27
User Manual
MN013016EN
Effective July 2022
Magnum PXR and Power Defense SB low
voltage power circuit breakers user manual
EATON
www.eaton.com
Figure 37. Spring release with optional latch switch
An optional Latch Check Switch (LCS) can be installed to indicate
when the circuit breaker is “ready to close .” Two versions of the
LCS are available .
The LCS wired to the spring release will not permit activation of the
spring release until the circuit breaker is fully charged and the trip
latch is reset (
) . If power is applied and maintained to the
spring release, an activation will occur when the circuit breaker is
“ready to close .”
The LCS for remote indication consists of one Form C contact wired
to the circuit breaker secondary contacts for integration into external
control schemes .
ote:
N
Wiring the LCS for remote indication directly in series with the SR
accessory is not recommended as this will override the “anti-pump” feature
of the electrical charging/closing system .
Undervoltage release
—The undervoltage release is an optional
device on both manually and electrically operated circuit breakers
(
) . It opens the circuit breaker when its supply voltage
falls to between or below 35–60% of rated voltage . If the release is
not
energized to 85% of its supply voltage, the circuit breaker cannot
be closed electrically or manually (
) .
Table 8. Undervoltage release
Control
voltages
Operational
voltage range
85–110%
Dropout
voltage
30–60%
Inrush/
continuous
power
consumption
Opening
time (ms)
24 Vdc
20–26 Vdc
7–14 Vdc
250 W
/ 18 W
70
32 Vdc
27–35 Vdc
10–19 Vdc
275 W
/ 15 W
70
48 Vdc
41–53 Vdc
14–29 Vdc
275 W
/ 18 W
70
60 Vdc
51–66 Vdc
18–42 Vdc
275 W
/ 18 W
70
110–125 Vdc
94–138 Vdc
33–75 Vdc
450 W
/ 10 W
70
220–250 Vdc
187–275 Vdc
66–150 Vdc
450 W
/ 10 W
70
110–127 Vac
94–140 Vac
33–76 Vac
450 VA
b
/ 10 VA
70
208–240 Vac
177–264 Vac
62–144 Vac
400 VA
b
/ 10 VA
70
380–415 Vac
323–457 Vac
114–249 Vac
480 VA
b
/ 10 VA
70
480 Vac
408–528 Vac
144–288 Vac
400 VA
b
/ 10 VA
70
600 Vac
510–660 Vac
180–360 Vac
400 VA
b
/ 10 VA
70
a
Required for 200 ms.
b
Required for 400 ms.
Figure 38. Undervoltage release
Figure 39. Shunt trip, spring release, and undervoltage
release installed
Auxiliary switch
—An auxiliary switch is an optional device providing
remote electrical indication if the circuit breaker is open or closed
(
) . Up to three auxiliary switches can be mounted in the
circuit breaker . Each switch has four Form C contacts for a total of
12 normally open and 12 normally closed contacts (
) .
Table 9. Auxiliary switch, overcurrent trip switch, and cell
switch contact ratings
Control voltages
Contact rating inductive load (amperes)
250 Vac
10
125 Vdc
0.5
250 Vdc
0.25
