Installing Fixed Circuit Breaker; Basic Circuit Breaker Assembly - Eaton NRX Instruction Manual

Section 3: General operation and circuit breaker description
Step 3: Carefully push the circuit breaker into its compart-
ment until it stops. The extension rails can now be folded
up and latched
Figure 21. Step 3.
Step 4: 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 20a). Rotate the
levering tool clockwise to the different available positions
(DISCONNECT, TEST, CONNECT).
N ote: The position indicator on the lower right portion of
the breaker indicates the position as each position
is reached. The levering detent system will also
engage, stopping breaker travel.
When the breaker reaches the CONNECT position, a
hard stop is encountered. Discontinue levering to avoid
damage due to torquing beyond the maximum of
15 ft-lbs (20.3 N•m).
Figure 22. Step 4.
14
Series NRX with PXR - type RF low voltage power (air) circuit breakers instruction manual MN013002ENH03 September 2016 www.eaton.com
Note: Full connect = hard stop
Step 5: 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.

Installing fixed circuit breaker

A fixed circuit breaker is solidly mounted in its structure
with no drawout feature. The circuit breaker is available in
rear-connected configurations (Figure 23) and can be mount-
ed on a suitable horizontal mounting surface using left- and
right- side mounting feet. Refer to Section 6 for breaker and
primary bus stab details and requirements.
Figure 23. Fixed breaker.

Basic circuit breaker assembly

Series NRX circuit breakers use a rigid frame composite
housing construction. This construction provides high-
strength structural properties, excellent dielectric charac-
teristics, and arc tracking resistance. They are available
with various connection configurations and specific ratings
dictated by the applicable standards (see www.eaton.com/
seriesnrx.)
Each pole has one primary contact assembly comprised of
a moving portion and a fixed portion. The exact design con-
figuration depends upon the breaker's frame size and inter-
ruption rating.