Why is the ATV312 tripping on SCF or short circuit fault on power up?


07 October 2021

ATV312 tripping SCF 

Product line:
Altivar 312, ATV312, ATV31

All models, all serial numbers 

The drive trips on a SCF or a Short Circuit Fault if the drive detects a short circuit on the output of the drive.       

-Make sure all of the motor parameters are set in the DRC menu to match the motor name plate.  
-Check to make sure you don't have a long cable run of more than 100 feet. If you do, we recommend installing a output load reactor.
-Test the drive operation without the motor connected; turn off OPL (output phase loss) in the FLT menu. Try running the drive open circuit at 15, 30, 45, and 60Hz checking the output voltage phase to phase with a true RMS digital meter for balance at each frequency level.

-Check the motor and cables connecting to the drive for shorts phase to phase and phase to ground. 
-Check connections in the motor junction box for proper wiring.  
-Install a motor protecting output filter or load reactor at the output of the drive.
-Reduce the switching frequency (SFR in the SEt- menu). 

If the SCF fault occurs with no motor or wiring connected to the drive, the drive will need to be replaced.

Refer to the attached ATV312 Programming manual BBV46385.

Note: Similar steps apply to the ATV12, ATV11, ATV32 and other Altivar Drive Products.