Eaton Magnum Power Defense SB, Руководство пользователя

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User Manual MN013016EN
Effective July 2022
Magnum PXR and Power Defense SB low
voltage power circuit breakers user manual
EATON www.eaton.com
Figure 26. Electrical motor operator to charge closing spring
Electrical operation
For electrically operated circuit breakers, the springs are normally
charged through the use of an electrical operator ( Figure 26 ) . The
springs can, however, be charged manually as just described in the
previous paragraph (
Figure 25
) .
Like the manually operated circuit breaker in the previous paragraph,
electrically operated circuit breakers can also be manually closed and
opened through the use of the front-mounted Manual OPEN and
Manual CLOSE buttons .
An electrically operated circuit breaker from the factory is also
equipped as standard with a spring release to close the circuit breaker
electrically . An optional shunt trip and undervoltage release are also
available to trip (open) an electrically operated circuit breaker .
Refer to page 26 , “Accessory devices” for more details on both
standard and optional devices .
Anti-pump feature
The Magnum PXR and PD-SB circuit breaker has both mechanical
and electrical anti-pump features . If the circuit breaker is closed on a
fault condition and trips open while the CLOSE signal is maintained,
(using the mechanical pushbutton, the spring release, or the trip
unit), it will not make subsequent attempt to close until the CLOSE
command is removed and reapplied .
ote: N
If the close signal is applied prematurely (before the breaker is
completely charged and latched), the CLOSE command will be ignored
until it is removed and reapplied .
For electrical closing, a Latch Check Switch (LCS) option is available
(see page 27 ), which will block the application of the electrical
CLOSE command until the breaker is ready to close .
Arc chambers
The Magnum PXR and PD-SB circuit breakers use arc chambers to
insulate and isolate individual poles from one another, from the rest
of the circuit breaker, and from operating personnel ( Figure 15 ) . Arc
chambers are molded and integral parts of the circuit breaker frame .
Enclosed within each arc chamber is an arc chute that mounts over
each set of primary contacts .
After the main contacts part, any remaining current is driven to the
arcing contacts ( Figure 27 ) . Magnetic action draws the arc to the arc
chute . As the arcing contacts separate, the moving arcing contacts
discharge into the arc chute plates while the integral arc runner also
helps to draw the arc into the arc chute ( Figure 28 ) .
Arc chute
The Magnum PXR and PD-SB arc chutes mount down over the arcing
contact . V-shaped arc chute plates attract the arc and interrupts it .
The top arc plate, which is a part of the arc chute itself, also helps to
attract the arc away from the moving arcing contact and up into the
arc chute’s V-shaped plates (
Figure 29
and
Figure 30
) .
Arc chute components are assembled in an insulating jacket, which
is removable from the top of the circuit breaker . Each arc chute has a
baffled top cover .
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Integral
arc runner
Top arc
plate
Current
flow
Current
flow
Figure 27. Cross section of conductor and arc control system
Integral
arc runner
Figure 28. Integral arc runner viewed from top of arc chamber
(arc chute removed, circuit breaker closed)
Electrical motor operator