Yet another newcomer, and from Sweden this time
From: Per Niva[SMTP:pna-at-pp.gellivare.se]
Sent: Tuesday, August 26, 1997 7:21 AM
To: Tesla List
Subject: Yet another newcomer, and from Sweden this time
I tried to introduce myself to the list some days ago, but
the only thing happening due to my post was Chip's disk
crashing. Now I'll have another shot. I guess it's called
I tried the usa-tesla list, but they just kept throwing HOKUM(tm)
at each other over some weird-science time travelling, free
energy issue. They also referred me to this list.
Here goes the old post:
> I just read an introduction message, and decided it might be
> about time for me too to introduce myself. I've been reading
> the list for some few weeks, done some heavy AltaVista searching,
> and started constructing my first coil(s).
> Since I live in Sweden, some things are quite differerent here.
> For example, neon signs are not allowed to use higher voltage
> than 4.5kV. What a pity! And this part of Sweden where I live is
> like Alaska to you people. I live some 150km north of the Arctic
> Circle, in a town with about 20000 people. The largest city in about
> 300km. Our local district (might be kind of like county to you folks,
> I'd guess) is like 19000 square km's, and in the whole area lives
> 22000 people. So neon sign companies are, well, a bit sparse... But
> at last I've managed to get two 4kV-at-45mA and two 3kV-at-45mA transformers,
> and since they're not center grounded, I can run them in series.
> I'm about to get a small pig soon, but it felt better to start out
> in the lightweight, shunted division.
> I've hooked up the transformers, arranged necessary safety
> arrangements to make me feel safe (like a power relay for the
> mains that has to be operated by two people at a distance from
> each other and from the experiment area and a solenoid dropping
> a shortcut bar over the power supply output and the caps. Good
> habits to have when the pig arrives...), and played around a
> bit with different things. Like barbecueing hotdogs...
> Then I went on building a capacitor bank, Leyden jar type,
> currently with 6 2 litre bottles of PET (Polyethylene
> therphtalate). Works like a charm, at least at just 50hz. Somebody
> mentioned something like 'If somebody offers you PET for dielectric
> in tesla work, run a mile in the opposite direction', but without
> mentioning why. Maybe somebody can inform me? (The plastic
> references I found could not.) I guess I'll switch to HDPE or
> PP bottles anyway soon.
> The plan for the first coil look like this:
> Running at 14kv-at-45ma, ~800 watts power supply.
> RFI protection on the HV side of the transformers,
> through choke coils wound some 30 turns around 2 1/2 inch
> ferrite powder toroids. Is this enough for 800W, or should
> I use filter caps too? (I will later anyway. I guess I'll unplug
> just about everything that could get fried from RFI kickback...)
> The filter cap values and types seems to be a matter of different
> opinions... Soon also a commercial RFI filter on the mains feed.
> Of course a safety gap, after the chokes.
> RF ground through 2-4 pieces of 3-4' steel (maybe copper) pipes,
> probably with some salt water feed possibility through them,
> spaced some 3' apart. The pipes would be connected with flexible
> multi-strand heavy copper wire. (About .6" dia of copper,
> grounding wire kindly sponsored by the railroad company). There
> will be about 15' of wire to the coil setup. Is this adequate?
> I guess it would be better with copper pipe cabling, but the
> flexibility of the wire is a Good Thing, and it happened to be
> what I had.
> Capacitor would be the PET bottle bank, if nobody tells me why
> I shouldn't use PET. Each of my bottles should give about 2.5-4.5 nF,
> and I seem to have plenty of marigin on strikethrough voltage even
> without connecting any bottles in series, at least with PET. With
> PE or PP I might have to connect two banks in series.
> I plan on winding at least three different secondary coils at once,
> to be able to switch between. First one should be about 500' of
> #24 wire on a 3" OD HDPE pipe, quite thick walled (Is that pipe OK?).
> This would give a resonance frequency of slightly above 850kHz.
> With terminal capacitance of some 6 or 7pf it would drop to around
> 600kHz. Is this too high? The 'real' coil I plan to use would be
> 4" OD, ~650 turns of #22 MW, frequency around 600kHz, dropping to
> about 400kHz with term cap. The problem is that I don't have any
> good pipe to wind it on. The plumbing supply stores haven't got such
> a large range of tesla coil-approved pipes here either. I have
> a 4" PVC pipe, kind of Schedule 40-looking. Is that bad, even if
> I bake it and cover it with 2-component polyurethane enamel? If
> it is, why? I intend to try winding a coil _without_ plastic former,
> by winding it on the sch. 40 pipe, painting it with this polyurethane
> compound, removing the pipe, and cover the inside too with the
> polyurethane compound. I guess this will be good, if it works and
> if it'll be rigid enough.
> The primary coil would at first be wound with some multi-strand,
> HV insulated, some 3/16" dia conductor, rather rigid wire. Later
> I'll switch to 1/4" or 3/16" copper pipe. Will there be coupling
> problems with the 3" secondary if I make the primary inside
> dia. wide enough to accept a 4" coil too?
> Ballpark calculations (all above are too, please correct me if I'm
> way out of line) gives that with the small coil, 10nF cap I'd need
> some 5 or 6 turns on the primary. Is that too few? Should I go for
> less capacitance and more turns on the primary? I'll make the
> primary tappable out to maybe 15 or 16 turns, to have experimentation
> possibility. The 4" coil would need about 8 turns on the primary.
> I haven't really calculated how big a cap my transformers can
> charge with out European 50hz mains. It seems that 10nF is OK, but
> my resettable slow 10A mains fuse in the power supply fires quite
> often. The 16A of the wall socket is fine though. Strange, since all
> of the transformers should need only about 5A. Guess it is the
> starting current. No coils has been tried yet though, just blowing
> things up with the cap bank...
> The spark gaps are open to suggestions. I have some thoughts, but
> nothing is even in the works yet. I plan on a static gap, with
> air blown from a old hoover. I'll probably build some series static
> gap. What do you people use for gaps? In the 800W class? I heard
> something about pictures on a gap many people are using. Please
> send them to me too, whoever had them (The original poster, I only
> need one copy...)
> Is the safety gap as critical in designing? Or could I use some
> round headed bolts or something?
> Well, this carried away quite some more lines of text than I'd
> intended to. I got carried away with the tesla plans, as usual...
> Please comment on anything, come with suggestions, and so on.
> Comments, suggestions, flames, the usual go-play-with-6volt-
> torch-batteries-instead-mails and anything at all goes either
> (preferrably) to the list or directly to me.
> Be hearing ya all,
> Per Niva
> Sorry, the sig block got lost somewhere...