41
Instruction Booklet
IB131006EN
Effective March 2019
Instructions for installation,
operation, and maintenance of type
VCP-W vacuum circuit breakers
EATON
www.eaton.com
5.3.2 Charging
Figure 21 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 ratchet 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 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 spring cranks go over dead center, and
the closing stop roller comes against the spring release latch. The
closing springs are now held in the fully charged position.
Closing springs may also be charged manually. Insert the mainte-
nance tool in the manual charging socket. Move it up and down
approximately 38 times until a clicking sound is heard, and the
closing springs charging indicator indicates “Charged.” Any further
motion of the maintenance tool will result in free wheeling of the
ratchet wheel.
5.3.3 Closing operation
Figure 20 shows the position of the closing cam and tripping linkage.
Note that in Figure 20a in which the circuit breaker is open and the
closing springs are discharged, the trip “D” shaft and trip latch are in
the unlatched position.
Once charged, the closing springs can be released to close the
circuit breaker 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 camshaft, in turn rotates the pole shaft through the main link to
close the circuit breaker.
In Figure 20c the linkage is shown with the circuit beaker 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 circuit breaker is held closed.
Figure 20d shows the circuit breaker in the closed position after the
closing springs have been recharged. Note that the spring charging
rotates the closing cam by one-half turn. Since the cam surface
in contact with the main link roller is cylindrical in this region, the
spring charging operation does not affect the mechanism linkage.
Since the primary contacts are completely enclosed in the vacuum
interrupter and not adjustable in any way, a “Slow Close” capability
is not provided with VCP-W circuit breakers.
5.3.4 Tripping operation
When the trip “D” shaft is turned either by the trip button or trip coil,
all links return to the original “Open” condition shown in Figure 20a.
5.3.5 Trip free operation
When the manual trip button is held depressed, any attempt to close
the circuit breaker results in the discharge of the closing springs
without any movement of the pole shaft or vacuum interrupter stem.
5.4 Control schemes
There are two basic control schemes for VCP-W circuit breakers: one
for DC control and one for AC control voltages (Figure 22), however,
there are many other more advanced control schemes that can
be configured by the switchgear provider. 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 voltage is applied, the spring charging motor
automatically starts charging the closing springs. When the springs
are charged, the motor cut off LS1/bb switch turns the motor off.
The circuit breaker may be closed by making the control switch close
(CS/C) contact. Automatically upon closing of the circuit breaker, the
motor starts charging the closing springs. The circuit breaker may be
tripped at any time by making the control switch trip (CS/T) contact.
Note the position switch (PS1) contact in the spring release circuit
in the scheme. The contact remains made while the circuit breaker
is being levered between the TEST and CONNECTED positions.
Consequently, it prevents the circuit breaker from closing automati-
cally, even though the control close contact (CS/C) may have.
