Siemens vacuum circuit breaker 38-3AH3 38 kV - Manual (Page 55)

Overhaul
1.7 Remove bolt (31.2), lock washer and
large washer at stationary contact of
the vacuum interrupter (24 mm
socket with extension). Carefully note
location of the conductive spacer
between vacuum interrupter and pole
support. This spacer has a concave
surface that must be handled with
care to avoid damage.
1.8 Using a deep 24 mm socket with an
extension, loosen and remove the
hex-cap screw fastening the upper
pole-support to the post insulator.
Completely remove the upper pole-
support and set aside.
1.9 Grasp the vacuum interrupter (30.0)
and withdraw vertically upward.
Assistance may be required to spread
the clamp and work the terminal
clamp off the movable stem of the
vacuum interrupter. FORCIBLE
TWISTING EFFORT IS NOT ALLOWED.
If the terminal clamp cannot be easily
removed, STOP!, check to be certain
hardware is loose and the clamp is
not binding.
2.0 Installing a vacuum interrupter
Note: Replacement vacuum interrupter
(30.0) will be received from the factory
with an eye bolt (36.3) in place, adjusted
and torqued to specific requirements. DO
NOT ALTER THE ADAPTER (eye-bolt)
SETTING.
2.1 Inspect all silver-plated connection
surfaces for cleanliness. Clean only
with a cloth and solvent. Do not
abrade, as this will damage the silver
plating.
2.2 Insert vacuum interrupter (30.0) in
the lower pole-support (40.0) with
the vacuum-interrupter label facing
away from the mechanism housing.
Slip terminal clamp (29.2) into
position on the movable stem.
2.3 Install the conductive spacer between
the fixed (upper) terminal of the
vacuum interrupter (30.0) and the
upper pole-support (20.0), with the
concave side of the spacer facing the
vacuum interrupter. Align vacuum
interrupter and fasten finger-tight
using heavy flat-washer, lock washer
and nut (31.2).
2.4 Fasten the upper pole-support to the
post insulator using finger pressure
only using hex-head (M16) bolt, lock
washer and flat washer.
2.5 Attach struts (28.0) to the upper pole-
support (20) and replace hardware
(M10), but do not tighten at this
time.
2.6 Couple levers (48.6) and drive link
(48.9) to the eye bolt (36.3), using
the pin supplied. Apply retention
clips. Appropriate pin is modestly
chamfered, not to be confused with
pin for the insulated coupler.
2.7 Raise terminal clamp (29.2) against
the spacer (29.3) on the movable
terminal of the vacuum interrupter
(36.1) and position the vacuum
interrupter (30.0) so that its groove
faces the connecting surface of
flexible strap (29.1). Refer to Figure
47: Illustration showing required
technique for fastening terminal-
clamp hardware on page 57 and
employ the technique illustrated to
fasten the terminal clamp. Note
opposing wrenches. Tighten the
bolt(s) of the terminal clamp to a
torque of 40 Nm (30 ft-lb), taking
care to see that the terminal of the
vacuum interrupter is not subjected to
excessive bending movement.
Note: Excessive bending movement
exerted while fastening the terminal clamp
will damage the vacuum interrupter.
2.8 Align pole support (20.0) correctly
and tighten bolt fastening it to the
post insulator. Fasten securely all
bolts associated with struts (28.0).
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