USF

Undervoltage

Schneider Electric · Altivar Machine ATV320 Variable Speed Drive

What does USF mean?

An undervoltage condition detected. This means the incoming AC supply voltage or the internal DC bus voltage has dropped below safe operating limits. This can cause erratic drive behavior, loss of motor torque, and can indicate issues with the power supply. The drive will trip to protect itself.

Additional Steps

Steps 1–2 are listed in Priority Fix.

  1. 3

    Verify connections to the drive's input terminals for looseness or corrosion.

  2. 4

    Consult with power utility or electricians to investigate power supply sags or interruptions.

Source: Schneider Electric Altivar Machine ATV320 Variable Speed Drive
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