Undertorque Detection 1

What does UL3 mean?

The drive detected that its output current was continuously below the threshold set in L6-02 for longer than the time specified in L6-03, when L6-01 was configured for undertorque detection. This fault indicates that the connected motor is operating under an unexpectedly low load, potentially due to a mechanical issue or process change.

Complete Troubleshooting Guide

1. 1

   Verify that parameters L6-02 (Undertorque Detection Level) and L6-03 (Undertorque Detection Time) are correctly set for the application's normal operating conditions and minimum load.

2. 2

   Investigate the mechanical system or process to confirm why the motor is underloaded (e.g., broken belt, pump cavitation, uncoupled load) and rectify the application/machine status.

3. 3

   Check motor current with an external meter to confirm actual load versus drive reading.