ULC underload fault

What does 8001 mean?

The selected signal has fallen below the user underload curve, indicating an underload condition. This often means the motor is running without sufficient mechanical load or there's a problem with the process being controlled. Sustained underload can waste energy or indicate a process issue.

• Loss of mechanical load on the motor shaft (e.g., pump running dry, broken conveyor belt, coupling shear pin failure).
• Motor current has dropped significantly below the configured underload curve threshold (e.g., parameter P7-21 'Underload curve 1 current').
• A process control valve or damper has opened unexpectedly, reducing the system backpressure or resistance.
• Incorrectly configured underload curve parameters (e.g., P7-21, P7-22, P7-23) causing a trip during normal, low-load operation.
• Faulty current sensor or measurement circuit within the drive, reporting an erroneously low motor current value.

Click steps to track your progress.

1. 1

   Visually inspect the mechanical system driven by the motor for signs of lost load, such as broken couplings, empty hoppers, or dry pumps.

2. 2

   Monitor the motor's actual current (e.g., via drive display or P_ACT_CURRENT) and compare it to the configured underload curve (P7-21 to P7-23).

3. 3

   Review and adjust the underload curve parameters (P7-21: Underload curve 1 current, P7-22: Underload curve 1 speed, P7-23: Underload curve 1 delay) to match the application's actual low-load profile.

4. 4

   Verify the integrity of the motor current measurement by comparing the drive's reported current with an external clamp meter measurement on one motor phase.

5. 5

   Check for blockages or unexpected openings in the process (e.g., pipe, duct) that could reduce the required mechanical work from the motor.