Cummins/Onan RGA-IN1 — Testing Generator Rotor
Testing & diagnosis
For the Cummins/Onan RGA-IN1, from the Cummins/Onan service manual.
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Procedure
- For grounds: remove rotor leads F1+ and F2- from rotating rectifier assemblies.
- Connect test leads between F1+ and rotor shaft, then between F2- and rotor shaft. Meter should register 100,000 ohms or greater.
- If less than 100,000 ohms, rotor is questionable. Oven dry and retest.
- Replace grounded rotor with new identical part.
- For open or shorted windings: remove rotor leads F1+ and F2- from rotating rectifier assemblies.
- Using ohmmeter, check resistance between F1 and F2 leads. Resistance at 77°F (25°C) should be 2.09 ohms, ±10%. If not, replace rotor.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 100,000 ohms or greater
- 2.09 ohms ±10% at 77°F (25°C)
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.