Cummins/Onan PCC Control 3100 Series — Aligning Generator with Engine (Angular Alignment)
Adjustments · Generator/engine coupling
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
- Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death.
Procedure
- Disconnect the negative (-) battery cable(s) before beginning.
- Fasten a dial indicator to the generator shaft or cooling fan with the sensing point on the capscrew head or flat surface of the drive disc at the bolt circle diameter.
- Bar the engine over in a clockwise rotation as viewed from engine flywheel; do not allow it to roll back on compression.
- Determine the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one revolution.
- Measure the distance from the center of the generator shaft to the indicator measuring point.
- Measure the distance from the generator side of the flex discs to the center of the generator mounting bolt.
- Compare the distances; multiply this ratio times one half the T.I.R. to approximate the amount of shims to remove or add.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- T.I.R. should not be more than .001" for each inch of radius (center of shaft to indicator axis).
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.