UNDERVOLTAGE

What does USF mean?

This fault indicates an insufficient incoming line supply voltage, a transient voltage dip, or a potential issue with the drive's internal precharge resistor. If the voltage drops below the drive's operational threshold, it will be unable to operate reliably or at all, causing unexpected shutdowns and potential component stress. Sustained undervoltage can prevent motor start-up or lead to erratic performance.

Complete Troubleshooting Guide

1. 1

   Check the incoming line voltage to ensure it consistently meets the drive's minimum specifications (e.g., ATV312 M2: 160 V, N4: 300 V, S6: 430 V).

2. 2

   Verify the voltage parameter settings within the drive's configuration to ensure they match the actual line supply.

3. 3

   If transient voltage dips are suspected, monitor the line voltage with a power quality analyzer. Consider using a line choke or UPS for stability.

4. 4

   If internal components (like a damaged precharge resistor) are suspected after ruling out external power issues, the drive may require replacement or professional service.