Service manual

4. Service 9-2013
2. Remove the stator and stator through studs.
3. Remove the nut and flat washer on the rotor through stud and remove the through stud.
(Use two nuts locked together at the end of the rotor through stud to loosen and remove
the stud from the crankshaft.)
4. Thread in a rotor removal rod (shortened rotor through stud or 7/16-14 UNC-2A threaded
rod) and turn it with a screwdriver until it bottoms in the crankshaft. Thread in and tighten a
9/16-12 UNC-2B bolt against the rod until the rotor breaks loose from the crankshaft.
Reassembly: Reassembly is the reverse of removal. Torque the nut on the through stud to 49
ft-lbs (67 N-m). If it is necessary to reinstall the engine-generator adaptor, torque the four
mounting bolts to 49 ft-lbs (67 N-m).
4.12 Testing the Generator
Rotor Winding Continuity: Test the rotor for grounded, open and shorted windings using an
ohmmeter. First test at the brush block terminals. If the resistance is high, remove the brush
block and test directly on the slip rings. Replace the brush block if a high resistance is due to
the brushes.
Rotor Ground Resistance Test: Set the ohmmeter to the highest resistance scale, or use a
megger. Touch one test probe to the rotor shaft and the other to one of the slip rings. Refer to
the Rotor and Stator Resistance Tests table for resistance values and any corrective action.
Rotor Winding Resistance: Touch the slip rings with the meter test probes. Refer to the Rotor
and Stator Resistance Tests table for resistance values and any corrective action.
Main Winding to Quad Winding: Test for short between main windings and quad windings.
Stator Ground Resistance Test: Set the ohmmeter to the highest resistance scale, or use a
megger. Set the ohmmeter to the highest resistance scale and then touch one test probe to the
stack and, in turn, the other to each stator lead. Refer to the Rotor and Stator Resistance Tests
table for measurement values.
Stator Winding Resistance: Use a meter (Wheatstone Bridge) having a precision down to
0.001 ohms to measure stator winding resistance values as shown in the Rotor and Stator
Resistance Tests table.
Stator Winding for Grounds: With an ohmmeter, measure each winding to the stator
laminations to check for bad insulation. Refer to the Rotor and Stator Resistance Tests table for
measurement values.
TABLE 12. ROTOR AND STATOR RESISTANCE TESTS
Tests Measurement Values
Rotor Ground Resistance Reading > 1 megohm (one million ohms) on megger, or
infinity on an ohmmeter
Rotor Winding Resistance F1 to F2 (at 75° F - room 27.59 ohms ± 10%.
temperature)
Main Winding to Quad Winding Open (infinity) for any winding
Stator Ground Resistance Reading > 1 megohm (one million ohms) on megger, or
infinity on an ohmmeter.
Stator Winding Resistance (at 75° F - room temperature):
L1 to N 0.094 ohms ± 10%
36 A030A239 (Issue 10)