Fanuc alarm 51
αi SPM · Fanuc αi SPM
What it means
DC link undervoltage reported on SPM; actual source normally the converter.
Likely causes
- PSM alarm 04 condition mirrored: supply dip / low input voltage
- Loose DC link bus bars between modules
Triage note: Combo rule: SPM 51 with PSM 4 = troubleshoot PSM/supply. CNC: SP0051 / 9051.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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DC link bus bar / short bar set
DC Link Bus Bar · Common cause
- View part →
A06B-6087-H126
Power Supply Module αi PSM (only if PSM confirms alarm 04 internally) · Check if others ruled out
Need the part urgently?
Send us alarm 51 with your machine details — typical RFQ turnaround is 24–48h.