Siemens 3AH3 Instruction Manual page 17

Trip-free coupling link (62.8.2) and trip-free
coupling lever (62.8.3) cause the spring-
return latch position to be dependent upon
the normal tripping components and the
racking interlock (if applicable). Thus,
whenever a trip command is applied or the
circuit breaker is not in the fully CONNECT
or TEST position (for drawout applications),
the trip-free coupling rod is no longer rigid,
effectively decoupling the drive lever and
jack shaft. Under these conditions the
vacuum interrupter contacts cannot be
closed.
Trip-free for the type SDV6 outdoor distri-
bution circuit breaker and some fixed-
mounted circuit breakers
For the type SDV6 outdoor distribution
circuit breaker and some other fixed-
mounted circuit breakers, the drawout trip-
free linkage (refer to Figures 7-10) is
replaced with simplified linkage. The trip-
free coupling rod (62.8) is replaced with a
straight coupling rod (refer to Figure 5), and
other parts associated with drawout
interlocking are eliminated.
The parts modified or eliminated are noted
in the relevant figures. In these circuit
breakers, the trip-free function is
accomplished by blocking the movement of
the close latch pawl (62.5.2) when the
manual trip pushbutton is actuated.
Opening (refer to Figure 5)
If the circuit breaker is to be opened
manually, the opening spring (64.0) is
released by pressing the OPEN pushbutton
(54.0). In the case of an electrical command
being given, the trip coil 52T (54.1)
unlatches the opening spring (64.0).
The opening spring (64.0) 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 Figures 13 and 14)
Insert the hand crank (50.0) with the over
running coupling pushed forward (50.6)
through the opening (50.1) onto hand crank
coupling (50.5) and turn it clockwise (about
48 revolutions) until the closing-spring
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
manual charging.
The special hand crank automatically disengages
if the spring-charging motor operates. In order to
avoid injuries as a result of the motor suddenly
starting up, the circuit breaker spring must only
be charged manually with the special hand crank
(50.0).
Manual closing (refer to Figure 6)
Press the close button (53.0). The CLOSE/
OPEN indicator (58.0) will then display
CLOSED and the closing spring condition
indicator (55.0) will now read DISCHARGED.
Manual opening (refer to Figure 6)
The opening spring (64.0) is charged during
closing. To open the circuit breaker, press
the Open pushbutton (54.0) and OPEN will
be displayed by indicator (58.0).
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