Cummins/Onan — Testing Main Rotor
Testing & diagnosis · Main rotor (generator field)
From a Cummins/Onan service manual covering: C30 D6, C33 D5, C35 D6, C38 D5. Check it applies to your exact model before use.
Applies to: Cummins/Onan C30 D6, Cummins/Onan C33 D5, Cummins/Onan C35 D6, Cummins/Onan C38 D5
Procedure
- Disconnect two main rotor leads from rotating rectifier terminals.
- Measure resistance between two leads with Wheatstone bridge or digital ohmmeter.
- Replace rotor if resistance not as specified in Table 6-1.
- Measure resistance between either lead and main rotor laminations.
- Replace rotor if insulation resistance less than 1 megohm.
- Torque terminals to 24 in-lbs (2.7 Nm) when reassembling.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Terminals 24 in-lbs (2.7 Nm)
Full service-parts list: Cummins/Onan C35 D6 →
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.