc Series 0i-D/0i Mate-D spindle alarm indicates that an input voltage drop was detected in the power circuit (Power Supply (PS) alarm indication: 4). This typically signifies a momentary power failure or poor contact in the magnetic contactor (MC).
Common Causes
- Input power supply voltage drop or sag affecting the spindle amplifier/PS unit.
- Momentary power failure or interruption of the AC supply.
- Poor contact, wear, or failure in the main magnetic contactor (MC) supplying power.
- Loose or corroded power wiring connections to the spindle amplifier or PS unit.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Measure the incoming three-phase AC power supply voltage to the spindle amplifier (or PS unit) to confirm it is stable and within specifications.
- 2
Inspect the main magnetic contactor (MC) for signs of wear, pitting, or poor contact; check its coil operation and auxiliary contacts.
- 3
Check all power wiring connections from the main supply breaker through to the spindle amplifier for looseness or corrosion.
- 4
Monitor the power supply for momentary voltage sags or interruptions, especially during machine operation or startup.
- 5
If the magnetic contactor shows signs of failure or malfunction, replace it with an equivalent unit.