36
Operation and maintenance of
IZM low voltage air circuit breakers
MOELLER www.moeller.net/de/support
10/09 AWB1230-1605
Effective October 2009
Figure 48. Shunt Trip, Spring Release, and Undervoltage
Release Installed
Figure 49. Auxiliary Switch (2A/2B)
Internal electrical accessories
Other electrical accessories are mounted inside the circuit
breaker. They can be factory or site installed. There are two
different internally mounted accessories:
•
Overcurrent trip switch (bell alarm)
•
Motor operator
Overcurrent trip switch (bell alarm)—An overcurrent trip switch
(bell alarm) is an optional device that is used with an optional
pop-out indicator (see “Mechanical accessories” on page 37 and
Figure 50). It provides an electrical indication when a circuit breaker
trips as a result of the trip unit reacting to an overcurrent condition.
Opening as a result of a circuit breaker’s manual open button, shunt
trip or undervoltage release does not cause the overcurrent trip
switch to operate. The overcurrent trip switch has (2a 2b) Form C
contacts (Table 9).
The status of the contacts changes when the trip indicator pops out.
This permits the switch to be used as an alarm or in conjunction
with a spring release to block a subsequent remote electrical
closing signal.
Figure 50. Mechanical Trip Indicator with Associated
Overcurrent Trip Switch
Motor operator—A Motor operator is an electric motor assembly
internally mounted in the circuit breaker (Figure 51 and Figure 52).
It charges the closing springs electrically for remote or local
operation. The motor operator can be factory or site installed
(Table 10).
To convert a manually operated circuit breaker to an electrically
operated circuit breaker, a motor operator kit is available.
Figure 51. Motor Operator Kit
Overcurrent
Trip Switches
Mechanical
Trip Indicator
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