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Equipment Description
01.4IB.77000B
PowlVac-ND® Vacuum Circuit Breaker
The interlock bar attached to the
secondary disconnect also actuates
the secondary trip prop shaft and the
close latch upon removal from the
circuit breaker. This final interlock
ensures that the circuit breaker is in the
open position and the main spring is
discharged prior to removal from the
compartment.
2) Closed Door Racking Mechanism
The closed door racking mechanism
consists of a racking shaft (Figure 7, d) with
racking crank arms (Figure 1, ab) at each
end, which are supported by the frame side
sheets. The racking shaft also supports a
worm gear assembly (Figure 7, b) 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.
The two bolts on the left side sheet and the
one bolt on the right side sheet serve as a
positive stop to the 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
“CONN”
.
Figure 7
Closed Door Racking Mechanism &
Interlock
a. Breaker Position Indicator
b. Worm Gear
c. Interlock Cam
d. Racking Shaft
e. Racking Drive Shaft Extension
c
b
d
e
a
D. c
IrcuIt
B
reAker
c
oMpArtMent
I
nterfAceS
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 has multiple contact
fingers which will mate with the stationary
primary disconnecting devices in the circuit
breaker compartment.
!
CAUTION
Do not handle or move the circuit breaker by
the primary disconnecting devices as damage
may occur.