2
Inverter Control Power Supply Undervoltage (SVM)
Fanuc · Series 30i CNC
What does 2 mean?
This alarm indicates an undervoltage condition in the control power supply of the Servo Amplifier Module (SVM). The control power supply (typically 24VDC) is essential for the internal logic and control circuitry of the inverter. A voltage drop below 22.8V can cause erratic behavior or module shutdown.
Common Causes
- Three-phase input voltage of the amplifier has dropped below 85% of its rated input voltage.
- The 24 V power supply voltage output from the PSM is lower than 22.8 V.
- Issues with the connector or cable (CXA2A/B) supplying control power.
Repair Steps
- 1
Check the three-phase input voltage of the amplifier — verify it is not lower than 85% of the rated input voltage.
- 2
Check the 24 V power supply voltage output from the PSM — verify it is not lower than 22.8 V.
- 3
Inspect the connector and cable (CXA2A/B) for damage, loose connections, or incorrect seating.
- 4
Replace the SVM if all power supply and cable checks are normal but the alarm persists.
Verified technical data. Last updated: March 2026
Source: Fanuc Series 30i CNC