Kohler 27EFOZ, Service Manual

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TP-5936 7/04 35 Section 7 Generator Troubleshooting
5. Contact the ohmmeter leads and readjust the
ohmmeter to zero ohms. Check the cold
resistance of the stator windings by connecting the
meter leads to the stator leads 1-2, 3-4, etc. See
Section 1, Specifications, for the stator resistance
values. If the stator resistance test is inconclusive,
perform a megohmmeter test on the stator as
described in the next step.
Note: Consider the stator good if the resistance
reading (continuity) is low and there is no
evidence
of shorted windings (heat
discoloration).
Note: When taking an ohmmeter reading using
lead 55, make the connection prior to the
in-line fuse.
Note: The stator resistance varies directly with
increased temperature.
6. If any of the stator readings vary during the
previous checks, replace the stator.
7. Check the stator for a short to ground condition
using a megohmmeter. See Figure 7-16 and
Figure 7-17. Apply 500 volts DC to any stator lead
from each winding and the stator frame. Follow the
megohmmeter manufacturer’s instructions for
using the megohmmeter. Repeat the test on the
other leads until all the stator windings have been
tested. A reading of 500 kOhms (1/2 megohm) and
higher indicates the stator is good. A reading of
less than 500 kOhms indicates deterioration of the
winding insulation and possible current flow to
ground. Repair or replace the stator.
1
5
6
7
8
9
F+
F--
AC
AC
AC
66
55
3
V4
4
1 2 B1 B2
F1 F2
1 4
3 6
P8
V1
3
2
4
TP-5936517
1. Voltage regulator power supply leads
2. Sensing leads (208--240 volts nominal)
3. Stator windings
4. Main field (rotor)
5. Rectifier module
6. Frame connection
7. Megohmmeter
8. Armature
9. Exciter field
Figure 7-16 Megohmmeter Connections on Stator,
1 Phase
1
2
3
4
6
8
7
5
F1 F2
9
TP-5936518
1. Voltage regulator power supply leads
2. Sensing leads (208--240 volts nominal)
3. Stator windings
4. Main field (rotor)
5. Frame connection
6. Megohmmeter
7. Rectifier module
8. Armature
9. Exciter field
Figure 7-17 Megohmmeter Connections on Stator,
3 Phase