Cummins/Onan — Initial Start and Checks
Operation · generator set
From a Cummins/Onan service manual covering: 400 DFEB, 450 DFEC, 500 DFFB. Check it applies to your exact model before use.
Applies to: Cummins/Onan 500 DFFB, Cummins/Onan KTA19-G2 engine, Cummins/Onan KTA19-G3 engine, Cummins/Onan KTTA19-G2 engine
Before you start
- High AC voltages present hazard of severe personal injury or death; during a no-load test there should be no AC output current readings.
- Inhalation of exhaust gases can result in severe personal injury or death; shut down and repair leaks immediately.
- Leaking fuel creates fire or explosion hazard.
Procedure
- Confirm that Field Circuit Breaker is at Reset position.
- Place the Lamp Test/Reset/Panel Lamp switch at LAMP TEST; all indicator lamps will illuminate; then place switch at PANEL LAMP.
- Place the Run/Stop/Remote switch at RUN; starter cranks and engine should start within a few seconds.
- Check oil pressure gauge reads 40 to 60 psi (275 to 414 kPa) at operating temperature.
- Check water temperature gauge reads 165° to 195°F (74° to 91°C).
- Check battery gauge reads approximately 24 to 28 volts while set is running.
- Check generator frequency meter is stable and reads nameplate rating (50 or 60 Hz).
- Check AC amperes: zero at no-load; all three phases approximately the same under load; no line current exceeds nameplate rating.
- Check line-to-line AC voltage at full load equals nameplate rating; adjust Voltage Adjust rheostat as necessary.
- Inspect the entire exhaust system visually and audibly for leaks.
- Inspect fuel supply lines, filters, and fittings for leaks; check flexible sections for cuts, cracks and abrasions.
- Stop the set by moving Run/Stop/Remote switch to STOP.
Tools required
- remote voltmeter (on sets without AC meters) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Oil pressure 40 to 60 psi (275 to 414 kPa)
- Water temperature 165° to 195°F (74° to 91°C)
- Battery gauge 24 to 28 volts
- Frequency same as nameplate rating (50 or 60 Hz)
Full service-parts list: Cummins/Onan 500 DFFB →
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.