Re: Primary Winding
Congratulations on your beginning in coiling! While I'm now where near an
expert, I think I can help you out with this one:
When instructing how to build your primary, most of the old texts simply
said, "wind a few turns of a heavy conductor." or something vague to that
extent. Most coilers now STRONGLY recommend NO LESS than 8 turns.
Personally, I usually put 15 turns into my primaries. (You see, when you
get your coil working, you must tune it to perfection by moving the
connection on your primary in or out, taking in or excluding turns. My six
inch diameter secondary coil has a 15 turn primary, but it tunes out at
about 9.5 turns.) Plenty of turns on the primary are always good. It means
you deon't need as much capacitance, same spark for less power, less strain
on the system in general.
Now, what to use for the primary conductor? The most common material among
coilers would have to be soft, copper "refrigerator" tubing. Solid wire is
a waste of copper because the current in a tesla circuit travels on the
_surface_ of the conductor ('skin effect' -happens with high frequency).
This is why tubing is a good choice. In most cases, (low to medium power
levels) 1/4 or 3/8 size tubing will work just fine. I recommend you buy no
less than a 100 foot roll (It's not very expensive). Other things will also
work though, your just looking for conductors with high surface area and no
sharp edges for high voltage to arc off of. Tubing is by far the easiest to
work with in most cases and almost definately the best for a first coil.
So, how do we wind this thing? Well the idea is to have the primary coil
wound around the secondary, with enough space between the two coils to keep
them from arcing over. For small to medium coils an inch or two should be
plenty of clearence. So basically, the secondary coil is situated
physically within the primary.
Hope this helps some and I hope I haven't told you things you already know,
Good luck, and email anytime if you get stuck.
Besk of Sparks,