37
Overhaul
loosen and remove hex bolt joining the interrupter
stationary contact to the bus extensions and stab
support. Remove primary extensions and save.
9.3. Circuit breakers rated 2000A using the VS10006
interrupter (
Figure 50
). Using a 24mm socket and
extension, loosen and remove hex bolt joining the inter-
rupter stationary contact to the primary extensions and
stab support. After removing the bolt carefully, remove
a 3/8 copper spacer, handle carefully and save
protecting the flat contact surfaces.
9.4. Circuit breakers rated 2000 and 3000A using the
VS10028 interrupter (
Figure 49
). Remove four hex
socket flat head screws joining the insulating support
plate to the upper primary stab support. A 5/32 (0.156)
hex key and 7/16 back up wrench will be required (hex
key socket preferred). These screws have been secured
with a thread locking adhesive. Preheating the fasteners
to 350°F using a hot air gun prior to breaking them free
is recommended. Remove, rejoin and save fasteners for
future use. Using a 24mm socket and extension, loosen
and remove the hex bolt joining the interrupter
stationary contact to the primary extensions. Using
9/16 socket and extension, remove four 3/8 hex bolts
fastening the upper primary stab support to the red
post insulator. Lift and remove, set aside with care. This
item is heavy, and two people may be required to safely
remove.
9.5. Circuit breakers rated 1200A using the VS15050
interrupter (
Figure 53
). Using 9/16 socket and 11/16
backup wrench, remove two 3/8 fasteners joining upper
primary extensions to the stab support. Rejoin hardware
and save with primary extensions for reuse. Using a
24mm socket and extension, loosen and remove hex
bolt joining the interrupter stationary contact to the bus
extensions and stab support. Remove primary exten-
sions and save.
9.6. Circuit breakers rated 2000 or 3000A using VS15050
interrupter (
Figure 54
). Remove four (two on each side)
hex socket flat head screws joining the insulating
support plates to the lower primary stab support. A
5/32 (0.156) hex key (hex key socket preferred) and
7/16 backup wrench will be required. These screws have
been secured with a thread locking adhesive.
Preheating the fasteners to 350°F using a hot air gun
prior to breaking them free is recommended. Remove,
rejoin, and save fasteners for future reuse.
Using a 24mm socket and extension, loosen and
remove the hex bolt joining the interrupter stationary
contact to the primary extensions. Using a 5/16 hex key
(hex key socket preferred), remove two 3/8 socket head
screws which secure the primary extension to the
primary stab support.
Using a 9/16 socket and extension, remove four 3/8
hex bolts fastening the upper primary stab support to
the red post insulator. Lift and remove, set aside with
care. This item is bulky and awkward, and an extra
person may be required to hold the primary extension
and the attached insulating support plates when the
bolts are being removed.
9.7. Circuit breakers rated 3000A with chair support
design interrupter (
Figure 55
). Remove the X washer
from each end of pin X in the pole bottom, spread the
levers and disengage from the pin. Let the push rod
drop down. Using a 24mm socket and extension,
loosen and remove the hex bolt joining the interrupter
stationary contact to the primary extensions. Remove
pole top from chair by removing four (4) hex socket
head cpa screw (M6 Allen wrench). Remove four (4)
hex socket head cap screw from pole bottom (M6 Allen
wrench). Remove vacuum interrupter with pole
bottom from chair. Remove the socket head cap screw
from movable stem of the vacuum interrupter. Remove
the four (4) hex head cap screws, which hold the
flexible shunts to the pole bottom.
10. (For all ratings except 3000A with VS015050
interrupter and chair support design) 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. With the clamp free,
the vacuum interrupter may be lifted clear of the
clamp and pole unit structure.
Vacuum Interrupter Replacement
11. Inspect all silver plated surfaces for cleanliness. Wipe
clean with solvent and clean rag. Do not abrade.
12. Insert replacement vacuum interrupter into the lower
stab support oriented according to the following table.
For interrupters having an evacuation nipple or tubula-
tion, the vacuum interrupter should be oriented with
the evacuation nipple or tubulation oriented as shown
in the table. If the interrupter does not have an evacu-
ation nipple or tubulation, the interrupter should be
oriented with the label towards the rear of the circuit
breaker (away from the operating mechanism).
VS-12015
Tubulation toward primary fingers
VS-25002
Tubulation toward primary fingers
VS-17006
Tubulation toward primary fingers
VS-10006
Tubulation toward mechanism housing
VS-10028
Tubulation toward mechanism housing
VS-15050
Label toward primary fingers
