Section 7: Test procedures
•
WARNING
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.
ANY TRIPPING OPERATION WILL CAUSE DISRUPTION OF
SERVICE AND POSSIBLE PERSONAL INJURY, RESULTING IN THE
UNNECESSARY SWITCHING OF CONNECTED EQUIPMENT.
TESTING A CIRCUIT BREAKER WHILE IT IS IN-SERVICE AND
CARRYING LOAD CURRENT IS NOT RECOMMENDED.
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.
When to test
Testing prior to startup can best be accomplished with the
circuit breaker out of its cell or in the TEST, DISCONNECTED, or
WITHDRAWN (or removed) cell positions.
ote:
N
Since time-current settings are based on desired system
coordination and protection schemes, the protection settings if altered
during any test sequence should be reset to their as-found conditions.
Test mode in trip unit
Enter the TEST submenu from the main menu. Select either
a phase or ground test. Next select either a trip or no trip
test. Select the level of current that is desired to test the unit.
A test level chosen above a setting will cause a pickup/trip
condition. If a pickup is not exceeded, the unit will remain in
a “testing” mode for three hours or until interrupted by a real
event or user pushbutton activity.
When performing a trip unit self test in TRIP mode, tripping
of the circuit breaker and activation of the associated alarm
relays can occur. This is important to consider before initiating
a test, since a circuit breaker or relay action can initiate other
equipment responses in the system even if the circuit breaker
is in TEST position of a switchgear cell. The one exception
to this is the ground trip self test function of the LSIA style
unit. A ground trip test will not actually trip the circuit breaker
but will only provide alarm display information and alarm relay
operation if this feature is enabled.
In the NON-TRIP mode of self test, the circuit breaker trip
function and any associated relay will not operate when
test alarm or test trips occur. The front panel indicating LED
will light as well as display alarm/trip cause and trip time
information.
The self test function cannot be entered if an alarm is already
present. This alarm will need to be cleared before any self
testing can be conducted. The self test function will terminate
if any of the following conditions occur after the start of testing:
28
EATON
www.eaton.com
• Any real phase current exceeds an alarm setting
• Any real ground current exceeds 0.1 per unit
• If real phase current exceeds 1 x (
I
r
) while conducting a
NON-TRIP test
• If real phase current exceeds 0.5 x (
I
r
) while conducting a
TRIP test
Functional field testing
•
CAUTION
PERFORMING TESTS WITHOUT THE EATON-APPROVED TEST KIT MAY
DAMAGE THE DIGITRIP UNIT.
Functional test kit (handheld)
Description of handheld test kit
A battery-powered test kit is available and capable of testing
trip elements for Series NRX circuit breakers, including power
up, instantaneous trip, short delay trip, and ground (earth) fault
trip. These test selections are chosen with the switch labeled
“Select Test” located in the upper right-hand corner of the test
kit (see
Figure 16
). The test currents are not adjustable for this
test kit.
Figure 16. Functional Test Kit
Test procedure
Complete procedural instructions for the Eaton functional test
kit can be found in the instructional literature which is packaged
with each test kit.
ote:
N
Disconnect cable from test kit to prevent accidental operation
and battery drainage. Reset the instantaneous setting to its original
condition. Reposition the LTM jumper to the as-found condition. Install
the small cover on the Digitrip and reconnect the plexiglass cover.
Effective September 2013
Instructional Leaflet IL01301064E
Operating Manual for Series NRX
Digitrip Trip Units 1150 / 1150i
