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2. Trip unit description
Power XPert® release triP unit for MagnuM PXr circuit breakers
MN013015EN January 2022 www.eaton.com
2.13 Operating temperature
All models of trip units are designed for industrial circuit
breaker environments where the ambient temperatures
can range from -20 to +65°C. (-4 to +149°F). If, however,
temperatures within the trip unit exceed this range, a factory
set over-temperature protection feature is set at 95°C (221°F)
which will trip the circuit breaker. The LONG cause of trip
indicator will illuminate.
Storage temperature is from -20 to +95°C (-4 to +203°F).
2.14 Trip unit, frame, and voltage modules within
the trip unit
There are three components of the system: the trip unit
module, the frame module, and the voltage sensing module
(PXR 25 systems).
The electronic trip unit module (ETU) is the main component
of the trip unit system. It contains the electronics which
support the protection functions, metering capability, user
interface, and communication features. It can be replaced
in the field for the same style unit or to a different style.
Note that upgrading may require the installation of other
sub-system components and wiring to enable full feature
support.
The trip unit module label is attached to the side and
contains the catalog number, PXR 20 or 25, and protection
information (LSI, LSIG, LISGA). Additionally, it contains the
Eaton style number, unit serial number, and revisions of the
hardware and firmware.
Figure 5. Trip unit label.
The frame module (FRM) is mounted permanently to the
circuit breaker frame. It should not be removed or replaced
under normal conditions. If it accidentally is damaged and
requires repair, Eaton Field Service must be consulted to
perform the work. The lower half of the plastic housing
contains the electronics that hold factory configured frame
information regarding the rating, calibration, settings, and
operation. The interface circuit for the sensors as well as the
configurable relays are mounted in the frame module.
A label is attached to the side of the frame module. It
contains a brief description, the Eaton style number, serial
number, and hardware revision.
Figure 6. Frame module label.
The voltage sensing module (VDB) is used with the PXR 25
and is secured in the top half of the of the plastic housing,
above the FRM. It converts the line voltage from the top or
bottom breaker terminals for sensing by the trip unit elec-
tronics. The choice of top or bottom terminals as the sensed
voltage can be changed in the field.
The three modules are interconnected via PCB-to-PCB
connectors. In addition, the modules connect to the breaker
and secondary terminals through a set of wiring harnesses.
The PXR 20/25 modules (ETU, FRM, VDB) used in Magnum
PXR circuit breakers are designed to be used as a set.
As such, they shall not be interchanged with PXR 20/25
modules from the Series NRX or PowerDefense NF/RF
circuit breaker families. The frame module in Magnum PXR
circuit breakers has a feature which will physically reject trip
units not designed for it. The feature prevents the screw,
which fastens the top of the control module to the frame
module and mounting plate, from engaging the threads.
Do
not tamper with or disable this rejection feature.
You can distinguish between Power Xpert Release trip units
designed for Series NRX or PowerDefense NF/RF circuit
breakers and those designed for use in Magnum PXR circuit
breakers based on the catalog numbers printed on the side
label of the PXRs.
•
PXR20V000… or PXR25V000… are designed to be used
only with Series NRX or PD-NF/PD-RF circuit breakers
(also known as v2 based on their firmware revision start-
ing with 02.XX).
•
PXR20NV30… or PXR25NV30… are designed to be used
only with Magnum PXR circuit breakers (also known as v3
based on their firmware revision starting with 03.XX).
