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50
Maintenance
01.4IB.77020
PowlVac-ND
®
and PowlVac-NDA
™
Series 4
Vacuum Circuit Breakers
3) Closing Spring Removal
The closing spring must be removed
in order to perform the slow closing of
mechanism.
Although main closing spring removal is
not necessary for lubrication, it may be
necessary for performing adjustments
or major overhaul tasks. Furthermore,
removal of the main closing spring permits
slow closing of the mechanism and the
vacuum interrupter contacts. For details,
Ch 5 Maintenance, B. Mechanism Area,
The procedure for spring removal is as
follows:
1. With the main closing spring discharged
and the circuit breaker contacts open,
remove the bolt at the top of the spring
rod together with the flat washer and
lock washer
2. Remove the horizontal bracket at
the top of the main closing spring by
unfastening the two attachment bolts
.
3. Remove the spacer from above the
bracket.
4. Turn the bracket 90˚, and replace it on
the top of the spring yoke
.
5. Place the spacer below the bracket with
the flat washer below it.
6. Insert bolt and tighten until the tension
is taken off the connecting rods
.
7. With a slight rocking motion of the main
closing spring assembly, the connecting
rods
can now be unhooked
from the spring yoke pins and the
main closing spring assembly can be
removed.
Note:
Care should be taken on reassembly
to ensure correct location of the flat
washer, lock washer and spacer.
Figure 17 Main Closing Spring Assembly
Installed
a. Bolt
b. Bracket
c. Attachment Bolt (2)
d. Lock Washer
e. Flat Washer
f. Spacer
a
b
d
f
e
c
Figure 18 Main Closing Spring Assembly
Compressed for Removal
d
c
b
a
a. Bracket
b. Flat Washer
c. Bolt
d. Connecting Rod