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What can cause an SCF2 (Impedant short circuit) fault on the ATV61 and ATV71 drives?

FA232437

28 September 2021

Issue:
Causes for SCF2 fault on the ATV61/ATV71 drives.

Product Line:
Altivar ATV61 and ATV71

Environment:
All

Cause:
Motor short circuit or grounding at the drives output.

Resolution:
Troubleshooting tips:
Check the motor wires and motor insulation with a 1KV Megger (make sure the motor is disconnected from the Drive)
Check your motor for proper grounding.
Make sure that you have a ground directly between the drive and the motor. 
Check your drives switching frequency and adjust if needed.
Check your auto diagnostics mode and run the Transistor test under 1.10 Diagnostics menu.
Consider adding a load reactor, dv/dt motor filter or a sinus filter if you have a long motor cable run between the drive and the motor.
Try running the drive open circuit without the motor leads connected at 20Hz, 40Hz, and 60Hz check the output voltages at each stage to see if the voltages are balanced.