I love the simplicity and the challenge. I'd never seen one work before and had a lot of fun building it. It amazes me still that I can produce an 18" arc from just a pair of nylons moving over a teflon rod. :)
--------------------------------------------
On Thu, 12/24/15, Teslalabor <teslalabor@xxxxxxxxxxx> wrote:
Subject: Re: [TCML] VDG pickups (was Ignition coil driver)
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Date: Thursday, December 24, 2015, 3:57 AM
Hello,
it seems that only self-exited van de graaf generators are
built by you
folks. Why not use an external DC source (10-20kV) and spray
the charge on
the belt, like all big generators do the job? Wouldn't that
be much easier
to realize than dealing with triboelectric scale and
humidity problems?
Regards,
Stefan
----- Original Message -----
From: "ExtremeElectronics.co.uk" <tesla@xxxxxxxxxxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, December 23, 2015 3:36 PM
Subject: Re: [TCML] VDG pickups (was Ignition coil driver)
> Doug,
> Looking at the triboelectric
scale for Polyethylene its near the -ve
> end, so contact with neoprene you will get a charge
build up, although
> that should be counteracted by a similar charge build
up at the other end,
> so the net gain would/should be zero.
>
> I agree about the spark losses. I always thought they
were negligible, but
> now I think of it they could be quite large,
especially if the gap from
> belt to collector is large. But the resistance of the
sheet must be quite
> large, so I would expect losses there too.
>
> I can see how these would work for the neutralisers in
a Wimshurst, but
> not for the collectors in either machine, as they are
to collect surface
> charge, pushed out towards the collectors by the
opposing charge on the
> roller or other plate of the Wimshurst and not in full
contact.
>
> Do you use the film for both collectors and
neutralisers in your
> wimshurst? Are they both in full contact with the
disks
>
> Derek
>
>
>
> On 23-Dec-15 1:38 PM, doug wrote:
>> Derek, I am sorry, I do not know the tribo
property's of the plastic.
>> Here is my theory on why it works so well;
>> With the pickups sitting a little away from the
belt you can see little
>> sparks passing, that is energy, like a spark gap.
With the pickup point
>> in contact with the belt there is no charge
dissipated from jumping the
>> gap.
>> I could be wrong on this theory, all I know is that
it works!
>> I use the same stuff on my Wimshurst machines in
contact with the discs
>> with great success.
>> Here is the link to my source>>
>> http://www.all-spec.com/products/65-18.html
>> Doug
>>
>> -----Original Message----- From:
ExtremeElectronics.co.uk
>> Sent: Wednesday, December 23, 2015 2:51 AM
>> To: Tesla Coil Mailing List
>> Subject: Re: [TCML] VDG pickups (was Ignition coil
driver)
>>
>> Doug,
>> So the film is actually
touching the belt?
>>
>> If so, then you are adding another place for
charge separation, as
>> well as collection. Any idea where on the tribo
electric scale the
>> conductive film sits?
>> Would that account for the extra current ?
>>
>> Derek
>>
>>
>> On 22-Dec-15 10:55 PM, doug wrote:
>>> Hi Derek; What you see is conductive plastic
film riding on the rollers
>>> attached with copper tape, rollers are PVC and
aluminum tape covered
>>> acrylic. I did do comparisons, plastic film
produced 30% more current.
>>> Belt Is neoprene.
>>> Doug
>>> -----Original Message----- From:
ExtremeElectronics.co.uk
>>> Sent: Tuesday, December 22, 2015 4:52 PM
>>> To: Tesla Coil Mailing List
>>> Subject: Re: [TCML] VDG pickups (was Ignition
coil driver)
>>>
>>> Doug,
>>> From what I can see
from the videos, you are using a thin piece of
>>> copper for your pickup. Have you done any
comparison between that, wires
>>> or gauze. Do you see an increase in current or
voltage ?
>>> What is the composition
of your rollers and belt ?
>>>
>>> Derek
>>>
>>> On 22-Dec-15 2:34 PM, doug wrote:
>>>> Hello Derek;
>>>> Thank you for your comments and including a
link to my youtube video. I
>>>> have included a link to my youtube page so
you can take a look at some
>>>> of my VanDeGraaff projects. I think all VDG
builders are using the wire
>>>> or screen type pickups on their VDG’s, I
have found something MUCH
>>>> better. You can see it in operation in some
of my videos.
>>>> https://www.youtube.com/user/dr043042#p/u
>>>> https://www.youtube.com/watch?v=YCWAH-J091c
>>>> https://www.youtube.com/watch?v=uoS7sOy2Src
>>>>
>>>> Thank you again, Doug J.
>>>>
>>>> -----Original Message----- From:
ExtremeElectronics.co.uk
>>>> Sent: Friday, December 18, 2015 11:35 AM
>>>> To: Tesla Coil Mailing List
>>>> Subject: Re: [TCML] Ignition coil driver
>>>>
>>>> You can get about 300W from 8 of them
though..
>>>>
>>>> http://www.extremeelectronics.co.uk/electronic/v8-tesla-engine/
>>>>
>>>> Derek
>>>>
>>>>
>>>>
>>>> On 18-Dec-15 2:30 PM, Jim Lux wrote:
>>>>> On 12/18/15 4:39 AM, doug wrote:
>>>>>> Hello; I am looking for some
information concerning Ignition coil HV
>>>>>> supplies. I am using 120V mains
through a light dimmer and wonder if
>>>>>> there is something better and more
robust than the dimmer? This
>>>>>> Ignition coil HV supply will be a
dual coil setup using a
>>>>>> 25.0uf/370VAC motor run Cap.
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Not as cheap..
>>>>>
>>>>> any of the standard capacitor discharge
electronic ignitions basically
>>>>> put 400V pulses into the coil to
generate HV.
>>>>>
>>>>> 6000 RPM in a 8 cylinder engine is 200
Hz
>>>>>
>>>>> typical energy per "pulse" is 100 mJ so
200 Hz is 20 W
>>>>>
>>>>>
>>>>>
_______________________________________________
>>>>> Tesla mailing list
>>>>> Tesla@xxxxxxxxxx
>>>>> http://www.pupman.com/mailman/listinfo/tesla
>>>>
>>>>
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>>>
>>>
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