Rockwell Automation 140U N-Frame Circuti Breakers Instruction Leaflet for N-Frame Circuit Breakers - Manual (Page 7)

Page 7
Wrap conductor cables with 3/8” nylon or equivalent rope
as shown in Fig. 2-5, having a minimum tensile strength
of 2000 Ibs, at 6” from terminals and every additional 6”
with 5 wraps or every additional 1” with 1 wrap.
Note: Steps 2.6 and 2.7 are not required for the
molded case switch.
2.6 Adjusting Trip Settings
The N frame circuit breakers have the trip unit built
in as an integral part of the breaker. The trip unit is
not field replaceable. The various trip unit settings are
described in section 4. They should be adjusted as
required at this point.
2.7 Rating Plug Installation
The circuit breaker requires the installation of a rating
plug to make it operational. The installed rating plug
establishes the maximum continuous current rating (I
n
) of
the circuit breaker. A typical rating plug is shown in
Fig. 2-6. Available rating plugs are listed in Table 1-2.
Fig. 2-6 Rating Plug
To install the rating plug perform the following steps:
Note: Before attempting to install the rating plug, the
arrow in the Push-to-Trip button portion of the plug
must be pointed toward the REMOVE position. This
can be done with a small screwdriver.
a. Position the rating plug as shown in Fig. 2-7.
b. Make sure the arrow on the rating plug Push-to-Trip
button is pointing at REMOVE. Adjust, if necessary,
using a flat blade screwdriver.
c. The projections on the rating plug shaft must line up
with the matching slot in the trip unit and the contact
pins must match with the sockets in the PC board.
d. Push the rating plug in as far as it will go. The electri-
cal contact pins will enter matching holes in the trip
unit.
Fig. 2-7 Rating Plug Installation
e. Place a flat blade screwdriver in the slot on the
Push-to-Trip button. Press approximately 1/16 inch
and turn button 90
°
clockwise.
f. If an adjustable rating plug is installed, four continu-
ous current settings are possible. Set the switch
marked A,B,C,D to the current rating desired.
The circuit breaker is now ready for operation.
Note: The reverse procedure is used to remove the
rating plug. Turn the Push-to-Trip button to the
remove position. This action will cause the circuit
breaker to trip. Then grasp the lip of the Push-to-Trip
button and gently pull. A small screwdriver placed
under the left edge of the Push-to-Trip button will
assist in removal.
3. OPERATION
3.1 Manual Operation
Manual operation of the circuit breaker is controlled by
the circuit breaker handle and the Push-to-Trip button.
The circuit breaker handle has three positions, two of
which are shown on the cover raised lettering to indicate
ON and OFF. On the handle, ON, OFF, and TRIP are also
shown by a color-coded strip for each circuit breaker han-
dle position: red for ON, white for TRIP, and green for
OFF (See Fig. 3-1.). The Push-to-Trip button checks the
circuit breaker tripping function and may be used to peri-
odically exercise the operating mechanism. The button,
located in the rating plug, is designed to be operated by
finger pressure.
40752-093(1) Effective 5/02