Re: 15" coil project

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

Original poster: "Brett Miller by way of Terry Fritz <twftesla-at-qwest-dot-net>" <brmtesla-at-yahoo-dot-com>

John,

Thanks for all the info.

> get about 1400 turns which should be enough.  You
> can
> try the 22awg if you're daring.   

Hmmm...I still may do that.

> You'll probably get 10 people telling you that large
> coils need
> real thick wire, that lots of turns are only good
> for small coils,
> etc.  Needless to say, I don't agree, but I can't
> really prove it
> since I've never built a very large coil.  

Yeah.  Neither have I, my biggest coil is my 6"
project.  But I plan on doing a lot of efficiency work
and some comparison studies.

> In my view, a coil should
> tend to scale up evenly in almost every way, aspect
> ratio,
> toroid size, wire sizes, etc, etc.  

I agree.  I am planning on winding a new secondary for
my 6" coil using 28AWG instead of 23AWG like my
current 1000 turn secondary.  I will use the same pvc
form material poly coating.  Every factor will be the
same except for the wire.  I will probably have to
redesign my primary first however...it has a few flaws
that bother me (30 degree inverted conical...only 14
turns) and would make a comparison study impossible.

> Some people have
> reported
> that they built a big coil using thick wire, and it
> gives good 
> performance, so therefore thick wire is best.  I

I would consider that to be highly dubious.  Until we
have some real empiracal data on the subject, any
conclusion based on anecdotal evidence is going to be
error prone...that's how we wound up with the
misconceptions from the Richard Quick era.

> never could 
> understand their logic, since they never did a
> comparison
> with thinner wire.

Exactly.  Someone with experience and adequate
equipment really needs to write a paper on how wire
gauge/turns etc. affect coil efficiency...hint..hint.

>  This sounds like a nice project
> you're planning.

Thanks.  I hope so.

-Brett

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