Cummins/Onan — Changing Genset Frequency
Adjustments · Generator/voltage regulator
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKAD, Cummins/Onan MDKAE, Cummins/Onan MDKAF
Before you start
- Incorrect electrical connections/adjustments can cause equipment damage, severe injury or death. Turn off genset and disconnect battery before adjustments.
Procedure
- Identify new frequency and voltage.
- Replace AC output circuit breaker if necessary for new load.
- Move 60 Hz/50 Hz switch on regulator board to desired value.
- Readjust engine speed for new frequency: 50 Hz 1500 RPM, 60 Hz 1800 RPM under no-load and full-load.
- Apply maximum rated load and adjust frequency fine adjust screw to desired frequency.
- Remove load and check no-load frequency is within 3 Hz of full-load frequency.
- Tighten lock nut.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 50 Hz: 1500 RPM
- 60 Hz: 1800 RPM
Full service-parts list: Cummins/Onan MDKAD →, Cummins/Onan MDKAE →, Cummins/Onan MDKAF →
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.