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Rusty,
I was wondering how long it was going to take for someone to change the subject line (it was only six messages from being me.)
You've been working field service long enough to know that fuses go bad, too. They de-solder; they break due to vibration; the ends corrode and lose connectivity.
Bob Nuckols takes the position that no flight-critical system should have circuit protection as a single point of failure. And fuse systems are cheaper than breakers.
I agree, however, with those whose military experience shows the value of breakers. I'm planning on a mixed system with resettable breakers for flight-essential systems, fuses for the rest. I'm further leaning toward the small amount of extra weight that would result from having redundant paths for the most essential circuits, such as the engine control. That would be two B+ leads one through a breaker, one through a slow-blo fuse; if the breaker pops due to a surge the fuse might not; if both blow, I know it was an overload; if only one fails, I'm the energizer bunny.
Dale R.
COZY MkIV-R13B #1254
Ch's 4, 5, 16, & 23 in-progress
From: "Russell Duffy" <13brv3@bellsouth.net>
Date: 2005/05/02 Mon AM 08:37:55 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: finally changed to fuses vs circuit breakers was Re: Ed's new rotor housings
if the CB doesn't reset I haven't lost anything over a fuse, BUT if it does
reset - it may save my butt or the aircraft. Hey Ed, how about if the CB trips because the circuit breaker IS the
problem? The only tripped breaker I've seen in a certified plane turned out
to be a bad CB. I've also seen bad CB's at home, and at work. Why add
another device that can fail?
Rusty (just couldn't resist resist)
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