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From: Dale Rogers <dale.r@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: finally changed to fuses vs circuit breakers 
Date: Mon, 2 May 2005 12:02:27 -0400
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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)