10
Instruction Leaflet
I. L. 29-885D
Effective August 2011
Instructions for Digitrip RMS 510 Trip Unit
EATON CORPORATION
www.eaton.com
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 11 through 18 . 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 2 .
The installed rating plug establishes the maximum continuous cur-
rent rating (I
n
), up to, but not exceeding the Frame Rating of the cir-
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 11 through 18 .
3.2 Long Delay Current Setting
There are eight (8) available Long Delay "Pick-up" Current Settings, as
illustrated in Figure 11 . Each setting, called "
I
r
”
, is expressed as a
multiple (ranging from 0 .5 to 1) of the rating plug current (I
n
) .
otee:
N
"
I
r
"
is also the basis for the Short-Delay Current Setting (see
Section 3 .4) .
Figure 11. Long Delay Current Settings.
3.3 Long Delay Time Setting
There are eight (8) available Long Delay Time Settings, as illustrated
in Figure 12, ranging from 2 to 24 seconds . These settings are the
total clearing times in seconds, when the current value equals six
(6) times
I
r
. The (LS) Time-Current Curve applicable for your circuit
breaker gives complete details (see Section 5) .
Figure 12. Long Delay Time Settings.
Long Delay
Available Settings
Setting
.5, ,6, .7, .8,
.85, .9, .95, 1
In Multiples of
Rating Plug
Amperes
I
r
I
r
I
r
I
n
(I )
n
I
r
.
,
,
Available Settings
12, 15, 20, 24
I...
Seconds at
6 Times
,
.
. .
.
.
6
x
Long
Time
Delay
Sec.
at 6 x
I
r
I
r
4
(I )
r
Long Delay Setting
2, 4, 7, 10,
otee:
N
In addition to the standard Long Delay Protection Element, the Digitrip
RMS 510 Trip Unit also has a Long Time Memory (LTM) function, which
serves to protect load circuits from the effects of repeated overload condi-
tions . If a breaker is re-closed soon after a Long Delay Trip, and the current
again exceeds the Long Delay Current Setting,
I
r
, the
LTM
automatically
reduces 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 .
In certain applications it may be desirable to disable the LTM function . The
LTM function can be disabled by (first opening the breaker and then) remov-
ing the Rating Plug and lastly moving the LTM jumper (inside the rating plug
cavity, see Figure 13) to its "INACTIVE" connection . (You can enable the LTM
function again any time you wish by moving the LTM jumper back to its origi-
nal "ACTIVE" connection .)
The action of the LTM is a factor to consider in performing multiple Long
Delay Time tests . (See Section 4 .4 .)
Figure 13. Long Time Memory "LTM" Jumper.
otee:
N
There is a condition under which the Long Delay Trip LED can errone-
ously indicate a LDT has occurred, even though the breaker is still closed .
This can happen when an overload current momentarily exceeds the Long
Delay Current Setting, Ir, so that the Long Delay LED flashes "RED" to indicate
the overload condition . Then if, at the very moment when the LED is "ON",
the load current would then suddenly drop to a value less than 10% of the
breaker frame (or current sensor) rating, the trip unit stops functioning while
the "4bit Latch Chip" (See Fig . 1) is set and the LED remains lit . If the current
would again increase to a value above the Long Delay Current Setting, I,, and
then return to normal, the LDT will reset itself . You can of course, manually
clear the LDT (or any other trip indication) at any time, by pushing the "PUSH
to RESET" button . (See Figure 2 .)
3.4 Short Delay Current Setting
There are eight (8) available Short Delay "Pick-up" Current Settings,
as illustrated in Figure 14 . Six settings are in the range from 2
to 6 times
I
r
and the other two settings are "S1" or "S2" times
I
r
(REMEMBER:
I
r
is the Long Delay Current Setting) . The values that
"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 5 .
Figure 14. Short Delay Current Settings.
Rating Plug Cavity
LTM
Active
. .
S1 and S2
2, 2.5, 3, 4
Available Settings
. .
.
Setting
In Multiples of
Long Delay Setting
Values are Specified on Rating Plug
5, 6, S , S
1
2
I
r
(I )
r
