Exciter Armature - Kohler 5EOZ Manual

5. Check the exciter field for a grounded condition.
Use a megohmmeter to apply 500 volts DC to the
FP or FN lead and the exciter field frame. Follow
the instructions of the megohmmeter manufacturer
when performing this test.
approximately 500 kOhms (1/2 megohm) and
higher indicates the field winding is functional. A
reading of less than approximately 500 kOhms
indicates deterioration of the winding insulation
and possible current flow to ground. Repair or
replace the exciter field.
4
1. Ohmmeter
2. Frame connection

3. Exciter armature

4. Exciter field
Figure 7-7 Megohmmeter Connections on the
Exciter Field
7.6 Exciter Armature
The exciter armature supplies excitation current to the
generator main field through the rectifier module. There
will be low or no generator output if the exciter armature
is inoperative. Test the exciter armature as described in
the following steps. Disassemble the generator set prior
to performing this test.
Exciter Armature Test Procedure
1. Disassemble the alternator.
2. Disconnect the armature leads from the rectifier
module AC terminals.
3. With an ohmmeter on the R x 1 scale, check the
resistance across the exciter armature leads. See
Figure 7-8. The armature resistance should be
0.6--0.8 ohms (continuity). No continuity indicates
an open armature winding. Replace the armature.
4. Perform a megohmmeter test on the exciter
armature as described in the next step. Consider
the exciter armature good if the resistance reading
(continuity) is low and there is no evidence of a
shorted winding (heat discoloration).
TP-6053 7/04
A reading of
1
P7
FP FN
2
3
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6
5
4
1. Main field (rotor)
2. Stator windings
3. Rectifier module
4. Ohmmeter
5. Armature
6. Exciter field
Figure 7-8 Exciter Armature Ohmmeter Test
5. Check if the exciter armature winding is ground.
Use a megohmmeter to apply 500 volts DC to
either armature lead and the armature frame.
Follow the instructions of the megohmmeter's
manufacturer when performing this test.
Figure 7-9. A reading of approximately 500 kOhms
(1/2 megohm) and higher indicates that the exciter
armature is functional. A reading of less than
approximately 500 kOhms indicates deterioration
of the winding insulation and possible current flow
to ground. Repair or replace the exciter armature.
7
6
4
5
1. Main field rotor
2. Stator windings
3. Rectifier module
4. Ohmmeter
5. Shaft connection
6. Armature
7. Exciter field
Figure 7-9 Megohmmeter Connections on Exciter
Armature
Section 7 Generator Troubleshooting
1
F+
AC
AC
AC
F--
2
3
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See
1
F+
AC
AC
AC
F--
3
2
558879
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