Undertorque Detection 2

What does UL4 mean?

The motor current has fallen below a secondary minimum value set in L6-05 for longer than the allowable time specified in L6-06. Similar to UL3, this suggests either incorrect parameter tuning for the current load or a fault in the machine's mechanical system that is causing reduced torque.

• Secondary undertorque detection level (L6-05) set too high, triggering on normal operation.
• Secondary undertorque detection time (L6-06) too short for the specific application's load dynamics.
• Mechanical issues similar to UL3 but potentially more subtle or occurring in a specific operating condition.
• Inaccurate current sensor calibration within the drive causing incorrect current readings.
• Temporary reduction in load due to process variations or material flow changes.

Click steps to track your progress.

1. 1

   1. Adjust the secondary undertorque detection level parameter (L6-05) to a value below the minimum expected motor current for the specific operating condition.

2. 2

   2. Lengthen the secondary undertorque detection time parameter (L6-06) to accommodate transient load drops or normal process fluctuations.

3. 3

   3. Thoroughly inspect the driven machine for any mechanical failures that would result in a significant drop in load torque.

4. 4

   4. Compare the motor current at which UL4 trips with the set value of L6-05 using the drive's monitor functions (e.g., U1-01).

5. 5

   5. Verify that the application's operating profile is consistent with the intended use of a secondary undertorque detection.

6. 6

   6. If using a multi-speed application, confirm the current sensor provides accurate readings across all operating ranges.