5.3
M ECHA'NISM OPERATIO N
Figures 1 OA, 1 08 and 1 O C show the mechaniSm com ..
ponents in the Closed, Tripped and Reset positions. The
closing spring is in the charged position for all of these
details.
Closed Position
-
As shown in Fig. 1 0A, the movable
contacts are pushed against the stationary contacts by
the toggle linkage. The toggle linkage is held in position
through the engagement of its cam rollers, item no. 5, with
the prop, item no. 2 and the secondary latch/roller item #6
·
and secondary latch #1 4 and trip latch #1 1 .
Tripped Position
-
The mechanism goes from the
Closed position to the Tripped position, shown i n Fig.
1 08, when the trip shaft, item no. 1 0, i s rotated by either
the manual trip button or one of the other trip devices.
The trip latch, item no. 1 1 is assembled to the trip shaft.
When the trip shaft rotates, the trip l atch disengages
from the secondary l atch rol ler. The secondary l atch
pivots, resulting in the coll apse of the toggle l i n kage.
Thi s col l apse along with the openi ng spring, item no. 1 5,
shown i n Fig . 1 0 C , causes the breaker contacts to open.
Reset Position
-
The mechanism is shown i n Fig.
1 OC. The closing cam, item no. 3, which is assembled to
the cam shaft, item no. 4, is rotated by the charging motor,
manual operating handle, or maintenance handle. The
cam engages the cam roller and partially extends the
toggle linkage. This allows the secondary latch item 1 4 to
pivot against the front frame as shown leaving a gap
between the trip latch and secondary latch roller. The
secondary latch is now in a position to engage with both
the trip latch and cam roller.
The breaker closes when the closing spring discharges
and rotates the cam item #3 against the cam roller item #5.
The togg le l i n kage is ful ly extended, pivoting the secon
dary latch from the front frame and engaging it with the
trip l atch and cam rol ler as shown i n Fig. 1 0A.
When the breaker is closed and the closing spring
d ischarged , the upper cam roller item #5 is supported by
the cam rather than the prop. This is the position the
mechanism must be in to check contact adjustment, refer
to Section 8.
1 1
1 4
6
FIG. 1 0A CLOSED
1 2
1 3 5
2 4
3
I
I
)1
I
II
J;
10 1 1
14 5
FIG. 1 0B TRIPPED
1 4
5
4
3
FIG. 1 0C RESET
2. Prop
3. Cam
4. Camshaft
5.
Cam Rol ler
6 .
Secondary Latch Roller
1 0. Trip Shaft
1 1 . Trip Latch
1 2. I nsu lated Coupling
1 3. Main Shaft
1 4. Secondary Latch
1 5. Opening Spring
5.4 CHARGING USING THE MAINTENANCE
HANDLE
The closing spring on electrically operated breakers can
be manually charged by using the maintenance handle
(5688386G1 ) as shown in Fig . 1 1 . The triangular socket in
the maintenance handle mates with the mechanism cam
shaft extension on the front right side of the breaker.
Using the knob on the handle, it will be necessary to align
this socket to fit on the end of the shaft when the handle
is positioned as shown.
FIG.
11
-
MAINTENANCE HANDLE
INSTALLED ON CAMSHAFT EXTEN SION
1 3
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