Cummins/Onan 1750DQKB — Testing the Main Rotor (Generator Field)
Testing & diagnosis
For the Cummins/Onan 1750DQKB, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 1750DQKB, Cummins/Onan DQKB, Cummins/Onan DQKC
Procedure
- Disconnect the two leads of the main rotor from the terminals on the rotating rectifier assembly.
- Measure resistance between the two leads with a Wheatstone bridge or digital ohmmeter.
- Replace the rotor if the resistance is not as specified in Tables 4-2/4-3.
- Torque the terminals to 24 in-lbs (2.6 N•m) when reassembling.
- Disconnect main rotor and voltage suppressor leads from terminals F1+ and F2– and isolate from ground; tag each lead.
- Connect the megger between one rotor lead and ground and conduct the test per Table 4-1.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Main rotor terminals 24 in-lbs (2.6 N•m)
Full service-parts list: Cummins/Onan 1750DQKB →, Cummins/Onan DQKB →, Cummins/Onan DQKC →
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.