Cummins/Onan — Checking AC Electric System While Running
Testing & diagnosis · AC control panel
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan GGHG, Cummins/Onan GGHH, Cummins/Onan V-10 WSG-1068 engine
Before you start
- High voltages are present inside the control box and generator output box when the set is running. Do not open the boxes while the set is running.
Procedure
- Check the frequency meter; generator frequency should be stable and match the nameplate rating.
- Turn the phase selector switch to each line-to-line phase selection (L1-L2, L2-L3, L3-L1) and read the AC voltmeter; at no load voltage should match nameplate rating.
- Turn the phase selector switch to each phase (L1, L2, L3) and read the AC ammeter; at no load current should be zero.
- Push the Reset/Lamp switch; all indicator lamps should light, confirming all bulbs are on.
- Have any burned out bulbs replaced.
Full service-parts list: Cummins/Onan GGHG →, Cummins/Onan GGHH →
Source: Cummins/Onan operator's 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.