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still more Tesla...


 RJ> I don't need a 12kv 60ma right now so if you have a 12kv 30ma (that
 RJ> works), i'll be happy to buy it off of you.  

You have to pick me up, take me out to the shop, and drop me back home.
I can give you a decent one for around $20.
 
 RJ> I have some questions on the primary coil, how thick should the 
 RJ> copper pipe be? 

I go with 3/8 inch od, or larger, soft copper water pipe or 
refrigerator tubing. 1/2 inch is pretty good.

 RJ> Does about 14 turns sound good for my 6" secondary?

Yes, 14 turns is about right, but 15 turns would be ideal.
 
 RJ> What kind of spacing should I have between turns.

1/4 to 3/8 of an inch spacing is all that is needed. The closer the
spacing the higher the inductance per unit volume of primary coil, 
the more energy that will be transfered in a smaller space (efficiency, 
efficiency...). Generally I space as close as possible on the primary,
right up the the point that the coil begins to arc between turns. This 
means I routinely use spacing of only 1/4 of an inch with tank circuit
voltages up to 25,000 Volts.

 RJ> I read that the primary should be as wide as the secondary is long 
 RJ> so I guess figuring out spacing wouldnt be too hard as long as I 
 RJ> know how many turns. Thanks. Ryan Jester

That was a ballpark rule of thumb to realign the thinking of "Classic"
Tesla coil builders who would use a tiny three turn primary that only
couples in the bottom 15%, or less, of the secondary winding. But it
is about right: my best systems had primary coils of closely spaced
soft copper pipe that were aproximately the same diameter as the
secondary coil winding length: These systems worked best when the
large primaries were tapped out at 12 - 15 turns, and the secondary
was equipped with a large toriod discharge terminal.

Richard Quick


... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12