1 0 - 1.
PURPOSE AND FUNCTION OF ENGINE
AND GENERATOR CONTROLS AND INSTRU-
b. Functional Theory of
into an analog signal that controls a
pulse width modulator.
If the speed
value is too high, the drive signal is
decreased and the pulse width modu-
lation output duty cycle decreases.
tactor enabling is the process by which
is supplied to the
As the engine continues to
accelerate, its speed is monitored by
the EECM microprocessor until
percent speed is reached.
that 100 percent speed has been reached
is determined by the microprocessor
which compares a stored value for 100
percent speed with the actual value on
the speed signal line. When that point
is reached, the engine is turning the
generator at a rate where the generator
power output is sufficient to supply
the load (start the aircraft). At 100
outputs a level on one of the four
lines to the switch
After buffering, this becomes
Generator enable is also sent off the
card through connector P4 to the GECM
to enable the GECM to control the
The lamp driver generates
the ready to load signal that is routed
from the EECN to the control panel
causing the READY TO LOAD lamp to come
on. When the operator sees the READY TO
LOAD lamp come on, he places the
CONTACTOR switch momentarily in the
then releases it back
to the normal center position.
places +24 Vdc on the (Contactor On)
line to the switch card where it is
MARINE CORPS TM 6115-34/8
shaped, then used to set a latch on the
switch circuit card.
The set output of
the latch is applied to a contactor
gate and buffer where it is gated with
a contactor enable output that the
microprocessor generates at this time.
The resulting gate output drives a
contactor relay driver which in turn
outputs an enabling contactor enable
through and out of the control panel
it becomes the contactor
enable level to the output contactor.
relay, allowing power to flow from the
generator through the closed contactor
relay contacts to the aircraft being
To show the operator that the
relay is closed, closure of another set
of relay contacts applies
through control panel terminal board
TB1 to the CONTACTOR CLOSED lamp. The
to verify that the
contactor relay is energized.
operator can monitor the voltage and
current being supplied to the air-
He is also able to regulate the
Voltage is displayed on the control
panel VOLTAGE meter, while current is
shown on the OUTPUT CURRENT meter.
Output voltage is controlled by turning
the control panel VOLTAGE ADJUST knob.
turning the knob is routed to the GECM
The operator adjusts the
knob while watching the VOLTAGE meter
until the meter reading is correct.
the HOURMETER is con-
nected across the VOLTAGE meter so that
it accumulates the number of hours that
voltage has been generated by the