Cummins/Onan — Flashing the Field (Self-Excited Generators Only)
Repair & overhaul · Exciter Stator
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DGBB, Cummins/Onan DGBC, Cummins/Onan DGCA, Cummins/Onan DGCB, Cummins/Onan DGDA, Cummins/Onan DGDB, Cummins/Onan DGEA, Cummins/Onan DGFA, Cummins/Onan DGFB, Cummins/Onan 4B3.9 engine
Before you start
- High voltage - use insulating protection
Procedure
- Shut down the generator and disconnect the AVR.
- Apply 110 to 220 VAC for one to two seconds to the X and XX leads using a diode for polarity.
- Include a 3 amp fuse to prevent over-excitation.
- Alternatively, while running without load and AVR connected, apply a 12 VDC battery for one to two seconds.
- Confirm polarity: positive (+) to X, negative (-) to XX.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan DGBB →, Cummins/Onan DGBC →, Cummins/Onan DGCA →, Cummins/Onan DGCB →, Cummins/Onan DGDA →, Cummins/Onan DGDB →, Cummins/Onan DGEA →, Cummins/Onan DGFA →, Cummins/Onan DGFB →
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.