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Ammeter back to basics

To: Jay_Laifman@countrywide.com
Subject: Ammeter back to basics
From: Jeff Howarth <jeff@v8tiger.demon.co.uk>
Date: Tue, 28 Nov 2000 20:21:16 +0000
HI Jay,

I think you may need to go back to basics and forget your assumptions on
what was wired right.

1. If the Ammeter is only registering when the engine is running, then
surely it must be measuring the output current from the ammeter.
        

Assumption - your battery is not going flat in all of this. therefore
the Alternator works.



2. If it does not budge when the lights are switched on with the engine
off then it is not measuring current out of the battery.

Assumption - the lights come on as usual

Forget positive or negative earth as all that would do is move the
needle in the opposite direction (and maybe a little smoke).

It points to the ammeter being wired in the wrong place

It sounds like it is wired in line with the alternator output rather
than in line with the electrical load. It should sit between where the
thick wire from the alternator joins the battery lead on the starter
solenoid and the fuse box. feeds (switched and unswitched).

If that's not clear come back to me.


regards


Jeff








In message <OFEAE445CC.09E7BF69-ON882569A5.005CA450@countrywide.com>,
Jay_Laifman@countrywide.com writes
>Unfortunately I wish that was the answer, but I know it was working fine
>before I switched alternators.  That's all I changed in the electrical
>system.  So, either the alternator does not really wire like the Nissan one
>did - and as both shops have told me it wires, or there is something else
>that is shot.
>
>This new alternator is from a Mazda RX7.  Is there any chance in the world
>that the rotary engines spun the other way or that it makes any difference
>even if it did to the functioning of the alternator?  I've had both
>answers!
>
>The oddest thing is still that as I turn things on - car 15 amps,
>headlights 10 amps, OD few amps, the ammeter keeps going up and never comes
>back down.  When I turn on the headlights with the car off, the ammeter
>sure doesn't show a 10 amp drain - if anything it doesn't budge.  But, I
>haven't tried it with the ignition on, but the engine off.
>
>Jay
>
>
>
>
>
>Marc James Small <msmall@roanoke.infi.net> on 11/28/2000 08:46:52 AM
>
>To:   Jay_Laifman@countrywide.com
>cc:   alpines@autox.team.net, tigers@autox.team.net,
>      british-cars@autox.team.net
>
>Subject:  Re: RX7 wiring diagram needed
>
>
>Jay
>
>The problem with your ammeter may just be that the wires to the meter are
>reversed.  If you converted your car from positive to negative ground and
>at that point switched the ammeter wiring and THEN replaced the ammeter
>with a negative-ground meter, you might have to flip the wires to the meter
>back again.
>
>Just a thought.
>
>Marc
>
>msmall@roanoke.infi.net  FAX:  +540/343-7315
>Cha robh bas fir gun ghras fir!

-- 
Jeff Howarth

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