Eaton NRX Instruction Manual - page 23
17
Section 4: Circuit breaker features and accessories
Series NRX with PXR - type RF low voltage power (air) circuit breakers instruction manual MN013002ENH03 September 2016 www.eaton.com
Figure 28. Installed PXR trip unit.
Table 2. Series NRX trip units.
Functions
PXR20
PXR 25
LSIG protection
Yes
Yes
Disable (I)
Yes
Yes
GF protection
Option
Option
GF alarm
Option
Option
Display
Yes
Yes
Programmable
No
No
Current metering
Yes
Yes
Power/energy metering
No
Yes
Power quality metering
No
No
Communication
Yes
Yes
Rating plug
A rating plug is not required with PXR trip units. See frame
rating module description.
Current sensors
Rogowski coil type current sensors are installed on the
load terminals at the bottom rear of the circuit breaker. The
sensors furnish the trip unit with a signal and the energy
required to trip the circuit breaker.
An external neutral current sensor is available for customer
installation, and must be ordered separately.
Frame rating module
The PXR frame rating module is mounted just behind the
trip unit and stores data related to the breaker’s ratings
(including the maximum continuous RMS current), manufac-
turing information, and health of the breaker frame.
The interchangeable trip unit attaches to the permanent
frame rating module. Since the PXR trip unit no longer
requires a fixed type rating plug, the continuous current (In)
rating is factory programmed in the frame rating module.
The programmed value of I
n
is shown on the trip unit’s
LCD display and printed on the Battery cover at the lower
right corner of the trip unit. The In rating displayed and pro-
grammed will be equal to or less than the breaker frame’s
maximum rated current as listed on the nameplate in
Figure 1.
The breaker’s I
n
rating can be re-programmed by interfac-
ing with the USB port on the trip unit. Please contact your
Eaton sales representative for details on proper re-program-
ming of the trip unit.
Frame rating modules installed on series NRX air cir-
cuit breakers with PXR are permanent and SHOULD
NEVER BE REMOVED. The frame rating module battery
cover with printed In rating (see Figure 7) should not be
changed without proper reprogramming of the trip unit.
The In rating programmed from the factory is displayed
in the lower left hand corner of the LCD screen when-
ever power is applied to the trip unit. The In displayed
on the LCD reflects the actual In rating of the breaker,
while the value on the battery cover is for reference only
when the LCD is not powered. The In rating displayed
on the LCD screen and In rating printed on the frame
rating module battery cover MUST ALWAYS AGREE.
See MN013003EN for more information.
Trip actuator
The low-energy trip actuator is a small electromagnetic
device that provides the necessary mechanical force to initi-
ate the tripping action of the circuit breaker. The electronic
trip unit provides a pulse to the coil of the trip actuator,
allowing the mechanical tripping action to take place. The
trip actuator is reset by the operating mechanism.
Fixed high instantaneous non-adjustable trip
Series NRX circuit breakers have a fixed instantaneous
non-adjustable setting. This fixed instantaneous trip will
initiate a trip at a high current peak which depends on the
circuit breaker type and rating. This setting is always active,
regardless of the instantaneous setting.
Non-automatic device
Series NRX is available in a non-automatic configuration. It
is derived from the corresponding NRX automatic breaker
but does not include the trip unit, Rogowski coil type cur-
rent sensors, and the high instantaneous trip feature. The
overall dimensions and the capability of mounting most
accessory items are maintained. Non-automatic device
are tested in keeping with UL489 and IEC 60947-2 require-
ments.