SV0443 Converter Cooling Fan Failure fault in Fanuc drive

SV0443 Converter Cooling Fan Failure fault in Fanuc drive

Description

SV0443 is specific to the Power Supply Module (PSM). While SV0444 is for the servo amplifier and SV0601 is for the servo radiator, SV0443 means the cooling fan located inside or on the Power Supply unit has failed. Modern PSMs communicate this status to the CNC via the serial bus. If the PSM fan stops, the regeneration circuit and main rectification bridge are at risk of overheating.

Cause

• Fan Aging: The bearings in the small internal fan have seized.
• Debris: A physical blockage (zip tie, wire, or chip) is stopping the fan blade.
• Connection: The small 2-pin or 3-pin connector connecting the fan to the PSM control board is loose.

Solution

1. Identify Unit: Look for the unit labeled "PSM" or "Power Supply" (Leftmost unit in the rack).
2. Check Rotation: Use a flashlight to check the fan on top of the PSM.
3. Replace Fan: Fanuc PSM fans are often modular cassettes. Squeeze the tabs, pull the cassette out, and snap a new one in. You usually do not need to remove the drive from the panel.
4. Warning: Do not stick objects into the fan while the unit is live. The PSM contains high voltage rails immediately adjacent to the fan housing.