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Re: Pri/Sec coiling
Hi Jeremy,
On Fri, 7 Feb 1997, Tesla List wrote:
> > Subject: Re: Pri/Sec coiling
>
> Subscriber: pwac-at-flinet-dot-com Fri Feb 7 23:37:18 1997
> Date: Sun, 26 Jan 1997 22:40:42 +0500
> From: Jeremy Bair <pwac-at-flinet-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Pri/Sec coiling
>
<big snip>
> > Hmmm, I was wondering as to how the two coils arced to each other. I
> > figured such that to make them arc, they have to be effectively
> > either partially (at least 90 degrees) or completely out of phase (180) as to
> > setup a large enough potential difference, else, I guess it might make a
> > display kind of interesting if two coils were attempting to arc to each
> > other and were in phase! Hmmm...has anyone done this?
> >
> > > As mentioned by the others, in a classical two coil, or magnifier,
> > > the sense of the coils matters not.
> >
> > Ah! <Click...bzzz, brain kicks in...> I thought I had a problem there,
> > however, both the secondary and primary on my coil are wound in the same
> > direction..
> >
Jeremy:
> Is the coil winding something you guys take for granted? I mean, I am
> getting ready to build my first, and that thought came accross my mind
> many times, I saw pictures apon pictures of coiling, and they went the
> same direction, so I didn't give it any more thought. But I guess we all
> have it clear, they SHOULD wind in the same direction right?
Yup, on the standard pri-sec coil system, wind both windings in the same
direction.
> So the whole deal with magnifier coils is that they are directly
> (inversely) out of phase, so each primary oscillation would cause both
> secondaries to release at separate identical times? (Newbee alert ;).
Not quite. Magnifiers have all three coils wound in the same direction.
It's the bipolar "split" coil systems that are in opposite directions.
> If anyone here has ever built a tesla coil running off one 12Kv 30ma
> neon, let me know, this will be my first. And possibly make another with
> two 15kv neons ;) if the first is successfull, and I take it I will
> learn a GREAT deal of information upon the completion of the first?
> Isn't that what practice is?
Yeh, one of my first coils was with a 10kv -at-30mA neon.
well, unfortunately, you may have slipped (unknowingly of course! :-) )
into a common rutt experienced by soem coilers, starting out with the
transformer and working to the toroid...not the best way to start, but
there are ways around it of course...
As you probably know, resonance is the key to TC operation, so with
everything set at close if not, correct values, then you get a relatively
good working system.
Well, in your case, you'll probably have to get some capacitors to make
up a value of around 0.006 - 0.007uF -at- 25KVDC+.
You'll probably be able to run a coil with a diameter of about 3 to
4inches, with a winding length of somwhere between 16 to 20 inches. I'd
suggest AWG #24 or #25 formvar or enamel coated Copper wire, close wound.
Primary coil of around 12 turns or so of 1/4" - 3/8" copper pipe.
Best try to wind in a flat "pancake" coil.
> Also, let me know if these prices are cheap for used neons.
>
> 12KV 30ma - 20$ (Franceformer)
> 15KV 30ma - 25$ " "
> 9KV 60ma - 20$ " "
>
> If they are good, I will order me up allot.
Well, they're about 1/2 the price they would cost in Australia!
> Also, I need to know if it is definatly a must to remove the transformer
> from the tar and metal caseing, and why people do it? I have heard
> people saying they boiled theirs in desel to get the tar off, and at
> what cost?
They only do it to rewind the coils. If they're working fine, leave them
as they are.
> Thanks people! Also (Man I am loaded today!!) if anyone has any "safety"
> notes for neon transformers let me know, things like, power is left in
> the neon after being unplugged, but not discharged, use a light build in
> the series of the power in to prevent the neon from being over worked.
> Etc!
Neon transformers are current limitted already, so you don't really need
anything in series on the primary side, except of course a variac for
protection. Best to wind a neon transformer up in power in a TC circuit
than blast it. I learnt the hard way in the past with the windings
shorting out, although, depending alot of other factors could determine
the xformers lifetime.
If the neon is centre tapped, ensure that tap is connected to Earth
(preferably a dedicated RF earth that is not connected to the 60Hz
household earth).
this also means that you have to centre tap your TC primary coil to this
earth aswell.
Centre tap neons are such that, say for instance your 12KV is centre
tapped, then effectively between one terminal and earth (centre tap) is a
potential of 6KV.
Simple safety, don't touch it when it's on!
Safe Coiling, and before plugging anything in, check everything, and if
unsure, ASK SOMEONE! :-)
Rod