4158

Common Causes

• Failed or stalled cooling fan on the inverter unit
• Blocked heatsink or air filter clogged with coolant mist and chips
• Sustained overload operation (heavy cutting, rapid cycling) overheating the drive
• High cabinet ambient temperature or failed heat exchanger/air conditioner
• Internal fault in the inverter unit itself

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 1 = Fixed code; inverter unit temperature abnormally high
2. 2Note the object: the named axis, or no object means the spindle inverter unit is the one overheating.
3. 3Lock out main power and allow the drive to cool and DC bus to discharge before opening the cabinet; heatsinks and terminals stay hot and charged after shutdown.
4. 4Check the inverter unit cooling fan(s) for rotation, noise or stalling, and clean dust, oil mist and chips from the heatsink fins and cabinet filters.
5. 5Verify cabinet ambient temperature and that the cabinet cooler/heat exchanger is running; clear blocked vents.
6. 6Review recent operation: if the alarm followed heavy cutting or high-duty rapid cycles, reduce load/cutting conditions and confirm the alarm does not recur at moderate duty.
7. 7If cooling and load are normal and the alarm persists, the inverter unit is suspect; record the alarm number, code and object and contact Okuma service.