Fagor alarm 4137: ERROR 308: Over-current at energy return circuit
CNC 8055 SERCOS drive error (DDS) · Fagor DDS drives
What it means
Excessive current was detected in the regeneration (energy return) circuit. The drive/system stops with the standard full shutdown; Fagor lists no user fix and directs persistent occurrences to service. Check the regen resistor and its wiring first since they carry this current.
Likely causes
- Degraded or partially shorted regen resistor
- Regeneration current beyond resistor rating
- Wiring/connector fault in the regen circuit
- Failed chopper transistor in the PSU regen stage
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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Regenerative resistor
regen-resistor · Common cause
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PS / XPS power supply
power-supply · Check if others ruled out
Need the part urgently?
Send us alarm 4137 with your machine details — typical RFQ turnaround is 24–48h.