Cummins/Onan LS-15M — Drying the Windings
Repair & overhaul · Generator windings
For the Cummins/Onan LS-15M, 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. The current will increase rapidly and must be monitored to prevent exceeding the generator rating.
Procedure
- Bolt the generator three phase output terminals together.
- Remove the housing cover of the accessory box and remove plug P10 from connector J10 of the voltage regulator output module (A37).
- Connect positive lead to Red wire of P10-6 (X) and negative lead to Brown wire of P10-3 (XX).
- Attach a clamp-on ammeter to the generator leads, set source to zero voltage, start the set and slowly increase excitation voltage.
- Obtain the highest current possible without exceeding generator rating.
- Run the genset approximately one hour, then repeat insulation resistance tests.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
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.