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GEI-86151 B
OPERATION
GENERAL
The
AKR-75
and AKR'100
breakers
are closed by
the
discharging
of
the energy stored
in
the closing springs
of
the
breaker.
As
the closing springs are discharged, the energy
is
directed into the closing cam
of
the breaker which causes the
moveable
breaker
contacts
to
be
forced against the station-
ary contacts, and,
at the same time causes the
opening
springs to
be
charged
so
they may open the breaker during
a
subsequent opening operation.
MANUAL CLOSING
Manually operated breakers are equipped with
a
handle
whlch
extends
from
the
escutcheon
of the
breaker.
Alter-
nately rotating
the closing handle
counterclockwise
then
clockwise
through approximately
120 degrees
of
rotation
through four complete cycles will cause the breaker
to
close.
During
the four
counterclockwise movements and
the
first
three clockwise movements
of the
handle,
the
springs
are
progressively charged.
After
approximately seven degrees
travel of the fourth clockwise handle movement,
the
spring
charge mechanism is driven
"over center"
and the energy
stbred
in
the
closing
springs
is
directed
into
the
closing cam
and causes
the
breaker to close. A charge-indicator,
num-
bered one
to
four,
visible through
the
breaker
escutcheon.
indicates
the
number
of
comolete handle movements that
have been
oerformed.
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ELECTRICAL CLOSING
On electrically operated breakers the closing springs
are
charged
by a
gear
motor. With
the springs discharged,
volt-
age
applied
to the
control circuit
will energize the
motor
through
the
"G" switch
contacts
-
see fig. 9. The
motor,
through
the gear
reduction
output crank,
compresses
lhe
closing springs until
they are fully charged. As this
fully
charged
position
is
reached, mechanically
operated
switches
"F"
and
"G"
reverse
their shown
position,
the
"G"
switch
deenergizlng the
motor and
the
"F"
switch establish-
ing
a
circuit to
the
"X"
relay. At
the
same
time,
a mechanical
prop
is
positioned
to
prevent
the
discharge
of the
fully
charged closing
spring.
With the closing
spring
propped
fully-charged,
the
breaker
is
ready
for
closing. This may
be
accomplished electrically by
depressing the closing switch
on
the breaker
(if so
equipped)
or by
a
remote closing switch. Operation
of
the closing switch
energizes
the
"X"
relay,
which
in
turn energizes the
closing
solenoid.
This removes
the prop,
releasing
the
closing
springs to close
the
breaker.
As the closing relay is energized,
it
energizes anti-pump
relay
"W".
lf
the closing switch
is
maintained closed, the anti-
pump
relay
will remain picked-up to prevent
a
second closing
operation
on the breaker in the event
it is
tripped
open
automatically.
The closing
impulse
must
be
released
and
reapplied before a second closing operation can
occur.
LEGEND
CC_CLOSING
SOLENOID
F
-
CUTOFF SWITCH,
CLOSED
WHEN CLOSING SPRING
IS
FULLY CHARGED.
G
_CUTOFF
SWITCH.
OPEN
WHEN
CLOSING SPRING
IS
FULLY CHARGED.
L
_AUXILIARY
SWITCH
M
_CHARGING
MOTOR
PB_CLOSE
PUSHBUTTON
ON
BREAKEB
ESCUTCHEON,
OPTIONAL.
TC
_
SHUNT
TRIP
DEVICE
W_ANTI-PUMP
RELAY
X_CONTROL
RELAY
t
,{,1
T_
I
I
I
CONTROL
SOURCE
-1T
"lI
1J
F
H:
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F-
-'l
I
Fl
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Fig.
9
Elementary diagram
for electricaily operated drawout
breaker.
contact positions
are
shown with
breaker
open and
closing springs discharged.
13
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