I.
B.
694C694-02
permanent magnet, a disc held by the magnet, a rod
acted on by a spring, a lever for tripping the breaker,
and a lever for mechanically resetting the actuator. The
trip unit's tripping pulse counteracts the effect of the per-
manent magnet, allowing the spring to separate the disc
from the magnet pole piece, while moving the rod to
actuate the trip shaft lever. The device is reset when the
breaker opens, since the reset lever causes the disc to
contact the magnet. If the disc is not fully reset, the trip
shaft lever will hold the breaker mechanism
in
the trip-
free condition, and the breaker cannot be reclosed.
3-8 OPERATING MECHANISM
The operating mechanism is of the spring charged
stored energy type. It consists of two major parts:
1. Stored energy or spring-charging mechanism
2. Mechanism for closing and opening breaker
The basic parts of these mechanisms are combined into
one sub-assembly. Two varieties of the mechanism,
manual and power operated spring charge, cover the
entire line of DSll and DSLll circuit breakers (Figures 3-
12 and
3-13).
FRONT
Mechanism
Frame
Manual Charge
Cam
Page
17
3-8.1 MANUALLY OPERATED CIRCUIT BREAKER
On manually operated circuit breakers, the closing
springs can be charged only by hand. This is accom-
plished through the use of a front mounted spring-
charge handle. The spring charge handle used with
manually operated circuit breakers is significantly longer
than the handle used with power operated circuit break-
ers. Actual closing of the breaker is done only
by
push-
ing
on
the front control panel close bar (Figure 3-3). An
optional electrical spring release, normally supplied only
on power operated circuit breakers, can be supplied
on
the manually operated version.
The breaker can be tripped open manually by pushing the
trip plate
on
the front control panel. Tripping will also occur
if the trip plate on the circuit breaker compartment door is
pushed while the breaker is
in
the CONNECT position.
Electrical tripping of a manually operated circuit breaker
can take place through the following devices:
• Optional shunt trip device
• Trip actuator energized from the electronic trip unit
• Optional undervoltage trip device
• Blown limiter indicator on DSLll type breakers
Main Drive
Link
REAR
(Close Springs Removed)
Open
& Close
Indicator
Figure 3-12 Typical Front/Rear Views
of
Manual Spring Charge Mechanism
Effective
07
/97
Courtesy of NationalSwitchgear.com
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