Cummins/Onan — Generator Voltage Adjustment
Adjustments · Generator Set
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- AC power within the cabinet presents a shock hazard.
Procedure
- Operate Run/Stop/Remote switch to RUN; GenSet starts but the transfer switch will not transfer.
- Observe generator output voltage matches the nameplate rating.
- If not, locate VOLT ADJUST; use a screwdriver to hold and loosen the locking nut.
- Slowly turn clockwise to increase or counterclockwise to decrease voltage to the nameplate value.
- Retighten the locking nut without changing the adjustment.
- Observe ammeter for zero current; repeat adjustment until nameplate voltage is obtained with zero current.
- Operate the Phase Selector switch to OFF and place the selector switch to STOP.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Voltage as specified on the nameplate
- Zero output current
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.