Cummins/Onan — Generator Brush Removal and Inspection
Maintenance · Generator brushes
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Do not use a substitute brush that may look identical; electrical characteristics may differ.
Procedure
- Remove generator fan guard and fan.
- Detach brush guide by removing end bell attaching screws.
- Tag leads 5 and 6 as marked on brush holder sides.
- Unscrew brush retaining screws and pull brushes from guide.
- Inspect brush faces for scoring and grooves.
- Replace brushes worn to less than 5/16 in length.
- Reinstall brushes in guide; check for sticking or binding.
Specs & values
- Replace brush when 5/16 in or less
- Inspect approximately every 500 hours
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.