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Power Circuit Breokers,
GEK-731O
the
breaker
is in
the "test"
position
or
the "con-
nected"
position.
This
limits
motion
to those parts
within
the
mechanism
frame, which
are relatively
inaccessible, and minimizes the
possibility of
an
accident.
RACKING'NECHANISIYT INIERLOCKS
(FtG. 8)
A
drawout
breaker
connected
to a
power
circuit
must not
be
allowed to
move
unless the breaker's
contacts
are
open. This requirement
is
met
by
automatically locking closed the sliding cover
in
the escutcheon when the
breaker
is
closed.
Unless this cover
is
moved, the drawout rack-
inghandle cannot be
used. Lockingisaccomplished
by link
(2),
Fig.
8 which moves
down
into
a notch
in
the cover ia response
to
the
main shaft being in
the closed
positi.on.
Another
aspect
of
the
interlock
arrangement is
that the openingmovementof the slidingcover
cams
the manual
trip
button
into the
tripped position'
keeping
the
breaker
"trip-free",
so a
closing cycle
of the mechanism
will
not
cause
any
closing move-
ment
of
the contacts. This condition
will
prevail
as
Iong as the drawout handle
is
engaged.
Another
interlock featwe
is the
breaker position
interlock.
This
makes
thebreaker
"trip-free"while
moving between
the "test" position
and
the
"con-
nected"
position.
When the
breaker
is
at
any
point
between these two
positions,
a
link
on
the
breaker,
which is
coupled
to
the
trip
shaft,
is
displaced by
the "ramp" cam
in
the
side of the breaker
housing.
This
holds the
mechanism latch out of position
and
keeps the breaker
open even
if
the closing springs
are discharged.
See
Fig.
4.
OPTIONAT
INTERTOCKS
The optional interlocks are key interlocks
and
door
interlocks.
On drawout breakers. these
de-
vices are mounted in the equipment
and
are part of
the breaker
enclosure.
Padlocks
may be used to
Iock the t'inner"
house
in
the
"disconnected" po-
sition.
On
all
breakers,
it is
possible to use
padlocks
to
lock the breaker
open
by placing the shackle of
the
padlock through
the trip
button hole and out the
slot in
the side
of
the
escutcheon.
This
holds
the
trip
button inthe
depressedposition
and
the
breaker
cannot
be closed.
Stationary
breakers may be
equipped
with
a
key
interlock
as
illustrated in
Fig.
7.
This illustration
shows
the
end
plate
assembly
of the
main shaft
when
the breaker
is open.
Pin
(3)
is
held away
from
the
path
of the lock
bolt
(4),
which
can
be extended,
aI-
-t-
1
. Lock
2. End Plate
3. Pin
4. Lock BoIt
5. Pin
6. Link
\
\
\
\
\
I
i
)
\
6
11
Fig.
7.
(134C2184) Key
inteflock
for
stati.orwrl breahers
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