Applicable Systems
PowerFlex 753
Symptoms
The PowerFlex 753 drive trips on fault F6 (Drive OverTemp). The heatsink temperature exceeds the safe operating limit. The drive display shows F6 and the cooling fan may not be audible.
Possible Causes
- Blocked or dirty drive cooling fan reducing airflow
- High ambient temperature in the electrical room (>40C)
- Excessive switching frequency causing higher IGBT losses
- Obstructed drive ventilation channels or clogged air filters
Troubleshooting Steps
- Step 1: Inspect and clean the drive cooling fan blades and intake grille
Fan spins freely and airflow is strong at the exhaust port - Step 2: Measure the ambient temperature in the drive room and verify HVAC operation
Room temperature is <40C or within the drive's derating curve - Step 3: Reduce the switching frequency (Parameter 38) to lower IGBT switching losses
Heatsink temperature drops below the alarm threshold under load - Step 4: Ensure drive mounting spacing (top, bottom, sides) meets Rockwell's minimum clearance
All clearances are >=100 mm or per the installation manual for the frame size
How to Reset
Allow the drive to cool for 10 minutes. Press the Stop key to clear the fault. Restart after confirming the cooling system is functional and ambient temperature is within limits.
Common Replacement Parts
- 20F11NC3P0JA0NNNNN: Allen-Bradley PowerFlex 753 3HP drive (Verify frame size for correct heatsink and fan assembly)
Frequently Asked Questions
- Q: What is the maximum heatsink temperature for PowerFlex 753?
Typically 85C for frame 1-2 and 90C for frame 3-5. The drive derates above 40C ambient.
- Q: Can I run the drive without the cooling fan?
No. Operating without the fan will cause thermal runaway and permanent IGBT damage within minutes under load.
Source: Rockwell Automation PowerFlex 750-Series Installation Manual, Publication 750-IN001
Category: Electrical