Which products are affected?
9300 vector 55…90 kW SW ≤ V6.3
What happens?
The output current (MCTRL-IACT) oscillates especially in the higher speed range. In extreme cases the current oscillations may lead to an overcurrent interruption (OC1 trip).
When does the problem occur?
- During operation in vector control mode (C0006 = 1) with speed feedback (C0025 > 1)
- and if the oscillation damping (C0234 > 0 %; influence of the oscillation damping) is activated at the same time.
During operation in the vector control mode with speed feedback the oscillation damping function for eliminating possible oscillations is not required due to the specific control structure. However, a current oscillation may be caused due to positive feedback effects in case of drive powers larger than approx. 55 kW if the oscillation damping is activated in this operating mode.
Possible diagnostics?
- Record the output current (e. g. the MCTRL-IACT signal) by means of an oscilloscope.
- Check the setting of the oscillation damping. C0234 = 20 % is set under Lenze setting.
Short-term measures/recommendations?
Deactivate the oscillation damping by setting C0234 = 0 %
Evaluation:
This behaviour has only been observed in the power range from 55…90 kW and it could only be detected in very few cases. The faulty behaviour can be eliminated by applying the workaround described before.
