Re: ??Where to get a POLE Transformer??

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 4/6/01 10:17:35 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes: 


>
> > 
>
> Hi All, 
>
> Out of curiosity, why's the aluminum wound pig crap?  There should be 
> little effect of oxidation on the internal connections, as it's submerged in 
> oil.  The 14kv10kva pig I got is aluminum wound.   If I'm remembering right, 
> aluminum wound pigs use foil vs wire (I'm sure more educated ppl can correct 
> me if I'm wrong).  The foil will have many times the surface area of the 
> wire, so it can carry more current. 
>  Besides all that, caps use aluminum, and they stand up to pretty chunky 
> current jolts with no trouble.  Only real drawback I can see to aluminum 
> over copper is the higher resistance once the surface is oxidized. 
>
> So I ponder, why is the aluminum pig crap? :) 
>
>
> Shad 


Hi Shad! 
I know many old-time electricians that have the "Aluminum is Crap" attitude. 
I believe it stems from the fact that Aluminum wire has a higher resistance 
(~1.75X) and lower heat dissipation than copper, requiring larger wires for 
the same current capacity. Fires started by overloaded wiring are much more 
likely to occur in buildings with aluminum wiring. The oxide problem you 
already mentioned, and there is the problem of chemical reaction at any 
interface with other metals. Properly sized however, it has the advantage of 
a lot less weight, and it is cheaper, which helps when hanging many large 
transformers from poles.   

Matt D.