Siemens 3AH3 Instruction Manual page 16

Item Description
54.0 Open pushbutton
62.8 Trip-free coupling rod
62.8.1 Spring-return latch
Trip-free coupling link
62.8.2
(draw bar)
1
64.0 Opening spring
64.2 Trip-latch pawl (not visible)
64.3 Lever
64.3.1 Pawl roller
Footnote:
For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is
1.
replaced with a straight coupling rod, and other parts associated with drawout
interlocking are eliminated.
Figure 6: Stored-energy operating mechanism (circuit breaker shown in CLOSED position)
(Drawout trip-free linkage shown)
16
62.8.1
1
1
62.8.2
62.8
64.0
When the charging mechanism is actuated
by hand with a hand crank (refer to Figures
12 and 13) or by a motor (50.4), the flange
(50.3) turns until the driver (50.3.1) locates
itself in the cutaway part of the cam disc
(62.3), thus causing the charging shaft to
follow. The crank (62.2) charges the closing
spring (62.0). When the closing spring has
been fully charged, the crank actuates the
linkage (55.1) via the control lever (55.2)
for the closing spring CHARGED indicator
(55.0), and actuates the limit switches
(50.4.1) for interrupting the motor supply.
At the same time, the lever (62.5) at the
other end of the charging shaft is securely
locked by the close latch pawl (62.5.2).
When the closing spring is being charged,
the cam disc (62.3) follows along, and it is
brought into position for closing when the
closing spring is fully charged.
Closing (refer to Figures 5, 7-10)
If the circuit breaker is to be closed
manually, the closing spring is released by
pressing the Close button (53.0). In the case
of remote electrical control, the close coil
52SRC (53.1) unlatches the closing spring
(62.0).
54.0
As the closing spring discharges, the
charging shaft (62.1) is turned by crank
(62.2).
64.3.1
The cam disc (62.3) at the other end of the
charging shaft actuates the drive lever
64.3
(62.6), with the result that jack shaft (63.0)
is turned by lever (63.5) via the coupling rod
(62.8). At the same time, the levers (63.1),
(63.5) and (63.7) fixed on the jack shaft
operate the three insulated couplers (48.0)
(refer to Figure 2) for the circuit breaker
poles. Lever (63.7) changes the OPEN/CLOSE
indicator (58.0) over to CLOSED. Lever
(63.5) charges the opening spring (64.0)
during closing, and the circuit breaker is
latched in the closed position by lever (64.3)
with pawl roller (64.3.1) and by pawl (64.2).
Lever (63.1) actuates the auxiliary switch
(68.0) through the linkage (68.1).
The crank (62.2) on the charging shaft
(62.1) moves the linkage (55.1) by acting
on the control lever (55.2). The closing
spring charged indication is thus canceled,
and the limit switches (50.4.1) switch in the
control supply to cause the closing spring to
recharge immediately.
Trip-free operation
(refer to Figures 5 and 6)
Trip-free for all drawout circuit breakers
and some fixed-mounted circuit breakers
The trip coupling rod (62.8 together with
62.8.1 and 62.8.2) permits the immediate
de-coupling of the drive lever (62.6) and the
jack shaft (63.0) to override closing action
by trip command or by means of the racking
interlocks.
The trip-free coupling rod (62.8) forms a
link between the drive lever (62.6) and the
jack shaft (63.0). The rigidity of this link
depends upon a spring-return latch (62.8.1)
carried within the coupling rod. The latch
pivots within the coupling rod and is
normally positioned to maintain the rigidity
of the coupling rod.