I ran into this same problem, but I found a cheap and easy solution that
seemed to solve the problems for me:
1. Make sure the collector is approx 4-5 feet off the ground, away from any
areas that could contribute to leakage (such as the motor, any sharp points
etc.)
2. Cover the edges of the hole with electrical tape, then press on a small
soft vinyl tube cut lengthwise.
3. This is the important part - Find some form of 1 inch wide rubber
material, thicker if possible, and wrap it tightly around the top of the
column right where it enters the collector, so the entrance hole is
'sitting' on it. The goal is to create a torus of sorts where the collector
can rest. I went for about 1 inch depth but I don't remember the exact
number of turns.
4. Now wrap the rubber torus with electrical tape (tightly) to keep it nice
and solid and also to reduce any sharp edges. You really want to do a good
job here the end result should look like a smooth solid torus made of
electrical tape.
This seems to create a corona ring of sorts, but of course this is
non-conductive - I don't know why it works so well, but it completely
solved any leakage problem I was having.
Matt
On Wed, Feb 8, 2017 at 5:26 AM, ExtremeElectronics.co.uk <
tesla@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> The biggest issue, is the hole where the belt comes through. If you can
> make that a gradual curve, or can make the belt small in relation to the
> diameter of the bowls they are great.
>
> My design has the down side of a large belt-hole and a not very well
> smoothed entry, If I could improve this I would get a much better output.
> Although on a good day It will arc from top to bottom, roughly 800mm
>
> I can't say what the change rate is, I did measure it when I built it, and
> I've improved the charging a number of times since, but I can't find any
> reference to the figures in my notes.
>
> The motor is small Como drills 191D, 12V ~ 3A, geared 2:1, but has plenty
> of power for the job, the belt runs at around 3M/Second flat out.
>
> Derek
>
>
> On 08-Feb-17 02:51, Matthew Sweeney wrote:
>
>> I've been able to get 3 foot sparks using two of those 14" Ikea bowls..
>> They work extremely well.
>>
>>
>>
>> On Mon, Feb 6, 2017 at 6:38 PM, Ed <evp@xxxxxxxxxxx> wrote:
>>
>> Awesome! Looks like a small motor - how long does it take to charge
>>> enough for a spark? Have you measured the output current?
>>>
>>> Ed
>>>
>>>
>>> On 2/6/2017 2:27 PM, ExtremeElectronics.co.uk wrote:
>>>
>>> I made mine from two Ikea bowls, a sheet of aluminium and loads of
>>>> filler.
>>>>
>>>> http://www.extremeelectronics.co.uk/static-machines/1mv-van-
>>>> de-graff-project-2/
>>>>
>>>> Commercial ones like that would cost a fortune to manufacture. Your only
>>>> other option would be see if they sell spares. Or contact a friendly
>>>> metal
>>>> spinning shop.
>>>>
>>>> Derek
>>>>
>>>>
>>>> On 06-Feb-17 20:39, doug wrote:
>>>>
>>>> Can anyone tell me where I might find a sausage shaped top load like the
>>>>> one pictured in this website?
>>>>> http://wikivisually.com/wiki/File:Van_De_Graaff_gen_03.jpg
>>>>>
>>>>> Doug J.
>>>>> _______________________________________________
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>>>>>
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>
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