Topless Coils

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

Original poster: "Christopher Boden by way of Terry Fritz <twftesla-at-uswest-dot-net>" <chrisboden-at-hotmail-dot-com>

>
>Original poster: <uncadoc-at-juno-dot-com>
>
>Hi all list members; Geek #1 and company.  Hey, you know what?   We tried
>our two 15/60 modified neon supply into our 6" dia.x23" tall coil with
>our array of barium titanate caps, and you know what?  IF we detune our
>coil by about 1 turn on the primary(more or less).  We found that the
>spark output from the top terminal has the same length.  In other words,
>all that big fat toriod on top of your Tesla is doing is  just making the
>spark look more impressive by moving the actual discharge of the top of
>the secondary to a plane that is simply further from the center of the
>coil itself, in relationship to the largeness of topload you apply.   IMO
>the spark length is the same with or without a toroid.  We can now see
>that if the coil is tuned properly that it will give the same size spark
>output regardless of the toroid.  It is simply a matter of tuning the
>tank for optimum output.   We can get a 6 foot multiple nasty spark off
>our secondary using a 1/4" toggle bolt as a topload.  And if we wish ,
>then we can set up the primary tuning to accommodate a giant 6"x24"toroid
>to get the same amount of spark.  Then we lay up and tune the coil for an
>additional 6"x24" toroid atop the first one.  The double toriods look
>mighty impressive, but the spark length as rated tuned output from the
>secondary is the same!    The Toroid size does not seem to have any
>impact on our coil at all.  We found that our coils do NOT need a monster
>topload for maximum output.  We can tune it to produce nasty sparks that
>just grow and grapple for the upper atmosphere with no topload at all.
>Could this be a result of the barium titanate cap tank we are using?  No,
>I think not!  We seem to see a mass multitude trying to get bigger sparks
>from their coils with a bigger topload. But what we have found with our
>experimentation,  that is not the case at all!  I think all that most
>coilers are doing is deceiving themselves by exaggerating the amount of
>spark they get from a toroid topload.  Yeah, a big fat nasty looking
>toroid!   A 2" brass ball on your secondary would give just as much
>spark.  The toriods just extend the spark area....    Maybe the perceived
>extension of spark on the secondary is just a matter of good tuning!   I
>think too many list members swear by the toroid topload.  I think it is
>baloney!   Tune well and give top Capacitance to the air around you!
>Reach out and you shall receive!    JMO.   Al


On the wall of the lab I have a sign that is one of our mantras.

"Great Idea, Bad Plan"

About 2 hours before I read this today, I was in the lab building the 
largest toroid I've ever seen IRL (The 13-M's is the biggest period).

The muse struck me and just for kicks I removed the collection of toroids 
and office furniture we had precariously balanced on top of Sam and fired it 
with just a wire point up on top, no topload at all. (Using a bolt is about 
the same, VERY little capacitance).

I fired teh coil for less than 5 seconds, because there was immediate 
breakout from the wire (about a foot), racing sparks (about time, I thought 
I was undercoupled), and wispy-wussy (yes, that's a technical term) hair 
thin streamers (more like directed corona) from the top few turns.

I STRONLY believe in the use of a toroid, for 2 reasons.

1. A capacitive topload. I like having a single arc to focus the energy 
into, too small a topload and you have multiple arcs, too big and you have 
no breakout (I've never had this happen). But if you get it just right, you 
have one or two high powered arcs, very tight, very nice.

2. Field control. The toroid controls the upper magnetic field of your coil 
and shapes where the streamers go. If it's too high or too low, you'll toast 
your secondary with upper-secondary breakout and racing sparks. I spent 3 
weeks and a TON of sponsor's money making those 3 secondaries. I can't do 
that again (though we have what may be the most over-dryed and coated 
secondaries on earth, lol).

In the right application, especially with low-powered, or properly designed 
coils you can use a very small, or nonexistant topload. I've seen some 
beautiful ones on www.ttr-dot-com with a brass ball and I KNOW Mr. Wysock 
wouldn't make a crappy coil (actually I'll bet he's made a couple hundred, 
but those are called prototypes and lead you to the REALLY good ones). If 
he's selling small-topload coils I'm sure he's got the bugs worked out.

I think a topload is something that is required as the coil and imput power 
get serious. With a 2"X8" OBIT coil a bolt will suffice. But I wanna see 
Electrum, or even MTC-1 fire without a topload. I'm willing to bet they fry.

Just my thoughts guys.

I spent the day today working on "The great and powerful pink-nipple topload 
of science" <da da da daaaaaaa> after thinking much on this whole "Field 
Control" issue. I decided the best possible shape for a topload isn't a 
sphere, OR a toroid, it's a combination of the two.

The Toroid pulls the field up and out, protecting the secondary. The sphere 
gives the most possible surface area for this type of capacitor, and that's 
what it's all about, surface area.

I made a 3' disk (the horizontal plate) and mounted 12 vertical disks, each 
1' in diameter around the periphery.

There's the toroid frame.

Then I had an apostrophe (that's an epiphane that isn't quite right) and cut 
a pair of semi-circles each about 3'dia (though they are actually 
half-elipses to make it a little taller) and mounted them vertically, 
crossing each other, on top of the toroid.

This makes the hemisphere frame on top of the toroid.

Now the fun part.

<Soap-Box>

I WOULD LIKE 10 MINUTES IN A BACK ALLEY WITH THE PERSON WHO CAME UP WITH THE 
IDEA OF MOUNTING CHICKEN-WIRE TO A TIGHT-RADIOUSED COMPOUND CURVE. THEY 
DESERVE TO BE BURNED, BLIND, AND BEATEN.

Thank you.

</Soap-Box>

After, half an hour, an hour, 2 hours, 4 hours, 5 hours of my young life 
wasted in trying to bend, scrunch and tweak chicken wire into a smoothly 
curved surface, I got it (kinda).

The frame is made from extruded styrofoam (the 1" thick pink stuff they use 
on houses) and is very strong and lightweight (next time I'm using plywood 
though, ever staple into styrofoam?

The chicken-wire is held in place with a LOT of 1" drywall screws.

Tomorrow, I'm covering the entire assembly with Aluminium tape and smoothing 
it all out.


Some tidbits....


1. If you have a topload half covered in chicken wire, and for some 
brain-damaged reason decide to test it on your coil. Remember that the FOAM 
won't conduct....but the DUST ON THE FOAM WILL and it will VERY quicky melt 
tracks along the surface and CUT RIGHT THROUGH certain pieces of the foam. 
These pieces will only be in the middle, the hardest to replace, and the 
most important.

2. Whomever invented Chicken wire is the antichrist.

3. Aluminum Tape can be gotten from any places that do Pipe Insulation (and 
some HVAC contractors) for free if you ask them sweetly. I have 6 new rolls 
:)

The Geek Group Bicycle-Wheel Toroid is still the easiest, cheapest, and 
best. But the Pink Nipple looks mighty cool.

And I'm STILL gonna try a 30Gal trash can, just for kicks. Maybe a 55Gal 
drum.

Any ideas on how to hang a topload without setting the roof on fire? If I 
use chain I'll just make the buiding into a topload (and promptly ground-out 
my secondary), will rope work? Thread?

Have fun!




Christopher A. Boden Geek#1
President / C.E.O. / Alpha Geek
The Geek Group
www.thegeekgroup-dot-org
Because the Geek shall inherit the Earth!




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