Protection Settings; General; Long Delay Current Setting; Long Delay Time Setting - Eaton Digitrip RMS 910 Instruction Leaflet

Instruction Leaflet I. L. 29-889B
Effective June 2011

3 protection Settings

3.1 General

Prior to placing any circuit breaker in operation, each Trip Unit pro-
tection setting must be set to the values specified by the person
responsible for the installation . The number of settings that must
be made is determined by the protection supplied as illustrated in
Figures 13 through 19 . Each setting is made with a rotary switch,
using a small screwdriver . The selected setting for each adjustment
appears in its respective rectangular viewing window as illustrated in
Figure 1 .
I
. - - - - - - - -
I I
.
.
,
"*" In Viewing Window
Indicates
2
I t Shape

Figure 19. Ground Fault Time Delay Settings.

The installed rating plug establishes the maximum continuous cur-
rent rating (I ), up to, but not exceeding the Frame Rating of the cir-
n
cuit breaker . Instantaneous and ground current settings are defined
in multiples of (I ) .
n
To illustrate the effect of each protection curve setting, simulated
Time-Current curves are pictured on the face of the Trip Unit . The
rotary switch used to make each setting is located nearest that
portion of the simulated Time-Current curve it controls . Should an
automatic "TRIP" occur (as a result of the current exceeding the
pre-selected value), the LED in the appropriate segment of the simu-
lated Time-Current curve will light "RED", indicating the reason for
the "TRIP" .
The available settings, along with the illustrated effect of changing
the settings are given in Figures 13 through 19 .

3.2 Long Delay Current Setting

There are eight (8) available Long Delay "Pick-up" Current Settings, as
illustrated in Figure 13 . Each setting, called " I
multiple (ranging from 0 .5 to 1) of the rating plug current (I
I
" " is also the basis for the Short-Delay Current Setting (see
N otee:
r
Section 3 .4) .
18
eaton corporation www.eaton.com
Gnd. Fault
Time
.3 Sec.
Available Settings
.1, .2, .3, .4, .5
Seconds w i t h
Flat Response
2
I t Shape
Returns to Flat
Responses at
Approximately
0.625
I
n
.1*, .3*, .5*
Seconds W i t h
2
I t Shape
", is expressed as a
r
) .
n
Instructions for Digitrip RMS 910 Trip Unit

3.3 Long Delay Time Setting

There are eight (8) available Long Delay Time Settings, as illustrated
in Figure 14, ranging from 2 to 24 seconds . These settings are the
total clearing times in seconds, when the current value equals six
(6) times I . The (LS) Time-Current Curve applicable for your circuit
r
breaker gives complete details (see Section 6) .
N otee: In addition to the standard Long Delay Protection Element, the Digitrip
RMS 910 Trip Unit also has a Long Time Memory (LTM)function, which serves
to protect load circuits from the effects of repeated overload conditions . If
a breaker is re-closed soon after a Long Delay Trip, and the current again
exceeds the Long Delay Current Setting,
the time to trip, to allow for the fact that the load circuit temperature is
already higher than normal, due to the prior overload condition . When the
load current returns to normal, the LTM begins to reset; and after about 10
minutes it has reset fully, so that next Long Delay trip time will again be the
"Setting" value . To reset the LTM quickly, see Section 4 .4, Item 3 .

3.4 Short Delay Current Setting

There are eight (8) available Short Delay "Pick-up" Current Settings,
as illustrated in Figure 15 . Six settings are in the range from 2
to 6 times I and the other two settings are "S1" or "S2" times I
r
(REMEMBER: I is the Long Delay Current Setting) . The values that
r
"S1" and "S2" have depend upon the type of circuit breaker, and are
specified both on the rating plug label (see Figure 9) and on the
applicable (LS) Time-Current Curve referenced in Section 6 .

3.5 Short Delay Time Setting

As illustrated in Figure 16, there are two different Short Delay curve
shapes, i .e ., fixed time (flat) and I
depends on the type of selective coordination chosen . The I
response will provide a longer time delay in the low-end of the short
delay current range than will the flat response .
Five flat ( .I, .2, .3, .4, .5 sec .) and three I
response time delay settings are available . The I
are identified by the suffix asterisk (*) that appears in the setting
viewing window . The I t response is applicable to currents less than
2
eight (8) times I the Long Delay Setting . For currents greater than 8
r
times I the I t response reverts to the flat response .
2
r
See also Section 1 .1 .5, Zone Interlocking .
N otee:

3.6 Instantaneous Current Setting

There are eight (8) available lnstantaneous Current Settings, as illus-
trated in Figure 17 . Six settings are in the range from 2 to 6 times
the rating plug value (I ), and the other two settings are "M1" and
n
"M2" times (I ) . The values that "M1" and "M2" have depend upon
n
the type of circuit breaker, and are specified both on the rating plug
label (see Figure 9), and on the applicable (I) Time-Current Curve ref-
erenced in Section 6 .
Breaker Trips
at 6T and GFT
Test A m p s

Test

Trip

Reset
Unit
Status

Figure 20. Integral Test Panel (Lower Right Corner of Trip Unit).

I
, the LTM automatically reduces
r
t response . The shape selected
2
t
2
t ( .I*, .3*, .5* sec .)
2
t response settings
2
Available "Test A m p s " Settings
"6T" = Phase Current Test at

6xI and TRIPS breaker;
n
"1, 2, 3, 8 or 10" x I Phase
n
NO
Current Test breaker
TRIP;
"GFT" Ground Current Test
=
and TRIPS breaker;
"GF" Ground Current Test
=
NO
breaker TRIP.
See Section 4.4.2 for inser-
vice test t r i p limitations.
Push, then release

b u t t o n t o reset Trip Unit.
Required following all automatic
trip and test operations.
Push, then release

button to test. Test operation
begins w i t h release of
pushbutton
r