Allis-Chalmers LA-1600, Instruction Book

Page: 7 / 100

A. DESCRIPT I ON The LA-1600 air circuit breaker has an
Interrupting
capacity of 50.000 amperes and a maximum continuous current rating of lbOO
amperes at 600 volts,
bO
cycles.
For information on
other
voltages or
frequencies. the factory should be consulted. It is available as a
manually-operated breaker or an electrical iy-operated breaker. The two
breakers are identical
with
the exception of the medium used to transmit
pCMer to charge the stored-energy springs.
A double-toggle. trip-free mechanism is used; that is. th
e
breaker contacts
are
fr
e
e
to open at any time.
if required.
regardless of the position of
the mechanism or the force being applied.
I.
Breaker
As the breaker has a single-frame type
construction.
most
of
t
h
e
latches and
linkages are arranged in pairs; however.
for
descriptive
purposes. they will be referred to as single items. Refer to Figure 2.
Detai
1
"A" shows the position of trip latch (216)
w
h
en
the breaker
contacts are open with the closing spring discharged. Movement
of
closing handle (201) downward rotates
cam
(208) against roller (205)
thus pivoting closing cam (210) clock\-.ise about pin (206) and extending
stored-energy springs (209) through
1 ink
(225) and pin (226}. Rotation
of
cam
(210) clockwise permits spring (217) to collapse toggle
l
in
k
ag
e
(213)
&
(220). At the same time, trip latch (216) is reset by torsion
spring
(2 28}
as shown in Oetai 1
"B".
Pushing down spring release latch
hood (202A) after the closing handle
is
returned to the
normal vertical
position. releases the energy in springs (209). Through link {225),
closing cam
(210)
is rotated counterclockwise
ag
ainst roller (219)
which
moves t
o
g
g l e linkage as shown in Detail "C11, to close the breaker
contacts. The closing operation
may be
interrupted at any
point by
functioning of the trip device, thus ensuring "trip-free" operation.
To open the breaker contacts, trip rod {207)
is
actuated. This rotates
trip shaft (215) clockwise which releases trip latch (216) as shown in
Detail 11A11• On b r
e
a
k
e
r s equipped with
a
shunt trip device, the breaker
contacts
may
be opened by operation of
a
remote trip control switch.
The
shunt trip device rotates the trip shaft
to
release the trip latch.
TABLE
I
SPRINGS:
CLOSING:
TRIPPING;
OR
OPE RATING PROCE DURE MANUA LLY-OPERATED BREAKE RS
Pull handle (201) down
all
the way
(
approximately
120°)
and return to
normal
vertical position. (Engagement
of pawl (211) with the ratchet teeth
prevents handle
re
v e
rs
a
l unti
I
the dcJWnward stroke is completed.)
Push d��n spring-release latch hood (202A) after handle
is
re turned
to normal vertical position.
Push in manual trip
rod (207).
If shunt trip
is
provided, operate remote trip control
switch (CST). (See Figure
3�)
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