Protection Settings; General; Long Delay Current Setting; Long Delay Time Setting - Eaton Digitrip RMS 810 Instructions Manual

Instructions for Digitrip RMS 810 Trip Unit

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 .
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
N otee: " " is also the basis for the Short-Delay Current Setting (see
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Section 3 .4) .
Long Delay
Setting
I
r
I
I
n
r

Figure 13. Long Delay Current Settings.

", is expressed as a
r
) .
n
I
I r
r
Available Settings
.5, ,6, .7, .8,
.85, .9, .95, 1
In Multiples of
Rating Plug
Amperes
(I )
n
Instruction Leaflet I. L. 29-888B

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 810 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 . Repeated
overload can cause LTM to trip the breaker after a time delay less than the
"Long Delay Time Setting" . 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 .
.
Long Delay
,
Time
Sec.
4
I
at 6 x
r
I...

Figure 14. Long Delay Time Settings.

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
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"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 .
. . .
. .
Setting
I
r
S1 and S2 Values are Specified on Rating Plug

Figure 15. Short Delay Current Settings.

eaton corporation www.eaton.com
Effective July 2011
I
, the LTM automatically reduces
r
,
Available Settings
2, 4, 7, 10,
12, 15, 20, 24
Seconds at 6 Times
Long Delay Setting
.
. . .
.
(I )
,
r
I
6 x
r
Available Settings
2, 2.5, 3, 4
5, 6, S , S
1
2
In Multiples of
Long Delay Setting
(I )
r
r
17