Re: questions

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

Original poster: "Dr. Duncan Cadd by way of Terry Fritz <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>

Hi Matt, Ed, All!

>Original poster: "Ed Phillips by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
>
>> Back in the dark ages, induction coils were used to feed Tesla
Coils the way
>> NSTs are now.  It's a good way to run a TC from a car battery.
Check out the
>> info on
>> <http://freeweb.pdq-dot-net/headstrong/ind1.htm>  He covers
step-by-step
>> instructions for reproducing early 1900's induction coils, Tesla
coils,
>> etc.etc.
>>
>> Matt D.
>
> Building such a coil would have to be a labor of love!  I've often
>contemplated it, but after reading several old books on "Induction
Coil"
>construction gave decided it "ain't worth the bother".
>
<snip>
>
>Ed


It is indeed a labour of love.  Mine is not yet mounted on its (West
African) mahogany baseboard, but when it is I shall post pictures etc.
Two pounds of 42SWG/38AWG/0,1mm enamelled double silk covered copper
wire were used for the secondary and wound in "pies" around a quarter
inch thick, id 1,5" od 3", maybe eighteen or so (can't remember the
exact number).  Each "pie" was insulated with a mixture of
beeswax/rosin and I used several thicknesses of wax-impregnated card
between each pie.  I had originally used just a couple of layers of
wax-impregnated paper and around 20 "pies" but lost a couple of "pies"
and the insulating tube between the primary and secondary when I got a
spark burn a hole between two "pies" on the inside.  [Note:  Tufnol is
an excellent material for this insulating tube.  If something burns a
hole even where you can't see it, the stink is diabolical and it can't
be ignored.]  It was a monumental pain to pull it all apart and
rebuild it.  It gives one inch sparks between half inch diameter ball
electrodes (*hot* - these sparks are thick, pink and wavy and they
ignite paper or card almost instantly) and with a ~1nF cap and the gap
closed right down, it drives a micro-TC giving two inch sparks.

It looks really cute and it has been an amazing learning experience,
but it's certainly not for the congenitally impatient ;-)  Just
building the Ruhmkorff commutator switch took a whole week . . .  I'm
hoping to pick up a decent 1nF cap at a ham rally this weekend (or
suitable MuC [multi-micro-cap] :-) so I can dispense with the stack of
broken CD cases, aluminium cooking foil and vaseline held together
with rubber bands which currently serves the purpose and press on with
finishing it.  When it's finally done, it is going to look like it's
straight out of a Victorian amateur's lab . . .

Dunckx
Geek#1113 (G-1)