TM 5-6115-593-12
TO 35C2-3-463-1
b.
Engine Starting. When the operator toggles
spring-loaded MASTER SWITCH S1 to the
START position, normal start/stop/run/ relay
K5 becomes energized through normally
closed contacts 5 and 6, and normally open
contacts 3 and 2 of S1. Upon release of S1,
relay K5 is held in its energized state by its
selflatching contacts 2 and 4. With K5
energized, run pilot relay K54 energizes
through the normally open contacts 1 and 5
of K5, and as a result normally open
contacts 1 and 2 of K54 close. Starter crank
limit relay K3 now energizes through
forward-biased
CR1
and
the
following
closed contacts: K19, speed switch SS1,
K6, K50, and K54. At this time magnetizing
current is applied to start solenoid L4
(through K3 contacts 1 and 2), and the
heavy duty contactors of L4 close, bringing
current to starter motor B2 causing it to
crank the engine. Simultaneous with the
previously described action, fuel solenoid L1
and engine run relay K1 are both activated
(through normally closed contacts K21, K19,
K6, K50, diode CR23, and contacts 1 and 2
of K54), allowing the passage of fuel to the
engine. Prior to starting, K1 normally closed
contacts place a short across terminals 22
and 23 of governor controller A106. This
ultimately
sets
the
engine's
hydraulic
governor for zero fuel output. Energizing
K1 at start time negates this function and
allows the passage of fuel.
c.
Starter Motor Protection. Depending on
which occurs first, cranking power will be
applied until the engine reaches a speed in
excess of 600 rpm or total cranking time
exceeds 30 seconds. When the engine
attains a speed over 600 rpm (in less than
30 seconds), speed switch SS1 opens,
subsequently deenergizing K3 and, then,
L4. With L4 deactivated, cranking action
ceases
when
the
contactors
of
L4
disconnect power from starter motor B2. If
the engine does not start, that is, does not
reach a speed in excess of 600 rmp, and
cranking time exceeds approximately 30
seconds, cranking will automatically cease
thereby preventing the possible burnout of
starter motor B2. Initially, when cranking
begins, time delay relay assembly TD1 is
turned on (through closed contacts of SS1,
K6, K50, and K54) and the timing process
commences. After a period of about 30
seconds, TD1 stops timing and connects
overcrank shutdown relay K19 to +24V DC
through contacts of SS1, K6, K50, and K54
thereby energizing K19. K19 now energized,
opens its normally closed contacts in series
with cranking relay K3 causing K3 to
deenergize, and subsequently, power is
removed from B2. To indicate that this has
occurred, OVER CRANK lamp DS51 lights
when it is returned to +24V DC through the
normally open contacts of K19 (in series
with DS51) and the path consisting of SS1,
K6, K50, and K54. If, as was previously
mentioned, engine speed goes over 600
rpm, SS1 opens and the just described
action does not occur.
d.
Ether Starting. As an aid to cold weather
starting, provisions are made to inject ether
into both of the engine air intake manifolds
while the engine is being cranked. The
application of this highly volatile fluid is
controlled by the ether solenoid, ether aid
control relay K24, and START AID switch
S2. During crank time, K24 is energized
through closed contacts of K6, K50, and
K54. At this time the normally open
contacts of K24, which are in series with the
ether aid control S2, close. Operating S2 to
the ON position activates the ether aid
control
solenoid
causing
a
measured
amount of ether to be loaded into the ether
aid device. Upon release of S2, this
measured amount of ether is forcefully
injected into the air intake manifolds. The
ether aid device may be used at any engine
speed up to 1200 rpm and for approximately
5 seconds afterwards (the 5-second delay is
explained
in
subparagraph
1-14th(2),
below).
e.
Louver Operation (Housed Sets). The
auxiliary housing kit
1-23
