Cummins/Onan — Replacing Transfer Switch Contacts (30 Through 400 Amperes)
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Never touch the transfer switch unless all power is removed; set the operation selector switch to STOP and disconnect the generator set starting batteries
- Filing the contact face destroys the mating surfaces
Procedure
- Remove the plastic hood from the transfer switch.
- Remove the washers and springs.
- Lift the contacts from the slide posts.
- Remove attaching screws from the stationary contacts.
- Install new contacts (curved silver contact surfaces facing inward).
- Reassemble the springs and washers.
- Reinstall the plastic hood.
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.