Cummins/Onan — Testing the Armature (AC Winding) for an Open Circuit
Testing & diagnosis · Armature AC winding / slip rings
From a Cummins/Onan owner's manual covering: 1.5UF-232S, 10.0UF-150S, 12.0UF-3S, 12.0UF-4S, 15.0UB-150S, 15.0UF-3S/104, 2.0UF-125S, 2.0UF-232S/32, 2.0UG-1S/135, 2.5UF-1S, 2.SUD-IS, 2.SUD-IS/ID…. Check it applies to your exact model before use.
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Procedure
- Place one test prod on one slip ring and the other prod on a second ring.
- The test lamp should light; if it does not, an open circuit is present.
- If there are three or four rings, test between each two in the same manner.
- Install a new armature if an open circuit is present.
Tools required
- test lamp set Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan owner's 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.