Cummins/Onan — Voltage Adjustment - Transformer Voltage Regulator
Adjustments · Transformer regulator T21
From a Cummins/Onan service manual covering: MDL3, MDL4, MDL6. Check it applies to your exact model before use.
Applies to: Cummins/Onan MDL3, Cummins/Onan MDL4, Cummins/Onan MDL6
Before you start
- Accidental starting of the set can cause severe personal injury or death. Disconnect the battery cables when repairs are made to the engine, controls, or generator.
Procedure
- Stop the generator set.
- Change tap connections on the transformer T21 to adjust output voltage.
- When replacement is necessary, install leads to the same terminals of the new transformer.
- Refer to the model wiring diagram or the generator reconnection diagrams under Test (Q).
Full service-parts list: Cummins/Onan MDL3 →, Cummins/Onan MDL4 →, Cummins/Onan MDL6 →
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.