Powell 38PV40ARMM-4, Instruction Bulletin

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16 Equipment Description
PowlVac 38™ ARM 3000A Series 4
Vacuum Circuit Breaker
01.4IB.65131
With the standard electrical control
scheme, as soon as the main closing spring
is discharged on a closing operation, the
charging motor is switched on to recharge
the springs. This leaves the main closing
cam in a position where a tripped linkage
can reset under the action of the reset
spring (Figure 3, w) and the primary and
secondary trip props can fall into the
reset position. The reset spring stretches
between an extension of the main cam
roller pin and a spring support pin located
on the left mechanism side sheet. The
latch check switch (Figure 3, c) , operated
by a lever on the trip shaft, will close as the
secondary trip prop reaches the fully reset
position.
2) Electrical Description
a. Charging Motor
The function of the charging motor
(Figure 2, k) is to compress the main
closing spring of the stored energy
mechanism, thus providing the
necessary energy to close the circuit
breaker. The charging motor, located
to the bottom right of the base pan, is
assembled to the circuit breaker by a
bracket that is bolted to the base pan.
b. Motor Cutoff Switch
The motor cutoff switch
(Figure 3, t) provides an electrical
break in the control circuit supplying
the charging motor when the main
closing spring is fully charged and the
stored energy mechanism is ready for
a closing operation. It is located to the
bottom right of the mechanism, and is
supported by a bracket which is bolted
to the circuit breaker base pan.
c. Anti-Pump Relay
The anti-pump relay ( Figure 2, b )
provides a logic function for the control
circuit which prevents a continuous
electrical close signal from causing the
circuit breaker to continuously re-close
after a trip signal. The anti-pump relay
is located on the right side of the left
spring support channel inside the
circuit breaker, and is supported by two
screws.
d. Operating Solenoids
Electrical operation of the circuit
breaker is accomplished using
operating solenoids.
The closing coil (Figure 3, o) is an
operating solenoid that is located at
the bottom center of the mechanism,
and is assembled to the circuit breaker
base pan by bolts accessible from
underneath the circuit breaker.
The primary shunt trip coil
(Figure 3, a) is located at the top left side
of the mechanism, and is assembled to
the lower frame channel by two bolts.
Either a secondary trip coil or an
undervoltage device may be furnished
as an option. When furnished, either of
these devices will be located at the top
right side of the mechanism, installed
on the lower frame channel. Only one
of these two operating solenoids may
be furnished on any one circuit breaker,
as both devices are located in the same
space.