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P a g e 16
5-2.3 LOADING SPRING
The contact loading spring is enclosed inside the
encapsulated pole. The contact loading springs maintain
the proper contact pressure to keep the contacts closed.
No re-adjustment of the breaker is needed after initial
assembly.
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. 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.
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
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
CRUSHING INJURY. DISCHARGE THE SPRINGS AND
OPEN THE CIRCUIT BREAKERS BEFORE PER-
FORMING ANY CIRCUIT BREAKER MAINTENANCE,
INSPECTION OR REPAIR.
CAUTION
WARNING
The spring stored energy operating mechanism is
arranged vertically in front of all VCP-Wind circuit
breakers (Figure 3-2). 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
5-2 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 5-3 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 36 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.
I.B. 70A2580H02
Effective November 2012
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