Cummins/Onan PCC Control 3100 Series — Drying the Windings
Repair & overhaul · Generator windings
For the Cummins/Onan PCC Control 3100 Series, from the Cummins/Onan service manual.
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 the accessory box housing cover and remove plug P10 from connector J10 of A37.
- Connect positive and negative leads of a variable 12 VDC source to P10 (positive to red wire P10-6 X, negative to brown wire P10-3 XX).
- Attach a clamp-on ammeter to the generator leads, adjust the 12 VDC source for zero voltage, start the set and slowly increase excitation voltage.
- Obtain the highest current possible without exceeding generator rating.
- Run the genset for approximately one hour, then repeat the insulation resistance tests.
- If further drying time is indicated, continue the drying process.
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.