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).

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 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.

2. 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.