34
PXR trip unit and communication modules
MAGNUM PXR PRODUCT GUIDE
PA013006EN September 2022 www.eaton.com
3
Common PXR unit features
All PXR trip unit models offer a wide array of common
features. These common features ensure unsurpassed
versatility, no matter which trip unit model is selected.
•
Current Sensors:
The air core Rogowski sensors are
installed at the rear of the circuit breaker on the lower
terminals. The sensors produce a voltage signal output
that is a derivative and proportional to the load current.
With air core sensors, linear output to the maximum
level can be achieved without saturation effects to the
signal. An additional current based iron core transformer
is used to provide the trip unit with the energy to power
up the trip unit and trip the circuit breaker.
•
Ratings:
Each Magnum PXR circuit breaker has a
designed Frame Current Rating that is labeled on the
nameplate of the breaker, as shown below.
The PXR trip unit has a plastic module that indicates the
programmed Continuous Current Rating (I
n
). This current
rating is programmable and cannot be adjusted to a higher
value than the Frame Current Rating value on the circuit
breaker front label. The I
n
current rating is equivalent to
the former use of rating plugs. To comply with standards
the marking is a field-replaceable label that can be ordered
from Eaton. The trip unit will also display the value of I
n
in the lower corner of the display when powered up to
confirm the programmed value.
The frame module that is part of the circuit breaker
performs several functions:
•
The frame module tells the trip unit the maximum
current rating for the construction of the breaker.
•
The frame module holds the manufacturing information
on the factory production of the breaker.
•
The frame module identifies what standards it was built
to comply with as a UL or IEC rated device.
The user interfaces are standard for both styles of trip
unit.
•
PXPM Software:
interfaces to the micro USB port on
the front of the trip unit.
•
Status LED:
A green light emitting diode (LED), labeled
Status, blinks approximately once each second to indi-
cate that the trip unit is operating normally. This Status
LED will also blink red if there is an issue detected in
the self-testing of the trip unit or protection system.
•
Cause of trip LEDs:
They are red LEDs on the face of
the trip unit that flash red next to the protection feature
to indicate the reason for an automatic trip operation,
for example earth fault (Ground), overload (Long),
delayed short circuit (Short) or short circuit with no
intentional delay (Instantaneous). A battery in the trip
unit maintains the trip indication until the Reset button
is pushed. On the lower part of the trip unit display
there is a battery indication symbol. If there are no bars
in the symbol, then the battery should be replaced.
•
Security cover:
A tamper-proof Plexiglas
®
cover sits on
the front of the trip unit. This cover can be closed and
will cover the ARMS switch so that an optional wire
tie can be used to discourage unauthorized entry if the
maintenance switch is in use. The cover can be used
with the PXR 20 to wire tie the cover and discourage
unauthorized access to the overcurrent protection
setting switches.
Figure 35. Nameplate breaker identification
Figure 36. Continuous current rating label