USF
Undervoltage or No Voltage
Schneider Electric · Altistart 22 Soft Starter
What does USF mean?
The input line voltage supplied to the soft starter has dropped below the permissible operating limits or is entirely absent. This condition prevents proper operation and can lead to control issues or motor stoppage.
Complete Troubleshooting Guide
- 1
Check the 'UIn' (Nominal Line Voltage), 'USd' (Undervoltage detection threshold), and 'USt' (Undervoltage time delay) parameters in the 'PrO' menu for correct configuration.
- 2
Measure the incoming line voltage to the soft starter to confirm it is present and within specified operational limits.