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19
Instructional Book
MN01301003E
Effective July 2011
Series NRX Low Voltage Power (Air)
Circuit Breakers User Manual
EATON CORPORATION
www.eaton.com
Figure 19. Step 3
Step 4e:
The breaker is ready to be levered. With the circuit breaker
OPEN, reset the detent system by sliding the grey button to the right,
then release (
Figure 18a
). Rotate the levering tool clockwise to the
different available positions (DISCONNECT, TEST, CONNECT).
otee:
N
The position indicator on the lower right portion of the breaker
indicates the position as each position is reached.
When the breaker reaches the CONNECT position, a hard stop
is encountered. Discontinue levering to avoid damage due to
torquing beyond the maximum of 25 ft-lb (33.3 Nm).
otee:
N
Full CONNECT
= Hard Stop
Figure 20. Step 4
Step 5e:
To remove the circuit breaker from any position or from
the compartment completely, reverse the insertion procedure just
described in Steps 1 through 4 by rotating the levering tool in a
counterclockwise direction. When the DISCONNECT position is
reached, the circuit breaker will no longer move out of the cassette as
a result of rotating the levering tool. At this point, the circuit breaker
can be pulled out of the cassette onto its drawout rails.
IMPORTANT
THE CIRCUIT BREAKER MECHANISM IS INTERLOCKED SUCH THAT CHARGED
CLOSING SPRINGS ARE AUTOMATICALLY DISCHARGED IF THE CIRCUIT
BREAKER IS LEVERED INTO OR OUT OF THE CELL. DISCHARGE TAKES PLACE
BETWEEN THE DISCONNECT AND TEST POSITIONS.
Operating mechanism
The Series NRX operating mechanism is a two-stage stored energy
trip-free mechanism. Energy is stored for a closing operation with
sufficient energy remaining to open the circuit breaker after a closing
operation.
All circuit breakers should be operated manually and/or electrically
before they are put into service. This can be done during the installa-
tion process or some later date prior to startup. To perform this opera-
tional check, follow the procedures outlined in this section.
Manual operation
On manually operated circuit breakers, the closing spring can only be
charged manually. To manually charge the spring and operate the circuit
breaker, proceed with the following three steps:
Step 1e:
Insert one finger in the curved recess behind the charging
handle and pull out and down.
Figure 21. Step 1
Step 2e:
It takes approximately seven full downward strokes to
complete the charging process. It is possible to manually recharge the
spring immediately after closing the breaker, before it has been tripped
open. The status of the spring (charged or discharged) is indicated in
the mechanism spring status window just above the pushbuttons.