UnderVoltage

What does F4 mean?

The drive has detected that the DC bus voltage has dropped below its predefined minimum operating threshold. This condition typically occurs due to low incoming AC line voltage, a momentary power interruption, or excessive voltage sag from the utility supply. Sustained undervoltage can prevent the drive from operating correctly, cause nuisance trips, or indicate a problem with the main power supply, potentially halting equipment operation.

Complete Troubleshooting Guide

1. 1

   Measure and monitor the incoming AC line voltage at the drive's input terminals to confirm it is within the specified operating range.

2. 2

   Check for momentary power interruptions or sags on the utility supply, which may require contacting the utility provider.

3. 3

   Verify that main disconnects and circuit breakers supplying the drive are fully engaged and properly sized.