Kohler 6.5-27EFOZD, Service

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TP-6255 7/06 65 Section 8 Component Testing and Adjustment
8.3 Exciter Field
Direct current from the battery magnetizes the exciter
field.
When the exciter armature rotates within the
magnetized exciter field windings, an electrical current
develops within the exciter armature. Test the exciter
field according to the following procedure.
Exciter Field Test Procedure:
1. Place the generator set master switch in the OFF
position.
2. Disconnect the generator set engine starting
battery, negative (--) lead first.
3. Disconnect the FN/FP leads.
4. Check the exciter field resistance by connecting an
ohmmeter across exciter field FN and FP leads.
See Figure 8-4. See Section 1, Specifications for
the resistance reading of a cold exciter field. A low
reading indicates an internal short and a high
reading indicates an open winding.
Repair or
replace the exciter field if the ohmmeter readings
indicate an inoperative exciter field (refer to
Section 9 for removal). If the resistance test is
inconclusive, perform a megohmmeter test on the
exciter field as described in the next step.
1
3
4
FN FP
TP-5983-7
2
1. ADC 2100
2. Ohmmeter
3. Exciter field
4. Exciter armature
5. Main field (rotor)
5
Figure 8-4 Exciter Field Resistance Test
5. Check the exciter field for a short-to-ground
condition. Use a megohmmeter to apply 500 volts
DC to the FN or FP lead and the exciter field frame.
See
Figure 8-5. Follow the megohmmeter
manufacturer’s instructions for using the
megohmmeter. A reading of approximately
1.5 MOhms and higher indicates the field winding
is functional. A reading of less than approximately
1.5 MOhms indicates deterioration of the winding
insulation and possible current flow to ground; if so,
replace the exciter field.
1
3
FN FP
4
5
TP-5983-7
2
1. ADC 2100
2. Megohmmeter
3. Frame connection
4. Exciter armature
5. Exciter field
6. Main field (rotor)
6
Figure 8-5 Megohmmeter Connections on the
Exciter Field