Re: newbie question - spark gap and toroid

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

Original poster: "ho \[shu\] huang" <shuhuang-at-singnet-dot-com.sg> 

Hey greg, thanks for replying.


>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.

I've haven't really run the coil extensively as it's in the lab now, and 
I'm at home. I'll prob bring it back during the December holidays for some 
major tweaking.

But from what I've observed, everythign's working quite well now. The gap 
remains cool to touch after a run...but that's prob because it's only on 
for less than 30s each time. I haven't noticed any pitting yet..I'll keep 
you guys updated. The good news is aluminium curtain rod is cheap. Abt 50 
cents a foot. ok not that cheap I guess...but until I get more proficient 
in accurately drilling holes into tubes, I'll stick with flat electrodes :)


>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 don't have compressed air handy, but i'll set up a small table fan to 
blow directly onto the gap. Let's see how that goes ...

>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.

I'll prob see if I can find one. I quite like the pool float toroid idea. 
With some paper mache, u have the perfect shape, minus the ridges!

>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.

haha funny!

well yeah I personally prefer the 2 wok covers over a toroid, but there's 
no harm building a traditional toroid and seeing how that goes. Someone 
also told me that the ridge arnd the middle of the toroid (where the wok 
covers at joined) may pose a problem. He used some technical term but the 
gist of what he was syaing was I was leaking electricity.

The wok covers were US$1.50 each BTW....much cheaper than the length of 
1.5" flexi hose (the sort that's connected to the waste water outlet in 
washing machines) I bought. (yeah i tried to wrap stuff around it to get it 
up to 3" - didn't work. THat toroid is embarrassing to look at!)

Shu





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