Fanuc alarm 12
αi SPM · Fanuc αi SPM
What it means
DC link overcurrent / IPM alarm - excessively large current flowed into the DC link of the main circuit; on SPM-2.2i to 11i indicates main-circuit IPM detected overcurrent/overload.
Likely causes
- SPM power element (IGBT/IPM) destroyed
- Motor power lead short / ground fault
- Motor winding insulation failure
- Dirty heat sink causing thermal death of power elements
- Speed sensor signal error
- Incorrect motor-specific parameters
Triage note: THE most-searched Fanuc spindle failure (AL-12 field guides everywhere; CNC numbers SP0012 / 9012 / SP9012). Hard failure that will not reset = dead transistor module, replace SPM. Intermittent = motor/cable insulation - megger before fitting the new SPM.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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A06B-6111-Hxxx / A06B-6112-Hxxx
Spindle Amplifier Module αiSP (rating-dependent) · Primary suspect
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IGBT/IPM module per SPM rating
IGBT Module · Check if others ruled out
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αi Spindle Motor per spec
Spindle Motor · Common cause
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Spindle motor power lead set
Motor Power Cable · Common cause
Need the part urgently?
Send us alarm 12 with your machine details — typical RFQ turnaround is 24–48h.