Fanuc alarm SP9004: SSPA:04 POWER SUPPLY ERROR
spindle alarm (serial spindle, alpha i) · Fanuc 0i-D
What it means
The power supply module detected a missing or severely unbalanced phase in the three-phase input feeding the drive train. Reported through the spindle channel because the shared PSM raises the condition; the spindle cannot be run safely on degraded input power.
Likely causes
- Open phase in factory supply, breaker or magnetic contactor
- Loose or burnt input terminal on the PSM
- Failed input fuse in one leg
Triage note: Measure all three phases at the machine input under load.
Need the part urgently?
Send us alarm SP9004 with your machine details — typical RFQ turnaround is 24–48h.