11
Instruction Leaflet
IL01301051E
effective September 2013
Operating Manual for Series NRX
Trip Units - Digitrip™ 520/520M
EATON
www.eaton.com
InsoallaoiNn and remNval
Installation of the trip unit
Align the Digitrip trip unit with the two guide grooves of the Series
NRX circuit breaker. Keep it parallel with the receiving, molded deck
plate. Press the unit into the circuit breaker until the trip unit seats
firmly into the receiving housing and the two latching tabs click into
place.
Figure 3.
Frame Module
Trip Unit
Locking Tabs
(Pry to open if
trip unit is to
be removed)
InsoallaoiNn Nf ohe Trip Unio inoN Frame MNdule Nf a Series
NRX Circuio Breaker
Rating plug installation
•
CAUTION
IF A RATING PLUG IS NOT INSTALLED IN THE TRIP UNIT, THE UNIT WILL
INITIATE A TRIP WHEN IT IS ENERGIZED. AN ORANGE LED LIGHT WILL LIGHT
ABOVE THE INST TEXT
Insert the rating plug into the cavity on the right side of the trip unit.
Wiggle the plug slightly to help align the pins on the plug with the
sockets in the cavity. The plug should engage with a slight insertion
force. At this point, it will be roughly 3/16” above the Digitrip and it
will take four turns to tighten it to its stop postion.
Figure 4. InsoallaoiNn Nf ohe Raoing Plug inoN ohe Trip Unio
Noee:
N
The wrong rating plug group for a particular circuit breaker frame will not
engage to the circuit breaker frame properly to tighten down (
SecoiNn 6
)
.
•
CAUTION
DO NOT FORCE THE RATING PLUG INTO THE CAVITY.
Use a 1/8-inch / 3 mm wide screwdriver to tighten the mounting screw
and secure the plug and the trip unit to the circuit breaker.
•
CAUTION
THE RATING PLUG SCREW SHOULD BE TIGHTENED ONLY UNTIL IT STOPS. DO
NOT USE A LARGE SCREWDRIVER. A 1/8-INCH (3 MM) WIDE SCREWDRIVER
BLADE IS ADEQUATE.
Trip unio/raoing plug remNval
To remove the rating plug from the trip unit, use a 1/8-inch / 3 mm
wide screwdriver to loosen the screw. It will take about four turns to
release it.
To remove the trip unit from the circuit breaker’s Frame Rating Module,
break the factory seal, deflect the two locking tabs, and pull to release
the unit from the mounting plate. Pull the unit to disengage the
molded, 24-pin connector from the circuit breaker. (
Figure 3
)
Wiring
The internal components of the circuit breaker and how they are wired
internally and externally to the circuit breaker secondary contacts are
shown in the breaker master connection diagrams provided as
Appendix
E and F.
Plexiglass cNver
A clear, tamper-proof, plexiglass cover fits on the Digitrip. This cover
allows the settings to be viewed but not changed, except by authorized
personnel. The plexiglass cover meets applicable tamper-proof
requirements. Security is ensured by the insertion of a standard meter
seal through the thumb screw holes. The plexiglass cover has access
holes for the Scroll pushbutton and Maintenance Mode setting (if
applicable).
VNloage supply inpuo/alarms
Auxiliary voltage requirements
When the circuit breaker is wired for external 24 Vdc input, it will
provide an auxiliary voltage supply so that the Digitrip 520M liquid
crystal display (LCD) will be functional even when the circuit breaker
has no load. The burden of the Digitrip is 6 VA. A Digitrip 520M trip unit
without auxiliary voltage will not display data until load current reaches
approximately 100A (single-phase) or 35A (three-phase) on the Series
NRX circuit breaker.
Ground alarm
Auxiliary voltage of 24 Vdc is required to provide either a ground trip or
ground alarm only output contact via the relay supplied for the Digitrip
520M trip unit.
Ground fault trip
The 520M (metering) styles will provide ground fault trip contacts
when the circuit breaker trips on a ground fault. You must then push
the Reset button in order to reset the internal contacts.