What are the causes SCF1 Short circuit fault on an Altivar ATV320 variable speed drive?

Issue:
Getting  SCF1 fault on an ATV320.

Product Line:
Altivar 320

Environment:
All

Cause:
Motor short circuit

Resolution:
SCF1 is a short-circuit event.
Except for a real short circuit event at the Alivar drive output (motor, motor cables) , the SCF1 can have another reason:
- high magnetizing current (motor saturated),
- low motor inductance (real vs measured),
- lack of symmetry in the motor circuit,
- motor cabling issue, or
- the motor itself.
The best way is to record scope (fast scope) with variables LCR (motor current, filtered), SLCR (motor current, non-filtered), RFR (motor speed) to see the moment when SCF1 occurs. Auto-tuning data can affect the occurrence of SCF1.
Try to lower LFA parameter a little and record the same Somove scope again (fast scope, sampling time 10 ms or faster if it reveals any anomalies) . Compare the results at different LFA. It is recommended to apply the same load cycle to find relevant comparisons.
Also, Check if the magnetizing current IDA measured by the Altivar corresponds to a reasonable value. (In * sqrt (1-(cos phi)^2)
Try different motor control laws.
Change switching frequency, sometimes it helps when increasing SFR, sometimes when decreasing.
Think about adding a motor choke as this choke can reduce ripples in motor current and so higher probability that SCF1 threshold will not be exceeded.

For those that cannot find IDA, LFA parameters, or do not have manuals, a picture from Somove in the attachment

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