Re: newbie question - spark gap and toroid

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


A 14 x 3 inch toroid would work best for a 30 mA NST.  We carry them in
stock if you need one.

Aluminum will limit your peak primary current somewhat but not too critical.
If you want the brightest sparks, then use copper on the pri SG.

At 30 mA you might find best performance with no blower at all.  Try it with
your setup to see what works the best.

Dr. Resonance

 >  >
 >  > I've got my tesla coil to work but I've got a couple
 >  > of quick questions for
 >  > you pros out there: -
 >  >
 >  > 1. My SG spark gap's made from aluminium curtain
 >  > rail, not copper pipe. The
 >  > rail is flat, so it's easier to mount. Does it
 >  > matter? My coil works, but
 >  > I'm not sure if aluminium hinders performance in any
 >  > way.
 >  >
 >  > 2. Does it matter that air isn't blown directly at
 >  > the sparks? Do the
 >  > sparks require a lot of air to be "quenched", or
 >  > will a bit of moving air
 >  > be enough? In other words, is more wind better?
 >  >
 >  > My spark gap (pic here:
 >  > http://web.singnet-dot-com.sg/~shuhuang/spark_gap3.jpg
 >  > ) sparks at the ends of the rails, which is sort of
 >  > shielded by the 10mm
 >  > thick plastic support. I can easily reconfigure it
 >  > so that the sparks get
 >  > most of the breeze from the fan, but I'm wondering
 >  > if it's worth the
 >  > effort. The fans blow, rather than suck, BTW.
 >  >
 >  > 3. I used 2 aluminium wok covers joined together
 >  >
 > (http://web.singnet-dot-com.sg/~shuhuang/tesla_coil_lab.jpg
 >  > ), ~210mm wide and
 >  > 320mm in diameter, as a toroid but I suspect a
 >  > traditioanl toroid might
 >  > work better. Believe it or not, I'm actually having
 >  > a hard time flexible
 >  > drainage pipe. It's apparently not used very often
 >  > any more...where I live
 >  > (SIngapore) anyway. I came across the pool float
 >  > toroid design on a
 >  > webpage, and I've found one on sale cheap. It's 23"
 >  > in diameter and 8"
 >  > thick. Is that too big a toroid for my 15kV 30mA,
 >  > 90mm 900 turns AWG 24
 >  > wire secondary coil, set up?
 >  >
 >  > thanks!
 >  >
 >  > Shu
 >
 >
 > Shu,
 >
 > Nice photos. Thanks for sharing.
 >
 > I don't know about aluminum for spark gap electrodes.
 > I've heard aluminum soon gets full of pits and holes
 > until it looks like a sponge. I have no first-hand
 > experience with it however. I've always used copper or
 > brass electrodes. On the other hand, it sure is a
 > nice-looking spark gap you built there--very neat and
 > professional. I think I'd go with the reality test--if
 > the spark gap works well, don't worry about the
 > aluminum.
 >
 > Moving air can have a profound effect on spark gap
 > performance. Try blowing a jet of compressed air
 > through the thing and see see what happens. If forced
 > air gives noticeable improvement, then you'll have to
 > do something about your air flow.
 >
 > I think a 23" X 8" toroid is too big for a 15kv/30ma
 > NST system. Child-size 20" x 5" vinyl pool toys are
 > common in the US. See if you can find one of those.
 >
 > Actually, the Wok covers make a pretty neat-looking
 > terminal. People use all kinds of crazy stuff for top
 > loads. Why not Wok covers? The important thing is that
 > it woks well, um, I mean works well.
 >
 >
 >
 >
 > =====
 > Gregory R. Hunter
 >
 > http:\\hot-streamer-dot-com/greg
 >
 >
 >
 >