MAINTENANCE AND ADJUSTMENT
74
to be 1200 rpm (= Nd). This requirement can
be
met by unlocking the adjusting lever (which
wo.
&o
cu",d in the preceding step), by turning
he
lever, and
by
,lo
wly raising the speed. Upon
locating that
pOSItion
of
adjusti
ng
leve
r at
which
the
control r
ac
k begins
to
come out
at
1200 rpm
of
ri
sing speed, bring the maximum·
speed stopper in
to
contact
wi
th
the
lever,
thereby
..
tting the maximum·speed p()sition
of
adjusting lever . The lever ansle for
tIus
position
is
prescribed
to
b.
47° ± S· .
3. Speed regulation
ad
justment
Wh
at "speed regulation" signifies
was
explained
pre
vi
ou
sly:
it
ref
ers
to
the
di
ffe
rtnce
between
two governed speeds: n
o-
load speed
an
d fu
ll
-
load
speed
for
a given
pOSition
of
the
adjus
ting
lever.
It
is
expresse
d
as
a
percentage
of
full·l
o
ad
speed:
Specd
regulation
= n040ad speed - full-load speed x 100(%)
full-load speed
Gonerally speaking, the smaller the speed regu-
lation, the better
is
the engine control; but
some
regu
l
ation
is
necessary
for
the
sake
of
running stability and the smallest regulation for
the type
of
aU~peed
governor
as
the
pr=nt
one is limited
by
the governor mechanism.
Moreover,
each.
engine
runs.
best
when
the
governor
is
set
to
provide
the
r
egulation
speci
·
fied for the engine.
For the
mlximum
speed position
of
.djusting
lever.
s
peed
regulation
is
rtpresented
by
that
port
io
n
of
the
characteriSlic
curve
from
point
"d"
to
point U e"
for
the
differential
speed
from
"NdO!
to
liNe."
In
the
present
governor
) the
regulation
can
be
changed by means
of
the adjust
in
g screw pro-
vided
in
the swivel lever. Tightening this screw
increases
the
tension
of
control
spring
to
reduc
es
the
value
of
regulatjoo,
and
vice
versa
.
WUh
a
small
r
egujat
io
n,
the
cur
ve
ud
"
.....
"e"
is
sharper
..
d,
if
it
should be too sharp, the
go
ve
rnor
wo
uld
become
too
sen
si
ti
ve
.
It
is
importanl
to
note that the speed regulation
of
an
engine
unit
(complete with its injection
pump
and
governor)
is
determined not
so
!ely
by the governor setting
but
by the character-
istics of the engine (which were explained
earlier
in
the discussion of the torque ,pring).
For the present engine, a
proper
regula
ti
on will
obtain
whe
n the
adjUsting
screw
(
on
the
swh'cl
lever)
is
&ot
as
follows:
Drive
in
t
he
adjus.ting
screw
as
far
as
it
w
ill
go
in
, and then back it away by four
(4)
rotations_
Four
n01ches
of
this screw correspond to one
(I)
rotation.
Ba
c
king
awa
y t
he
scr
ew
increases
the regulation
(making the curve
"d
" - "e" less sharp). Never
back it
.way
by more than 24 notches (6 rota-
tions) or the
thre.ded
engasement
of
the sc
re
w
will
be
so
small
as
to
in
vite
a
h.azardous
condi-
tion.
4. Re-adjustrnent
of
maximum-speed stopper
"'t
-
ting
Changing the speed reguiatlon by tightening
or
loosening
(he
adjusting.
Screw
is,
in
substance
,
dlanging the tension
of
tlte control spring.
Fo
r
this reason, after each repositioning
of
the
adjusting
screw,
the
position of
maximum....speed
stopper for determining "
Nd
"
(th
e speed
at
which the governor begins
to
perform its high-
speed
conlrol action) must be changed
to
raise
or
lower "Nd
u
to
a proper level by repeating
the
proce
ss
described
above
.
(!roTE)
In
the table
of
standard adjustment
dalO,
the
angular
position of
thl!
adjusting
lever
assumes
that
40°
is
vertical
.
c)
Adaptor adjustment
1.
Move
the adjusting le
ver
to make it bear asainst
the
maximum-speed stopper, and install the
adaptor
in
it
s
normal
position
in
the
tension
lever.
2. Run the pump at "No" (= 900 rpm). ThIs
should move
the control rack inward
to th
.2 :t
0.1
rnm
(0.362 ± 0.004 in.) position
(= Ra);
if
not,
change the thickness
of
shim
plate (3) indicated in this illustration
3. Raise the pump
speed from
"Na"
to
"Nb
."
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