The ObF fault occurs when the DC bus voltage spikes up over 840VDC. If the drive is telling the motor to stop but the fan is being pushed by other fans, could be regenerating energy back onto the bus of the drive. Have customer to monitor the DC bus voltage on the + and - terminals.
Measure the line voltage and compare to the displayed line voltage (Uln, in the display menu).
Measure the DC Bus voltage (Should be square root of 2 times the input line voltage).
Increase the DEC parameter (Adjustment menu).
Set the BrA parameter (drC menu) to yes. This allows the deceleration ramp to be automatically increased to avoid overbraking fault. The BrA should be set to no, if using a braking resistor.
What can we do if we have OBF or OCF fault on ATV58 while we use the breaking resistor ?
OBF or OCF
Recheck all the motor parameters.
Monitor the output current to see if it is drawing more than the FLA of the motor.
Check the Braking Resistor