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The rotation of the primary cross shaft rotates
two outer phase bell cranks which compress
the outer opening springs (Figure 17, Item 1).
The primary cross shaft also rotates two sets of
inner drive cranks that in turn rotate two outer
sets of secondary drive cranks, (Figure 18, Item
2) As the outer secondary drive cranks rotate
about the secondary cross shaft, the center drive
cranks are rotated. The rotation of the second-
ary drive cranks close the vacuum interrupters,
and compresses the wipe springs on all three
phases . (Figure 18, Item 1) The interrupters are
driven closed through insulated operating rods.
(Figure 18, Item 4). This interrupters are driven
closed through insulated operating rods (Fig-
ure 18, Item 4)
The rotation of the primary cross shaft (Figure
17, Item 4) also changes the auxiliary switch
position. (Figure 17, Item 3) The position flag
on the front panel will then indicate "CLOSED".
After the breaker is closed, the charging motor
is again energized and the closing spring is
charged as described under "CLOSE SPRING
CHARGING". Spring charging is possible when
the breaker is in the closed position because
the linkage is held in place by the prop.
1
Opening Spring
2
Outer bell cranks
Figure 17. Opening spring & auxialliary
switch left side view
Courtesy of NationalSwitchgear.com
3
Auxilliary switch
4
Primary cross shaft
PowerVac
Chapter 5. Operation
5-5 Opening Operation
By either energizing the trip solenoid (Figure 13
Item 3) or depressing the manual trip button
(Figure 1, Item 7), the trip latch (Figure 16, Item
6) is rotated, permitting the linkage to collapse.
The vacuum interrupter contacts will then open
under the force of the wipe springs (Figure 18,
item 1) and opening springs (Figure 17, item 1).
At the end of the opening stroke, the center
phase secondary drive cranks hit the dashpot
limiting overtravel and rebound.
Rotation of the Primary cross shaft from the
closed to the open position operates the auxil-
iary switch (Figure 17, Item 3) opening the trip
coil circuit. When the closing spring has been
recharged,( Figure 13, Item 1) the linkage is re-
set allowing the trip latch (Figure 16, Item 6) to
rest in place on the trip roller, ready for another
closing operation. If the closing spring has not
been recharged, the trip latch will be held out
of position. A latch-checking switch, 52 LCS
(Figure 15,Item 7) will not close unless the latch
is in its normal position. The contacts of the
latch-checking switch are part of the closing cir-
cuit and will not allow for an electrical close
until the latch is reset.
1 Wipe spring
2 Secondary drive crank
3 Secondary cross shaft
Figure 18. Wipe Spring assembly-
left side view
21
5kV Vertical Lift
®
4 Insulated operating rod
5 Wipe indicator
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