Kohler 27EFOZ, Service Manual

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TP-5936 7/04 19 Section 6 Controller Troubleshooting
Section 6 Controller Troubleshooting
6.1 Controller
This section covers the controller troubleshooting
procedure for generator sets equipped with a relay
controller and related engine components.
Refer to
Section 1.4 to identify the controller external
components. Refer to Figure 6-1 to identify the
controller internal components.
A-359001-C
1
2
3
4 5
6
7
3
4
5
8
1. Controller circuit board
2. K25 relay (fuel solenoid)
3. Hourmeter
4. DC circuit breaker
5. Start/stop switch
6. Voltage regulator circuit board
7. K20 relay (starter solenoid relay)
8. AC circuit breaker location
Figure 6-1 Controller Internal Components
6.2 Controller Sequence of
Operation
The following describes the controller sequence of
operation during generator start, run, stop, and fault
shutdown modes. Use the LEDs on the controller circuit
board to assist in the troubleshooting process.
An
illuminated LED indicates that the respective relay is
receiving power; the LED does not indicate whether that
relay is energized.
Refer to the wiring diagrams in
Section 10, Voltage Reconnection and Wiring
Diagrams.
6.2.1 Start
Close the start/stop switch between N and 47 (local or
remote starting).
The K2 relay energizes. The normally open K2 contacts
close to energize the K3 relay (LED3 lights), the K25
(fuel solenoid) relay, the controller hourmeter, and the
generator armature exciter field.
The K25 normally open contacts close to energize the
fuel solenoid.
The K3 relay normally open contacts close to energize
the K20 (starter) relay. The K20 relay normally open
contacts close to energize the S relay (starter solenoid).
The S relay normally open contacts close to energize
the starter motor.
The normally closed low oil pressure (LOP) contacts
open.