Allis-Chalmers LA-1600, Instruction Book

Page: 28 / 100

I n
g
e
a r (235)
are
at the top p
os i
t i
o
n,
they have
m o
v
e
d plunger
(233) against the roller of
mo
t o
r
cut-off switch (232)
to
shut
of f the motor. As t he springs a re charged, a rm (231) mus t
engage the r ol l er of spring-position switch (230).
Pi
l ot h o l es
a re provided in t he moun ting bracket for d ri
ll i
ng and ro l l ­
pinning the
replacement a
ss
em
b
l
y In
t
h
e
cor rect position.
b) Gear
- Refer
tp Figure 2A
On
LA-1600 breakers, prov i s i ons are made f o r
a
d ju
s
t
ing
the
precise position where the gear toggle linkage disengages fr�n
t he gear segmen t. This is se t d u r i ng produc tion testing,
b
u
t
the following method may be used for readjustment. Tighten screw
{242) and
n
u
t (243)
to
raise r
o
l l
e
r
(244)
slightly so t
h
a
t
when
the
breaker is
o p
e r at
e d electrically,
s
p
r
in
g
release
latch (202)
does
no
t
prop t he needle bea ring of c l osing cam (210) in the
spring charged position. When this occurs, the
breaker main
m
o
v
a
b
l
e
contacts will close
automatically. From
this
position
of
t
h
e
screw, n u t and ro 1 1 er, J
oosen
the
screw to
lower t he
roller
to the
p
o
i
n
t where
the
sp ring·
release latch wi 11 prop
the
c
l
o
s
in g cam ne
e
d
l
e bearing in the spring
charged
p
o
s
it
i
o
n
.
During t his adj ustment sequence, breDker
o
p
e
ra ti on
should be
controlled by
means
of
t
h
e
toggle switch on the
front
of
the
breaker.
E.
CONTACT REPLACEMENT
- Refer to F
i
gu
r
e
6.
of
m a i
n
cur ren t
carrying contacts and
a rc
i
n
g
Init i al cont act make and final contact break
contacts.
T
h e main con tac ts are n o t subject
surfaces a re clad with an al l oy facing which
wear
a
n
d a
r
c
e r
o
s
i
o
n
.
The c
o
n
t
a
c t
s tructure cons i sts
contacts a r ranged so that
is
by
means of
t
h
e
arcing
to arcing. The actual contact
greatly reduces mechanical
When inspect i on
of t h
e alloy f acing
I
n
d
i c
a
t es that
t h
e
contacts should
be
replaced,
i
t should
be
n oted t hat hinge
c
o
n
t
a
ct
fingers (620),
m
a in contac t
finge r s (b l 7)
and
arcing
c
o
n
t a
c
t
s
(619)
ar
e
spring loaded.
T
he
r
e
f
or
e
,
extreme
care
must be exercised in removal and installation of any
of the
contacts.
I . Main
C
o
nt
a
c
t
With t he
b
r
e
a
k e
r
contacts open and t
h
e
sto red-energy springs
dis­
charged, main contact fingers (617) may
be removed
by loosening screws
{623)
e
n
o
u gh to
rei ieve the compression
on springs {622) as shown
.in
Oet&i
I
"A".
T
h
e r
e
are two
springs behind
e
a
ch fin ge r and it
is
important
t ha t
they
be
pos
i
ti
o
n
e
d
properly
u
p o n rei nstllllation. I f
difficulty
is experienced
in
co
r
r
e
c
t ly
pos i tioning t hese
springs, the
u pper
a
n
d
lower primary
d
i
s c
o
nn
e
c
t
s (119 - Figure 1) may be
r
e
m
o
v
e
d
from each phase and
the breaker
Inver ted to rest on t h
e ends of
c
o n
n
ec tor
s
(624) and
(628).
After
the
contact fingers
are r
e p l
a c ed
,
connector (624)
s
h
o
u l
d be
positioned in
the
cen ter of
the
slot
in
t he
molded base to
a
s
s
u
r
e
correct alignment of
t h
e
primar y disconnect fingers.
- 9 -
(