Siemens GMSG

Vacuum interrupter/operator
Trip-free functionality
Refer to Figure 15: Stored-energy
operating mechanism on page 20.
Trip-free functionality is accomplished by
blocking movement of the close latch pawl
(62.5.2) when the manual trip pushbutton
(54.0) or associated locking provisions for
preventing closing are in use (e.g., trip-free
padlock provisions).
Opening
If the circuit breaker is to be tripped locally,
the tripping spring (64.0) is released by
pressing the trip button (54.0). In the case
of an electrical command being given, the
shunt-trip coil 52T (54.1) unlatches the
tripping (opening) spring (64.0). The
tripping spring turns the jack shaft (63.0)
via lever (63.5); the sequence being similar
to that for closing.
Rapid auto-reclosing
Since the closing spring is automatically
recharged by the motor-operating
mechanism when the circuit breaker has
closed, the operating mechanism is
capable of an "Open-Close-Open" duty
cycle as required for rapid auto-reclosing.
The circuit breaker is suitable for use in
applications with a rated reclosing-time
interval of 0.3 seconds, per ANSI/IEEE
C37.06-2009.
Manual operation
Electrically-operated vacuum circuit
breakers can be operated manually if the
control supply should fail.
Manually charging the closing spring
Refer to Figure 16: Use of manual-spring
operation crank on page 22.
Insert the hand crank (50.0) in hole (50.1)
and turn it clockwise (about 48
revolutions) until the indicator (55.0)
shows CHARGED. The hand crank is
coupled with the charging mechanism via
an over-running coupling; thus the
operator is not exposed to any risk should
the control supply be restored during
charging.
Manual closing
To close the circuit breaker, press the close
button (53.0). The OPEN/CLOSED indicator
(58.0) will then display CLOSED and the
closing-spring condition indicator (55.0)
will now read DISCHARGED.
Manual opening
The tripping spring is charged during
closing. To open the circuit breaker, press
the trip button (54.0) and OPEN will be
displayed by indicator (55).
Note: For arc-resistant type GM-SG-AR
switchgear, the circuit breaker can be
opened manually when the circuit breaker
compartment is closed (refer to "Racking
crank engagement procedure" on
page 11).
Indirect releases (dual-trip or
undervoltage) (optional)
The indirect release provides for the
conversion of modest-control signals into
powerful mechanical-energy impulses. It is
primarily used to trip medium-voltage
circuit breakers while functioning as a
secondary (dual-trip) release or
undervoltage-release device.
23