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Distribution Breaker
.Section
9. Repair and Replacement
guiding the tip of the operating rod into the base of
the movable contact rod on the vacuum interrupter.
Mter the breaker is fully closed install the coupling
clamp.
General
The following inforn1ation covers in detail the proper
method of removing various parts of the breaker in
order to make any necessary repairs.
This section
includes only those repairs that can be made at the
installation on parts of the breaker that are most subject
to damage or wear.
4. Check and adjust the erosion indicator (4) Fig. II
(if new intemlpter assembly is installed), and the
Wipe and Gap as described in Table 2, Items 4 and
5.
9-1 Entrance
Bushing
Rem 0 val
In the event that an entrance bushing must be removed,
the current transformer on that bushing must first be
removed to allow the removal of the grounding spring.
The grounding spring is a long coil spring hooked
together at the ends to form a garter which is passed up
over the bushing ground sleeve. Within the coil spring is
a bare conductor, the ends of which come out of the
spring and are terminated in a single terminal. The
terminal is anchored to the roof frame. The terminal
must be disengaged and the garter removed before the
bushing is removed. The procedure is reversed for
reinserting a bushing. The ground sleeve referred to
above is in the form of a conductive coating applied
directly to a section of the lower end of the bushing.
The garter makes electrical contact with the ground
sleeve and the conducting leads terminated in the
terminal complete the connection to ground potential.
5.
Perform the Vacuum Intemlpter Integrity test.
9-3 Pin Retaining Rings
9-4 Control Switches
Control switches may be removed from their mounting
brackets by disconnecting the wires and removing the
two mounting screws. Use a small screwdriver to remove
and replace the switch on the bracket checking that the
correct type, normally open or normally closed, is used.
Re-install wire and adjust per Section 6, Control
Switches.
9-5 Trip Coil Replacement
Tools Required
5/16" Allen wrench -9/16" combination end wrench -
7/16" socket -7/16" combination wrench -1/4" square
drive ratchet -1/4" square 3" extension -Locti1e #271 or
equivalent -Needle nose pliers
9-2 Replacement
of Interrupter
Assemblies
Inten"Upters are supplied as pole units which include the
vacuum inten"Upter mounted in the inten"Upter support.
Perfonn the operation in the following sequence:
1. Charge closing spring and install gag plate.
2. Depress the close and then the trip buttons.
1. Close the breaker and remove the interrupter
clamp, (4) Fig. 9. Open the breaker and remove
the four bolts holding the pole assembly to the
mechanism and remove the old pole assembly.
3. Pump the manual close handle 3 -4
times to
transfer all remaining spring pressure from the
spring crossbar to the gag plate.
4. With the 5/16" Allen wrench remove the pivot bolt
(10), Figure 16, and the closing spring (1 ).
2. Set the new pole assembly in place and install the
four mounting bolts.
5.
Then remove the spring crossbar and its support
plate by removing the two 3/8" bolts retaining it.
3.
Close the breaker using the Slow Closing Oper-
ation. Perfonn the closing operation slowly while
6.
Disconnect the trip linkage tension spring.
27
These rings are widely used in the Ml.r18H mechanism
to retain pins. They can be installed and removed with
a pair of standard plieI:s.
DO NOT REUSE after
removal. To remove, slowly squeeze the removal ears
while pulling. To install, position on the pin groove and
squeeze the installation ears closed to not more than
1/16 inch gap between ears.
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