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Wendell Voto wrote:
----- Original Message -----
From: "WALTER B KERR" <jbker@juno.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Monday, May 09, 2005 8:23 AM
Subject: [FlyRotary] Re: EC2 redundancy
Jim S wrote:If we've mostly agreed that we're sizing fuse/CB to protect
the wire and
not the component, what would be the point of redundant feeds to a
common power line inside the box?
What failure mode are we protecting against with this scheme? ... Jim S.
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We are protecting against a defective fuse such as Paul had or a direct
short in one of the lines that has blown a good fuse. The other line will
continue to operate the EC2 if you have diodes to prevent a backfeed. Of
course you wish to separate the wires to prevent the burning one from
destroying the 2nd one.
Bernie
If one line is shorted and they are tied together in the box, then both
lines - fuses or breakers - will see the short fault and trip.
Wendell
Or worse. Both fuses/breakers see the fault and together they're strong enough to overcome it. A single 10A fuse blows after little spark in the open end of the cracked wire insulation. No problem. But what happens when you provide the 'arc welder' some backup.
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