Vic Whitmore wrote:
>
> JAMES_S_WALLACE@HP-Canada-om1.om.hp.com wrote:
> >
> > Well, I can't really comment on the overdrive, except, I'd really like
> > one in my car!
> > As far as the copper/aluminum mix: If a connection gets a little
> > loose, a galvanic reaction occurs, generating heat..
> > This is why, if you have aluminum wiring in your house, it is
> > recommended that you periodically go around and tighten the screws on
> > your receptacles and switches. Around here, it used to be a big deal
> > when buying a house if it had aluminum wiring. You could just about
> > argue the price down by the cost of re-wiring the place in copper..
> > Haven't heard much of this lately though. Maybe there aren't any of
> > those houses left...
> > Now my galvanic reaction theory's a little rusty, so to speak, so
> > perhaps someone can elaborate (Trevor?)...
> > Regards,
> > Jim Wallace
> > '60 TR3 TS81417
> >
> > ______________________________ Reply Separator
>_________________________________
> > Subject: Re: wiring and OD tranny for TR6
> > Author: Non-HP-van (van@nucmar.physics.fsu.edu) at HP-USA,mimegw5
> > Date: 7/28/97 3:58 PM
> >
> > > "re-engineered" with lamp cord. The centre of the fire seemed to be
> > > coming from a Marrette, and when I took it apart - guess what - one
>of
> > > the lamp cords was copper, and the other was aluminum!
> > >
> > > My personal conclusion: don't do this..
> > >
> > > Jim Wallace
> > > miraculously still alive in Canada.>
> >
> > Two questions:
> > 1) Why the objection to the mixed conductors?
> >
> > 2) What is the story on TR6 overdrives. They seem to be precious
> > objects. What was the ratio (ball park) of OD's to non OD
> > TR6's. I have a '76 that has the overdrive eblem on the back but
> > someone has nicked the original unit and replaced it with a
>non-OD...
> > No sig file, Van
> Hey, I have aluminum wiring in my house. I've lived in it for 13 years
> without any spontaneous electrical fires. You just have to convert your
> high current outlets and switches to aluminum compatible components..
> The problem stems from alumumin's (aluminium for the Brits)
> characteristic to form to the joint (soft metal). I would suspect as the
> joint gets sightly warm, it expands by a small amount and eventually
> becomes loose. The joint now oxidizes and creates an "ohmic" contact. In
> other words, it has resistance. When current passes through the
> connection, it gets warm due to the resistance. Remember Ohm's Law?
> Dependent on the amount of resistance and cuurent the joint can get to
> the point of melting insulation, smoke, and fire. I've heard of a joint
> compound that you can put on aluminum wiring connections for A.C wiring
> but have never had the need to use it in my house (or car for that
> matter)..
> I believe the problem in the Marrette was due to the same type of
> situation. A sightly loose joint and a little oxidation or corrosion
> will result in the heat build-up when current is flowing..
My apologies for not signing this itel
Vic Whitmore
76 Spitfire
Thornhill, Ontario
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