Overbraking

What does ObF mean?

This fault indicates a DC bus overvoltage condition, most commonly caused by the motor regenerating energy back to the drive, such as during rapid deceleration or when driving an inertial load. If the regenerated energy cannot be dissipated, it can cause the DC bus voltage to rise above safe limits. Persistent overvoltage can stress and damage the drive's power stage components (e.g., IGBTs).

Complete Troubleshooting Guide

1. 1

   Increase the deceleration time (dEC or dE2 parameter) to reduce the rate at which the motor regenerates energy.

2. 2

   If fast deceleration or high inertial loads are required, install a braking resistor and a suitable braking unit to dissipate the excess regenerated energy.

3. 3

   Check the incoming line voltage for stability, as transient spikes or high nominal voltage can contribute to DC bus overvoltage during regeneration.