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I.B. 94A1994R01
Page 18
Effective: April 2005
WARNING
KEEP HANDS AND FINGERS AWAY FROM BREAKER'S INTERNAL
PARTS WHILE THE BREAKER CONTACTS ARE CLOSED OR THE
CLOSING SPRINGS ARE CHARGED. THE BREAKER CONTACTS
MAY OPEN OR THE CLOSING SPRINGS DISCHARGE CAUSING
CRUSHING INJURY. DISCHARGE THE SPRINGS AND OPEN THE
BREAKER BEFORE PERFORMING ANY MAINTENANCE, INSPEC-
TION OR REPAIR ON THE BREAKER.
THE DESIGN OF THIS CIRCUIT BREAKER ALLOWS MECHANICAL
CLOSING AND TRIPPING OF THE BREAKER WHILE IT IS IN THE
"CONNECT" POSITION. HOWEVER, THE BREAKER SHOULD BE
CLOSED MECHANICALLY ONLY IF THERE IS POSITIVE VERIFI-
CATION THAT LOAD SIDE CONDITIONS PERMIT. IT IS RECOM-
MENDED THAT CLOSING THE BREAKER IN THE "CONNECT"
POSITION ALWAYS BE DONE WITH THE CUBICLE DOOR
CLOSED. FAILURE TO FOLLOW THESE DIRECTIONS MAY
CAUSE DEATH, PERSONAL INJURY, OR PROPERTY DAMAGE.
ELECTRICAL TRIPPING CAN BE VERIFIED WHEN THE BREAKER
IS IN THE "TEST" POSITION.
5.4.1 CLOSING SPRING CHARGING
Figure 5-5 shows schematic section views 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 shaft to which are attached two closing spring
cranks (one on each end), the closing cam, drive plate, and a free-
wheeling ratchet wheel.
The ratchet wheel (11) is actuated by an oscillating ratchet lever
(9) and drive pawl (10) driven by the motor eccentric cam. As the
ratchet wheel rotates, it pushes the drive plates which in turn rotate
the closing spring cranks and the closing cam on the cam shaft.
The motor will continue to run until the limit switch "LS" contact
disconnects the motor.
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 get charged.
The closing springs are completely charged, when the spring cranks
go over dead center and the closing stop roller (14) comes against
the spring release latch (3). The closing springs are now held in
fully charged position.
The closing springs may also be charged manually as follows:
Insert the maintenance tool in the manual charging socket. Move it
up and down several times (about 36) until a clicking sound is heard
and closing spring status indicator shows "charged" (Figure 3-3).
Any further motion of the maintenance tool will result in free
wheeling of the ratchet wheel and will not result into advance of
charging.
5.4.2 CLOSING OPERATION
Figure 5-6 shows the positions of the closing cam and tripping
linkage for four different operational states. In Figure 5-6a the
breaker is open and the closing springs are discharged. In this
state, the trip latch is disengaged from the trip "D" shaft (unlatched).
After the closing springs become charged, the trip latch snaps into
the fully reset or latched position (Figure 5-6b).
Instructions for VR-Series
Replacement Breakers for
Westinghouse Type B20B/B22B
When the spring release clapper (5) moves into the face of the
spring release coil (electrically or manually), the upper portion of the
clapper pushes the spring release latch (4) upward. When the
spring release latch moves, the cam shaft assembly is free to rotate.
The force of the closing cam (8), moving the main link (2), rotating
the pole shaft (1) (which charges the opening spring). This moves
the three operating rods (9), closes the main contacts and charges
the contact loading springs (not shown). The operational state
immediately after the main contacts close but before the spring
charging motor recharges the closing springs is illustrated in Figure
5-6c. Interference of the trip "D" shaft with the trip latch prevents
the linkage from collapsing, and holds the breaker closed.
Figure 5-6d shows the breaker in the closed state after the closing
springs have been recharged. The recharging of the spring rotates
the closing cam one half turn. In this position the main link roller
rides on the cylindrical portion of the cam, and the main link does
not move out of position.
5.4.3 TRIPPING OPERATION
When the trip bar "D" shaft (11) is turned by movement of the shunt
trip clapper (5), the trip latch will slip past the straight cut portion of
the trip bar shaft and will allow the banana link and main link roller to
rise. The energy of the opening spring and contact loading springs
is released to open the main contacts. The mechanism is in the
state illustrated (Figure 5-6b) after the breaker is tripped open.
5.4.4 TRIP-FREE OPERATION
During the normal closing process, the position of the trip latch (4)
and banana link (3) causes the main link roller (10) to move in a
fixed arc such that the main link can drive the pole shaft. If the trip
latch is released by rotation of the trip bar "D" shaft before or during
the closing process, the main link roller rises to a position which
prevents the main link from driving the pole shaft (trip free opera-
tion). When the manual trip button is held depressed or the trip
linkage is raised, any attempt to close the breaker will discharge the
closing springs, without any movement of the pole shaft or vacuum
interrupter stem.
5.5 CONTROL SCHEMES
There are two basic control schemes for each series of Type VCP-
WR breakers, one for DC control and one for AC control voltages
(Figure 5-7). Specific wiring schematics and diagrams are included
with each breaker.
There may be different control voltages or more than one tripping
element, but the principal mode of operation is as follows:
As soon as the control power is applied, the spring charging motor
automatically starts charging the closing spring. When the springs
are charged, the motor cut off LS1/bb switch turns the motor off.
The breaker may be closed by making the control switch close
(CS/C) contact. Automatically upon closing of the breaker, the
motor starts charging the closing springs. The breaker may be
tripped any time by making the control switch (CS/T) contacts.
Note the position switch (PS1) contact in the spring release circuit
in the scheme. This contact remains made while the breaker is
being levered between the TEST and CONNECTED positions for
appropriately retrofitted breakers. Consequently, it prevents the
For more information visit: www.EatonElectrical.com
IB01301018E
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