Eaton Digitrip RMS Series, Instructional Leaflet

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4.4 Digitrip RMS 910
The Digitrip RMS 910 Trip Assembly is similar to the Digitrip
RMS 810. It is a communicating trip unit that provides all
the functions described in Section 4.3 plus the addition of
the following locally displayed and remotely communicated
features:
1. Phase to Phase Voltages Vab, Vbc, Vca
2. System Power Factor (PF)
3. Total Harmonic Distortion (THD) for Ia, Ib, Ic
The THD calculation also includes the individual harmonic
currents up to the 27th harmonic as a percentage of the
fundamental. Also included with the THD are provisions for
waveform capture information via a host computer. Detailed
information is provided in I.L. 29-889.
4.5 Digitrip OPTIM Model Consider-
ations
Trip unit testing is carried out by using the OPTIMizer Hand
Held Programmer, the Breaker Interface Module, or a
remote computer to select values of test current within a
range of available settings. Basic protection functions are
not affected during test operations. The testing capability is
not intended for live primary current interruption. Two types
of tests are possible, the “No Trip” and the “Trip” tests.
Testing is not permitted to proceed if there is greater than
0.4 per unit of current flowing on a phase circuit or 0.2 per
unit of current on a ground circuit. The maximum permitted
current value can be determined by multiplying the appro-
priate per unit value (0.4 or 0.2) times the ampere rating of
the installed rating plug. An auxiliary power module (Cat.
No. PRTAAPM) can be used to bench test a trip unit when
the auxiliary power module is connected to a 120V 50/60Hz
supply.
 CauTION
“TrIp” TEsTINg Of a CIrCuIT BrEakEr IN ThE CEll “CON-
NECTED” pOsITION Is NOT rECOmmENDED. ThE TrIppINg
OpEraTION Of ThE CIrCuIT BrEakEr wIll CausE sErVICE DIs-
rupTION aND pOssIBly pErsONal INJury rEsulTINg frOm
uNNECEssary swITChINg Of CONNECTED EQuIpmENT. ThIs
kIND Of TEsTINg shOulD ONly BE CONDuCTED IN ThE “TEsT,”
“DIsCONNECTED” Or “rEmOVE” CEll pOsITIONs.
4.6 Digitrip OPTIM 750
Digitrip OPTIM 750 Trip Units provide true rms sensing and
utilize a fixed interchangeable rating plug to establish the
continuous trip rating of the circuit breaker. Rating plugs are
interlocked to prevent use between different circuit breaker
types.
Precise system coordination is provided by the following
time-current curve shaping adjustments:
1. Long delay pickup
2. Long delay time with selectable I
2
t or I
4
t curve
shaping
3. Short delay pickup
4. Short delay time with selectable flat or I
2
t curve
shaping
5. Instantaneous pickup
6. Ground fault pickup
7. Ground fault time with selectable flat or I
2
t curve shaping
The trip units also have a selectable powered/unpowered
thermal memory to provide protection against cumulative
overheating should a number of overload conditions occur in
quick succession.
The trip unit information system utilizes battery backup LEDs
to indicate the trip mode following an automatic trip opera-
tion. The LEDs are complemented by trip event informa-
tion that is stored in memory after a trip condition. This trip
information can then be accessed via the OPTIMizer Hand
Held Programmer, the Breaker Interface Module, or over the
IMPACC System. A trip reset pushbutton is provided on the
trip unit to turn off the LED indication after an automatic trip.
The battery status is also LED indicated through the use of a
pushbutton.
Selectable early warning alarms, capable of being indicated
locally and remotely, are provided to help keep a system
operating and productive.
All OPTIM Trip Units are capable of monitoring the following
data:
1. Steady-State value of phase, neutral, and ground currents
2. Minimum and maximum current values
3. Average demand current
4. Cause of trip (Long Delay, Short Delay, Instantaneous or
Ground Fault)
5. High load current alarm
6. Magnitude of fault current responsible for an automatic
trip operation
Monitoring and Control
Trip units are capable of two way communication via a
network twisted pair for remote monitoring and control. The
circuit breaker, through the trip unit, is able to respond to
open and close commands via the communication network.
To close the breaker, an electrical operator or spring release
option is required.
Effective July 2010
Instructional Leaflet
IL8700C39-04
10
eaTOn CORPORaTIOn www.eaton.com