Today's Message Index:
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1. 10:34 AM - Pull type aircrat Circuit Breakers and other types.... (David Lloyd)
2. 06:05 PM - Re: Pull type aircrat Circuit Breakers and other types.... (Fred Fillinger)
3. 06:34 PM - Re: Pull type aircrat Circuit Breakers and other types.... (Joemotis@aol.com)
Message 1
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| Subject: | Pull type aircrat Circuit Breakers and other types.... |
--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
Anyone familiar with the "insides" of the typical circuit breakers (CB) that we
use on our aircraft?
I am curious what the mechanism is that makes a CB go intermittent or bad, particularly
the low amperage units.
Also curious if "pulling" and resetting the breaker occasionally might be good
for it, by possible cleaning or re-setting any contact points inside. I have
never cut one apart and looked at the mechanism...especially the low current units.
Let's hear from the gurus.....
David
Message 2
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| Subject: | Re: Pull type aircrat Circuit Breakers and other types.... |
--> Avionics-List message posted by: "Fred Fillinger" <n3eu@comcast.net>
David Lloyd wrote:
> Anyone familiar with the "insides" of the typical circuit breakers
(CB)
> I am curious what the mechanism is that makes a CB go intermittent
> or bad, particularly the low amperage units.
The # of cycles will be in the data sheet for pullable types. For
example, the P & B W-23 is 10,000 cycles, 6,000 at 100% of rated load.
Of course, not in their literature is anything about the "mechanism
that makes a CB go intermittent or bad, particularly the low amperage
units." Especially if you're referring to the kind you can't pull, is
this documented somewhere?
Reg,
Fred F.
Message 3
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| Subject: | Re: Pull type aircrat Circuit Breakers and other types.... |
--> Avionics-List message posted by: Joemotis@aol.com
Most breakers lever, push pull etc are all very similar. That is, a spring
loaded device that is tripped by a resistive element that when it heats up
unlatches or pushes over the spring loaded trip device. Another style uses a
clicker BI metallic spring that literally "pops" when it passes more than the
rated current.
All large breakers (480, 4160,6600,14.4K volt 3 phase) in 90++ buildings I
do energy management on, with ranges from 5 amps to 5000 amps, are exercised
yearly.
Joe Motis
601 XL
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