36
EATON
www.eaton.com
Maintenance Mode current setting
The Maintenance Mode status and setting can be accessed
from the Program Settings submenu and then select the System
Settings menu. The initial screen will show if the Maintenance
Mode is on or off. The next screen will allow the mode to
be turned on or off if it was previously turned on locally. The
Maintenance Mode setting when armed is adjustable for different
levels of trip current for arc reduction: 1000, 2000, 3000, 4000,
5000 Amps for the NRX-NF frame and 4000, 8000, 12000, 16000,
20000 Amps for the NRX-RF frame circuit breaker. The adjustable
current settings allow for different levels of protection. A higher
level may be needed when for example another load feed from this
breaker may contain motors that are being started and create large
inrush currents over the lowest trip current level. The selection
of one of the reduction settings should be determined and
selected by a person who is experienced in power system
analysis.
Actuating Maintenance Mode
There are three ways to actuate the Maintenance Mode setting.
One method is locally via programming setpoints submenu in
the Maintenance Mode section. Enabling the setpoint will turn
on a blue LED that confirms that the function is on.
For the other method of actuating the Maintenance Mode
function, this switch must be in the position labeled 0/1.
With this setting, a remote switch wired through the circuit
breaker secondary contacts 33 and 34 can remotely arm
the Maintenance Mode setting. A high quality gold plated or
palladium contact is required in this application. The blue LED
will verify that the function is armed.
A third method to arm the Maintenance Mode setting is via a
communication device. When Maintenance Mode is enabled
via device communications, it must be disabled by device
communications.
Remote Indicator
Either Relay 1 or 2 can be programed to close when
Maintenance Mode is enabled. This contact can be used to
indicate remotely that the Maintenance Mode setting is armed.
Refer to diagram below for a wiring of this remote (blue light)
indicator.
Tripping and testing
The Maintenance Mode function will provide fast tripping
even when the regular Instantaneous is set to OFF. The
Instantaneous LED position is also used to indicate a trip
initiated by the Maintenance Mode setting. The Maintenance
Mode Trip message will be displayed after a trip.
Operating Manual for Series NRX
Digitrip Trip Units 1150 / 1150i
Section 12: References
MN01301001E
Series NRX NF Circuit Breaker Manual
MN01301003E
Series NRX RF Circuit Breaker Manual
IL01301074E
Rating Plug
IL01301031E
Source Ground / Zero Sequence Sensor
IL01301032E
Neutral Current Sensor Series NRX NF
IL01301046E
Neutral Current Sensor Series NRX RF
IL5721B13
Functional Test Kit (Universal)
IL01301067E
Functional Test Kit (ACB only)
TD01301014E
Series NRX NF and RF Wiring Diagrams
Section 13: Time-current curves
The time-current curves are listed below for particular trip unit
models. All protection function time-current settings should
be made by following the recommendations of the specifying
engineer in charge of the installation.
AD01301005E
Application Data
This document includes all curves for both Series NRX NF and
Series NRX RF circuit breakers:
I
2
t Long Delay and Short Delay
I
4
t Long Delay and Short Delay
IEC - A (normal inverse)
- B (very inverse)
- C (extremely inverse)
IEEE/ANSI -
M
oderately
I
nverse,
V
ery
I
nverse,
E
xtremely
I
nverse
Instantaneous
Ground Fault
Maintenance Mode
Use the link/path below to access time-current curves at
Eaton’s Web site:
http://www.eaton.com/Electrical/USA/Support/Documentation/
TimeCurrentCurves/index.htm
Effective September 2013
Instructional Leaflet IL01301064E
