I understand the Line &
Load, but my AIRPAX units have what looks like some kind of a sensor
circuit. There are three small connectors between the Line & Load.
I cannot tell you specifically about the AIRPAX breakers. Aside from the
line and load connections on circuit breakers there are two other kinds
of connections that some circuit breakers have.
One kind is alarm contacts. When the breaker opens the alarm contacts
change state and can be used to turn on a light or actuate and alarm.
Somewhere hundreds of miles away on a CRT terminal a message may appear
such as "Circuit Breaker number 4 at Black Mountain relay site has opened."
The other kind of extra terminals on some circuit breakers is used as a
way to trip the breaker using some condition in another part of the
equipment other than over current through the main current path in the
breaker. For instance there might be an air flow sensing microswitch.
When the air flow is stopped due to fan failure or inlet blockage, the
total current may not increase and cause the breaker to open, yet you
would like to shut the system down before it over heats. Applying a
voltage or ground connection to one of these auxiliary terminals can be
another way to trip the breaker.
DE N6KB
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