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Re: newbie TC questions

> Original Poster: Jan Florian Wagner <jwagner-at-cc.hut.fi>
>
> here's one more newcomer to TC!

Welcome!


> Tomorrow I get one or two NSTs, for free. Can't still believe it,
> first call at a neon sign company was a success!

Congrats! I had to call a few places to get mine. ;)


> It would be great if you could give me some tips on the secondary coil
> design, if I am on the right tracks with this mini secondary form size?
>
> diameter 2", height 10"
> 648 turns of AWG 27 emalled copper wire

Hmmm... I've never done one that small before, but the rule of thumb is a 4:1
height to width ratio, so you're close. Make sure to leave an inch or two at
each end of the secondary to make it eaiser to work on.


> Before I forget it there's one thing that I'd be glad if someone could
> help me with. That "magnet wire" for winding the secondary has me
> puzzled. Is it just plain, normal, varnished copper wire? If not, what's
> it made of and what would be a place to get it?

Ordinary enamelled copper wire is exactly what you want. They call it magnet
wire because it's very usefull for coils and, well, magnets. ;) You can get it
all over the place, I got mine from a local surpluss shop.


> Oh, I've still a few questions (sorry if they seem boring or plain
> stupid... ). Here they are anyway:
>
> a) should the secondarys RF ground really be connected to the center tap
> of the NST in the design in which the RF ground is also in the
> middle of the safety gap? It seemed odd to me because wouldn't the toroids
> discharge strike straight away into the primary as it is connected to the
> ground over a 4.5kV potential (for a 9kV NST)?

I usually connect my NST center tap to the AC line ground and the saftey gaps
and lower secondary to the RF ground. I've heard of people using the RF ground
for the NST, I doubt it would matter as long as you make a good RF ground
connection. The electricity will follow the best path to ground, and it's not
through the NST, so it's pretty safe. The secondary discharge usually goes up
and out, sometimes you will get primary strikes, that's what a strike rail is
for. But since the secondary streamers will follow ion trails, and heat the
ions they will tend to want to go up. (Heat rising and all that)


> b) may the RF ground be connected to the drainage/water pipe system, or
> the wall outlets ground, or, should it be an additional ground made with
> pipes hammered into earth. (hard to do from here, it's 3 floors down ;)

It should be a seperate ground from the main AC line. Sometimes the watter
pipes are isolated and will work, but I recomend you get some ground rods from
the local home repair store and use them instead. Make sure to have your
utility lines marked before driving ground rods into the ground.. They get
angry if you break a gas line or something equally hard to fix. ;) In the
states it's a free service the utility companies provide.

For a ground 3 floors down, I suggest you throw a ground line out the window.
;) Use a flat wide conductor. It seems to work better, and is usually cheaper
too. Just get some copper roof flashing when you buy the ground rods, and cut
it into strips and solder together. ;)


> d) are ignition coils and rectified tv flybacks useful at all for powering
> TCs?

Not really, they just don't put out enough power. Maybe for small coils.
Personally, I'd rather make plasma balls or something like that with flybacks.
;)


> hope my english was readable, and the questions not too boring = too
> many...

Naw... we're all newbies at some point, I probably still qualify as one! :)
And your english is fine. Make sure to read the archives at www.pupman-dot-com and
look up the saftey info as well. You can never be too safe, this is dangerous
stuff, so respect it.

Travis
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