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Circuit breaker
Closing
type
operations
SDV7-SE outdoor
distribution circuit
10,000
breaker
Table 6: Overhaul schedule
36
Overhaul
Introduction
The following procedures along with the
troubleshooting charts in this instruction
manual (refer to pages 42-43), provide
maintenance personnel with a guide to
identifying and correcting possible
malfunctions of the circuit breaker.
Circuit breaker overhaul
Table 6 gives the recommended overhaul
schedule for the type 3AH35-SE operating
mechanisms. These intervals assume that
the circuit breaker is operated under "usual
service conditions" as discussed in ANSI/IEEE
C37.04 section 4 and elaborated in C37.010
section 4. If the circuit breaker is operated
frequently, the overhaul interval in Table 6
may coincide with the maintenance interval
in Table 2: Maintenance and lubrication
schedule on page 25.
Replacement at overhaul
The following components are replaced
during an overhaul of the circuit breaker,
when required:
Vacuum interrupters as determined by
vacuum integrity test, contact erosion or
according to overhaul schedule (refer to
Table 6)
Close coil, 52SRC
Trip coil, 52T.
When these parts are changed, locking
devices must also be removed and replaced.
These include lock washers, retaining rings,
retaining clips, spring pins, cotter pins, etc.
1. Replace vacuum interrupter; instructions
follow.
2. Close coil (52SRC) and trip coil (52T).
a) Remove two "push on" terminal
connections
b) Remove two M4 hex-head screws and
remove solenoid.
c) Install replacement coils with new M4
x 10 hex-head screws (Siemens part #
00-000-443-820) and new lock
washers for M4 (Siemens part #
00-000-288-316).
d) The coil-mounting screws must be
installed using thread locking
adhesive (Loctite #222, Siemens part
15-133-281-007) and primer (Loctite
primer T (#7471), Siemens part
15-133-281-005).
e) Connect wires to coils with new wire
terminals (Siemens part #
15-171-600-002).
3. Lubricate operating mechanism
according to maintenance and
lubrication information (refer to page
25).
4. When work is finished, operate circuit
breaker and close and open several
times, and check that all screw
connections are tight.
Replacement of vacuum interrupters
Replacement vacuum interrupters are
furnished as a complete assembly. They
have been completely tested and
dielectrically and mechanically conditioned.
It is recommended that one vacuum
interrupter be removed and replaced
completely rather than removing two or
more vacuum interrupters at a time.
The following procedure in check list format
describes the procedure for removing and
replacing a vacuum interrupter. Components
may be identified by reference to Figure 20:
Vacuum interrupter replacement illustration
on page 38 and Figure 21: Illustration
showing required technique for fastening
terminal-clamp hardware on page 39.
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