20
IZM63 / IN63 low voltage air circuit breaker
MN013014EN May 2021 www.eaton.com.cn
Section 3: Circuit breaker description and operation
3-3.1 Manual operation
On manually operated circuit breakers, the closing spring
can only be charged manually. To manually charge the spring,
insert one finger in the recess behind the charging handle
and pull out. This permits a gloved hand to grasp the handle
and begin charging. It takes from five to seven downward
strokes on the charging handle to complete the manual
charging process. It is possible to manually recharge the
spring immediately after closing the circuit breaker and
before it has been tripped open. Standard manually operated
circuit breakers are closed and opened by hand using the
Manual ON and Manual OFF buttons respectively located on
the front of the circuit breaker (Figure 3-4).
Performing either operation is accomplished by pressing and
releasing the appropriate button. Access to these pushbut-
tons can be limited by the use of an optional, padlockable
cover. In addition, complete access to the ON button can be
prevented with an optional prevent close cover. The status of
the springs and the primary contacts is always indicated in
an indicator window just above the pushbuttons.
Electrically operated optional devices are available to auto-
matically close or trip a manually operated circuit breaker. An
electrical spring release is available to close a manually oper-
ated circuit breaker. Two optional devices, a shunt trip, and
an undervoltage release, are available to automatically trip
(open) a manually operated circuit breaker. These optional
devices can be installed easily in the field. For more details
on these devices, refer to Section 4-1 and 4-2 in this booklet.
An electrical operator that is used to charge the closing
spring automatically can be added to a manually operated
circuit breaker in the field (Figure 3-8). Manually operated cir-
cuit breakers are pre-wired to accept this addition.
3-3.2 Electrical operation
For electrically operated circuit breakers, the springs are
normally charged through the use of an electrical operator
(Figure 3-8). The springs can, however, be charged manually
as just described in the previous paragraph(Figure 3-7).
Like the manually operated circuit breaker in the previous
paragraph, electrically operated circuit breakers can also
be manually closed and opened through the use of the
front-mounted Manual ON and Manual OFF buttons.
An electrically operated circuit breaker from the factory is
also equipped as standard with a spring release to close the
circuit breaker electrically. An optional shunt trip and under-
voltage release are also available to trip (open) an electrically
operated circuit breaker. Refer to Section 4-1 for more details
on both standard and optional devices.
3-3.3 Anti-pump feature
The circuit breaker has both mechanical and electrical
antipump features. If the circuit breaker is closed on a
fault condition (and trips open while the CLOSE signal is
maintained), using either the mechanical pushbutton or
the electrical close coil, it will not make another attempt to
close until the close command is removed and reapplied.
For electrical closing, a Latch Check Switch (LCS) option
is available (see “Plug-in electrical accessories” on page
35) that will block the application of the electrical close
command until the breaker is ready to close (Section 4-1).
Figure 3-7 Electrical motor operator to charge closing
spring
Figure 3-8 Charging motor can be installed in the field
(installed)
