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Re: [TCML] Toroid & VDG

Hi Doug,

By putting the grounded toroid in close proximity to the VDG sphere, you effectively increased the capacitance of your VDG topload versus its surroundings. A simple capacitor is nothing more than two conductors (i.e., the sphere and toroid) separated by an insulating medium (air). Depending on the geometry and orientation of the sphere and toroid, it's quite possible that you increased the effective capacitance of the sphere by a factor of 2-4, and perhaps more. Assuming that the VDG charged the sphere to the same potential, you had 2-4X the stored energy as when you just had the isolated VDG sphere. Since this energy is mainly concentrated in the electrical field between the toroid and sphere, you'll see significantly higher energy "capacitor discharges" when you short-circuit the system.

Best wishes,

Bert Hickman
Stoneridge Engineering, LLC
World's source for "Captured Lightning" Lichtenberg Figure sculptures,
magnetically "shrunken" coins, and scarce/out of print technical books

Doug wrote:
I have been experimenting with my 14" VanDeGraaff and found something
interesting. I made a Toroid from 4" semi ridged vent pipe it is 20"
dia. and has no center plate, it is just a ring. With the VDG running
full bore the spark to the regular discharge wand or my hand is
tolerable and not to fat, but when I pick up the toroid ,[which is not
connected to the VDG] and get it within about 4" from the VDG sphere I
receive a substantial jolt and a very fat loud spark between the sphere
and toroid, quite uncomfortable to hold! It would seem that the toroid
is acting as a capacitor just being somewhere near the sphere.

On 8/25/2015 11:30 AM, David Boyle wrote:
I made a large vdg for the Calgary Science Center in the early 80's. You
can see some pictures on my website:


We found that the problem with most rubber belts is that they are doped
with carbon black to make them less of an insulator and to reduce
sparking. It wasn't until we were given a true belt made by the Van de
Graph corporation that we got really good sparks.

We charged the belt with a 10kv dc supply from a photocopier. The
re-entrant edge at the bottom of the sphere is very important. We found
a metal spinning shop that made our large sphere for $400. We needed a
crazy strong motor - 1 hp - because driving a 10kv belt into a 600kv
sphere is hard work.

Calgary is very dry so it worked well most of the year. High humidity
and smoke filled rooms would really cut down on the output.

On 15-08-25 10:21 AM, John Nelson wrote:
Thanks for sending those.  You have given me some ideas that I can
work on.  Instead of bowls for the sphere I use garden gazing balls.
They come in many sizes and look great, but the same old problem of
the opening is there.  I can see that you have tried to cut down on
the corona like I have using rings.  I tried rings made out of copper
tubing and plate aluminum and still get corona discharge.  I have
tried to turn the opening upward like the ones you can buy, but have
not been successful.  The main problem is that the gazing balls are
made out of stainless and the professional ones are aluminum.
Aluminum is much more malleable and is easy to shape.  There is a
company that will form any size ball up to 36 inches and will also
form the opening that is turned upward.  I contacted them and they
only want $4000 to make one.  Might as well be 4 million to me.  I
would make a nice display though.  I keep on entering the lottery,
but so far I have only won one dollar.  3999
  to go.  A
s far as the belts, I have been using vinyl strips that is used in
upholstery.  Vinyl does not work on rounded rollers as I will not
conform to the round shape.  It is too stiff.  I got some exercise
latex straps, cut them to length, fastened the ends together and tried
to run them, but I think the material is too thin as it did not work.
I could use some heavier latex, but I don't know where to get it.
As far as Tesla coils are concerned, I have made several, the first
one in high school back in the 50's.  I got a kit from Tesla works,
(Alan) and it works OK, but I wanted bigger.  I then got a solid
state one from Dan McCauley (Eastern Voltage Research), but it does
not work and they can't fix it.  $2100.00 down the tubes. It now just
collects dust in my garage.  I contacted the man in Oklahoma that
built the very large one he runs outdoors, but he won't release any
information on how it is built.  You can see it run if you search
"very large Tesla coil".
I have a larger VDG in partial assembly, but am waiting on how to
solve the belt walk issue and the corona issue as well.  A search for
thicker latex is next, I guess. I can machine any parts I need as I
have a machine shop.


-----Original Message-----
From: msweeney23@xxxxxxxxx
Sent: Mon, 24 Aug 2015 20:54:02 -0500
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] Seaching for Mike Delosier

Here are some videos from my older models. I did build a six foot model
with a 14inch sphere running at 10x power delivery. It was a beast but
caused me much trouble due to extremely high electrical field
around the sphere opening. I used steel Ikea bowls and they just wanted
buckle when I radius them. I have made a few corona rings that help,
I'm not so good at joining the two ends and soldering a nice smooth

All my devices are completely home built including PVC form (well I
purchased the PVC), belts, rollers, corona tubes, comb assemblies and
various discharge rods. Of course the motor and hemispherical bowls
items I could not make myself. Note all devices are extremely quiet- I
high quality bearings everywhere and drill press for accuracy.

My  6 foot high-power version was insane throwing off continuous
to 40 inches in length which seems way more than possible using a

I have cannibalized my large generator and am building two 3 foot
positive/negative generators in an attempt to 'double' the voltage
gradient. We shall see!

Next project is a new Thunderstorm built very high quality and full
self-contained re-pumping. After that it's either a giant Van De Graaff
a tesla coil. I can build belts up to 6inches wide and many 10's of
long, but I cant yet built large spheres over 14inches =(








https://www.youtube.com/watch?v=em67iXD5-ms  (voltage specified is

https://www.youtube.com/watch?v=I37C5qWRi3A (voltage specified is

https://www.youtube.com/watch?v=cQTRKiYsCEc (just for fun).

Any questions please let me know, I'm certainly no expert but have
a few tricks to provide excellent charge rates, smooth operation, and
reduction in expensive (my 6ft long 2ft wide belts are only $3 each and
work better than any other I have tried).


Matt Sweeney

On Sat, Aug 22, 2015 at 9:54 PM, wt5y <wt5y@xxxxxxxxx> wrote:

Cornel dubilier 942c20p15k-f   .15uf 2000v  caps can be had $4.99 ea

Sorry don't know mike.  Someone else may.
If you don't mind can I see some of the van DE Graaf you've made ie
website,youtube?  And what are Kelvin thunderstorm project, will
but never heard of it.

John cooper WT5YWt5y@xxxxxxxxx
Sent from my Samsung GALAXY S5™, a Cricket 4G LTE smartpho

-------- Original message --------
From: Matthew Sweeney <msweeney23@xxxxxxxxx>
Date: 08/22/2015  16:10  (GMT-06:00)
To: tesla@xxxxxxxxxx
Subject: [TCML] Seaching for Mike Delosier

Hello, I recently joined this mailing because I didn't know it
don't make tesla coils any more but I produce large Van De Graff
and simple kelvin thunderstorm projects to amuse myself and keep my

Anyway I visited my local Axe-MAn today and learned that they have a
customer named  Mike Delosier who lives in minnesota and has some
impressive coils.

I am hoping very much to contact Mike but I have not been able to find
e-mail address. I don't see any recent posts with his name so maybe he
not a member anymore?

So, if anyone knows him, I would be delighted to send him an email.
Alternatively he can send ME an e-mail as to be less intrusive:

I did build several decent coils over 20 years ago with home made
class capacitors and a horribly inefficient stationary spark gap. I
have any protection circuitry in place but somehow my HV transformers
survived, however my capacitor eventually exploded.

Now I have three perfect 15,000v 250ma NST's just sitting waiting
for a
purpose - so I think it's time to start planning a new build. I have
built a proper solid state coil and am considering this option. But a
traditional rotary spark-cap coil with high-voltage capacitors
would be
much less effort. The secondary will be 5 Feet and using enameled

I'm looking for good sources of (cheap) high voltage capacitors and
info on recent developments in the field. I especially am
interested in
inductor usage to prevent spikes back to the NST. Also I need some
on secondary wiring cable is there a preferred variety for recent
Ill use copper tubing for primary. I may also build my own rolled
capacitors but I'm thinking obtaining newer HV caps in a bank may
be cheaper.

If there other members in the Minnesota/Wisconsin I would also like to
connect. I'm desperate to find a powerful coil to blow my nephews

Thank you for any help you can provide. I'll be reviewing the lists
for new info also but direct contact for any suggestions would be


Matt Sweeney
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