Underload Condition

What does UC mean?

This fault occurs when the motor loading level drops below the configured [Underload level] (F611) for a period longer than the [Underload detection time] (F612), and parameter F610 is set to 1 (Fault). It indicates that the motor or driven equipment is not adequately loaded, potentially due to a mechanical issue, disconnection, or incorrect parameter settings. If left unresolved, prolonged underload can cause instability, motor overheating due to inefficient operation, or damage to the motor and driven equipment.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Monitor the motor current using the drive's display (e.g., by setting F710 to 2 for [I Mot]) and compare it against the expected operating current. Check for consistent readings or abnormal fluctuations.

2. 4

   Inspect motor and drive power connections for any loose wiring, intermittent contacts, or signs of wear that could lead to an incorrect current reading or actual power delivery issues.