plug-in unit as all the other Digitrip models. There are two
style offerings –Phase Protection with Ground Fault Trip
(Cat. P106LSIG) and Phase Protection with Ground Fault
Alarm (Cat. P107LSIA).
The front panel of the unit has four cause of trip LEDs
and a telephone type receptacle for programming set-
tings, testing and displaying phase currents via a sepa-
rate hand-held unit called the OPTIMizer. (The
OPTIMizer is used primarily for initial setup of an indi-
vidual breaker.) There are up to ten trip functions that can
be programmed which includes both a
I
²
t and a
I
t
curve for the Long-Time Slope. There is also typically ten
times the number of setpoints compared to a front adjust-
able trip unit for each function.
All transmittable data as well as programming of the trip
curve settings can also be communicated over a twisted
pair wiring network via breaker
'
s secondary terminals
C11, C12 to either a host computer or a panel mounted
Breaker Interface Module (BIM).
Harmonics information including total Harmonic Distor-
tion, the individual harmonic currents involved up to the
27th harmonic and waveform capture for the three phase
currents and the neutral is accessible via communica-
tions.
The Digitrip OPTIM 1050 will also provide Power and
Energy Monitoring functions via communications. The
breaker requires the PT Module (Fig. 5) to provide this
functionality. Also included is a Power/Relay module to
provide power for communication functions and relay out-
puts for alarming.
4.8 Reset Operation
Following overload, short circuit, or ground fault tripping
events on Digitrip Types 610, 810, and 910, the Digitrip
“Trip Reset
"
pushbutton must be depressed before the
circuit breaker handle can be reset (trip/reclose feature).
The Digitrip RMS 310, 510 and Digitrip OPTIM 750 and
1050 in R-frame do not require a trip reset push-button
operation to reset the breaker
'
s mechanism. However, a
trip reset push-button operation is required to clear cause
of trip LED.
5.0 PRINCIPLE OF OPERATION
5.1 General
The circuit breaker is tripped automatically under fault
current conditions by the combined action of three com-
ponents:
1.
The sensors which determine the current level.
2.
The Digitrip RMS Trip Unit, which provides a trip-
ping signal to the Flux Shunt Trip when current and
time delay settings are exceeded.
3.
The flux shunt trip which actually trips the circuit
breaker.
Schematically, this may be represented as illustrated in
Fig. 6. This arrangement provides a very flexible system
covering a wide range of tripping characteristics. Not only
is the Digitrip RMS Trip Unit adjustable, but selection of
rating plugs provides a wide range of continuous current
ratings.
The automatic overload and short circuit tripping charac-
teristics for a specific circuit breaker are determined by
the ratings of the installed current sensors, rating plugs
and the selected functional protection settings. Specific
settings instructions are provided in the applicable trip
unit instruction leaflet referenced in Section 8.2 of this
instruction book.
When the functional protection settings are exceeded,
the Digitrip RMS Trip Unit supplies a trip signal to the flux
shunt trip. Thus all tripping operations initiated by the pro-
tection functions of the Digitrip RMS Trip Unit are per-
formed by secondary control circuitry, with no mechanical
or direct magnetic action between the primary current
and the mechanical tripping parts of the breaker and with
no external control power required.
5.2 Digitrip RMS Trip Assembly
The basic Digitrip RMS Trip Assembly, as illustrated in
Figs. 1, 2 and 4, includes the following which could vary
slightly depending upon the exact model of the Digitrip
Trip Unit installed:
1.
Digitrip RMS or Digitrip OPTIM Trip Unit
2.
Rating Plug
3.
Auxiliary Current Transformers
-
3 or 4 depending
upon whether or not ground fault or neutral protec-
tion is included. These are installed on back-
mounted PC board.
4.
Stab-in Terminal Block for Trip Unit
5.
Power/Relay module (Digitrip RMS Trip Unit Mod-
els 610, 810, 910 and Models 750 and 1050.)
EATON CORPORATION www.eaton.com
Page
9
Effective Date October 2010
Instruction Leaflet 29C713E
Effective October 2010
4
