Cummins/Onan — Voltage Adjustment (Test P)
Adjustments · voltage regulator VR21
From a Cummins/Onan service manual covering: DL4, DL6, DL6T. Check it applies to your exact model before use.
Applies to: Cummins/Onan DL4, Cummins/Onan DL6, Cummins/Onan DL6T
Procedure
- Center the panel-mounted voltage adjustment knob vertically.
- Start the set and allow it to stabilize at the correct frequency and speed.
- Standard regulator: turn R18 counterclockwise to decrease voltage, clockwise to increase; set no-load voltage (e.g. 246 volts for 120/240 connection).
- Standard regulator: turn R26 counterclockwise until voltage hunts, then clockwise until stable.
- Switching regulator: turn R36 counterclockwise to increase voltage, clockwise to decrease; set no-load voltage.
- Switching regulator: turn R5 counterclockwise until voltage hunts, then clockwise until stable.
Tools required
- voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- For a 120/240 volt connection, set no-load voltage for 246 volts
Full service-parts list: Cummins/Onan DL6 →
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.