Stop; Automatic Safety Shutdowns - Kohler 7.5EOR Service

6.1.3

Stop

Rock the start/stop switch on the controller front panel to
the STOP position and release the switch to stop the
generator set. Release the switch to prevent energizing
the AH relay and unnecessarily heating the intake
manifold. In the STOP position, the start/stop switch
provides a ground through two blocking diodes
energizing the K4 relay (LED4 lights). The normally
open K4 contacts close, latching the energized K4 relay.
At the same time, normally closed K4 contacts open,
deenergizing FP and the K25 relay. The normally open
K25 contacts open, deenergizing the FS and disrupting
fuel flow. Turning off the fuel supply and the fuel pump
shuts off the engine.
When the engine shuts off, generator output decays and
deenergizes relays K1 and K5 (LED1 and LED5 go out).
The normally open K1 contacts open, deenergizing the
K2 relay (LED2 goes out).
deenergizes, the normally open K2 contacts open,
interrupting the power to the remaining controller relay
circuits, including the K4 relay. Relay K4 unlatches,
returning the controller circuits to a normal prestart
condition.
32 Section 6 Controller Troubleshooting
When the K2 relay
6.1.4

Automatic Safety Shutdowns

The engine has two switches that monitor critical
operating conditions:
D
The High Engine Temperature (HET) switch closes
when engine coolant temperature approaches an
unsafe level.
D
The Low Oil Pressure (LOP) switch closes when oil
pressure is insufficient, indicating inadequate engine
lubrication.
During normal running, closing either switch shuts down
the engine. During startup, normally open contacts of
the K5 relay disable this shutdown for 5--10 seconds
after the engine starts to allow monitored conditions to
stabilize.
Closing the normally open K5 contacts enables the
engine safety switches. If either switch closes, the K4
relay energizes (LED4 lights).
causes the normally open K4 contacts to close, latching
the energized K4 relay.
At the same time the K4 contacts close, the normally
closed K4 contacts open, deenergizing FP and the K25
relay. The normally open K25 contacts open,
deenergizing FS and disrupting fuel flow. Turning off the
fuel supply and the fuel pump shuts off the engine.
When the engine shuts off, generator output decays and
deenergizes relays K1 and K5 (LED1 and LED5 go out).
The normally open K1 contacts open, deenergizing the
K2 relay (LED2 goes out) and opening the normally
open K2 contacts, interrupting power to the remaining
controller relay circuits, including relay K4. Relay K4
unlatches, returning the controller circuits to a normal
prestart condition.
Energizing relay K4
TP-6073 4/06