Kohler 8.5RMY Service Manual page 31

Problem Possible Cause
No generator Defective stator (open, grounded, or
output voltage p g shorted windings)
K1 relay (NC) contact open
Brushes sticking in holder
Rotor slip rings dirty or corroded
Worn brushes
Defective or misadjusted voltage
regulator
Low engine rpm
No AC output
Circuit breaker open or defective, if
equipped
Circuit breaker tripping because of
overload on generator set
No battery voltage to voltage regulator
during cranking: (+) and (--) terminals
on regulator
Blown voltage regulator fuse
Open wiring, terminal, or pin in buildup
circuit or voltage regulator circuit
Brushes sticking in brush holder or
broken brush spring
Rotor slip rings dirty or corroded
Defective rotor (grounded windings)
Defective stator (open, grounded, or
shorted windings)
Defective or misadjusted voltage
regulator
Defective K3 relay (field flashing) in
relay controller circuit board
TP-5867 11/02
Corrective Action
Test and/or replace.
Check continuity.
Check springs and alignment.
Check and/or service.
Replace worn brushes.
Excite (rotor) separately.
Check engine speed using a
tachometer or frequency meter.
Note: Hz x 60 = rpm
(Example 57 x 60 = 3420 rpm)
Reset breaker to ON position.
Check AC voltage on generator
side of circuit breaker.
Reduce load.
Check for DC voltage at voltage
regulator terminals listed.
Replace fuse; if fuse blows again,
check voltage regulator and/or
stator auxiliary windings.
Check continuity.
Check brush position and
condition.
Check slip ring condition.
Check voltage and continuity.
Check voltage and continuity.
Excite rotor separately and check
for AC output. Readjust voltage
regulator.
Test/replace relay controller circuit
board.
Reference
Section 6, Component
Testing and Adjustment
Section 4, Controller
Troubleshooting and 9,
Wiring Diagrams
Section 6.6, Brushes
Section 6.6, Brushes
Section 6.6, Brushes
Section 6, Separate
Excitation, and 6.3.1, Voltage
Regulator Test
—
Section 1.6, Service Views,
for location
O/M
Sections 6.3, Voltage
Regulator, and 9, Wiring
Diagrams
Sections 6.3, Voltage
Regulator, and 9, Wiring
Diagrams
Sections 6.3, Voltage
Regulator, and 9, Wiring
Diagrams
Section 6.6, Brushes
Section 6.4, Main Field
(Rotor)
Section 6.4, Main Field
(Rotor)
Section 6.5, Stator
Section 6.3, Voltage
Regulator
Section 4, Controller
Troubleshooting
Section 3 Troubleshooting 21