Cummins/Onan MDKC Generator Set

⚠ Incorrect flashing procedure can damage the voltage regulator; do not exceed 5 seconds

Tools: 12-volt storage battery, 10-amp fuse, momentary-on switch, diode

1. Assemble a 12-volt battery, 10-amp fuse, momentary-on switch, and diode as shown.
2. Connect positive lead to F1(+) exciter stator lead and negative lead to F2(-) exciter lead.
3. Close the switch just long enough for output voltage to build up, not longer than 5 seconds.
4. Check output voltage, then shut down and restart the generator set at no load.
5. Verify output voltage builds up without field flashing; if not, check wiring continuity.

⚠ Fuel vapor fire/explosion hazard

⚠ Heavy set can cause injury if dropped

1. Disconnect generator set negative (-) battery cable at the battery terminal.
2. Disconnect generator set positive (+) battery cable from the wire harness.
3. Disconnect the remote control plug wire from the generator set, if applicable.
4. Disconnect generator load wires and tag for identification when reconnecting.
5. Disconnect exhaust system and support brackets or hangers to allow set removal.
6. Disconnect fuel line at the generator set housing and plug the fuel line end.
7. Verify the generator set is adequately supported before loosening mounting bolts.

⚠ Accidental starting can cause severe injury or death

⚠ Generator components are heavy and can cause injury if dropped

Tools: hoist, sling or stator handling tongs, gear puller

1. Disconnect negative (-) battery cable to prevent accidental starting.
2. Remove control box cover and disconnect all stator leads; mark leads if unclear.
3. Remove end bell cover and remove field leads F1 and F2.
4. Remove load wires and flexible conduit from control box.
5. Remove leads from the DC voltage regulator plug on bottom of saddle.
6. Remove capscrews securing control box mounting saddle to the stator.
7. Pull stator leads through opening as control box/saddle is lifted free.
8. Set control box and saddle on top of engine.
9. Remove end bell stud nuts and slide off end bell and exciter stator.
10. Support stator with hoist and lifting device; support engine before removal.
11. Remove stator assembly, placing it on its side without touching the rotor.
12. Using hoist and sling, remove capscrews attaching drive disc to engine flywheel.
13. Remove rotor assembly and place on wood block in horizontal position.
14. Remove bolts holding drive disc and fan to rotor shaft and to each other.
15. Use a gear puller on the inner race to remove the end bearing from the rotor shaft.

⚠ Generator components are heavy and can cause severe injury if dropped

1. Slide exciter rotor over generator shaft and woodruff key; install exciter nut and torque.
2. Connect generator field leads to F1+ and F2- terminals on exciter assembly; torque.
3. Press the end bearing onto the rotor shaft.
4. Assemble rotor fan and drive disc to engine flywheel with chamfer toward flywheel side.
5. Install air baffle.
6. Move stator into position over rotor with leads at top; apply Molykote grease to bearing mating surfaces.
7. Install end bell stud bolts through stator into generator adapter.
8. Install end bell assembly with generator lead opening at top.
9. Torque end bell stud nuts to 20 ft-lb (27 N·m).
10. Tap end bell at horizontal and vertical with lead hammer to relieve stress; re-torque nuts.
11. Feed stator and control leads through opening and secure saddle to generator.
12. Connect all applicable control leads (F1, F2, battery charging) and verify connections secure.
13. Connect leads to the DC voltage regulator plug on bottom of saddle.
14. Install the end bell cover and connect stator wires to load wires.
15. Connect negative (-) battery cable and test generator operation.

1. Stop the generator set and disconnect starting battery leads, negative (-) lead first.
2. Disconnect (and label if necessary) the wires from the voltage regulator.
3. Remove mounting screws from the old voltage regulator, then install new regulator.
4. Reconnect wires removed in step 2 to the proper terminals.
5. Set voltage per the Voltage Adjustment procedure.