Magnum
38
1812.900A
Figure 3-37: Auxiliary Switch (2A/2B)
3.8.2
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 section 3.8.3 and
Figure 3-38). 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 3-6).
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.
Motor Operator - A Motor operator is an electric motor
assembly internally mounted in the circuit breaker (Figure
3-39 and Figure 3-40). It charges the closing springs
electrically for remote or local operation. The motor
operator can be factory or site installed (Table 3-7).
To convert a manually operated circuit breaker to an
electrically operated circuit breaker, a motor operator kit is
available.
Figure 3-38: Mechanical Trip Indicator with Associated
Overcurrent Trip Switch
1 Overcurrent Trip Switches
2. Mechanical Trip Indicator
Figure 3-39: Motor Operator Kit
Figure 3-40: Motor Operator Installed in Narrow Frame
Circuit Breaker
1
2
