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IZM32 / IN32 low voltage air circuit breaker
MN013017EN May 2022 www.eaton.com
Section 7: Inspection and maintenance
7-4.1 Functional field testing
NOTICE
Before doing any work on drawout type circuit breakers,
make sure that the breaker is levered out to the TEST or
the DISCONNECT position. During the levering-out and
levering-in of the circuit breaker, be aware of any signs that
would indicate that the levering process is not working
properly . If working on a fixed circuit breaker, bus systems
should be de-energized for convenience and safety. The
circuit breaker should be switched to the OFF position and
the mechanism springs discharged.
Eaton recommends that the following functional tests be
performed on the circuit breakers as part of any maintenance
procedure. The circuit breaker should be removed from service and
Eaton notified if the circuit breaker fails to perform any of these
tests successfully.
Manual operation functional test
Charge the breaker mechanism springs either using the charging
handle or the motor operator. Press the ON pushbutton to close
the breaker manually and verify closing by noting the state of
the indicating flag. Charge the breaker mechanism springs either
using the charging handle or the motor operator. If using the motor
operator, disconnect power to it to prevent automatic recharging.
Press the OFF pushbutton to manually open the breaker. Press
the ON pushbutton to manually close the breaker. Is the breaker
closed? Press the OFF pushbutton to manually open the breaker.
Is the breaker open? Repeat this entire described test procedure
three times.
Electrical operation functional test
This test procedure is based on the assumption that the breaker is
equipped with optional shunt trip and spring release accessories. If
one accessory is missing, substitute the manual button to replace
the accessory’s function. Charge the breaker mechanism springs
either using the charging handle or the motor operator. Close the
breaker by applying rated voltage to the spring release accessory
and verify closing by noting the state of the indicating flag. Charge
the breaker mechanism springs either using the charging handle or
the motor operator. If using the motor operator, disconnect power
to it to prevent automatic recharging. Open the breaker by applying
rated voltage to the shunt trip accessory. Close the breaker
using the spring release accessory. Is the breaker closed? Open
the breaker using the shunt trip accessory. Is the breaker open?
Repeat this entire described test procedure three times.
Trip unit overload functional test
This test uses the self-test function or the PXPM software. Charge
the breaker either using the charging handle or the motor operator.
Press the ON pushbutton to close the breaker manually and verify
the state of the closing indicator. Charge the breaker either using
the charging handle or the motor operator. If using the motor
operator, disconnect power to it to prevent automatic recharging.
Trip the breaker with a trip unit and verify whether the indicator
is popped out, and then reset it. Press the ON pushbutton to
manually close the breaker. Is the breaker closed? Trip the breaker
with a trip unit. Verify whether the indicator (if so equipped) is
popped out and then reset it. Reset the blinking red LED on the
trip unit by pressing the Reset/Battery Test pushbutton.
7-4.2 Arc chute inspection
When a circuit breaker experiences a high-level fault or during
regularly scheduled maintenance periods, the circuit breaker’s
arc chutes and arc chambers should be inspected for any kind of
damage or dirt. Be especially alert for signs of significant erosion
of the V-shaped plates inside the arc chute.
Figure 7-1 Top rear view of circuit breaker (with one
arc chute removed)
Figure 7-2 Bottom view of arc chute
Arc chute removed
Baffled cover
Arc chamber
Alternating
V-Shaped
Plates
NOTICE
