B&R Servo Drive 8V1022.00-2 Overvoltage Fault Repair

Overvoltage

If an overvoltage fault occurs, the B&R drive keypad will display ‘ov’.

This fault indicates that the voltage in the DC bus has exceeded the overvoltage detection level. For a 208 V bypass drive, the trip limit is 410 V. For a 408 V bypass drive, the trip limit is 820 V (or 740 V when parameter E1-01 is set to less than 400).

Possible cause:

Deceleration time too short, regenerative energy flows from motor to drive

Too fast an acceleration time causing the motor to exceed speed

A ground fault in the reference output circuit causes the DC BUS capacitor to overcharge.

Incorrect parameters associated with Speed Search (including speed search after momentary power down and fault restart)

B&R drive input supply voltage too high

Drive fails to operate due to noise interference

Incorrect load inertia setting

Motor oscillation occurs

Suggested actions are listed in the order of each of the above cases:

Increase the deceleration time for parameter C1-02, or you can enable stall prevention during deceleration for parameter L3-04

A sudden acceleration of the B&R drive can trigger an overpressure alarm, so the acceleration time needs to be increased. Enable Overvoltage Suppression (set parameter L3-11 to 1) and lengthen the S-curve at the acceleration end.

Correct the ground short circuit and re-power on the drive:

Enable the speed search restart function (set parameter b3-19 to 1 to 10 depending on your application), adjust the current level and deceleration time during the speed search (parameters b3-02 and b3-03) and perform a static auto-tuning for the wire-to-wire resistance, then set parameter b3-14 to 1 to enable the speed estimation speed search.

Reduce the drive input supply voltage within the limits outlined in the B&R drive specifications

Check and separate the main circuit, control wires, and earth wires. Ensure that the drive and motor are properly grounded. Install noise filters on the input and/or output side of the drive. Place the wiring in metal conduit. Finally, reduce the carrier frequency at parameter C6-02

Check the load inertia setting when using KEB, overvoltage suppression or stall prevention during deceleration. Adjust the load inertia ratio to match the load at parameter L3-25