Cummins/Onan — Changing Genset Frequency (50/60 Hz)
Adjustments · Voltage regulator / governor
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKUB, Cummins/Onan MDKWB
Before you start
- Disconnect starting battery positive terminal first to disable the genset before adjustments
Procedure
- Turn the generator set off and open the control box
- Move the 60 Hz/50 Hz switch on the regulator board to the desired value
- Remove all load and connect a frequency meter across the output
- Loosen and back off the lock nuts on the speed adjustment screws
- Turn the set on with no load and adjust low/high speed screws per conversion direction
- Tighten lock nuts once target frequency is reached (53 Hz or 63 Hz stop points)
- Center the voltage adjustment pot and adjust output voltage to rated value ± 5 VAC
- Fine tune output voltage with the faceplate pot and recheck
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan MDKUB →, Cummins/Onan MDKWB →
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.