Eaton Magnum PXR User Manual

21
User Manual MN013016EN
Effective July 2022
Magnum PXR and Power Defense SB low
voltage power circuit breakers user manual
EATON www.eaton.com
Operating mechanism
The Magnum PXR and PD-SB operating mechanism is based on
the proven cam and spring design of the Magnum DS power circuit
breaker. It is easily accessed by removing four cover screws and the
front cover (Figure 24). The mechanism is a two-step stored energy
mechanism. Potential energy is stored to close the circuit breaker.
Sufficient energy to open the circuit breaker remains available after
a closing operation.
Manual operation
On manually operated circuit breakers, the closing spring can only
be charged manually. To manually charge the spring, insert one finger
in the recess behind the charging handle and pull out. This permits
a gloved hand to grasp the handle and begin charging (Figure 25).
It takes from 5 to 7 downward strokes on the charging handle to
complete the manual charging process. It is possible to manually
recharge the spring immediately after closing the circuit breaker
and before it has been tripped open.
Standard manually operated circuit breakers are closed and opened
by hand using the Manual CLOSE and Manual OPEN buttons
respectively located on the front of the circuit breaker (Figure
18). Performing either operation is accomplished by pressing and
releasing the appropriate button. Access to these pushbuttons can
be limited by the use of an optional, padlockable cover. In addition,
complete access to the CLOSE button can be prevented with an
optional prevent close cover. The status of the springs and the
primary contacts are always indicated in an indicator window just
above the pushbuttons.
Electrically operated optional devices are available to automatically
close or trip a manually operated circuit breaker. An electrical spring
release is available to close a manually operated circuit breaker.
Two optional devices, a shunt trip, and an undervoltage release,
are available to automatically trip (open) a manually operated circuit
breaker. All of these UL Listed optional devices can be installed
easily in the field. For more details on these devices, refer to
page 26, “Accessory devices” in this manual.
An electrical operator, which is used to charge the closing spring
automatically, can be added to a manually operated circuit breaker
in the field (Figure 26).
Figure 24. Typical electrically operated drawout circuit breaker
with front cover removed
Figure 25. Circuit breaker closing springs being
manually charged (Magnum DS shown)
b
f
h
a
Secondary wiring points
b
Field installable accessories
(three maximum)
c
Trip unit
d
Electric charging motor
e
Manual charge handle
f
Operations counter (optional)
g
Padlockable levering device access door
h
Breaker position indicator
g
e
d
c
a

Eaton Magnum PXR Specifications

General

Brand	Eaton
Model	Magnum PXR
Category	Circuit breakers
Language	English