ATV320 OLF fault after long run, what to check first?
My Altivar Machine ATV320 drive is throwing an OLF (Motor Overload) fault. It happens after the machine has been running for a long time at what seems like a high load. What should I check first?
The OLF fault on a Schneider Altivar ATV320 indicates that the drive's internal motor thermal protection has tripped due to excessive motor current. This typically occurs after extended periods of high load, repeated starts, or heavy duty cycles. The drive's thermal model has detected that the motor is overloaded.
Likely causes and checks
1Motor mechanically overloaded
- Points to it
- The motor is drawing current above its rated capacity because the process or machine load has increased.
- Check
- Measure the actual motor current and compare it to the motor's rating plate. Inspect the driven machine for any signs of increased resistance or blockage.
2Motor Thermal Current (ITH) setting is incorrect
- Points to it
- The drive's thermal protection setting for the motor current is not correctly configured, leading to premature tripping.
- Check
- Verify the [Motor Th Current] ITH setting in the drive's parameters against the motor's rated current from its nameplate. The setting should be within the range of 0.2 to 1.5 times the nominal current (In).
3Poor motor cooling
- Points to it
- The motor is unable to dissipate heat effectively, causing its temperature to rise and trigger the overload protection.
- Check
- Check the motor's cooling fan for proper operation and ensure the fan cover is not blocked or dirty. You can also check the motor's thermal state (THR) in the drive's error record (THP1) to confirm if it was running hot.
Next check: After addressing any identified cause, allow the motor to cool down completely before attempting to clear the fault and restart the drive. The OLF fault can be cleared by ATR or RSF once the motor has cooled and the cause is resolved.
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