Re: Interested in coils...

        Re: Interested in coils...
        Tue, 8 Apr 1997 08:12:50 -0400 (EDT)
        tesla-at-america-dot-com (Bob Schumann)
        Tesla List <tesla-at-pupman-dot-com>

>        Interested in coils...
>  Date: 
>        Thu, 17 Apr 1997 20:55:38 -0400
>  From: 
>        Corey Edmunds <corey-at-efni-dot-com>
>    To: 
>        tesla-at-pupman-dot-com
>Hi Everyone!
>Just so you know, my name is Corey Edmunds.  I live in a small town near
>North Bay, Ontario, Canada. Im 15 years old and I am a interested in
>making a Tesla Coil.  I have poked through the archives -at- ftp.funet.fi
>and well i still have a few questions about materials/construction...

        Welcome to the List! There are many people here to help you
as they did me - and continue to!

>-Neon Sign Transformer
>        -How much should a used one cost
>        -What voltage/amperage should I ideally get?
>        -Where can I get one? (Local Neon Shop?)

Unless you come from a rich family, have won the lottery, or
just have money to blow, don't buy a new neon transformer.
Richard Hull, a coing great, has put it best when he says
that neon sign transformers are 'doomed' in Tesla coil usage.
Look in the phone book's yellow pages for sign companies that
do neon and go the shops and ask for old transformers. Tell
them what you are using it for. Many sign companies will
GIVE you old transformers or sell them cheaply. Common
voltages are 9kv, 12kv, and 15kv for Tesla coils usage. The
transformer outputs are most commonly 30ma, 60ma, 120ma with
30ma being the most common. Transfomers can be 'paralleled'
for greater current. Ifthis is you first coil, for safety's
sake and learning curve, use a smaller transformer like maybe
a 9kv or 12 kv at 30ma. You can construct your coil so that 
later you can swap in/out other transformers.

>-The wire
>        -Where can I get it from (A hardware store?)?

It's doubtful you will find magnet wire at a hardware store.
You can look in the suppliers section of this page:

Marlin P. Jones maybe a place to buy magnet wire and also
powered iron core forms you can use to make your RF chokes
You can call for a free catalog at 1-800-432-9937
A common wire guage for Tesla coils is #22

>        I think i will try to make some sort of salt water-bottle
>Would beer bottles & veggie oil         work in it?

Can't comment here on the bottle capacitors though I have read
that people have used them with success and have posted their
results to the list. I saved the money and bought a commercial
capacitor and would not give it up for anything!

>        -What's the dif. between an achemedes spiral and a pancake

They are both the same thing. A lot of coilers use the
'inverted cone' type primary for small to medium coils
due to the position of the field created by it in relationship
to the secondary coil.

>        -About how many turns should I use?

A lot of coilers are using 1/4 inch or better SOFT copper
water tubing to make the primarys. A 50 foot roll will get
you somewhere around 14 to 15 turns. It is best to design
the system to tune out 10 turns or more.

>        -What is the best material?
>        -What is the best shape?

The primary is best accomplished by 'surface area' and it is
said that copper straping or belts would be close to ideal,
however because of the 'edges' of the strapping, there may
be losses and corona. The copper water pipe seems to be mostly
used as it has good surface properties and no edges.

>        I have a few "C" shaped things off a TV tube.  Would 2 taped
>work for the ferrite cores?

Get the Marlin P. Jones catalog and check out the powered iron
core forms they have there...not to expensive.

>        (Just a curiosity..)
>What is a VARIAC and what are they used for??

I always like to think of a VARIAC as VARI-AC.
The variac is an autotransformer that allows you to
control AC voltages. Coilers use these to slowly
'bring up' the voltage to a Tesla coil system instead
of just 'socking' the juice to them. I have used them
to tune my coil at lower voltages before I crank them
up to full power.

>Well thats about it...
>        Thanks!
>                Corey Edmunds
Hope this helps

Bob Schumann