Cummins/Onan — Adjust voltage adjust potentiometer R21
Adjustments · R21 voltage adjust potentiometer
From a Cummins/Onan service manual covering: 4A2.3, 6A3.4-GS, 6AT3.4-GS, DL4, DL6, QSA3, QSA4, QSA6. Check it applies to your exact model before use.
Applies to: Cummins/Onan DGAB, Cummins/Onan DGAC, Cummins/Onan DGAD, Cummins/Onan DGAE, Cummins/Onan DL4, Cummins/Onan DL6
Before you start
- Contact with high voltage can cause severe personal injury or death.
Procedure
- Loosen locking nut of R21 and adjust to mid-range.
- Start genset and bring temperature to normal.
- With no load, turn Phase Selector to read output voltage and current.
- Adjust R32 for approximate desired voltage.
- Fine-adjust with R21 and tighten locking nut without changing setting.
Tools required
- Insulated screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan DGAB →, Cummins/Onan DGAC →, Cummins/Onan DGAD →, Cummins/Onan DGAE →, Cummins/Onan DL6 →
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.