Eaton 36W-VAC25, Instructions For Installation, Operation And Maintenance

Page: 24 / 48

I.B. 3A74499B
Page 18
Effective 11/97
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 Westinghouse vacuum 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.
5-1.5 POLE UNIT SUPPORT MOLDING
DO NOT PLACE THE BREAKER IN ITS COMPART-
MENT WITHOUT ALL PARTS OF THE POLE UNIT
SUPPORT MOLDING BEING IN PLACE. THE
ABSENCE OF A COVER ON ALL 95 KV BIL RATED
BREAKERS FROM 630 THROUGH AND INCLUDING
1250 AMPERES CAN CAUSE A CATASTROPHIC
FAILURE RESULTING IN DEATH, SEVERE PERSON-
AL INJURY OR PROPERTY DAMAGE.
The W-VAC design utilizes continuous glass polyester
moldings to support individual pole units. All 95 KV BIL
630 through 1250 ampere rated breakers require an
additional cover to be added to the support molding,
resulting in the support molding being enclosed on all
four vertical sides (Figure 5-4).
5-2 STORED ENERGY MECHANISM
KEEP HANDS AND FINGERS AWAY FROM THE
BREAKER'S INTERNAL PARTS WHILE THE BREAK-
ER CONTACTS ARE CLOSED OR THE CLOSING
SPRINGS ARE CHARGED. THE BREAKER CON-
TACTS MAY OPEN OR THE CLOSING SPRINGS DIS-
CHARGE CAUSING A CRUSHING INJURY. DIS-
CHARGE THE SPRINGS AND OPEN THE BREAKER
BEFORE PERFORMING ANY BREAKER MAINTE-
NANCE, INSPECTION OR REPAIR.
The spring stored energy operating mechanism is
arranged vertically in front of all W-VAC breakers. It
includes all the elements for storing the energy, closing
and tripping of the breaker, as well as manual and elec-
trical controls. The manual controls are all front accessi-
ble. Motion to close and open the interrupter contacts is
provided through operating rods connecting the mecha-
nism
pole shaft to the bell cranks of the inter-
rupter assemblies.
5-2.1 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 5.5 and as follows:
a. Breaker open, closing springs discharged
b. Breaker open, closing springs charged
c. Breaker closed, closing springs discharged
d. Breaker closed, closing springs charged
!
CAUTION
!
WARNING
!
WARNING
Figure 5-4 Type W-VAC 95 kV BIL breaker shown with
left hand cover removed for clarity purposes. All three
covers must be in place before application.