Cummins/Onan — Manual System Operation (paralleling verification)
Operation · PowerCommand paralleling system
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DGBB, Cummins/Onan DGBC, Cummins/Onan DGCA, Cummins/Onan DGCC, Cummins/Onan DGDA, Cummins/Onan DGDB, Cummins/Onan DGEA, Cummins/Onan DGFA, Cummins/Onan DGFC
Before you start
- Use extreme caution when performing phase relationship testing.
Procedure
- Place all generator set RUN/OFF/AUTO switches in OFF and master control switch in manual mode.
- Start one generator set in RUN and allow it to reach rated speed and voltage.
- Manually close the paralleling breaker using the breaker close pushbutton.
- Check phase relationship of the generator set output to its Bus PT module (voltage difference between L1 of Bus PT and generator PT/CT should be zero).
- Start a second set and verify voltage and frequency match the bus; observe the digital synchroscope.
- Check phase relationship across the open breaker on two phases simultaneously with a digital voltmeter when synchronized.
- Close the oncoming breaker and observe voltage, frequency, amp and kW metering on all sets.
- Apply load and verify proportional load sharing within plus or minus 5%.
- Remove load and return RUN/OFF/AUTO switches to AUTO.
Tools required
- Hand-held digital voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan DGBB →, Cummins/Onan DGBC →, Cummins/Onan DGCA →, 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.