Cummins/Onan — Commutator Mica Undercutting
Repair & overhaul · Generator Commutator
From a Cummins/Onan service manual covering: 10C, 10CW, 10CW-150R, 5CW, 5TW-0R, 6CW-54R, 7.5C, 7.5CW, 8CW. Check it applies to your exact model before use.
Applies to: Cummins/Onan 10CW, Cummins/Onan 10CW-150R
Procedure
- Remove brush springs and brushes.
- Tag and disconnect leads; remove end bell.
- Use mica undercutting tool or hacksaw blade.
- Cut mica between commutator bars to 1/32-inch depth.
- Remove burrs and clean spaces.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Mica undercut depth 1/32 inch
Full service-parts list: Cummins/Onan 10CW →, Cummins/Onan 10CW-150R →
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.