Braking resistor phase unsymmetry

What does A06921 mean?

This alarm indicates that the three phases of the braking chopper resistors are not symmetrical, meaning there's an imbalance in their resistance values. This could be due to issues with the feeder cables or an incorrectly set monitoring threshold. Asymmetry can lead to uneven current distribution and reduced effectiveness of the braking chopper, potentially causing other faults.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   If resistor values are confirmed symmetrical and healthy, consider increasing parameter p1364 (Braking resistor phase unsymmetry threshold) if nuisance alarms occur, ensuring it doesn't compromise system safety.