From: Jim Pennino
Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Fri, 27 Sep 2002 14:59:06 +0000 (UTC)
Organization: Special Solutions, LLC
NNTP-Posting-Date: Fri, 27 Sep 2002 14:59:06 +0000 (UTC)
User-Agent: tin/1.4.5-20010409 ("One More Nightmare") (UNIX) (SunOS/5.9 (sun4u))
In rec.aviation.owning Dennis O'Connor wrote:
> There is a group that discusses this sort of thing... The Aeroelectric
> Connection, which is aimed at electrical knowledge for homebuilders wiring
> their airplanes... Robert Nucholls has a book out that goes into these
> issues in fine detail.... He has decades of experience in aviation
> electronics in ga, commercial, and military projects... Suggest that you
> get his book, read it, then if you are so inclined we can discuss it
> Yes, the first solid state radios were fault intolerant, but that went away
> decades ago... BTW, a 28 volt (nominal)TSO'd radio has to withstand
> repetitive spikes of over 600 volts for certification..
True, but (we all knew the "but" was coming) decades ago is when most
GA electronics were built and when all this started.
If all the relays, solenoids, etc. have reverse diodes across them, and
all the electronics have MOVs and a decent design, this is a non-problem.
However, there is still a lot of old stuff out there.
If you feel your stuff was adequately designed to avoid the problem, just
ignore switch sequencing.
Of course, by taking this gamble, you have nothing to gain if you're right,
and a lot to lose if you're wrong.