Cummins/Onan — Adjusting Quad Winding Generator Voltage Using Digital Display
Adjustments · Quad winding generator / voltage adjustment
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDDC, John Deere 4045TFM engine, John Deere 6068TFM engine
Before you start
- Hazardous Voltage! Touching uninsulated live parts can result in severe personal injury or death.
Procedure
- Start the generator set and let voltage and frequency stabilize for 5 to 10 seconds; disconnect all loads.
- Rapidly press START 6 times during the first minute after startup to enter voltage adjust mode.
- To adjust voltage up, press and quickly release START (approx. 0.6 volts per press).
- To adjust voltage down, press and hold START for about 1 second.
- Wait about 20 seconds for status change from Volt Adj to Running, then press STOP to save.
- Restart the generator set and check voltage.
- Recalibrate AC voltage on the digital display as instructed in the Operator Manual.
Specs & values
- Each press/release changes voltage approximately 0.6 volts.
Full service-parts list: Cummins/Onan MDDC →, John Deere 4045TFM engine →
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.