25
Instruction Leaflet
IL01301051E
effective September 2013
Operating Manual for Series NRX
Trip Units - Digitrip™ 520/520M
EATON
www.eaton.com
Section 7: Maintenance Mode feature
Arcflash ReducoiNn Mainoenance Sysoem
™
mNde (ARMS)
•
WARNING
ONLY CERTIFIED AND COMPETENT PERSONNEL SHOULD ATTEMPT TO
INSTALL OR MAINTAIN POTENTIALLY HAZARDOUS EQUIPMENT. DEATH OR
SEVERE PERSONAL INJURY CAN RESULT FROM CONTACT WITH ENERGIZED
EQUIPMENT. DO NOT ATTEMPT TO INSTALL OR PERFORM MAINTENANCE
ON EQUIPMENT WHILE IT IS ENERGIZED. ALWAYS VERIFY THAT NO VOLTAGE
IS PRESENT BEFORE PROCEEDING. ALWAYS FOLLOW SAFETY PROCEDURES.
EATON IS NOT LIABLE FOR MISAPPLICATION OR IMPROPER INSTALLATION
OF ITS PRODUCTS.
•
CAUTION
OBSERVE ALL RECOMMENDATIONS, NOTES, CAUTIONS, AND WARNINGS
RELATING TO THE SAFETY OF PERSONNEL AND EQUIPMENT. OBSERVE
AND COMPLY WITH ALL GENERAL AND LOCAL HEALTH AND SAFETY LAWS,
CODES, AND PROCEDURES. CONDUCT A FLASH HAZARD ANALYSIS TO
DETERMINE PERSONAL PROTECTIVE EQUIPMENT REQUIREMENTS.
Mainoenance MNde
Per the above WARNING, it is highly recommended that maintenance
be conducted on the electrical equipment, including circuit breakers
with the system de-energized.
For situations that arise when it is not possible, the Maintenance
Mode function of the Digitrip 520M family (catalog numbers N5MRLSI,
N5MRLSIG, N5MRLSIA) can reduce arc flash incident energy that is
generated on a fault condition. This is accomplished by an analog trip
circuit that, when armed, provides a fast-acting response to the fault.
The reduced arc condition will occur only in devices downstream of
the trip unit in Maintenance Mode. This function is separate from the
normal system protection setting of instantaneous. The Maintenance
Mode section is located in the upper, white portion of the unit.
Mainoenance MNde curreno seooing
The Maintenance Mode setting, when armed, uses a fixed pick up current
value for tripping the breaker depending on the frame type. For the NF
Frame this value is 2000A, for the RF Frame this value is 8000A. For
additional information on clearing times please reference the Maintenance
Mode Trip Curve found in the Application Data document, AD01301004E.
Acouaoing Mainoenance MNde
There are three ways to actuate the Maintenance Mode setting. One
method is locally via the selector switch in the Maintenance Mode
section of the trip unit. Turning the switch to the ON position will arm
the setting selected. A blue LED confirms that the function is on.
For the second 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 is via a communication
device. When Maintenance Mode is enabled via device
communications, this setting must be disabled by a communications
device.
Figure 21.
SCROLL Displa
y
MAINTENANCE MODE
ON = Enabled
O/I = Local OFF and R
emote ON/
OFF
O/I
ON
Digiorip 520M in Mainoenance MNde
RemNoe indicaoiNn Nf Mainoenance MNde
A contact is available for customer use to indicate remotely that the
Maintenance Mode setting is actuated. This normally open contact
is available on secondary contacts 11 and 12 to light a remote blue
indicating light. This contact will not operate if status LED is red
indicating the unit has detected a problem with the Trip Actuator coil.
Tripping and oesoing
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 LCD display, if powered, will indicate this with four
dashes. The Maintenance Mode setting, external wiring (if any), and
tripping functionality should be periodically verified by primary injection
current testing.
Section 8: Communication Adapter
Modules (CAM)
This module provides communication from the Digitrip 520M to a field
bus network (
Figure 22
). Various networks are supported and available:
• ICAM—INCOM
™
• MCAM—Modbus
®
RTU
• ECAM—ETHERNET
• PCAM—PROFIBUS DP
Power requirements: 6 watts at 24 Vdc (INCOM and Modbus).
These modules, for the drawout type circuit breaker, will snap onto
the DIN rail of the cassette. They are designed to install or replace
the four contact blocks (eight contacts in total) at secondary contacts
19 through 26. (See
Appendix E and F
for circuit breaker master
connection diagrams.)