Instruction Book
Page 29
IB131009EN
W-VAC, WVACR, and W-VACW designs utilizes contin-
uous glass polyester moldings to support individual pole
units. All 95 KV BIL 630 through 1250 ampere rated
breakers require an additional cover to be added to the
support molding, resulting in the support molding being
enclosed on all four vertical sides (Figure
5-4a
).
All 3150 ampere breakers, no matter what the rated
voltage or BIL level, utilize continuous one piece glass
polyester moldings to support and enclose individual
pole units (Figure
5-4b
). No additional covers are
required as just described for 95 KV BIL 630 through
1250 ampere rated breakers.
5-2 STORED ENERGY MECHANISM
5-2.2 CHARGING
Figure
5-6
is a schematic view of the spring charging
parts of the stored energy mechanism.
The major component of the mechanism is a cam shaft
assembly which consists of a drive shaft to which are
attached two closing spring cranks (one on each end),
the closing cam, drive plates, and a free-wheeling ratch-
et wheel. The ratchet wheel is actuated by an oscillating
mechanism driven by the motor eccentric. As the ratchet
wheel rotates, it pushes the drive plates which in turn
rotate the closing spring cranks and the the closing cam
with it.
The closing spring cranks have spring ends connected
to them, which are in turn coupled to the closing springs.
As the cranks rotate, the closing springs are charged.
When the closing springs are completely charged, the
KEEP HANDS AND FINGERS AWAY FROM THE
BREAKER'S INTERNAL PARTS WHILE THE BREAK-
ER CONTACTS ARE CLOSED OR THE CLOSING
SPRINGS ARE CHARGED. THE BREAKER CON-
TACTS MAY OPEN OR THE CLOSING SPRINGS DIS-
CHARGE CAUSING A CRUSHING INJURY. DIS-
CHARGE THE SPRINGS AND OPEN THE BREAKER
BEFORE PERFORMING ANY BREAKER MAINTE-
NANCE, INSPECTION OR REPAIR.
The spring stored energy operating mechanism is
arranged vertically in front of all circuit breakers. It
includes all the elements for storing the energy, closing
and tripping of the breaker, as well as manual and elec-
trical controls. The manual controls are all front accessi-
ble. Motion to close and open the interrupter contacts is
provided through operating rods connecting the mecha-
nism pole shaft to the bell cranks of the interrupter
assemblies.
5-2.1 OPERATION OF STORED ENERGY
MECHANISM
The mechanism stores the closing energy by charging
the closing springs. The mechanism may rest in any one
of the four positions shown in
figure 5.5
and as follows:
a. Breaker open, closing springs discharged
b. Breaker open, closing springs charged
c. Breaker closed, closing springs discharged
d. Breaker closed, closing springs charged
spring cranks go over dead center, and the closing stop
roller comes against the spring release latch. The clos-
ing springs are now held in the fully charged position.
Closing springs may also be charged manually. Insert
the maintenance tool in the manual charging socket
(Figure 4.1a). Move it up and down approximately 38
times until a clicking sound is heard, and the closing
springs charging indicator indicates "Charged". Any fur-
ther motion of the maintenance tool will result in free
wheeling of the ratchet wheel.
5-2.3 CLOSING OPERATION
Figure
5-5
shows the position of the closing cam and
tripping linkage. Note that in Figure
5-5a
in which the
breaker is open and the closing springs are discharged,
the trip "D" shaft and the trip latch are in the unlatched
position as in Figure
5-5b
.
The closing springs can be released to close the break-
er by moving the spring release latch out of the way.
This is done electrically or manually by depressing the
spring release lever, which turns the spring release latch
out of the way of the closing stop roller. The force of the
closing spring rotates the cam shaft through the spring
cranks. The closing cam, being attached to the cam
shaft, in turn rotates the pole shaft through the main link
to close the breaker.
In Figure
5-5c
the linkage is shown with the breaker in
the closed position before the closing springs have been
recharged. Interference of the trip "D" shaft with the trip
latch prevents the linkage from collapsing, and the
breaker is held closed.
Figure
5-5d
shows the breaker in the closed position
after the closing springs have been recharged. Note that
the spring charging rotates the closing cam by one half
WARNING
Summary of Contents for 120W-VAC16
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