Cummins/Onan — Generator Voltage Adjust (Without Detector AC Option)
Adjustments · VRAS-2 voltage regulator
From a Cummins/Onan service manual covering: 200 DFP, 250 DFM, 275 DFM, 300 DFM. Check it applies to your exact model before use.
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Before you start
- High voltages in the control present an electrical shock hazard which can cause severe personal injury or death. Proceed with care!
Procedure
- Open control panel doors, locate VRAS-2 (upper left), and refer to Figure 20 to locate terminal board TB1 and R32 potentiometer.
- Connect an accurate 2% voltmeter to VRAS-2 terminal board TB1-2 and TB1-3 terminals.
- While observing the voltmeter, insert a screwdriver into R32 potentiometer and slowly turn to increase or decrease voltage until adjusted to the rated nameplate voltage.
- Disconnect voltmeter from TB1 and close control panel doors.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- adjust to rated nameplate voltage
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.