Preparation; Vacuum Interrupter Removal; Vacuum Interrupter Replacement - Siemens SDV-4A Instruction Manual

Overhaul
Open End or Box End Wrenches:
• 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, and 7/8 in.
Socket Wrenches: (1/2" drive preferred)
• 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, and 7/8 in.
• 18, 19 and 24mm (deep sockets)
• Ratchet
• 2 Extensions (6" maximum)
• Torque Wrench (0-150 ft-lbs.)
Hex Keys Wrenches: (socket type preferred)
• 3/16, 1/4 and 5/16 in.
• 8 and 10mm
Miscellaneous:
• Screw Drivers: 0.032 x 1/4 in. wide
and 0.055 x 7/16 in. wide
• Pliers
• Hot Air Gun
• "Loctite" Threadlocker 242
• "Loctite" Primer T

Preparation

Identify tube family, and breaker voltage and continuous
current rating. The tube will have an identifying nameplate
showing the family designation, the breaker voltage and
continuous current rating can be taken from the breaker rat-
ing label. Note the VS17006 vacuum interrupter can be iden-
tified by its insulating shrink tube which covers the name-
plate.
Check the "Index of Figures" to find the appropriate side el-
evation picture of the breaker pole unit assembly. Confirm
that the figure applies by comparing the figure carefully to
the breaker.
Read through the replacement procedures, noting recom-
mended tools, gauging requirements and torquing limits. etc.

Vacuum Interrupter Removal

Before starting work, be sure that the operator springs have
been discharged and the breaker is open.
1. Repeat the spring discharge check described in the sec-
tion entitled Installation checks and Initial Functional
Tests.
Primary tasks of this check are:
1.1. De-energized the breaker control power.
1.2. Press the Trip pushbutton followed by the Close
pushbutton followed by the Trip pushbutton again.
1.3. Verify the Spring Condition Indicator shows DIS-
CHARGED and the Main contact Indicator shows
OPEN.
2. Make provisions to save and retain hardware. Rejoin
fastener parts (bolts, nuts, washers, lockwashers, etc.)
as they are removed. Save in an appropriate container.
3. Remove the phase barriers (when so equipped) from the
high voltage compartment for easier access to the inter-
rupters. Set aside for reinstallation later.
4. Remove the two snap rings from either end of the pins
of the pivot block. With a large flat bladed screwdriver,
pry the lever arms from the pivot block. Grasp and pull
the coupling rod toward you with one hand while prying
the lever off the pin, first on one side, then on the other
side of the pivot block. Once both levers are free from
the pivot block pins, the levers will be pulled down
abruptly due to the vacuum pulling the interrupter closed.
5. Locate the small pin passing through the levers and the
eye of the rod end bearing of the interrupter. Remove
the two snap rings from the ends of this pin and push
the pin out through the side openings of the polehead.
Retain the pin, spacers and snap rings for later use.
6. Loosen the jam nut on the rod end bearing. Remove the
rod end bearing by turning counterclockwise.
7. Refer to Figure 40, and using the procedure shown to
secure head and nut proceed to loosen the bolts which
fasten the flexible shunt clamp to the movable contact
of the interrupter. Remove shunt clamp hardware, set
aside for reinstallation later.
8. Check the clamp on the movable contact to ensure that
it will slide freely from the interrupter movable stem. The
clamp may have to be wedged or worked open in order
to slide freely from the interrupter.
9. Remove the cap screw(s) (may be three or one depend-
ing on design) in the stationary end of the interrupter.
Move the stationary end of the interrupter sideways un-
til it is clear of the polehead and withdraw the interrupter.

Vacuum Interrupter Replacement

10. Inspect all silver plated surfaces for cleanliness. Wipe
clean with solvent and clean rag. Do not abrade. In-
spect the replacement interrupter for evidence of dam-
age such as dents, cracks or chips. Manually pull on the
moving terminal of the interrupter to check vacuum in-
tegrity; there should be a noticeable resistance to move-
ment (approximately 20 lbs.).
11. Unless the vacuum interrupter replacement kits contains
a new copper spacer and associated mounting hardware,
the spacer (when so equipped) and associated mount-
ing hardware removed with the vacuum interrupter will
be reused. Handle spacers carefully protecting the flat
contact surfaces. Make sure contact surfaces are wiped
clean prior to installation. If the spacer is attached to the
old interrupter, remove it and attach it to the new inter-
rupter.
Note: Stationary contact is annealed copper.
Thread damage will occur if threads are crossed.
Be sure the bolt(s) can be fully engaged with light
manual torque.
35