Instructions for
Digitrip RMS 500 Trip Unit
Table of Contents
1 .0
General Description . . .... ...... . . .. ... ..... . .
1 .1
Protection .... . .. . ... ........... . .. ......... .
1.2
Information . ... .. .... . ... . ... . ... ... ..... .. . .
1 . 3
Testing . . ... .. . .. . ... . ... . ... . ... ... . . ... ... .
2. 0
UL Listed Devices . ... .... . . .. . ... ... .. . .. ... .
3 . 0
Principle of Operation . . ... . ... .... . . ..... ... .
3.1
General .... . ..... . ... . .. . .... . ... .. . .. .. ... .
3.2
Trip and Operation Indicators .. . ... ... .. .. ... .
3.3
Test Provisions . ....... . ... .... ... ..... ... .. .
3. 4
Making Current Release (Discriminator) .... .. .
3.5
Instantaneous Override . ........... . . ... .... .
3.6
Zone Interlocking ... .... . ... ....... ... .. . . . . .
4.0
Protection Settings .. . .... ... . ...... . .. . . ... . .
4.1
General ... ... ... ... . .. . . ...... . ... ... ..... . .
4.2
Long Delay Settings ..... . ... .... .......... . .
4.3
Long Delay Time Settings .... . ........ ... ... .
4.4
Short Delay Pick-up Settings ........ ... .. ... .
4.5
Short Delay Time Settings . ... ......... .. . .. .
4.6
Instantaneous Pick-up Settings . ... ... .. ... .. .
4.7
Ground Fault Current Pick-up Settings ....... .
4.8
Ground Fault Time Delay Settings . ...... . . .. .
5.0
Integral Test Panel - Test Procedure ... .. ... . .
5.1
General .. ... .... ... . ... .... .......... .. ... . .
5.2
When To Test ....... ... .... ....... ... ..... . .
5.3
Test Provision ....... ... . .... ......... . . ... . .
5.4
Mode of Conducting Tests ... ......... ... .. . .
5. 4.1
Control Power ... .... .... . ....... . . . .. ... ... .
5. 4.2
By Not Tripping the Breaker ...... ... ..... ... .
5. 4.3
By Tripping the Breaker ....... ... ... ... ..... .
6 . 0
Back-up Battery .... ... ........ ... ... ... ... .. .
6 . 1
General . ... ... ... . ... ..... ... . ... .. . .... . .. .
6. 2
Battery Check .. ... .... ........ ... ..... ..... .
6. 3
Battery Replacement ........... ... . . . ....... .
7.0
Auxiliary Power Module . .... ... ...... ..... .. .
8.0
Rating Plug .. ... . ... .... .... ... ... ... ... . . .. .
9. 0
References . . ... . ... ........ ... ... . .. . . . .. .. .
9.1
Type DS Low Voltage AC Power Circuit
Breakers .. .... .... ........... ... ... ...... .
9.2
Type SPB Systems Pow-R Breakers ......... . .
9.3
Digitrip RMS Trip Assemblies .... ... .. ..... . .
9.4
Series C® R-Frame Molded Case Circuit
Breakers ....... . ... ..... . .. ........... ... .
WARNING
DO NOT ATTEMPT TO INSTALL OR PERFORM MAIN
TENANCE ON EQUIPMENT WHILE IT IS ENERGIZED.
DEATH OR SEVERE PERSONAL INJURY CAN RESULT
FROM CONTACT WITH ENERGIZED EQUIPMENT.
ALWAYS VERIFY THAT NO VOLTAGE IS PRESENT
BEFORE PROCEEDING WITH THE TASK, AND
ALWAYS FOLLOW GENERALLY ACCEPTED SAFETY
PROCEDURES . THE WESTINGHOUSE ELECTRIC
CORPORATION IS NOT LIABLE FOR THE MISAPPLI
CATION OR MISINSTALLATION OF ITS PRODUCTS.
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The user is cautioned to observe all recommendations, warn
ings and cautions relating to the safety of personnel and equip
ment, as well as all general and local health and safety laws,
codes, and procedures.
The recommendations and information contained herein are
based on Westinghouse experience and judgement, but should
Effective May, 1 98 9 Supersedes I.L. 2 9-8 5 1 dated March, 1 988
I.L.
29-851 -A
not be considered to be all-inclusive or covering every appli
cation or circumstance which may arise. lf any questions arise,
contact Westinghouse Electric Corporation for further infor
mation or instructions.
1 . 0 General Description
1 . 1 Protection
The Digitrip RMS 5 00 Trip Unit, illustrated in Fig. 1 , is a micro
processor based type trip suitable for use in type SPB Systems
Pow-R circuit breakers and types DS and DSL low voltage AC
power circuit breakers and Series C® R-Frame molded case
circuit breakers.
The trip unit provides true RMS current sensing for proper
correlation with thermal characteristics of conductors and
equipment. Interchangeable rating plugs are provided to estab
lish the continuous current rating of each circuit breaker.
The Digitrip RMS 5 00 Trip Unit is completely self-contained
and when the circuit breaker is closed, requires no external
control power to operate its
protection systems.
It operates
from current signal levels and control power derived through
current sensors integrally mounted in the circuit breaker.
The Digitrip RMS 5 00 Trip Unit is available in six optional pro
tection models. Each trip unit may be equipped with a maxi
mum of five phase and two ground (time-current) adjustments
to meet specific application requirements. These protection
models include the following types which are further illus
trated in the nameplate examples shown in Fig. 2.
Figure
Type Protection
2. 1
Long Time/Instantaneous
2.2
Long Time/Short Time
2.3
Long Time/Short Time/Instantaneous
2.4
Long Time/Instantaneous/Ground
2. 5
Long Time/Short Time/Ground
2 . 6
Long Time/Short Time/Instantaneous/
Ground
1.2 Information
Identifier
(LI)
(LS)
(LSI)
(LIG)
(LSG)
(LSI G)
Red LED indicators are provided on the face of the trip unit
to indicate the mode of an automatic trip operation. A bat
tery is provided to maintain the mode of trip LED indication
following an automatic trip operation.
Green LEOs are provided to indicate the operational status of
the trip unit and the status of the back-up battery mounted in
the rating plug.
1 .3 Testing
An integral test panel, including a test selector switch and test
and reset pushbuttons, is provided to test the circuit breaker
in either a "Trip" or "No-Trip" test mode under qualified
conditions.
2.0 UL Listed Devices
Digitrip RMS 5 00 Trip Units are listed by the Underwriters
Laboratories, Inc. for use in types SPB, DS and DSL and
Series C R-Frame circuit breakers under UL File E7819.
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