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Hi, Ed....thanks for the links. After
successfully resetting fuses in military aircraft, I feel more comfort in
knowing that I at least have the option to reset or not to reset. In one
case, it was the landing gear motor on a King Air that got pretty hot during
touch-and-go's during a checkride. Once the motor cooled, the circuit breaker
was successfully reset, and we were able to lower the gear. I am replacing my
fuel pump fuses with CB's.
Anyway, the purpose of
this email is to comment on the fuse that blew on my fuel pump circuit. We
looked at it with a maginfying glass, and there was no dark or black area around
the break, as there often appears after a fuse blows. What we did notice,
however is that the gage of the wire inside the fuse looked suspiciously small.
We compared it to 5 or 6 other 20 amp fuses we had, and the wire was definately
smaller in gage. It looked to be the same size as a 7 1/2 amp fuse we compared
it to. It did, however have the standard yellow plastic cap and marking of 20 on
it. It definately was a lighter gage wire used for the fuse portion than
the other 20 amp fuses we had. Possibly a manufacturing defect, or maybe it was
a 7 1/2 amp fuse and it received a yellow cap marked 20 amps somewhere along the
assembly line or ??? Don't know the answer to this one, but there is no
doubt at all that the wire was similar in size to a 7 1/2 amp fuse. Maybe
something to look at when installing them. Might have been made on a Monday or a
Friday. FWIW. Paul Conner
----- Original Message -----
Sent: Monday, May 02, 2005 8:16 AM
Subject: [FlyRotary] To Fuse or not to
Fuse
Since this is the umpteenth time that the fuse vs
CB topic has come up (not just on the rotary lists but aircraft list in
general), and certainly won't e the last, I decided to do something different
than just spout my views on the topic. I surfed the net and see if I
could find anything on it.
Here are some of the URLs I found of
interest.
This guy actually did some tests and found among
other things that a fuse rated capacity can slowly degrade with repeated high
current flows even if below its burst point. But, read it and draw your
own conclusions.
This one has an interesting summary, but since
they are presented by the makers of CB can be considered Biased
Another maker of CB propaganda, however they do
point out that you can not test a fuse since it is destroyed if it proves it
works at the specified rating where as you can a CB
Here is Bob K's and his well reasoned
argument FOR fuses
It appears that there is as much debate outside
the aviation community (or more) about fuses Vs CB. It appears to me the
CB is winning there simply because of convince rather than any technical
advantage - That is once the problem causing the short is fixed, you
simply reset the CB rather than trying to find a fuse of the right rating and
shape to replace the blown one and possibly sticking in the wrong
fuse. And you know Americans - convince before all else {:>) -
At least that's the way it appears to me.
Ed
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