Cummins/Onan 1750DQKB / 3200 Series — Generator/PCC Control Isolation Procedure
Testing & diagnosis · Generator / PCC control
For the Cummins/Onan 1750DQKB / 3200 Series, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 1750DQKB, Cummins/Onan DFE
Before you start
- This test involves unregulated excitation of the generator. To prevent damage due to overcurrent, make sure all loads are disconnected and all faults cleared from the generator output terminals.
- HAZARDOUS VOLTAGE. Touching uninsulated parts inside the control housing and power output boxes can result in severe personal injury or death.
Procedure
- Throw the line circuit breaker OFF and shut down the set.
- Open the control box and remove plug 10 from connector 10 of the voltage regulator output module (A37).
- Prepare to measure output voltage across the generator terminals while the set is running.
- Bring two jumpers from a 12 volt battery for connection to the X (Field +) and XX (Field -) pins of plug 10.
- Check polarity again; polarity must be correct or the test will be inconclusive.
- Start the set and connect the jumper from the battery negative (-) terminal to the XX lead.
- If rated output voltage or higher is obtained and voltages are balanced, the generator circuitry is probably okay.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Normal excitation voltage ranges from approximately 10 VDC at no-load to approximately 40 VDC at full-load
- X = Red wire of connector 10-6
- XX = Brown wire of connector 10-3
Full service-parts list: Cummins/Onan 1750DQKB →, Cummins/Onan DFE →
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.