Re: Toroid Design Features

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Toroid Design Features
From: Tesla List <tesla-at-stic-dot-net>
Date: Sun, 9 Nov 1997 13:23:07 -0600
Approved: tesla-at-stic-dot-net

From: 	Alfred C. Erpel[SMTP:aerpel-at-op-dot-net]
Sent: 	Sunday, November 09, 1997 10:08 AM
To: 	'Tesla List'; Tesla List
Subject: 	Re: Toroid Design Features


CC>>>>>>>>>>>>>>>>>
I'm in the process of deciding on how to prioritize coil improvements for
the next few winter months.  Near the top of the list is the toroid.  I am
going to get pricing for a spun aluminum toroid and that is where a question
pop's up right away.
Many of us have made a toroid using a similar set of design features.
Specifically, a flat center disk surrounded by the "Donut".  The large
radius Donut clearly prevents the premature spark breakout, but results in a
shape that may increase the cost of a spun aluminum item.  Here's the real
question.  When I draw up a design to take to a local spinning supplier, I
would like to have as much flexibility as possible to control the cost.  I
see a toroid that would be, let's say 10" thick with a 5" edge radius as
being just as effective as one with the 10" diameter outer donut coupled to
a thin center disk.  I hope the cost would also be lower.  The capacitance
should be almost identical too.  Have I missed something here, or would the
thick top hat be just as effective?  We have many local metal spinning job
shops and any flexibility in the design would sure be a benefit.  Thanks in
advance for any comments.
<<<<<<<<<<<<<<<<CC

    Your biggest cost having this part spun will be the tooling that it is
spun on ($1200 ?). I have been wondering about a faceted toroid.  Break the
toroid up into many sections (8, 10, 20 or more) and then you can bend each
(identical)section from flat sheet metal and weld/braze them together to
form a toroid consisting entirely of planes.  This could look just as cool
as a round toroid (cooler?) and could be formed using standard press brake
tooling.  I don't know whether the lines and points on this faceted toroid
would be a plus or minus towards the desired sparking effect of a tesla
coil.  If you pay for tooling to spin a curved toroid, (ignoring tooling
cost) the cost of each curved toroid would be less than a faceted toroid,
but if you are buying only one toroid the total cash outlay would be less
for a faceted toroid.
  I can't comment (no nothing) on capacitance issues.