12
Instruction Leaflet
I. L. 29-885D
Effective August 2011
Instructions for Digitrip RMS 510 Trip Unit
EATON CORPORATION
www.eaton.com
otee:
N
For Testing Purposes Only: When using an external single phase current
source to test low level ground fault current settings, it is advisable to use
the Auxiliary Power Module (APM) (see Section 1 .3 and Figure 10) . Especially
when the single phase current is low, without the APM it may appear as if the
trip unit does not respond until the current is well above the set value, leading
the tester to believe there is an error in the trip unit when there is none . The
reason this occurs is that the single phase test current is not a good simula-
tion of the normal three phase circuit . If three phase current had been flow-
ing, the trip unit would actually have performed correctly . Use the APM for
correct trip unit performance whenever single phase tests are made . .
3.9 Ground Fault Time Delay Setting
As illustrated in Figure 18, there are two different Ground Fault
curve shapes, i .e ., fixed time (flat) and I
2
t response . The shape
selected depends on the type of selective coordination chosen . The
I
2
t response will provide a longer time delay in the low-end of the
ground fault current range than will the flat response .
Five flat ( .1, .2, .3, .4, .5 sec .) and three I
2
t ( .1*, .3*, .5* sec .)
response time delay settings are available . The I
2
t response settings
are identified by the suffix asterisk (*) that appears in the setting
viewing window . The I
2
t response is applicable to currents less than
0 .625 x I
n
, (the I
n
value is marked on the installed rating plug) . For
currents greater than 0 .625 x I
n
, the I
2
t response reverts to the flat
response .
otee:
N
See also Section 1 .1 .5 on Zone Interlocking .
Figure 18. Ground Fault Time Delay Settings.
.1*, .3*, .5*
.1, .2, .3, .4, .5
I
Available Settings
- -------
I
I
.
Seconds with
Flat Response
,
.
.
Shape
Returns to Flat
Responses at
Approximately
0.625
Seconds With
“*” In
Shape
Indicates
Shape
.3 Sec.
Gnd. Fault
Time
I
n
I t
2
I t
2
I t
2
Viewing Window
4 Test Procedures
4.1 General
DANGER
DO NOT ATTEMPT TO INSTALL, TEST OR PERFORM MAINTENANCE ON
EQUIPMENT WHILE IT IS ENERGIZED. DEATH OR SEVERE PERSONAL
INJURY CAN RESULT FROM CONTACT WITH ENERGIZED EQUIPMENT.
DE-ENERGIZE THE CIRCUIT AND DISCONNECT THE CIRCUIT BREAKER
BEFORE PERFORMING MAINTENANCE OR TESTS.
REFER TO THE APPLICABLE CIRCUIT BREAKER INSTRUCTION LEAFLET
SUPPLEMENT (LISTED IN SECTION 5) FOR COMPLETE INSTRUCTIONS.
CAUTION
TESTING A CIRCUIT BREAKER UNDER "TRIP CONDITIONS" WHILE IT IS IN
SERVICE AND CARRYING LOAD CURRENT, WHETHER DONE BY LOCALLY OR
BY REMOTE MEANS, IS NOT RECOMMENDED.
ANY TRIPPING OPERATION WILL CAUSE DISRUPTION OF SERVICE
AND POSSIBLE PERSONAL INJURY RESULTING FROM UNNECESSARY
SWITCHING OF CONNECTED EQUIPMENT.
TESTING OF A CIRCUIT BREAKER THAT RESULTS IN THE TRIPPING OF THE
CIRCUIT BREAKER SHOULD BE DONE ONLY WITH THE CIRCUIT BREAKER
IN THE "TEST" OR "DISCONNECTED" CELL POSITIONS OR WHILE THE
CIRCUIT BREAKER IS ON A TEST BENCH.
4.2 When To Test
Tests can be conducted with the breaker in the "connected" cell posi-
tion while carrying load current . However, as stated in the caution
note in Section 4 .1, good practice will limit circuit breaker in-service
"trip tests", where required, to maintenance periods during times of
minimum load conditions . Testing is accomplished with the breaker
out of its cell or in the "Test", "Disconnected", or "Withdrawn" (or
Removed) cell positions .
otee:
N
Since time-current settings are based on desired system coordination
and protection schemes, the protection settings selected and preset in accor-
dance with Section 3 should not be altered during or as a part of any routine
test sequence .
4.3 Testing Provisions
As indicated in Figure 19, six different "Test Amps" settings (1, 2, 3,
6T, 8 and 10 x I
n
) are available for testing the phase elements of the
Trip Unit, and two settings (GF and GFT) are provided for testing the
ground element .
CAUTION
A SETTING OF EITHER 6T OR GFT WILL TRIP THE CIRCUIT BREAKER (SEE
SECTIONS 4.1 AND 4.4.3.).
FOR ANY COMBINATION OF THE PHASE PROTECTION SETTINGS, AN
APPROPRIATE "NO TRIP" CONDITION CAN BE SET TO TEST THE LONG
TIME, SHORT TIME, AND INSTANTANEOUS TRIP SETTINGS WITHOUT
TRIPPING THE CIRCUIT BREAKER (SEE SECTION 4.4.2).
IN THE "GF" TEST POSITION, THE LEVEL OF TEST CURRENT, BASED ON I
,
IS ADEQUATE TO DEMONSTRATE THE OPERATING CONDITION OF THE TRIP
UNIT WITHOUT TRIPPING THE CIRCUIT BREAKER. THIS IS A FUNCTIONAL
CHECK ONLY, NOT A CALIBRATION.
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