I see the same effect if I hold a metal toroid (like a bundt pan) near my
spherical collector. Significantly more power. I also have a second 14inch
sphere that can be used to produce extremely thick powerful arcs, but the
distance is lower.
I find the best results using a small spherical discharge with a rounded
nut glued on to it. It literally doubles the spark length.
Matt
On Tue, Aug 25, 2015 at 3:23 PM, Doug <doug11642@xxxxxxxxxxx> 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:
>>
>> 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
>>>>> _______________________________________________
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>>>>> Tesla@xxxxxxxxxx
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