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Re: Pseudo Toroid Design
From: Chuck Curran[SMTP:ccurran-at-execpc-dot-com]
Sent: Sunday, November 09, 1997 8:34 PM
To: Tesla List
Subject: Re: Pseudo Toroid Design
>
>From: Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
>Sent: Sunday, November 09, 1997 2:16 PM
>To: Tesla List
>Subject: Pseudo Toroid Design
>
>
Hello Fr. Tom
I found your comments to be most helpful. The first item that helped a lot
was the point relative to the center section of the toroid. I had become
fairly sure, remembering past points made over the last couple of years that
the center didn't appreciably impact the toroid's effectiveness. I am never
willing to go charging off without, ah, double checking however!
Your description of a toroid design was very interesting. I do have one
question about the 2 inch diameter thin walled aluminum pipe. I had been
using as large a radius as possible on my bigger coil to prevent early
breakout. Specifically I presently have a 56" diameter toroid with a 10 1/2
inch diameter "Donut" as the outside ring. I chose that diameter to keep
the spark in until the toroid was holding as big a charge as possible. How
would the 10 foot diameter sheet metal ring capped top and bottom by the 2
inch pipe rings do on breakout?? Have you made one of these already?
I was going to draw up a print to show a toroid that you might see clearer
if I describe it like one of those cookie tins we all seem to see around
Christmas. It would be thick like the cookie tin across the entire
diameter. I was going to draw a flat disk with the edges radiused up at a
6" radius covering 90 degrees. One of these could be place on top of the
other and then TIG welded together. A central supporting tube would have to
be installed internally in the exact center for proper support if a light
gauge aluminum sheet were used, like 16 or 18 gauge. This shape would
eliminate the double curve required on a standard shape toroid and reduce
fabrication costs---Design for Manufacturability and save the wallet! Since
my current toroid is 56 inches in diameter, I would hope for something in
this range. If they would tell me they could do it with a 5 1/2 inch radius
for less money instead of 6", I'd be very pleased, since the exact dimension
is not critical to me, as long as it was a constant around the entire spun
half.
Your idea would really be a lot less expensive, I am very curious about the
2" edge radius and how it would compare to the standard toroids most of us
have been creating. Thanks for your feedback on my post.
Chuck Curran
>Chuck,
>What makes a toroid so good for TC use is its ability to shape the e-fields
>so that breakout is supressed at the top and bottom, and instead tends to
>occur at the outer rim of the toroid.
>
>The inside of the toroid actually contributes next to nothing to the
toroid's
>characteristics. In fact, if you look at Tesla's patent drawings you will
find
>that he leaves the inner section out completely. He also shows the toroid's
>surface as being composed of many small half-spheres. The interesting thing
is
>that the mutual action of the surface e-field shapes of a toroid-like
structure
>is such that it will tolerate a fair amount of surface irregularity and
still
>act as if it were perfectly smooth.
>
>Simplification: Concentrate on making the outer rim and enough of the top
and
>bottom of the toroid shape smooth enough to be useful. Do not worry about
the
>inner part of the topload, as it adds nothing to the toroid's usefulness in
>TCs.
>
>Imagine that you had two 31.4 foot lengths of thin-wall aluminum pipe with
a 2
>inch
>diameter. If you could "roll" these somehow into two big 10 foot diameter
>circles
>you would have the beginnings of a huge toroid. I say the beginnings,
because
>you could use these two large circles of pipe as a sort of glorified corona
>guard for a sheet of aluminum 31.4 feet long and say two feet high.
>
>Roll the sheet of aluminum into a circle about ten feet in diameter. use
pop
>rivets or whatever to join the ends. A short strip of metal on the inside
can
>be used to join the ends so there is no bulging overlap of the actual
sheet.
>Now mount the two large metal tube rings, one along the top, and the other
>along the bottom. The idea is to let the metal tube rings shield the sharp
>upper and lower edges of the sheet metal cylinder. The rings can be
attached
>quite readily by using sheet metal screws and affixing the sheet metal to
the
>INSIDE of the tube rings. Don't worry about corona. The inside of the ring
is
>quite shielded.
>
>When finished you will have a pseudo-toroid that has a tremendous outside
>surface area and fairly reasonable corona protection at the edges. You can
>create a suspension mechanism by having an inner metal plate (reasonably
thick)
>with holes punched around its rim connected via guy wires to the
aforementioned
>sheet metal screws that hold the outer sheet and tubular rims together. The
guy
>
>wires would then connect up like bicycle spokes to the inner metal hub.
>If the guy wires are attached to the lower rim and made to be a bit longer
>than required, then the hub will be connect to these guy wires at an angle
such
>that the hub allows the lower rim to hang significantly below the hub. That
>will
>allow greater shielding of the top of the secondary coil.
>
>Properly connected such a suspension mechanism would make a simple central
>support structure. The total weight of the pseudo toroid would be small
>compared to its effective capacitance size. The neat thing is that such a
>design can be effectively carried out without recourse to expensive and
>hard to get parts.
>
>Bending the corona guard rings is the hardest part. If the diameter of the
>ring is large, then the bending is easier, at least as far as applied force
>goes.
>Of course, there is nothing to stop you from using dryer duct as the
>corona guard, but then you may need to strengthen the assembly with
>some form of internal framing. Because the inside is effectively shielded,
>you could easily get away with using almost anything for the internal
framing.
>
>If you do go with aluminum tubing, you can make a simple tubing bender out
of
>sturdy wood, such as two by fours. What you do is build a wooden section of
>an arc covering several degrees. The tubing is then bent around this arc
>piece by piece, just like with an electrician's tubing bender. Note that
such
>tubing benders have one side designed so that it grasps the pipe during
>bending, but then allows it to slip forward a few inches for the next bend
>sequence. You are all smart people. Figure out your own modifications.
>
>Modify the basic idea as needed. It can be scaled up as well as down. Use
your
>own ingenuity and exploit the materials that YOU have readily available.
>
>Hope this helps.
>Fr. Tom McGahee
>
>
>