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I made a large vdg for the Calgary Science Center in the early 80's. You
can see some pictures on my website:
http://h2g.ca/miscellaneous.html
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.
>
> Thanks
>
> John
>> -----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 potentials
>> around the sphere opening. I used steel Ikea bowls and they just wanted
>> to
>> buckle when I radius them. I have made a few corona rings that help, but
>> I'm not so good at joining the two ends and soldering a nice smooth joint
>> =(
>>
>> 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 were
>> items I could not make myself. Note all devices are extremely quiet- I
>> used
>> high quality bearings everywhere and drill press for accuracy.
>>
>> My 6 foot high-power version was insane throwing off continuous charges
>> up
>> to 40 inches in length which seems way more than possible using a 14inch
>> sphere.
>>
>> I have cannibalized my large generator and am building two 3 foot
>> dual-pole
>> 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
>> or
>> a tesla coil. I can build belts up to 6inches wide and many 10's of feet
>> long, but I cant yet built large spheres over 14inches =(
>>
>> https://www.youtube.com/watch?v=Fb-tWeJ3Z0U
>>
>> https://www.youtube.com/watch?v=ABKCGXuJDlw
>>
>> https://www.youtube.com/watch?v=eRsl6rs2cEo
>>
>> https://www.youtube.com/watch?v=Hs3K0C1CeVk
>>
>> https://www.youtube.com/watch?v=O3CSO9fIQu0
>>
>> https://www.youtube.com/watch?v=o8ZHrSiVEXs
>>
>> https://www.youtube.com/watch?v=v6KdIKDr4Tc
>>
>> https://www.youtube.com/watch?v=em67iXD5-ms (voltage specified is likely
>> incorrect)
>>
>> https://www.youtube.com/watch?v=I37C5qWRi3A (voltage specified is likely
>> incorrect)
>>
>> https://www.youtube.com/watch?v=cQTRKiYsCEc (just for fun).
>>
>> Any questions please let me know, I'm certainly no expert but have
>> learned
>> a few tricks to provide excellent charge rates, smooth operation, and
>> huge
>> reduction in expensive (my 6ft long 2ft wide belts are only $3 each and
>> work better than any other I have tried).
>>
>> Thanks!
>>
>>
>> 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
>>> from
>>> easternvoltageresearch.com
>>>
>>> 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 Google
>>> it
>>> 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 existed.
>>> I
>>> don't make tesla coils any more but I produce large Van De Graff
>>> generators
>>> and simple kelvin thunderstorm projects to amuse myself and keep my
>>> nephews
>>> amazed.
>>>
>>> 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
>>> his
>>> e-mail address. I don't see any recent posts with his name so maybe he
>>> is
>>> 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:
>>> msweeney23@xxxxxxxxx
>>>
>>> I did build several decent coils over 20 years ago with home made plate
>>> class capacitors and a horribly inefficient stationary spark gap. I
>>> didn't
>>> 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
>>> never
>>> 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 magnet
>>> wire.
>>>
>>> I'm looking for good sources of (cheap) high voltage capacitors and much
>>> 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
>>> advice
>>> on secondary wiring cable is there a preferred variety for recent coils?
>>> 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
>>> actually
>>> 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 minds
>>> =)
>>>
>>> Thank you for any help you can provide. I'll be reviewing the lists
>>> looking
>>> for new info also but direct contact for any suggestions would be
>>> welcomed.
>>>
>>> Regards,
>>>
>>> Matt Sweeney
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
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>
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