Siemens 3AH Instructions, Installation, Operation, Maintenance page 25

Overhaul
1.5 Free struts (28) from the upper pole support (20).
Loosen the strut hardware on the lower support
(40) and swing the struts forward and downward.
1.6 Loosen screws fastening the centering ring (28.1).
1.7 Remove bolt (31.2), lockwasher and large washer
at stationary contact of the vacuum interrupter.
Carefully note location of the conductive spacer
between interrupter and pole support. This spacer
has a concave surface which must be handled with
care to avoid damage.
1.8 Using a deep socket, loosen and remove hex
capscrew fastening the upper pole support to the
post insulator. Completely remove the upper pole
support and set aside.
1.9 Grasp the vacuum interrupter (30) and withdraw
vertically. Assistance may be required to work the
terminal clamp off the movable stem of the tube.
FORCIBLE TWISTING EFFORT IS NOT ALLOWED.
If the terminal clamp cannot be easily removed,
STOP!, check to be certain hardware is loose, and
that the clamp is not binding.
Figure 17. Vacuum Tube Replacement Illustration
2. Installing an Interrupter
NOTE: Replacement interrupter (30) will be received
from the factory with an eyebolt (36.3) in place, ad-
justed and torqued to specific requirements. DO NOT
ALTER THE ADAPTER SETTING.
2.1 Inspect all silver plated connection surfaces for
cleanliness. Clean only with a cloth and solvent.
Do not abraid.
2.2 Insert interrupter (30) in the lower pole support
(40) with the evacuation nipple (P) (if applicable)
facing the mechanism housing. Slip terminal
clamp (29.2) into position on the movable stem.
Figure 18.
Technique for Fastening Terminal Clamp Hardware
2.3 Install the conductive spacer between the fixed
(upper) terminal of the vacuum interrupter (30) and
the upper pole support (20), with the concave side
of the spacer facing the vacuum interrupter. Align
and fasten "finger tight" using heavy flat washer,
lock washer and nut, (31.2).
2.4 Fasten the upper pole support to the post insula-
tor using finger pressure only using hex head
(M16) bolt, lock washer and flat washer.
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