MARINE CORPS TM 6115-34/8
PURPOSE AND FUNCTION OF ENGINE
AND GENERATOR CONTROLS AND INSTRU-
b. Functional Theory of Operation.
meter allows the operator to see that
the generator set batteries are being
charged while the engine is running.
Signal lines are routed directly to the
and connected to the
BATTERY CHARGING ammeter.
(7) Status monitoring
trol. Both engine and generator status
are monitored by the EECM while the
engine is running and the generator is
If a malfunction is
detected, the EECM either attempts to
correct the problem or automatically
removes power from the contactor (if
the contactor is energized) and shuts
down the engine.
To make these deci-
sions, the EECM microprocessor monitors
the engine monopole speed sensor, EGT
and oil pressure.
the EECM microprocessor
monitors the overload,
and temperature status via
signals sent to it from the GECM. A
three-fourths of a second to see if it
microprocessor software program takes
exception of a minor overspeed con-
any detected fault results in
display of the fault on one of the
power to the
aircraft by a disabling of the con-
tactor relay, and an automatic shutdown
of the engine.
(a) Engine fault detection and
An engine fault consists of
an overspeed, overtemperature, or low
oil pressure condition.
monitored via the speed signal line to
the EECM, overtemperature is monitored
via the EGT line to the EECM, and oil
pressure is monitored via the oil
pressure and signal line to the EECM.
The only fault that does not cause an
shutdown is an
condition between 100 and 109 percent
frequency of pulses on the speed signal
line indicates such a condition, fuel
flow to the engine is decreased as
If speed increases above
109 percent, or any of the other three
processor disables the contactor to
prevent current from flowing to the
aircraft being started.
This is done
by disabling the contactor enable line
from the microprocessor to the con-
tactor gate and buffer on the switch
This switches the gate output to
disable the contactor relay driver and
disable the output contactor signal.
When this occurs, the generator set
contactor relay deenergizes to remove
power from the aircraft.
the contactor relay also removes +24
Vdc from the control panel CONTACTOR
turning it off. At the
the microprocessor places
one or more signals on
lines to the switch
Regardless of where the
fault lies, the generator enable signal
is always disabled which turns off the
lamp driver circuit. The READY TO LOAD
line is thereby disabled, turning out
the READY TO LOAD lamp and stopping the
output on any one of the status control
lines to indicate where the fault is
If the fault is determined