is overcurrent protection, which is achieved by analyzing
the current signals received from the circuit breaker current
sensors and initiating trip signals to the circuit breaker trip
actuator when pre-determined current levels and time delay
settings are exceeded.
The protection section of the Digitrip RMS Trip Unit can
be equipped with up to five phase and two ground fault
time current adjustments. The short delay and ground fault
pick-up adjustments can be arranged for either a flat or I
2
t
response. The exact selection of the available adjustments
must be chosen to satisfy the protection needs of the spe-
cific installation.
LEDs provide mode of trip indication for ground fault, over-
load and short circuit trip operations.
Digitrip RMS Trip Unit types LS and LSG are not equipped
with an adjustable instantaneous trip element, but are
provided with a making current release (discriminator). A
high-level instantaneous override circuit is provided to insure
rapid circuit clearing under abnormal fault current conditions.
Digitrip RMS Trip Units are available in four basic models,
the Digitrip RMS 510, 610, 810 and 910 (Figure 2a). Sepa-
rate instruction leaflets referenced in Section 8.1 cover the
features and functions of each model. This instruction book
is arranged to describe the unique features of each type as
applied in Types DSII and DSLII Low-Voltage AC Power Cir-
cuit Breakers. Table 1 presents the available characteristics
of each of the four trip unit models.
The Digitrip OPTIM Trip Unit System utilizes two basic trip
unit models with the Type DSII Low Voltage AC Power Circuit
Breaker, the OPTIM 750 and OPTIM 1050 Trip Units (Figure
2b). The featured parts of a Digitrip OPTIM Trip Unit System
are:
1. OPTIM 750 or 1050 RMS sensing trip units
2. OPTIMizer Hand Held Programmer
3. Breaker Interface Module
The OPTIMizer Hand Held Programmer plugs into the front
of OPTIM 750 or 1050 Trip Units to access, display and con-
figure trip unit information, and establish trip unit addresses.
The panel mounted Breaker Interface Module provides all
the same features and capabilities as the OPTIMizer Hand
Held Programmer, plus energy monitoring, local/remote indi-
cation, and communications capabilities, except that only the
Hand Held Programmer can establish trip unit addresses.
Separate instruction manuals, referenced in Section 8.3,
cover all the details associated with the OPTIMizer Hand
Held Programmer and the Breaker Interface Module.
The following circuit breaker accessories are available to pro-
vide supplementary protection, signaling and test functions:
(Refer to Section 3.10 of I.B. 694C694 for details)
1. Undervoltage Trip Device
2. Portable Test Kit - See CAUTION on page 4.
3. Latch Check Switch
4. Auxiliary Switches
5. Overcurrent Trip Switch
3.0 Ratings Plugs
Rating Plugs, as shown in Figure 3, determine the continu-
ous current rating of the circuit breaker. All protection func-
tion settings on the face of the trip unit for the Digitrip RMS
510, 610, 810 and 910 are expressed in per unit multiples
of the plug rating (I
n
) or the long delay current setting (I
r
).
The Digitrip OPTIM 750 and 1050 use the same rating plug
family as Digitrip RMS. The plug rating (I
n
) determines the
maximum continuous current rating of the circuit breaker. All
the protection function pickup settings are based on the plug
rating (I
n
). These pickup settings are ultimately loaded into
the trip unit in per unit, but are displayed as an ampere value
for ease of use by the user.
Available rating plugs are shown in Table 2. Plugs are suitable
for 50 or 60Hz operation, but must be selected to match the
desired continuous current rating of the circuit breaker as
well as the installed sensor rating.
Rating plugs are equipped with a back-up battery, as shown
in Figure 3, to maintain the trip indication following a circuit
breaker tripping operation when external control power is
not available. The battery is a long-life lithium type that is
replaceable from the front of the trip unit without remov-
ing the rating plug. Replacement types and instructions are
provided in the Digitrip RMS Trip Unit instruction leaflets
referred to in Section 8.1.
Following a trip operation and with no supplementary control
power available, the battery would maintain the mode of trip
LED for approximately 60 hours.
Effective July 2010
Instructional Leaflet
IL8700C39-04
3
eaTOn CORPORaTIOn
www.eaton.com
Summary of Contents for Digitrip RMS Series
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