OK wait, I'm thinking through what you are saying trying to adapt it to my
limited technical knowledge in this area. Are you talking about the static
field on the collector, in combination with the insulator, creating a
connection with the lower brush area and thus allowing the nst output to
work it's way back up to the collector?
I'm quite a novice on this area, but I know there is some idea with
lightning once the path is connected to one leader then the entire charge
can empty through that 'channel'. I've read some things about how at very
high voltages you start to see weird properties that seem to defy the
actual normal 'insulation' of the air itself and thus allow lower HV to
penetrate much further than it otherwise could?
So, it doesn't matter about how much I insulate my HV driver because
eventually it's going to get exposed to some area inside the insulating
tube near the belt and that is in fact the danger?
I've noticed on my shorter VDG's sometimes they suddenly 'charge-out' with
a pop but no visible arc. I figured it could be the charge actually running
down the inside of the insulating tube itself and connecting with the
ground brush. Actually even on my 6ft VDG I've noticed this sometimes
especially on very cold, dry days.
Very interested...
On Thu, Sep 10, 2015 at 12:40 AM, Carl Noggle <cn8@xxxxxxx> wrote:
> As a general rule, in HV design you should use as little insulation as
> possible, since dielectric surfaces charge up and distort the desired
> fields and create sliding sparks. Voltages can jump 4 or 5 times as far on
> a dielectric surface as in air. Attachments of dielectrics to metal should
> be done in low-field regions.
>
> ---Carl
>
>
>
>
>
>
> On 9/9/2015 3:55 PM, Matthew Sweeney wrote:
>
>> Yeah i built one before but i have a set of these nst sitting here needing
>> a use. With current limiting i think ill be safe there is no possible
>> conductive path up to the collecter and i use lots of insulating. Im
>> specifically interested in how a positive and negative vdg will interact
>> because i see noticeable differences when i switch the polarity on my
>> single vdg.
>>
>> All my rectifying and current limiting components will be potted and i use
>> HV cable upto 40K just to be sure. And that all goes in a plastic
>> container
>> covering the entire bottom section including motor, rollers etc.
>> On Sep 9, 2015 3:42 PM, "ExtremeElectronics.co.uk" <
>> tesla@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> Why not use a fly back, If you look around you can find them with a
>>> tripler that will give you 30-40KV DC.
>>> The only down side is that you can't reverse the current
>>>
>>> There were some cheap ionizers on ebay a while back, they might be a good
>>> start too.
>>> For safety I'd aim for low voltage powered HV devices. I'd be very wary
>>> of
>>> using an NST. In a fault situation or a HV DC discharge from the VDG to
>>> the
>>> NST output, they could create a high current path to whatever the VDG was
>>> connected to, or arcing to at the time. This could easily be lethal.
>>>
>>> Derek
>>>
>>>
>>>
>>> On 09-Sep-15 6:11 AM, Matthew Sweeney wrote:
>>>
>>> Oh I forgot to mention, any good suggestions for current limiting here?
>>>> 30ma is far too much for a VDG am I'm sure most of it's going to be
>>>> wasted
>>>> anyway. Do i need a good old variac or some other cheaper alternative?
>>>> Will
>>>> a light dimmer really work i this situation?
>>>>
>>>> Thank you!
>>>>
>>>> Matt Sweeney
>>>>
>>>>
>>>> On Wed, Sep 9, 2015 at 12:01 AM, Matthew Sweeney <msweeney23@xxxxxxxxx>
>>>> wrote:
>>>>
>>>> Hello, all does anyone know a good source for HV diodes for rectifying
>>>>
>>>>> NST? Specifically up to 15KV at 30ma I would assume I need to account
>>>>> for
>>>>> RMS so probably around 20KV.
>>>>>
>>>>> I think I can get away with just one for half wave and maybe a cap for
>>>>> smoothing it a bit, but that would need to be a pretty decent cap to
>>>>> deal
>>>>> with 60HZ at that voltage.
>>>>>
>>>>> I'm using this to build a HV DC fed VDG does anyone have any hints or
>>>>> suggestions? I know I can find both diodes and caps in microwave ovens
>>>>> but
>>>>> its a pain to pull them apart and they are commonly too low voltage.
>>>>>
>>>>> I have found a few online retailers just wondering if there may be an
>>>>> alternate source, or anyone have some for sale etc.
>>>>>
>>>>> Thanks for any help!
>>>>>
>>>>> Matt Sweeney
>>>>>
>>>>> _______________________________________________
>>>>>
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>>
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