danfoss warning 12

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In Danfoss VFD (FC-102, FC-202, FC-302, or FC-51), Warning 12 stands for Torque Limit. This warning occurs when the drive is trying to pull more torque than the limits programmed in the parameters. Unlike an "Alarm," a "Warning" usually allows the drive to keep running, but it will restrict the speed or current to protect the motor and the drive.

Common Causes

  1. Mechanical Overload: The most likely cause. The motor is struggling to turn the load (e.g., a jammed conveyor, a blocked pump, or a seized bearing).

  2. Aggressive Ramps: The Acceleration Time (Ramp-up) is too short. The drive is trying to get the motor up to speed faster than the load allows.

  3. Incorrect Motor Data: The drive doesn't know the motor's true capabilities because the nominal current or torque settings were entered incorrectly during setup.

  4. Limits Set Too Low: The safety limits in the drive are set below what the application actually requires.

How to Fix & Troubleshoot

1. Check for Mechanical Issues

Verify that the motor can turn freely. If it's a pump, check for clogs; if it's a fan, check the belts and dampers.

2. Extend Ramp Times

If the warning only appears when the motor is starting up, your ramp is too fast.

  • Increase Parameter 3-41 (Ramp 1 Ramp Up Time).

  • Increase Parameter 3-42 (Ramp 1 Ramp Down Time).

3. Adjust Torque Limit Parameters

If you are certain the motor and application can handle more force, you can increase the internal limits:

  • Parameter 4-16: Torque Limit Motor Mode (Default is usually 110% or 160%).

  • Parameter 4-17: Torque Limit Generator Mode (Braking).

4. Verify Motor Settings

Ensure the drive has the correct info from the motor nameplate:

  • Check Parameter 1-20 through 1-25 (HP/kW, Voltage, Frequency, Current, and Speed). If the Current (1-24) is set too low, Warning 12 will trigger prematurely.

Key Difference: Warning vs. Alarm

  • Warning 12: The drive stays running but limits its output. The yellow LED will be on. It will disappear automatically if the load drops.

  • Alarm 12: If the drive stays in Warning 12 for too long, it may "trip" into Alarm 12 to prevent overheating. This requires a manual [Reset].

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