Cummins/Onan — UFRO Adjustment
Adjustments · Voltage regulator VR21
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Procedure
- Check that the frequency selection jumper is connected for the application (50 Hz or 60 Hz).
- Adjust the UFRO pot so the LED lights as frequency drops to 47 Hz (50 Hz) or 57 Hz (60 Hz).
- Turn the pot clockwise to reduce the knee point frequency.
Tools required
- Frequency meter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- LED lights at 47 Hz for 50 Hz application or 57 Hz for a 60 Hz application
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.