'
SECTION 5-Breaker Operation
A breaker may
be
equipped to operate either manually
or electrically. Both types of operation result in the same
fast-closing movement as far as the contact action is
concerned. The variation is in the way energy is stored in
the closing spring, and how it is released.
5.1
MANUAL CLOSING
Manually operated AKA breakers are constructed with
front-mounted handles. Handle operation resets the
mechanism and fully charges the closing spring. A com
plete charge is accomplished in either cranking the han
dle through one cycle (1 35-degree swing) or three cycles
(50-degree swing). Manually operated breakers manufac
tured after July, 1984 can only
be
charged by cranking
the handle through one cycle.
The CLOSE button
mounted on the escutcheon, is used to manually close
the breaker contacts and the TRIP button is used to open
them.
If equipped with a closing solenoid, a manual breaker
may
be
closed remotely by a control switch or relay.
Before this can
be
done, however, the closing spring has
to be charged by hand. The closing solenoid is an op
tional accessory and is not supplied unless specified in
the breaker order.
CONTROL
SOURCE
'I
X
G l
X
cc
cc
w
5.2 ELECTRICAL CLOSING
On electrically operated breakers the closing springs are
charged by a gear motor. With the springs discharged,
voltage 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 the
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 deenergizing the motor and the "F" switch estab
lishing 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". If 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.
The closing springs on electrically operated breakers
can be manually charged. The breakers can also be man
ually closed. Refer to Section
5.4
for this procedure.
TC
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 PUSHBUTION ON
BREAKER ESCUTHEON.
OPTIONAL
TC-
SHUNT TRIP DEVICE
W-
ANTI-PUMP RELAY
X-
CONTROL RELAY
FIG.
9 -
ELEMENTARY DIAGRAM FOR ELECTRICALLY OPERATED DRAWOUT BREAKER.
CONTACT POSITIONS ARE SHOWN
WITH
BREAKER OPEN AND CLOSING SPRINGS DISCHARGED.
1 1
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