SV0601 Cooling Fan Failure (External) fault in Fanuc drive

SV0601 Cooling Fan Failure (External) fault in Fanuc drive

Description

While SV0444 refers to the tiny fan inside the drive, SV0601 refers to the large "Radiator Fan" mounted on the back or top of the amplifier. This fan blows air through the large aluminum heat sink fins to dissipate the heat generated by the IGBTs. On Alpha-i series drives, these fans are modular and easily replaceable. The alarm is generated because the drive monitors the fan speed pulse. If the fan is clogged or spinning too slowly, the drive inhibits operation to prevent the power modules from thermal destruction.

Cause

This is a standard wear-and-tear failure.

• Debris Blockage: The heatsink fins act as a filter for shop air. Chips, dust, and oily sludge build up between the fan and the fins, physically stopping the blades.
• Bearing Failure: The fan runs 24/7 in many shops. The bearings eventually seize.
• Connector Oxidation: The 2-pin or 3-pin power connector on the top of the drive may have poor contact.

Solution

Unlike internal board repairs, this is a user-serviceable item.

1. Locate the Fan: It is usually accessed from the top of the drive. Fanuc designed many of these with "quick release" plastic tabs.
2. Check Rotation: Use a flashlight. Is the fan spinning? If it's trying to wiggle but stuck, it's a bearing failure.
3. Cleaning: Remove the fan. Blow compressed air through the aluminum heatsink fins of the drive (from top to bottom). A surprising amount of dust will exit the bottom. Clean the fan blades.
4. Replacement: Ensure you replace it with the correct voltage fan (24VDC is standard for Fanuc). Like the internal fan, it requires the third sensing wire to clear the alarm. Bridging the sensor wire to ground usually does not work on newer i-series drives.