Cummins/Onan — AC Winding Open Circuit Test
Testing & diagnosis · armature ac winding
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
- For 120/240-volt single phase, contact test leads to the two collector rings nearest the ball bearing.
- If the lamp fails to light, an open circuit in that winding is indicated.
- Repeat contacting the two collector rings nearest the commutator.
- If the test is made between the two middle rings, the lamp should not glow.
- If it glows, a short between the two windings is indicated.
Tools required
- test lamp set Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.