Cummins/Onan ESG-642 Engine

⚠ This test involves unregulated excitation; disconnect all loads.

⚠ HAZARDOUS VOLTAGE.

Tools: Voltmeter, 12 volt battery, Jumpers

1. Throw line circuit breaker OFF and shut down the set.
2. Remove control housing side cover; disconnect exciter stator X and XX leads from AC harness.
3. Prepare to measure output voltage across generator terminals while set runs.
4. Connect a 12V battery jumper positive (+) to X lead (Field +).
5. Check polarity again; polarity must be correct.
6. Start the set and connect battery negative (-) jumper to XX lead.
7. If rated output voltage or higher and all phases balanced, generator is likely OK.
8. If unbalanced troubleshoot main stator; if uniformly low troubleshoot exciter and field circuits.

Tools: Ohmmeter, Feeler gauge

1. Remove fuel pump control cover, disconnect wiring jack, unscrew assembly from top of day tank.
2. Holding assembly vertical, test continuity between each pair of colored leads; all readings zero.
3. Lift each float to 1/8 inch (3 mm) below the C-clip stop and test continuity; all readings infinity.
4. Use pipe thread sealant when replacing the assembly.

⚠ HAZARDOUS VOLTAGE.

Tools: Voltmeter, Wheatstone bridge or digital ohmmeter

1. Disconnect PMG leads PMG 2, 3 and 4 from AC harness connectors.
2. Start engine and let speed stabilize.
3. Measure voltage across PMG 2&3, PMG 3&4 and PMG 4&2.
4. Voltage should be at least 150 VAC (50 Hz) or 180 VAC (60 Hz) and equal.
5. Stop set and measure resistance across each pair; each winding approximately 4.4 ohms.

1. Remove jumpers between TB1-5 & TB1-6 and TB1-7 & TB1-8; connect two jumpers between TB1-6 and TB1-7.
2. Move selector switch S103 on control PCB to down position for 240 VAC.
3. On control transformer, remove jumpers between H1 & H3 and H2 & H4; connect two jumpers between H2 and H3.

1. Remove jumpers between TB1-6 and TB1-7; connect one between TB1-5 and TB1-6 and one between TB1-7 and TB1-8.
2. Move selector switch S103 on control PCB to up position for 120V.
3. On control transformer, remove jumpers between H2 and H3; connect one between H1 and H3 and one between H2 and H4.

⚠ Improper installation of CTs will cause a 1459 Reverse Power shutdown error.

1. Face the dot on the CT toward the generator (current flows into the dot).
2. Route CT1 on U load leads (A phase), CT2 on V load leads (B phase), CT3 on W load leads (C phase).
3. 6-lead sets: route generator output leads through the CTs.
4. 12-lead sets: route load wires through the CTs.
5. Connect CT secondary wire 1 to pin 1; 2/3 to pin 2 (high voltage) or pin 3 (low voltage).

⚠ Do not use fan blade to bar over engine.

1. Bar the engine until a flywheel gear tooth lines up in the center of the mounting hole.
2. Thread the sensor in gently by hand until it just touches the gear tooth.
3. Back it out one quarter turn and set the locknut.

⚠ Do not add water in freezing weather unless the engine will run two to three hours to mix water and electrolyte.

1. Check the level of the electrolyte at least every 200 hours of operation.
2. Fill the battery cells to the bottom of the filler neck.
3. If cells are low on water, add distilled water and recharge.
4. If one cell is low, check the case for leaks.

Tools: Battery hydrometer

1. Use a battery hydrometer to check the specific gravity of the electrolyte in each battery cell.
2. Hold the hydrometer vertical and take the reading.
3. Correct the reading by adding four gravity points (0.004) for every ten degrees above 80 °F (27 °C).
4. A fully charged battery has a corrected specific gravity of 1.260; charge the battery if below 1.215.

⚠ Electrostatic discharge will damage circuit boards.

⚠ Accidental starting can cause severe personal injury or death.

Tools: Grounding wrist strap, InPower Service tool

1. Create a capture file of genset parameter values using InPower before replacing Base board.
2. Attach grounding wrist strap clip to chassis ground screw and place strap on wrist.
3. Turn off or remove AC power from the battery charger.
4. Remove the negative (-) battery cable from starting battery.
5. Remove/replace the circuit board.
6. After replacing Base board, write previous settings using the capture file.

⚠ Electrolyte is a dilute sulfuric acid harmful to skin and eyes. Wear goggles and rubber gloves/apron.

Tools: Damp cloth

1. Keep the batteries clean by wiping them with a damp cloth whenever dirt appears excessive.
2. If corrosion is present, remove battery cables and wash terminals with 1/4 pound baking soda in 1 quart water.
3. Be sure the vent plugs are tight to prevent cleaning solution from entering the cells.
4. After cleaning, flush the outside of the battery and surrounding areas with clean water.
5. Coat the terminals with petroleum jelly or non-conductive grease to retard corrosion.

⚠ Contact with used engine oil can cause cancer or reproductive toxicity. Do not contact oil or breathe vapors; use rubber gloves and wash exposed skin.

⚠ Dispose of used oil and filters properly.

1. Refer to the Cummins engine Operation and Maintenance Manual for the lubricating oil and filter changing procedure.
2. Refer to Specifications in Section 2 of this manual for oil capacity.
3. Use oil that meets Cummins recommendations/specifications.