I.L. 29C883E
5.0
TESTING
A test receptacle is built into each trip unit to allow use of
the STK2 Test Kit. The Test Kit performs a test of the
Long Delay, Short Delay and Ground Fault functions.
6.0 FRAME RATINGS AND RATING PLUGS
The
Frame Rating
of a circuit breaker is the maximum
RMS current it can carry continuously. The maximum
Short-circuit Current Ratings of the circuit breaker are
usually related to the Frame Rating as well.
It is often desirable to be able to choose a current value
less than the full frame rating, to be the basis for the
coordination of the circuit breaker's protection functions,
without affecting its short-circuit current capability. For the
Digitrip 31
0
Trip Unit this is implemented by changing the
Rating Plug.
For Adjustable Rating Plugs, Table 1-2, the primary cur-
rent carrying conductors used with the breaker must be
sized to correspond with the maximum setting of the rat-
ing plug, in accordance with National Electric Code
req u
i rements.
The
Rating Plug
(See Fig. 5.2) fits into a special cavity to
complete the trip unit.
The
Rating Plug
current rating,
is the basis for the
trip unit current settings:
1) The long delay protection function of the trip unit is set
2) The short delay pick-up setting is a multiple of
3) The ground pick-up setting is independent of
Rating Plugs for the Digitrip
RMS 31
0
Trip Units are
marked for and may be applied on both
50
and 60 Hz
Systems.
at
Complete catalog descriptions of all available rating
plugs are given in the applicable circuit breaker supple-
mentary instruction leaflets (see Section 7.0).
7.0 REFERENCES
7.1
Digitrip RMS Trip Assemblies
I.L.
I.L. 29-885
I.L. 29-886
I.L. 29-888
7.2 R-Frame
Molded Case Circuit Breakers
29-1 07
Frame Instruction Leaflet
Supplementary Instructions for
Instructions for Digitrip
RMS 31
0
Trip Unit
Instructions for Digitrip
RMS 510 Trip Unit
Instructions for Digitrip
RMS 61
0
Trip Unit
Instructions for Digitrip RMS 81
0
Trip Unit
R-Frame used with Digitrip
RMS Trip
Units
Typical Time-Current Characteristic
Curve for R-Frame Circuit Breakers
I.L.
Master Connections Diagram for
R-Frame Circuit Breaker with Digitrip
RMS Trip Units
DANGER
BEFORE YOU FIT THE RATING PLUG INTO THE TRIP
BE SURE TO CHECKTHAT THE BREAKER
TYPE AND FRAME RATING, MATCH THOSE
PRINTED ON THE RATING PLUG COVER.
INSTALLING A RATING PLUG THAT DOES NOT
MATCH THE BREAKER TYPE AND FRAME RATING,
CAN PRODUCE SERIOUS
AND/
OR
FAILURE OF THE PROTECTION SYSTEM.
Effective
February 2006
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