7
Instruction Leaflet
I. L. 29-885D
Effective August 2011
Instructions for Digitrip RMS 510 Trip Unit
EATON CORPORATION
www.eaton.com
NOTICE
AFTER EACH TRIP OPERATION (WHETHER DUE TO OVERCURRENT
PROTECTION OR REMOTE CONTROL) THE AUTOMATIC LOCKOUT-AFTER-
TRIP FEATURE OF THE DIGITRIP RMS 510 TRIP UNIT MAINTAINS THE
CIRCUIT BREAKER IN A "TRIP-FREE" CONDITION, PROVIDED 120 VAC
CONTROL POWER REMAINS AVAILABLE. THE TRIP UNIT MUST BE RESET
BEFORE THE CIRCUIT BREAKER CAN BE CLOSED AGAIN. THE RESET CAN
BE ACCOMPLISHED EITHER LOCALLY BY PRESSING AND RELEASING THE
"TRIP RESET' PUSH BUTTON (SEE FIGURE 2).
1.1.3 Discriminator (High Initial Current Release)
(For Types LS and LSG Trip Units Only)
When the Digitrip RMS 510 Trip Unit is not equipped with an
adjustable instantaneous protection setting, i .e . types LS or LSG, a
DlScriminator circuit (or high initial current release) is provided . The
non-adjustable release is pre-set at eleven (11) times the installed
rating plug current (I
n
) . The DlScriminator is enabled for approximate-
ly ten (10) cycles following the initial current flow through the circuit
breaker, provided the load current exceeds approximately 10% of the
circuit breaker frame (or current sensor) rating . Whenever the load
current falls below 10% the discriminator is rearmed . The release,
once rearmed will remain enabled until the load current passing
through the circuit breaker has exceeded the 10% value for 10
cycles . The DlScriminator trips the circuit breaker, instantaneously
the "OVERRIDE / DIS" LED will light "RED ."
In the event the breaker is not intended to trip out on a circuit
whose current could initially be higher than 11 x I
n
, it is possible to
make the DlScriminator inactive .
If a circuit breaker would close onto a high short-circuit current,
when the DlScriminator is inactive, type
LS
or
LSG
Trip Units will
rely on the short-time delay function before tripping . If the fault
current exceeds the short-time withstand current capability of the
circuit breaker, the OverRlDe protection function will trip the breaker
without delay (see Section 1 .1 .4) . Also, please see Section 1 .1 .5 for
other exceptions when Zone lnterlocking is employed .
The DlScriminator (high initial current release) can be made inactive
by turning the "
OVERRIDE/
" setting switch (nearest the bottom edge
of the Trip Unit) from the "
DIS
" position, to the "[blank]" position (see
Figures 4 and 7) .
otee:
N
This switch has eight (8) positions, and seven (7) of the positions show
"DIS" in the window, ONLY ONE position shows "[blank]" .
otee:
N
When the "OVERRIDE/"window shows "[blank]", the only fast-acting
high short-circuit protection available is the OVERRIDE (Fixed
Instantaneous) (see Section 1 .1 .4 .) .
1.1.4 OVERRIDE (Fixed Instantaneous)
Each Digitrip RMS 510 Trip Unit has a Fixed Instantaneous "Override"
analog trip circuit pre-set to a value no greater than the short-time
withstand current rating of the circuit breaker in which the Trip Unit
is installed . Since the specific values vary for different circuit break-
er types and ratings, refer to time-current curves, listed in Section 5,
for the values applicable to your breaker . If the breaker trips due to
high instantaneous current, the "
OVERRIDE/
" LED will light "RED" .
1.1.5 Zone Interlocking
Zone Selective lnterlocking (or Zone Interlocking) is available (see
Figure 1) for Digitrip RMS Trip Units having Short Delay and/or
Ground Fault protection . Zone Selective lnterlocking provides the
fastest possible tripping for faults within the breaker's zone of pro-
tection, and yet also provides positive coordination among all break-
ers in the system (mains, ties, feeders and downstream breakers) to
limit the outage to the affected part of the system only . When Zone
lnterlocking is enabled, a fault within the breaker's zone of protection
will cause the Trip Unit to:
•
Trip the affected breaker instantaneously, and
•
Send a signal to upstream RMS Digitrip Trip Units to restrain from
tripping immediately . The restraining signal causes the upstream
breakers to follow their set coordination times, so that only the
minimum service is disrupted, while the fault is cleared in the
shortest time possible .
This signal requires that only a single pair of wires be connected
from the interlock output terminals of the downstream breaker's
Trip Unit, to the interlock input terminals of the upstream breaker's
Trip Unit . For specific instructions see the applicable connection dia-
grams for your breaker listed in Section 5 .
otee:
N
If a breaker (M) receives a Zone lnterlocking signal from another
breaker (F) that is tripping, but the fault current level is less than the setting
for breaker (M), the presence of the Zone lnterlocking signal from the other
breaker (F) can not cause breaker (M) to trip .
CAUTION
IF ZONE INTERLOCKING IS NOT TO BE USED (I.E.: STANDARD TIME-
DELAY COORDINATION ONLY IS INTENDED), THE ZONE INTERLOCKING
TERMINALS MUST BE CONNECTED WITH JUMPER WIRES, AS SPECIFIED
ON THE CONNECTION DIAGRAMS FOR YOUR BREAKER (SEE SECTION
5), SO THE TIME DELAY SETTINGS WILL PROVIDE THE INTENDED
COORDINATION.
For examples of how Zone Selective lnterlocking may be used, See
Appendix A .
