Eaton 380 VCP-W 21, Инструкции по установке, эксплуатации и техническому обслуживанию

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Page 24
I.B. 3A74792H08
Effective
09/2014
5-2.3 LOADING SPRING INDICATION
The contact loading spring indicator is an additional
method provided to indicate conditions within the vacuum
interrupter, as well as the overall system condition. The
visible indication, on each phase, is used to indicate
whether the contact loading springs are maintaining the
proper contact pressure to keep the contacts closed.
Severe contact erosion or an adjustment need after an
interrupter assembly replacement would result in an
unacceptable indication from this indicator (Figures
6-4
and
6-5).
5-2.4 CONTACT WIPE AND STROKE
Contact wipe is the indication of (1) the force holding the
vacuum interrupter contacts closed and (2) the energy
available to hammer the contacts open with sufficient
speed for interruption.
Stroke is the gap between fixed and moving contacts of
a vacuum interrupter with the circuit breaker open.
The circuit breaker mechanism provides a fixed amount
of motion to the operating rods. The first portion of the
motion is used to close the contacts (i.e. stroke) and the
remainder is used to further compress the preloaded
wipe spring. This additional compression is called wipe.
Wipe and Stroke are thus related to each other. As the
stroke increases due to the erosion of contacts, the wipe
decreases. A great deal of effort has been spent in the
design of all Eaton vacuum circuit breakers, in order to
eliminate the need for field adjustments of wipe or stroke.
CAUTION
THERE IS NO PROVISION FOR IN SERVICE
ADJUSTMENTS OF CONTACT WIPE AND STROKE.
ALL SUCH ADJUSTMENTS ARE FACTORY SET AND
SHOULD NOT BE ATTEMPTED IN THE FIELD.
5-2
STORED ENERGY MECHANISM
WARNING
KEEP HANDS AND FINGERS AWAY FROM THE
CIRCUIT BREAKER’S INTERNAL PARTS WHILE THE
CIRCUIT BREAKER CONTACTS ARE CLOSED OR
THE CLOSING SPRINGS ARE CHARGED. THE
CIRCUIT BREAKER CONTACTS MAY OPEN OR THE
CLOSING SPRINGS DISCHARGE CAUSING A
AND OPEN THE CIRCUIT BREAKERS BEFORE
PER- FORMING ANY CIRCUIT BREAKER
MAINTENANCE, INSPECTION OR REPAIR.
The spring stored energy operating mechanism is
arranged vertically in front of all VCP-W and VCP-WR
circuit breakers (Figure
3-5).
It includes all the
elements for storing the energy, closing and tripping
of the circuit breaker, as well as manual and electrical
controls. The manual controls are all front accessible.
Motion to close and open the interrupter contacts is
provided through operating rods connecting the
mechanism pole shaft to the bell cranks of the
interrupter assemblies.
5-3.1 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
5-4
and as follows:
a. Circuit breaker open, closing springs discharged
b. Circuit breaker open, closing springs charged
c. Circuit breaker closed, closing springs discharged
d. Circuit breaker closed, closing springs charged
5-3.2 CHARGING
Figure
5-5
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 maintenance tool in the manual charging socket.
Move it up and down approximately 38 times until a
clicking sound is heard, and the closing springs