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53.0
54.0
55.0
58.0
59.0
Figure 13: Operating mechanism controls and indicators
18
53.0
54.0
55.0
58.0
59.0
Manual close button
Manual open/trip button
Charged/discharged indicator
Open/closed indicator
Operations counter
Circuit breaker pole
Refer to Figure 14: Type GMSG vacuum circuit
breaker pole section on page 19.
The vacuum interrupter (30.0) is rigidly
connected to the upper terminal and pole
support (20.0) by its terminal bolt (31.2). The
lower part of the vacuum interrupter is
stabilized against lateral forces by a centering
ring (28.1) on the pole-support (40.0). The
external forces due to switching operations
and the contact pressure are absorbed by the
struts (28.0).
Current-path assembly
Refer to Figure 14: Type GMSG vacuum circuit
breaker pole section on page 19.
The current-path assembly consists of the
upper terminal and pole support (20.0), the
stationary contact (31.0) and the moving
contact (36.0), that is connected with the
lower terminal (29.0) by terminal clamp
(29.2) and a flexible shunt (29.1).
Vacuum interrupter
Refer to Figure 9: Vacuum interrupter cutaway
view on page 15.
The moving-contact (36.0) motion is aligned
and stabilized by guide bushing (35.0). The
metal bellows (34.0) follows the travel of
contact (36.0) and seals the vacuum
interrupter against the surrounding
atmosphere.
Switching operation
Refer to Figure 14: Type GMSG vacuum circuit
breaker pole section on page 19.
When a closing command is initiated, the
closing spring, that was previously charged by
hand or by the motor, actuates the moving
contact (36.0) through jack shaft (63.0), lever
(63.7), insulated coupler (48.0) and lever
(48.6).
The motion of the insulated coupler is
converted into the vertical movement of the
moving contact.
The moving-contact motion is controlled by
the guide link (48.9), that pivots on support
(40.0) and the eye bolt (36.3).
During closing, the tripping spring and the
contact-pressure springs (49.0) are charged
and latched by the pawl (64.1). The closing
spring is recharged immediately after closing.
In the CLOSED state, the necessary contact
pressure is maintained by the contact-
pressure spring and the atmospheric pressure.
The contact-pressure spring automatically
compensates for contact erosion, which is
very small.
When a tripping command is given, the
energy stored in the tripping- and contact-
pressure springs is released by pawl (64.2).
The opening sequence is similar to the closing
sequence. The residual force of the tripping
spring arrests the moving contact (36.0) in
the OPEN (TRIPPED) position.
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