Malcom, et al.
I used that length recommended in the post you refer to. THe length was a few
inches. No good for
me! I needed much more length (12"-15").
Here is what I did:
First I turned on all the accessories and ignition. I read the "dischage"
reading on the ammeter.
I then attached a female spade clip on one end of a long piece of wire (2
feet). This connected
to the least accessible terminal on the ammeter.
Then I attached another female and male spade clip on another wire about 5" in
length.
The length was just enough to conveniently access the end of the wire after the
female
end was attached to the more accessible ammeter terminal. The male connector
was of
the type which fully seals when mated with the female connector so nothing will
short it out.
I then progressively shortened the long wire until I got the ammeter to read
(with the shunt)1/2 of the
reading without the shunt.. (an inch + or - makes negligible difference).
WHen I determined the
proper length, I attached the female end on the wire, mated the two wires
together, and
VOILA A meter now calibrated to 60 amps positive and negative. Took about 30
minutes to
figure out what to do when the recommended length was way off. Took another 30
minutes to do the job.
The meter does not peg on startup with a 70 amp alternator.
-Tony
ARhodes@compuserve.com
>Message text written by INTERNET:triumphs-owner@autox.team.net
>From: Malcolm Walker <walker05@camosun.bc.ca>
>Subject: Re: I need a broken amp meter for TR 2/3/4..Anyone??
>
>
>On Mon, 17 Jan 2000 Z27407@aol.com wrote:
>
>> I need a broken amp meter for an experiment. I have recently put a
>> alternator on a TR4a and the customer wants to have an original looking amp
>> meter that will read correctly with the high output alternator and I think
>> that I can modify a factory amp meter to read up to 60 amps accurately. I
>
>FWIW, ammeters aren't that accurate. They're only an approximation of
>what's going on. (or NOT going on)
>
>> just need a broken meter that I can take apart and rework since there is no
>> guarantee that this will work. I dont want to destroy a good working meter..
>
>You can alter the reading on an ammeter without getting into the guts of
>it. You need a shunt.
>
>A shunt is basically a piece of wire that lets 'most' of the current go
>around the ammeter instead of through it.
>
>A while back someone calculated the size & length of steel wire required
>to bring the ammeter scale 'down' so that it would read higher (I think 55
>A instead of 30A) I can't remember the final results but I think it was
>around 5 inches of 10 or 12ga wire, shorting the terminals on the ammeter.
>
>...Of course you still need to pull the bezel off and change the numbers,
>if necessary, but IMHO it's an easier fix than fiddling around inside, and
>it's 100% reversible.
>
>Anyone got the correct numbers for the Magic Wire?
>
> -Malcolm<
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