Cummins/Onan PCC 3100 Generator Set

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

1. Verify the dot on the CT faces toward the generator.
2. Verify CT21 is on U load leads, CT22 on V load leads, CT23 on W load leads.
3. Verify the correct CT secondary terminal (pin 2 high voltage / pin 3 low voltage) is used.
4. Check CT/PT wiring if a 335 Reverse Power shutdown occurs.

⚠ HAZARDOUS VOLTAGE. Touching uninsulated high voltage parts inside the control and power output boxes can result in severe personal injury or death.

Tools: Wheatstone bridge or digital ohmmeter

1. Disconnect leads P2, P3 and P4 from the voltage regulator.
2. Start the engine at the set and let the speed stabilize.
3. Measure voltage across lead pairs P2-P3, P3-P4 and P4-P2.
4. Voltage should be at least 150 VAC for 50 Hz sets and at least 180 VAC for 60 Hz sets.
5. Stop the set and measure electrical resistance across lead pairs P2-P3, P3-P4 and P4-P2 with a Wheatstone bridge or digital ohmmeter.
6. Each winding should have a resistance of approximately 4.4 ohms.

Tools: Ohmmeter, Feeler gauge

1. Remove the fuel pump control cover, disconnect the wiring jack and unscrew the assembly from the top of the day tank.
2. With an ohmmeter, test for continuity between each pair of colored leads while holding the assembly vertical; all readings should be zero.
3. Lift each float, in turn, to 1/8 inch (3 mm) below the C-clip stop above it and test for continuity; all readings should be infinity.

1. The dot on the CT must face toward the generator (conventional current flowing into the dot).
2. CT21 - U load leads (A phase); CT22 - V load leads (B phase); CT23 - W load leads (C phase).
3. Route the appropriate leads through each CT.
4. 6 lead generator sets - generator output leads are routed through the CTs.
5. 12 lead generator sets - load wires are routed through the CTs.
6. Connect CT secondary wire marked 1 to pin 1; wire marked 2/3 to pin 2 for high voltage or pin 3 for low voltage gensets.
7. The lead from CT terminal #1 connects to the metering circuitry; the lead from terminal #2/3 connects to ground.

1. Remove the end bell cover for access to the motor wiring terminals.
2. Disconnect the brown lead from motor terminal P103-3 and connect it to terminal P103-6.
3. Disconnect the red lead from motor terminal P103-2; it will be connected to the piggy-back terminal on the lead connected at motor terminal P103-3.
4. Cut the white lead from its ring connector at motor terminal P103-4; strip 1/2 inch (12 mm) of insulation for splicing to harness lead P103-WHITE.
5. Connect each lead of the five-lead wiring harness to the motor terminal or lead marked on it.
6. Connect the red motor lead to the piggy-back terminal at motor terminal P103-3.
7. Secure the end bell cover.

⚠ Do not use fan blade to bar over engine. That can damage blades and cause property damage and personal injury.

1. Bar the engine until a gear tooth on the flywheel 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.

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

⚠ Disconnect the negative ground cable before working on any part of the electrical system or the engine.

1. Keep the batteries clean by wiping them with a damp cloth whenever dirt appears excessive.
2. If corrosion is present around the terminal connections, remove battery cables and wash terminals with a solution of 1/4 pound of baking soda added to 1 quart of 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. Keep the battery terminals clean and tight; coat terminals with a light application of petroleum jelly or non-conductive grease.

1. With the generator shut down, the AVR disconnected, a diode for polarity and a 3 amp fuse, apply 110 to 220 VAC for one to two seconds to the X and XX leads of the exciter stator.
2. Alternatively, with the set running and disconnected from all loads, apply 12 VDC from a battery for one to two seconds, + to X and − to XX.

⚠ The bearing must be filled with the same type of grease used when the generator was manufactured and MUST NOT be mixed with any other type.

Tools: Grease gun

1. Make sure grease gun nozzle and re-lubricating fitting are free from contaminants or abrasive material.
2. With the generator running, apply the specified re-lubrication grease fill quantity through the grease fitting.
3. Run the generator for at a minimum of 10 minutes to allow excess grease to exhaust.
4. Check inside the PMG cover for expelled grease. Clean out as necessary.

⚠ Filters should be handled with care to prevent damage. If the filter does become damaged, install recommended replacement part.

Tools: Low pressure compressed air

1. Loosen fastener(s) and remove air cleaner housing end cap.
2. Remove the air filter element from the filter housing.
3. To clean, blow low pressure compressed air (30 psi/207 kPa) through the element from the clean side. Hold the nozzle at least 1 inch (25 mm) away to avoid damaging the element.
4. Soak the filter for at least 15 minutes in water and Donaldsons D1400 solvent (or equivalent other cleaning solvent) to remove soot and carbon as well as dirt.
5. Rinse with clean water (low pressure) and allow to air dry. Do not blow dry. Reinstall when dry. Replace the filter after two cleanings to avoid restricting airflow.

1. Activate the control ON switch for automatic operation. The PUMP light comes on and the pump fills the tank.
2. The fuel level in the tank is automatically kept between a set of pump-on and pump-off float gauge switches.
3. The PUMP light indicates when the pump is running; it goes on and off as fuel is pumped to maintain the proper level in the tank.