What does OCA fault mean on the ATV21 and ATV212 drives?

FA174648

18/06/2020

Issue:
OCA fault on ATV21/ATV212 drives?

Product line:
Altivar 212, ATV212, S-Flex

Environment:
All models, all serial numbers.

Cause:
Overcurrent during start-up or ground fault

Resolution:
OCA – short-circuit detected in drive output inverter stage during motor startup

Check that Line and Load cables are connected to the proper terminals.  Line cables go to R/L1, S/L2 and T/L3.  Load or motor cables go to U/T1, V/T2 and W/T3. 

Disconnect the motor leads from the drive.  Using a 1000V Megger, check the motor and motor leads for shorts or ground fault.

Try a voltage balance test.  With the motor leads still disconnected, set parameter F605 to 0 (disable Output Phase Failure).  Run the drive at 20Hz, 40Hz and 60Hz.  At each speed measure the line to line output voltages to see if they are balanced.