GE Industrial Solutions EntelliGuard 800–2000 A Frames, 240–600 Vac Maintenance Manual - Manual (Page 28)

EntelliGuard™ 800–2000 A Power Circuit Breakers
Chapter 5. Breaker Maintenance
18
5.5 Breaker Mechanism Operation
and Adjustment
Figure 11, Figure 12, and Figure 13 show the mechanism
components in the CLOSED , TRIPPED , and RESET
conditions, respectively. Numbers in parentheses refer to
the indicated items in the figures listed in Table 5. The
closing spring is in the charged position for all of these
details.
Closed Position
– The movable contacts are pushed against
the stationary contacts by the toggle linkage, as illustrated
in Figure 11. The toggle linkage is held in position
through the engagement of its cam roller (4), with the
prop (1), the secondary latch/roller (5), the secondary
latch (10), and the trip latch (7).
Tripped Position
– The mechanism goes from the CLOSED
position to the TRIPPED position, illustrated in Figure 12,
when the trip shaft (6) is rotated by either the manual trip
button or one of the other trip devices. The trip latch (7)
is assembled to the trip shaft. When the trip shaft rotates,
the trip latch disengages from the secondary latch roller
(5). The secondary latch pivots, resulting in the collapse
of the toggle linkage. This collapse, along with the open-
ing spring (11), shown in Figure 13, causes the breaker
contacts to open.
Reset Position
– The closing cam (2), assembled to the
cam shaft (3), is rotated by the Charging Motor, manual
charging handle, or maintenance handle. The cam
engages the cam roller and partially extends the toggle
linkage. This allows the secondary latch (10) to pivot
against the front frame, as illustrated in Figure 13, leaving
a gap between the trip latch (7) and secondary latch roller
(5). The secondary latch is now in a position to engage
both the trip latch and cam roller (4).
The breaker closes when the closing springs discharge
and rotate the cam (2) against the cam roller (4). The
toggle linkage is fully extended, pivoting the secondary
latch (10) from the front frame and engaging it with the
trip latch (7) and cam roller (4), as shown in Figure 11.
When the breaker is closed and the closing spring is dis-
charged, the upper cam roller (4) is supported by the cam
(2) rather than the prop (1). The mechanism must be in
this position to check contact adjustment, as described in
Chapter 6.
Figure 11. Breaker mechanism in the CLOSED position.
Figure 12. Breaker mechanism in the TRIPPED position.
Figure 13. Breaker mechanism in the RESET position.
1 Prop 7 Trip latch
2 Cam 8 Insulated coupling
3 Camshaft 9 Main shaft
4 Cam roller 10 Secondary latch
5 Secondary latch
roller
11 Opening spring
6 Trip shaft
Table 5. Key to numbered parts in Figure 11, Figure 12, and
Figure 13.