22
Instruction Book
IB182017EN February 2017 www.eaton.com
5kV, 7.5kV, & 15kV DHP-VR
Replacement Circuit Breaker
a. Breaker open, closing springs discharged.
b. Breaker open, closing springs charged.
c. Breaker closed, closing springs discharged.
d. Breaker closed, closing springs charged.
The mechanism is a mechanically “trip-free” design. Trip-free is
defined later in this section.
In normal operation the closing spring is charged by the spring
charging motor, and the breaker is closed electrically by the
switchgear control circuit signal to energize the spring release coil.
Tripping is caused by energizing the trip coil through the control
circuit.
For maintenance inspection purposes the closing springs can be
charged manually by using the maintenance tool and the breaker can
be closed and tripped by pushing the “Push to Close” and “Push to
Open” buttons on the front panel.
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, INSPECTION 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 VERIFICATION THAT LOAD SIDE CONDITIONS
PERMIT. IT IS RECOMMENDED 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
“DISCONNECT / TEST” POSITION.
4.4.1 CLOSING SPRING CHARGING
Figure 4.15 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 (6) is actuated by an oscillating ratchet lever
(12) 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 (9) comes against the
spring release latch (1). The closing springs are now held in the fully
charged position.
The closing springs may also be charged manually as follows: Insert
the end of the maintenance tool into the manual charge socket
opening and charge the closing springs by moving the handle up
and down the full range of motion. When charging is complete the
ratchet will no longer advance and the spring charged / discharged
indicator displays “charged”. (Figure Set 3.3). Any further motion of
the maintenance tool will not result into advance of charging.
4.4.2 CLOSING OPERATION
Figure 4.16 shows the positions of the closing cam and tripping
linkage for four different operational states. In Figure 4.16.a 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 4.16.b)
When the spring release clapper (Figure 4.15, Item 13) moves into
the face of the spring release coil (electrically or manually), the upper
portion of the clapper pushes the spring release latch (1) upward.
When the spring release latch moves, the cam shaft assembly is
free to rotate. The force of the closing cam (Figure 4.16.b, Item 5),
moving the main link (2), rotating the pole shaft (4) (which charges
the opening spring). This moves the three operating rods (3), 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 4.16.c. Interference of the trip “D”
shaft with the trip latch prevents the linkage from collapsing, and
holds the breaker closed.
Figure 4.16.d 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.
4.4.3 TRIPPING OPERATION
When the trip bar “D” shaft (Figure 4.16.b, Item 9) is turned by
movement of the shunt trip clapper (11), 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 4.16.b) after the breaker
is tripped open.
4.4.4 TRIP-FREE OPERATION
When the manual trip button is held depressed, any attempt to close
the breaker results in the closing springs discharging without any
movement of the pole shaft or vacuum interrupter stem.
4.5 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
4.5). 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 racked between the TEST and CONNECTED positions for
appropriately retrofitted breakers. Consequently, it prevents the
breaker from closing automatically, even though the control close
contact may have been made while the breaker is racked to the
CONNECTED position.
When the CS/C contact is made, the SR closes the breaker. If
the CS/C contact is maintained after the breaker closes, the Y relay
is picked up. The Y/a contact seals in Y until CS/C is opened. The
Y/b contact opens the SR circuit, so that even though the breaker
would subsequently open, it could not be reclosed before CS/C was
released and remade. This is the anti-pump function.
