Fuses versus Breakers

wrote:
writes:


Generally, you size a breaker several times the normal operating
current. So if your vario draws 0.1A a 0.5A breaker would be a good
choice. The voltage drop is proportional to current, so at 0.1A it
will be less than 0.4V. This should be of no consequence to your
vario. A fuse will have a lower voltage drop, but isn't resetable.


No, you should size a fuse acording to the WIRE! So if you wire is
rated for 5A, then fit a 5A fuse.

The fuse rating certainly shouldn't exceed the rating of the wire (or
switches used). It wouldn't be uncommon to have wire rated for 20 amps,
which is more than you want for the fuse rating in this application.


Be sure to check inrush current
and fit a `slo blo' if needed.


Bad idea. Slow blow fuses have much higher resistance than
normal ones, leading to increased voltage drop.



While a fuse is highly reliable, it isn't perfect. And you can be
assured that if it does fail it will be at the worst possible
moment.


The best way I know of to increase fuse reliability is to replace
them every few years. Or it is for 3AG or the like.

Never seen that one before. I've flown for 25 years without replacing
fuses, and never had one fail.

-Dave