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If the system is a 4
-
wire system with a neutral current
sensor, apply the same current as described above
through one phase of the breaker, returning through the
neutral sensor, as shown in Fig.
14-2.The breaker should
not trip, and the alarm indicator,
if
supplied, should not
operate.Repeat the test on the other two phases.
If the system is a 3
-
wire system with no neutral current
sensor, apply the same current as described above
through any two phases of the breaker, with the connec
-
tions exactly as shown in Fig. 14
-
3. The breaker should
not trip, and the alarm indicator,
if
supplied, should not
operate. Repeat the test using the other two combinations
of breaker phases.
a
CAUTION
FIELDTESTING SHOULD BE USED FOR
FUNCTIONALTESTING AND NOT FIELD
CALIBRATION
OFTHE DIGITRIP RMS 310 GROUND
FAULTTRIP UNIT.
ANY TEMPORARY CONNECTION MADE
FORTHE
PURPOSE OF CONDUCTING TESTS SHOULD BE
RESTOREDTO PROPER OPERATING CONDITIONS
BEFORE
RETURNINGTHE BREAKERTO SERVICE.
The results of the test are to be recorded on the test form
provided with the equipment.
7.0
RATING PLUG
The rating plug, as illustrated in Figure 15, is used to
establish the continuous ampere rating of the related
circuit breaker.
For adjustable rating plugs (Table 1
-2), the primary
current carrying conductors used with the breaker must
be sized to correspond with the maximum setting of the
rating plug, in accordance with National Electric Code
requirements.
The Long Delay protection function of the trip unit is set at
the rating plug value
((,).The Short Delay and Instanta
-
neous protection functions are set as a multiple of In.The
Ground Fault protection function is independent of
In.
Different rating plugs are available (Table 1
-
2) to match
the desired current rating and type of circuit breaker into
which the trip unit is to be installed.
Complete catalog descriptions of all available rating plugs
are given in the applicable circuit breaker supplementary
instruction leaflets (see Section
8.0).
8.0 REFERENCES
8.1 Series C L
-
Frame Molded Case Circuit Breakers
29C105 Frame Instruction Leaflet
AD 29
-
1 67L
8.2 Internal Accessories:
The following types of internal
accessories, which mount on the trip unit, are available for
use. The number of the instruction leaflet covering the
installation of each accessory is shown.
Typical Time
-
Current Characteristic
curves for L Frame Breakers
.
Alarm (Signal)/Lockout (ASL) Switch
...........
I.L. 29C183
.
Auxiliary Switch
...........................................
I.L. 29C123
.
ShuntTrip
....................................................
I.L.29C146
.
Low Energy Shunt Trip
................................
I.L. 29C147
Undervoltage Release Mechanism (Handle
Reset
...........................................................
I.L. 29C170
Effective
March 2003
I.L. 29C615E
Courtesy of NationalSwitchgear.com
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