Not sure what the single failure mode is here that would cause such grief.
Alternator diodes tend to fail open circuit. Failed regulator may put many
additional volts on the bus to the extent that other things pop, although
the battery will act as a swamp until it boils dry or the alternator is
isolated.
A fuse (to protect the wiring) in the alternator line would prevent the
battery discharging through any short circuit there; further the battery
wiring would logically be stouter than that to the alternator, making it
unlikely in the extreme that it was that that was burning.
A shorted battery cell is cannot be isolated from itself.
Duncan mcF.
----- Original Message -----
From: "Fred Fillinger" <fillinger@ameritech.net>
Subject: Re: Europa-List: Batteries
<fillinger@ameritech.net>
>
> >> "........ if there's two independent
> >>sources of power (spelled batteries)......"
> >
> > Possibly, under the FARs.
> > JAR-E is more relaxed and only calls for two independent sources of
> > electrical power; there is nothing that explicitly prohibits one of
these
> > being the engine-driven generator, so long as the electrical system can
> > allow each to operate independently of the other
> >
> > Duncan McF.
>
> JAR-E would then be loose! In again reading our old and new regs, I see
> now that the artful change in wording is now such that the 914 probably
> can't be certified at all either. It may be significant in that the
> only such approval here has been on a motorglider.
>
> My only question is if the alternator or regulator fails, AND there's
> the smell of smoke and abnormal readings on amps/volts, one should
> disconnect the battery at the battery relay, not just disconnect the
> alternator and wait to see if the smoke goes away. What then will cause
> the engine to continue to run? If one doesn't have a relay, and the
> smoke is electrical but no circuit protector pops, there's no way to
> stop the smoke without waiting for the battery to discharge or a
> necessary circuit to go open through heating. Then the engine quits.
>
> Fred F.
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