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Equipment Description
IB-60201
2) Standard Racking Mechanism
The standard racking mechanism consists
of a racking shaft (Figure 3, m) with racking
crank arms (Figure 3, l) at each end which
are supported by the frame side sheets. The
racking shaft also supports a worm gear
assembly (Figure 3, n) at the right end just
inside the right side sheet. In addition, the
racking crank arms have rollers attached to
each end of the racking shaft which engage
the vertical slots of the racking cams in the
circuit breaker compartment. Rotation
of the racking crank arms will drive the
circuit breaker into or out of the connected
position. This action also operates the
compartment shutters. As the racking drive
shaft rotates, the worm rotates the worm
gear until the threaded plate which moves
along the racking shaft encounters either
a front or back sleeve attached to the shaft
and prevents any further rotation. At this
time, the breaker position indicator on
the front of the circuit breaker will display
“BREAKER CONNECTED”
, or
“BREAKER TEST/DISCONNECTED”
.
In addition, a bolt on the left side sheet
serves as a backup to the threaded plate,
providing a positive stop to the left crank
arm. This positive stop prevents further
rotation of the racking shaft, thus stopping
circuit breaker travel. At this time, the
breaker position indicator on the front of
the circuit breaker will display
“
BREAKER CONNECTED
”.
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c
oMpArtMent
I
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1) Primary Disconnecting Devices
There are six primary disconnecting
devices on the circuit breaker. They are
arranged, two per phase, with the upper
device connected to the stationary end
of the vacuum interrupter, and the lower
device connected to the moving end of the
vacuum interrupter assembly. Each primary
disconnecting device (Figure 3, c & g) has
multiple contact fingers which will mate
with the stationary primary disconnecting
devices in the circuit breaker compartment.
Do not handle or move the circuit breaker by
the primary disconnecting devices, as damage
may occur.
CAUTION
CAUTION
!
2) Secondary Disconnecting Devices
Control power is transferred from the
metal-clad switchgear to the circuit breaker
by means of the secondary disconnect
device. The secondary disconnect
receptacle (Figure 1, m) is located on the
bottom right side of the circuit breaker.
The secondary disconnect plug is attached
to the switchgear and is located on the
right side wall of the circuit breaker
compartment. This arrangement allows the
secondary connection to be visible in all
positions of the circuit breaker.
3) MOC (Mechanism Operated Cell Switch)
Actuator
The MOC, located in the switchgear, is
operated by a lever which extends from
the circuit breaker operating mechanism.
Movement of the MOC actuator
(Figure 2, i) is directly related to the
movement of the circuit breaker
mechanism and contacts.
