Back EMF too high

What does WARNING 127 mean?

This warning, specific to PM motors, indicates that the back electromotive force (EMF) voltage has exceeded 90% of the inverter's maximum voltage threshold (U invmax) and has remained high for over 5 seconds. This condition suggests that the motor is generating excessive voltage, potentially due to overspeeding or regenerative braking issues, which could lead to overvoltage trips.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Ensure the drive is correctly parameterized for the specific PM motor being used, especially for applications with high inertia or frequent deceleration.