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GEK-721
01,
Low
V
oltoge Swifchgeor
a9
.2'
.tr
n
FlG.
l9
(0625E0376) Rqckoui mechonism
for
AK
breokers
RACKOUT MECHANISM OPERATION
AK
BREAKERS
Part
numbers
in
Figure
19
refer
to
part
numbers
on
Drawing
0673D0500 Sheet
627
Groups
05
or
06.
The rackout
mechanism
is
operated
by
pushing
the
handle onto
the end
of
the
jackscrew
shaft and
rotating
the handle.
Clockwise
rotation
moves
the
breaker
into
the
house
and
counter-clockwise
rotation
moves
the
breaker
out. Approximately
17
turns
of the
handle
will
move
the
breaker
from the
DISCONNECTED to
the CONNECTED
position. To properly
engage
the
handle
with
the
jackscrew
shaft,
the
slot
in
the
end
of
the handle should
align
with
the
pin
through
the
shaft. When
the pin
is
so
aligned,
the
square
hole
in
the
handle
will
be
engaged
with
the
square
drive
end
of
the
shaft.
The
rackout
mechanism
is interlocked
so
that
the
circuit
breaker
must
be open
before
the
operating handle can
be
inserted.
When
the
breaker
is
closed,
an
interlock link
operated
by
the breaker
cross
bar
blocks
the interlock
link-
age on
the
rackout
mechanism
and
prevents
the
tube
(63)
from
being
moved
back
to fully
expose
the
square shaft
end.
The
pin
(105)
in
the
jackscrew
shaft
engages
in a
slot
in
the
tube.
This slot
prevents
rotation
of
the shaft
and
also
assures
that the
interlock
linkage
must be
moved
through
a prescribed distance before operation
of the
mech-
24
anism is
possible.
When the tube is
pushed
back
so
that
it
will
clear
the pin, a
cam surface on
the interlock slide (46)
engages
a
trip link
on the
side
of
the breaker and holds
it
trip
free as long
as
the handle
is
engaged
or the
interlock
tube
is
in
the
retracted
position.
There
is
also a stationary
cam
in
the
house
which
holds
the
breaker
trip
free
as
it
is
moved
between
the
CON-
NECTED
and
TEST
positions.
This
stationary
cam
comes
into
operation
before
the
primary
disconnects
have
parted
and
is
operable whether
or not the rackout
handle
is
en-
gaged.
The
breaker
thus
cannot be
closed
when
it
is
be-
tween
the
TEST
and
the CONNECTED
positions. From
the TEST
to
the
DISCONNECTED
position,
the
breaker
can be
closed
when
the rackout
handle
is
disengaged and
the
pin in
the jackscrew is aligned
with
the
slot
in
the
inter-
lock tube
so that the interlock
linkaee
is in
the
reset
position.
An indicator (75) which
is
visible through
an
opening
in
the
front
of the
door
shows
the position of the
breaker
in
the house. The
TEST position
is reached when the
line
on
the
indicator label
marked
TEST is
aligned
with
the stationary
line
on the
indicator
housing.
In this
position, the
breaker
can
be
operated when
the
pin
(105) and the slot
in
the
interlock tube
are aligned and
the rackout handle is
dis-
engaged.
The
secondary
control
power
disconnects
are
en-
gaged
and
the primary
power
disconnects
are
open
in
this
position.
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