98
New generation IZM97, 99 low voltage air circuit breaker instruction manual
MN013010EN February 2020 www.eaton.com.cn
Section 8: Inspection and maintenance
8-4.1 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 lever-
ing-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 per-
formed on the circuit breakers as part of any maintenance pro-
cedure. 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 oper-
ator, 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 Type P release self-test function, the Digitrip
Test Kit, or the hand-held Functional Test Kit. 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.
8-4.2 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 dam-
age or dirt. Be especially alert for signs of significant erosion of the
V-shaped plates inside the arc chute.
Figure 8-1 Top rear view of circuit breaker (with one arc
chute removed)
Figure 8-2 Bottom view of arc chute
Arc chute removed
Baffled cover
Arc chamber
Alternating
V-Shaped
Plates
