Cummins/Onan — Drying the Windings
Maintenance · Generator windings
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DFAA, Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCB, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan DFE
Before you start
- Voltage must begin at zero volts and be gradually increased or equipment damage will result.
Procedure
- Bolt the generator three phase output terminals together.
- Remove accessory box cover; remove plug P10 from A37 J10.
- Connect variable 12 VDC positive to P10-6 (X), negative to P10-3 (XX).
- Attach clamp-on ammeter; adjust source for zero voltage and start set.
- Slowly increase excitation to highest current without exceeding rating.
- Run the genset approximately one hour, then repeat insulation tests.
- Continue drying if further drying time is indicated.
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 DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →, Cummins/Onan DFE →
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.