Powerflex 453 VFD fault

Hello everyone,

We are using a Powerflex 753 VFD to control a motor which lifts and descends loads. The drive goes into fault code 12 (HW Overcurrent) and code 36 (SW Overcurrent) multiple times while its descent in the loaded condition. The drive does not go into fault when:

1. It ascends or descends in no load.

2. Ascends in load condition.

Therefore the fault occurs only in one direction under loaded condition.

I have google searched and tried changing a few parameters [Parameter 43 (Flux Up Enable) and Parameter 44 (Flux Up Time), Parameter 70 (Autotune) and Parameter 621 (Slip RPM at FLA) to 0], but it didn't affect the faults.

Any ideas why? Any solutions?
>No DC bus over-Voltage fault?

The reason for the query on DC Bus over voltage is because the symptoms you describe suggest the motor is regenerating.
When installed was a brake resistor fitted?