Fagor alarm 4074: ERROR 301: Ballast circuit of the power supply module heatsink overheated
CNC 8055 SERCOS drive error (DDS) · Fagor DDS drives
What it means
The ballast (regeneration) section of the power supply module got too hot, normally after absorbing heavy or frequent braking energy. The system stops with the standard CNC shutdown sequence. Let it cool and reduce the regenerated energy per cycle.
Likely causes
- Excessive deceleration cycles dumping energy into the ballast
- Ballast section fan/ventilation failure
- Vertical-axis or high-inertia duty beyond PSU regen capacity
- Ambient temperature too high
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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PS / XPS power supply (ballast stage)
power-supply · Common cause
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External regenerative resistor
regen-resistor · Check if others ruled out
Need the part urgently?
Send us alarm 4074 with your machine details — typical RFQ turnaround is 24–48h.