Undertorque

What does UL3 mean?

A UL3 condition signifies an undertorque situation where the motor's output torque drops below the configured L6-02 level for the duration set in L6-03. This can be set as either an alarm or a fault and detected continuously or only when at speed agreement. It often indicates a broken belt, loss of load (e.g., a pump running dry or a disconnected shaft), or a mechanical failure that reduces the required torque. Unresolved undertorque can lead to inefficient operation or potential damage to equipment (e.g., pump cavitation).

Complete Troubleshooting Guide

1. 1

   Inspect the mechanical system for broken belts, worn couplings, loss of process material (e.g., no water in a pump), or other mechanical disconnections.

2. 2

   Verify that the motor and drive are correctly sized for the application's typical load, ensuring the undertorque level is meaningful.

3. 3

   Adjust L6-02 (Torque Detection Level 1) and L6-03 (Torque Detection Time 1) to an appropriate level to detect actual loss-of-load conditions without nuisance trips during normal operation.

4. 4

   Check L6-01 to confirm if the condition is set to trigger an alarm or a fault, and if detection is only at speed agreement or continuously during run.