Re: Home Made Variac

To: tesla-at-pupman-dot-com
Subject: Re: Home Made Variac
From: Luc <ludev-at-videotron.ca> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 12 Feb 2000 18:49:54 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Tesla List wrote:

> Original Poster: Bunnykiller <bigfoo39-at-idt-dot-net>
>
> Tesla List wrote:
> >
> > Original Poster: Ed Phillips <evp-at-pacbell-dot-net>
> >
> > Tesla List wrote:
> > >
> > > Original Poster: "Kristian Ukkonen" <kukkonen-at-cc.hut.fi>
> > >
> > > Tesla List wrote:
> > > > Original Poster: Ed Phillips <evp-at-pacbell-dot-net>
> > > > Tesla List wrote:
>
>   It looked like copper or at least a metal, and I
> > would think it would short out several turns.  I suspect that anyone who
> > would go to that much trouble would know enough to use the right brush
> > material.
> >
> > Ed
>
> Hmmmm...   im lost now ....   why wouldnt a carbon brush "short out" the
> several turns as a metallic "brush" would ???  arent both materials made
> to conduct electricity ???  I understand that carbon has some
> resistivity to it but is it that high that it would matter compared to
> say a metallic brush?
>
> Scot D

You only short 2 adjacent windings around 1 volt if you take the ohm law
V=I*R :with metal you could have tens of amps but with graphite i dont
know the exact resistance if you have just 2 ohms you couldn't have more
than .5 amp.