41
Overhaul
Introduction
The following procedures along with Table
9: Troubleshooting on page 49, provide
maintenance personnel with a guide to
identifying and correcting possible
malfunctions of the circuit breaker.
Circuit breaker overhaul
Table 7 gives the recommended overhaul
schedule for the type 3AH35-MA 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 7
may coincide with the maintenance interval
in Table 3: Maintenance and lubrication
schedule on page 29.
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. Lubricate operating mechanism
according to maintenance and
lubrication information (refer to pages
29-31).
3. When work is finished, operate circuit
breaker and close and open several
times, and check that all screw
connections are tight. Refer to
“Installation checks and functional tests”
on pages 6-9.
When it necessary to replace electronic
components (for example, the controller
board (105.0) in Figure 21: Controller board
replacement or a capacitor board (107.1) in
Figure 22: Capacitor board replacement on
page 43), it is necessary to provide the
circuit breaker serial number (as for any
parts needed), and in addition, the MLFB
number of the magnetic actuator. The MLFB
number is located on a label in front of and
below the magnetic actuator, as shown in
Figure 16: Magnetic-acutator operator
mechanism lubrication on page 31.
Controller board replacement
When replacing controller board, use
appropriate procedures to avoid electrostatic
discharges, which could damage the new
controller board.
A replacement controller board is supplied
with replacement washers and nylon insert
locknuts. Tools required for replacement of
the controller board are a 7 mm wrench and
a 5 mm hex key.
1. Remove the front cover of the operator
housing.
Circuit breaker type
Closing operations
SDV7-MA outdoor
distribution circuit
breaker
10,000
Table 7: Overhaul schedule
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 7)
Controller board
Capacitor boards
Power supply.
