GEK
..
7302
Installation and Operation
of
Type
AK
Power Circuit
Breakers
A closing
s~gnal
now
given energizes
the control relay X whose contacts
close
and complete the
circuit
through
tµe
closing
relay
coll. Wlth the
closing
relay
coll
energized the
breaker
closes
as
described
above. At the sa1ne
time
the closing
relay
contact closes to energize the antl-pump
relay
causing
its
contacts to
reverse
prou
viding the
antt~pump
feature.
When
the bl'eaker
closes,
the mechanlN
cal operated
G switches close to energize
the motor again and the F switches open
and
cte~energlze
the control -relay.
The
aUxlUary switch contact opens preventing
the control relay from being energized untll
the
breaker
is tripped open. With the G
switches close"d, the motor charges the
closing springs ready for the next closing
operation.
MANUAi,
OR
MAINTENANCE CLOSING
OF
~;r.~;CTR!CAL
BREAKERS
All
electrical
breakers
may
be closed
manually
by
means
of
the maintenance
handle furnished with the
breaker
qr
switch-
gear.
To close
AK~15/25
breakers:
1. Place the two
small
hooks of.the handle
into the two
slots
located in the lower
portion
of
the front escutcheon.
2.
Rotation of the
long-
end
of
the handle
downwards
forces
the
shorter
end
Of
the handle upwards against the bottom
of
the solenoid
armature,
and closes
the
breaker's
contacts.
To
close
AK-2/3-50/75/100
breal1ers:
1. Place the ratchet
tyPe
maintenance
handle
on
the shaft that
protrudes
from
the
gear
reduction unit.
2. Operate handle until the spring charge
indicator reads charged.
3. Continue to operate handle until the
closing springs discharge and close the
contacts.
To
close
AK-50S/75S/100S, AKF2C,
2D
breakers
and
breakers
equipped with
·the quick closing mechanism:
NOTE: All
AKD,
or
AKD-5 drawout type
break.era equipped with the quick closing
mechanism cannot normally be closed1uan-
ually when in the racked in (connected
position), due to mechanicaldesignedinter-
ference between the enclosure and the
spring discharge
lever'
on
the
breaker,
If
manual closing
is
desired
with the
breaker
racked in, the interference feature must be
removed, othel'wise
the.
breaker
can be
manually closed in the
test
position
or
fully
racked out position only. ·
1.
With the ratchet type maintenance
hand~
le applied to the
gear
box shaft, operate
the handle. until the springs
are
fully
charged, The fully charged position
is
indicated by the spring charge indicator
and
by
solid
resistance
to
any
further
handle operation.
2. Push
down
on
the push to close
lever
to
release
the energy
stored
in the closing
springs which closes the breaker·
1
s
con~
tacts.
To close AK-4/G
..
50
breakers:
NOTE:
AK-4A
andAK~6A
drawout
breakers
will be
11
tx·J.p
..
free
11
if the racking mechanism
is
in
any
Rosition other than the "'l'EST"
or
"CONN
position,
If
the
breaker
is
on
a workbench
or
on the extended
rails,
and
it
is
to
be closed with the maintenance
handle, operate the drawout mechanism
as
far
as
it
will
go
in a clockwise direction.
This will put the mechanism in the
"connect~
ed" position, and the
breaker
maybe closed.
If
this
is
done, the mechanism will have
to
be
reset
to the "disconnected" position
before
it
can be
reinserted
into the
breaker
compartment in the enclosure.
1. Place the maintenance handle
on
the end
of
the camshaft below the motor.
2.
Operate the handle until the closing
spring goes over center
and
the
breaker
closes.
If
the
breaker
ls a
11
quick
..
close
11
breaker,
type AK-4/5m60S, the spring will
not release upon going
over
center, but
will be held off by a blocking
link.
This
can
be
released
by
pulling forward
on
the
closing solenoid
armature
located beneath
the mechanism, This can be done safely,
since
no
moving
parts
are
located
in
this
space.
TRII>PING
The break.er
is
tripped open
by
the
displacement
of
a mechanism latch, which
allows a toggle linkage supporting the
movable contacts in the closed position to
collapse, This trip latch is fastened
rigidly to a trip shaft which runs hori
..
zontally from left
to
right through the
breaker.
All
of
the means provided
for
tripping the
breakeroperatethroughstriker
arms
which displace the mechanism
trip
latch
by
moving against
trip
paddles fastened
on
the
trip
shaft. Looking
at
the
breaker
from
the right, counterclockwise rotation
of
the
trip
shaft causes the
breaker
to
trip;
clockwise movement
resets
the mechanism
latch. The manual
trip
button, overload
devices, shunt
trip,
undervoltage tripping
device, and
reverse
current
trip
all
operate
in this fashion to
trip
the
breaker,
The
movement
of
the
striker
arms
of all
of
these, when activated, should move from
l/32
to
1/16
inch beyond
the
point
at
which
tripping
occurs.
This
is
what
is
meant by
the expression, "positive tripping
11
,
NOTE: BEFORE
MAKING
ANY
ADJUST-
MENTS
~·o
TRIP
DEVICE SETTINGS, THE
BREAKER SHOULD BE
IN
THE
OPEN
POSITION
AND
CONTROL POWER
HE·
MOVED,
Most
AK~2
and
AK~4
aircircuitbreak
...
ers
are
equipped with
series
overcurrent
trip
devices either
of
the dual magnetic
type (instantaneous and
time
delay tripping)
or
instantaneous alone.
Breakers
are
designed to
carry
up
to 1
OOo/
0
of
the con-
tinuous
current
rating
of
their
trip
devices.
Any
attempt to
carry
higher
currents
for
a prolone;ed period will cause overheating
and possible damage,
All AK-3 and AK-5 type
air
circuit
breakers
will be equipped with Power
Sensol'* overcurrent
trip
devices. The
time
current
band
as
well
as
the pickup
settings
of
this device
are
adjustable. A
single captive thumb screw adjusts
all
three
phases for any
particular
characteristic
or
setting. Should a thumb
screw
be in
..
advertently
left
loose the Power Sensor*
will
revel'ttothe
''minimum''pickup settings
or
"maximum" time delay bands
accord-
ingly,
If
after
installation
1
nuisance tripping
occurs, check the Power::sensor*forproper
settings
as
required
for
the specific appli
.....
cation and tighten all the thumb
screws
on
the Power S'ensor*,
For
a inore detailed discussion
of
the
construction, operation, and application
of
overcurrent
trip
devices
refer
to
the follow··
ing publications:
1. Maintenance manual for specific
breaker
involved (see
11
Maintenance
11
).
2.
"Selection and Application of Pow
...
er
Circuit
Breakers''
GE'l'
..
1113,
TYPE AKU AND BREAKERS WITH FUSE-BREAKER COMBINATIONS
Open Fuse Lockout Device
'l'his device may be furnished with any
of
the above type
breakers,
The open fuse
lockout device consists
of
3 separately
oper-
ated devices (one
per
b1·eaker pole) each
wired in
parallel
to corresponding
breaker
fuses. These devices
are
tnouhted on the
*
Trade~Mark
of
General Electric Company
B
left hand side
of
the
breaker
(looking
from
front). 'l'he purpose
of
this device
is
to
trip the
breaker
upon the blowing
of
any one
of
the
breaker
fuses. This energizes the
coil
of
the device causing the
armature
to
engage the
trip
paddle, thereby tripping the
breaker.
Once operated, the
armature
is
latched in the closed
air
gap position
allowing the
reset
button
to
extend forward
indicating which fuse has blown, and simu1
..
taneously holding the
breaker
in the
trip
..
free
position until the latch closed
armature
is
released
by
the operating
of
the 1uanual
reset
button.
Courtesy of NationalSwitchgear.com
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