12

Torque limit exceeded

Danfoss · VLT AutomationDrive FC 301/302

What does 12 mean?

The motor or generator torque has exceeded the configured limit defined in parameter 4-16 Torque Limit Motor Mode or parameter 4-17 Torque Limit Generator Mode. Parameter 14-25 Trip Delay at Torque Limit can elevate this condition from a warning to an alarm after a set delay.

Common Causes

  • Sudden increase in load or mechanical obstruction causing the motor to demand torque beyond configured limits (e.g., P4-16, P4-17).
  • Rapid acceleration or deceleration demand exceeding the drive's and motor's torque capabilities for the set ramp times.
  • Incorrectly set torque limits (e.g., P4-16 Torque Limit Motor Mode) that are too restrictive for the application's actual demands.
  • Feedback sensor (e.g., encoder) issue leading to inaccurate speed or position data, causing the control loop to command excessive torque.
  • Motor parameter misconfiguration (e.g., P1-20, P1-21) leading to incorrect torque estimation by the drive.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Review parameter 4-16 (Torque Limit Motor Mode) and 4-17 (Torque Limit Generator Mode) settings against application requirements and motor capabilities.

  2. 2

    Monitor instantaneous motor torque (e.g., P16-24) during operation to identify when the limit is exceeded.

  3. 3

    Inspect the mechanical load for binding, obstructions, or sudden changes in friction that would demand high torque.

  4. 4

    Increase acceleration and deceleration ramp times (e.g., P3-41, P3-42) to reduce instantaneous torque demands.

  5. 5

    If operating in closed loop, verify encoder feedback integrity (e.g., signal level, proper counts) using drive diagnostics (P16-52).

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Verified technical data. Last updated: March 2026

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Source: Danfoss VLT AutomationDrive FC 301/302