FYI
One day when driving home from work in my beat up series 1 alpine the engine
quit and everything electrical was dead. The fuses were still good and after
a few minutes of troubleshooting I discovered that the Ammeter was dead. I
cobbled together a jumper and drove home. Upon further investigation I found
that the internal conections on the ammeter had corroded and were not making
good contact. After a little clean up and reassembly, everything was just
fine. The moral of the story is that although it may be rare, ammeters like
anything else can fail. Just be prepared and have fun.
Happy Beamming
> ----------
> From: Roger Gibbs[SMTP:rgibbs(at)pacbell.net]
> Reply To: Roger Gibbs
> Sent: Sunday, February 21, 1999 12:29 PM
> To: Jerome Yuzyk
> Cc: alpines(at)autox.team.net
> Subject: Re: ammeter: in series or parallel?
>
> Jerome Yuzyk wrote:
> >
> snip
>
> >So, this means that a single instrument failure can stop the car from
> >starting. Hmmm...
>
> I would guess that an Alpine has many "single point failures". If you
> started
> with the electrical system you might have the following:
>
> component failure mode effect
>
> battery cell short reduced voltage, current
> battery cell open no electrical power
> battery case crack same a cell open
>
> battery cable open no electrical power
> battery cable short to chassis multiple cases: smoke,
> heat, fire, battery rupture,
> no electrical power
>
> alternator open charging system won't work
> alternator short to chassis same as battery cable short to chassis
>
>
> and on and on..... because of the Alpine's limited fuse system there are
> many
> component and harness failures which can render an engine inoperative. In
>
> other systems (engine, fuel) there is a single fuel pump, a single fuel
> line
> which if crimped or blocked can stop an engine. A single oil pump, and
> oil
> pump bypass. The list, if fully completed, would probably be several
> pages in
> length.
>
> If one were to continue this process you might then add in the likely
> probability of the failure mode happening. Take the following two cases:
> 1)
> the engine has a single crankshaft, but the probability of a failure in
> the
> crank (like it suddenly breaks in two pieces) is pretty low for most
> people's
> uses (not true necessaily for racing). Case 2) there is a single oil
> bypass
> valve which, if it sticks open, results in very low oil pressure AND the
> probability is not very low. (it has happened to me)
>
> Which brings us to the question at hand: the ammeter is a single point
> failure, what to do about that. A solution is, as Tom wrote, to wire a
> shunt
> switch across the ammeter. Whether you choose to do this or not depends
> on
> how nervous you are about this happening to you. How probable is an
> ammeter
> failure ? I have never had an ammeter failure. I am not familiar with the
>
> Lucas design, but if it is like the design I am familiar with it consists
> of a
> shunt wire in parallel with the meter movement. Although the meter may be
> of
> modest reliability, the shunt wire ought to be pretty high in the
> reliability
> arena.
>
> Anybody out there have their ammeter fail and disable their electrical
> system
> ?
>
> -Roger
>
> .
>
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