The possibility always exists that you will lose your alternator output at
some point, regardless.  It could be temp overload blows the fuse, the
diodes die, armature contacts, loose connection, belt break, mechanical
problem, whatever.  Therefore, I believe it prudent to have some
"NOTICEABLE" - can't fail to get your attention - indication of the problem.
All the more important, because alternator loss can be subtle as the case of
the subie problem - unlike when a connecting rod lets go.

I flew six years with two batteries due to the critical nature of the
electrical system in an all-electric aircraft before finally deciding the
extra 16-22lbs of battery was not necessary PROVIDED you had a good
indication of system failure, had a already thought-out decision about what
you could turn off (essential bus can make that a one switch decision) AND
you swapped out the battery each year or otherwise ensured its capacity
(Load testing, etc).

My alternator normally puts out 14.6 volts in flight, the last couple of
flights its been only putting out 13.8 volts - right at the edge of my lower
voltage limit.  While that is marginally enough to keep the battery charged,
the main point is something has changed.  I initially found the belts to be
loose and thought that was the problem, tightening them seem to help for one
flight, but the 13.8 volts returned on the next flight.  So while I am
grounded awaiting my new gear box and prop, I will yank the alternator and
take it in to have it tested.  I don't like things that change without me
knowing why - especially with the electrical system.

FW

Ed

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From: <lm4@juno.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, June 01, 2004 10:00 AM
Subject: [FlyRotary] Re: Subaru Cozy has an eventful first flight.


> He probably has # 6 wire on the system ( 65 amp ).
> 80% of that being 52 amps makes everything OK. Right ?
> Larry Mac Donald
>
> On Tue, 1 Jun 2004 09:35:52 -0400 "John Slade" <sladerj@bellsouth.net>
> writes:
> >  > Can I ask a question?  Why does he have a 50 amp fuse on a 60 amp
> > alternator?
> > Apparantly he got BAD advice from an electrical guy.
>
>
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