Re: Alternators (From almost a year ago), off the cuff scruff-You may not want to read-But all of Gary's stuff is informative or at least funny,I hope.

[farna@xxxxxxx]

Well, thanks for setting us straight Gary! Just leave names out next time. We all make mistakes, and sometimes get our heads up our rears when we "know" something, only to find out later we're wrong. I try not to do that, just to remain skeptical unless someone comes up with some real proof or a better explanation -- like you just did -- one very good explanation too! Corrections should always be appreciated!! 


On December 5, 2005 Gary Walker wrote:

> A lot has been written lately about the demerits of "off the cuff"
> information.  I wrote what I thought at one time was an informative reply to
> a person on list and was rewarded with a smug "...this is completely
> wrong..."  .     I knew that I was right in what I said but incomplete on
> the subject which was the purpose of the isolation diode in the Motorola
> alternator so I chose to remain silent until I rehapened upon some
> literature to back up my claim.
>    My statement was this ( as copied and pasted ) ;
> 
> You can run one of these Motorola alternators without the isolation diode
> but it is like replacing a fuse with a slug.   The diode mounted in a red
> stamped steel heat sink plate on the back side of the alternator is there to
> protect the internal diodes which are much harder to replace.  Clip your
> jumper cables on backwards and the isolation diode may go, but the circuit
> to the internal diodes should then be open and protected.
>       Gary Walker
>    A lister retorted  ( apparently off the cuff ) so I dropped the subject,
> not having time to find a source to back me up.   HOWEVER, now after almost
> a year, I happened to notice that on page 62 of Chilton's Copyright 1971 AMX
> & Javelin Repair and Tune Up Guide     the following ;
>    "The alternator generates three phase alternating current, which is
> changed to direct current by six silicon diodes. The entire DC output of the
> alternator is then passed through the ISOLATION DIODE.  The ISOLATION DIODE,
> mounted on an external heat sink on Motorola models and internally on
> American Motors made and Prestolite alternators, is quite important, in that
> it, like all diodes, will pass current in one direction only.  IT THEREFORE
> PROTECTS THE ATERNATOR FROM EXCESS BATTERY VOLTAGE FEEDBACK."
> (  I rest my humble case )
> 
>      The text goes on to list two other benefits of the isolation diode and
> a " SIDE BENEFIT" as quoted in the text, that is, according to my detractor,
> the sole purpose of the item in question.   (  Which  in my humble opinion
> only comes into play, by the way, if one or more of the internal diodes have
> already become partly or completely shorted internally and are thus leaking,
> which goes back to the isolation diode which is probably already shot at
> this point.)   ( I have had meters since the seventies and know how to use
> them and I also have an alternator spin up testing machine. )    I have a
> lot to learn but I did not fall out of my tree yesterday, Mr. Crooks.
>                Your AMC Friend,
>                 Gary Walker,   owner of some old AMC stuff,  including the
> Grant Rebel F/C  et al
> P.S.   I'll have another stroke at the bloke that believes that any time a
> change is made to a part in process of production that the part number (
> casting, stamping or whatever ) always changes.    They MAY, but I assure
> you they do not always change.   I just completed 30 years of hellacious
> work with GM.   I know Jack AND Jill.


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