OC1 or OU-TRIP during activation of GSB at high rotary speeds
Question:
What can be the cause of OC1- or OU-TRIP if the DC brake is activated at high rotary speeds?
Answer:
During activation of the DC brake (MCTRL-GSB or Auto-GSB) the drive controller sets DCTRL-IMP briefly (100 ms) in order to be able to reduce magnetisation in the motor before a DC voltage is injected in the motor. At high speeds (e. g. with medium-frequency motors) this time may not be sufficient so a high residual voltage remains owing to the residual magnetism and the high speed and a high motor current flows. The drive controller can then respond with OC1- or OU-TRIP.
Remedy:
Add a function block TRANS1 (normally toff = 500 ms) to the DCTRL-IMP signal, extending the pulse inhibit via input DCTRL-CINH1 during activation of the DC brake.
