Cummins/Onan 3100 series — Disassembling the PMG
Repair & overhaul · Permanent Magnet Generator (PMG)
For the Cummins/Onan 3100 series, from the Cummins/Onan service manual.
Applies to: Cummins/Onan DGBB, Cummins/Onan DGBC, Cummins/Onan DGCA, Cummins/Onan DGCB, Cummins/Onan DGCC, Cummins/Onan DGDA, Cummins/Onan DGDB, Cummins/Onan DGDK, Cummins/Onan DGEA, Cummins/Onan DGFA, Cummins/Onan DGFC
Before you start
- Accidental starting of the generator set while working on it can cause severe injury or death.
- Always disconnect a battery charger from its AC source before disconnecting the battery cables.
Procedure
- Disconnect the starting battery cables (negative (-) first).
- Remove the PMG cover and disconnect the leads at the connector.
- Remove the bolts and clamps securing the PMG stator to the generator frame and carefully pull away the stator.
- Remove the rotor center bolt and pull away the rotor; the rotor is magnetic and will attract iron filings.
- Put the rotor in a clean plastic bag until remounted; do not take it apart or it will lose its magnetism.
Specs & values
- Torque the rotor center bolt to 40 ft-lbs (54 Nm)
- The stator leads must be at 12 o'clock
Full service-parts list: Cummins/Onan DGBB →, Cummins/Onan DGBC →, Cummins/Onan DGCA →, Cummins/Onan DGCB →, Cummins/Onan DGCC →, Cummins/Onan DGDA →, Cummins/Onan DGDB →, Cummins/Onan DGEA →, Cummins/Onan DGFA →, Cummins/Onan DGFC →
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.