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Figure 23: Secondary disconnect on
the circuit breaker
Figure 24: Secondary disconnect
inside the switchgear
Figure 25: Auxiliary switch
28
Following every tripping operation, the striker
pin (23.0) must be reset to its normal position
by loading the spring (31). This takes place
automatically via the operating mechanism of
the circuit breaker.
Since the striker pin of the undervoltage
release 3AX1103 is latched only when the
armature is attracted, this trip is provided
with a screw (29.0) (refer to Figure 21:
Undervoltage lock/operate selection on page
27).
This screw is provided to allow locking the
striker pin (23.0) in the normal position for
adjusting purposes or for carrying out trial
operations during circuit breaker servicing.
Position A (locked) disables the undervoltage
release. Position B is the normal (operating)
position.
Capacitor-trip device
The capacitor-trip device is an auxiliary
tripping option providing a short-term means
of storing adequate electrical energy to
ensure circuit breaker tripping.
This device is applied in circuit breaker
installations lacking independent auxiliary-
control power or a station battery. In such
installations, control power is usually derived
from the primary source.
In the event of a primary-source fault, or
disturbance with resulting reduction of the
primary-source voltage, the capacitor-trip
device will provide short-term tripping energy
for circuit breaker opening due to the
protective relay operation.
The capacitor trip includes a rectifier to
convert the 120 or 240 Vac control voltage to
a dc voltage that is used to charge a large
capacitor to the peak of the converted-
voltage wave (refer to Figure 22: Capacitor
trip device on page 27).
Shock absorber
A type GMSG vacuum circuit breaker is
equipped with a sealed, oil-filled, viscous
damper or shock absorber (61.8) (referto
Figure 15: Stored-energy operating
mechanism on page 20). The purpose of this
shock absorber is to limit overtravel and
rebound of the vacuum interrupter movable-
contacts during the conclusionof an opening
operation. The shock-absorber action affects
only the end of an opening operation.
Secondary disconnect
Signal and control power is delivered to the
internal circuits of the circuit breaker by an
arrangement of movable-contact fingers
(refer to Figure 23: Secondary disconnect on
the circuit breaker) mounted on the top of the
circuit breaker.
When the circuit breaker is racked into the
TEST or CONNECT position in the metal-clad
switchgear, these disconnect fingers engage
a mating-disconnect block on the inside of
the switchgear (refer to Figure 24: Secondary
disconnect inside the switchgear). These
electrical connections automatically
disengage when the circuit breaker is racked
from the TEST to the DISCONNECT position.
All of the control power necessary to operate
the circuit breaker is connected to this
disconnect block inside the switchgear. The
external trip- and close- circuits and
associated circuits are also connected to the
same disconnect block.
Auxiliary switch
Figure 25: Auxiliary switch shows the circuit
breaker mounted auxiliary switch. This switch
provides auxiliary contacts for control of
circuit breaker closing and tripping functions.
Contacts are available for use in relaying and
external logic circuits. This switch is driven by
linkages connected to the jack shaft.
The auxiliary switch contains both "b"
(normally closed) and "a" (normally open)
contacts. When the circuit breaker is open,
the "b" switches are closed and the "a"
switches are open.
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