8
Low-voltage of Capacitor Module (ECM)
Fanuc · Alpha i Series AC Servo Motor and Spindle
What does 8 mean?
The voltage across the Capacitor Module of the ECM has dropped below its minimum operating voltage. This can indicate an insufficient charge or a problem with the charge circuit.
Common Causes
- The voltage across the capacitor module drops below the minimum required for operation.
- Capacitor module internal failure or degradation.
- External load drawing excessive current from the module.
- Battery or power source supplying insufficient voltage.
- Faulty voltage sensing circuit for the capacitor module.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Measure the voltage across the Capacitor Modules.
- 2
Check the ECM control module's charging circuit and its input power supply.
- 3
Ensure continuous power supply to the ECM is stable.
Verified technical data. Last updated: March 2026
Related Faults
Source: Fanuc Alpha i Series AC Servo Motor and Spindle