[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [TCML] Toroid Shielding
Hello David,
Thanks for your well explained reply. Previously I had always just accepted the toroids part in protecting the top of the secondary without really querying how it was achieved. It's obvious and common sense now, but in my quest to get my streamers going down rather than up most of the time, I started looking around at other coils and trying to come up with an explanation. Hence the crazy thinking!
Phil
--------------------------------------------------
From: "David Petzer" <davepetzer@xxxxxxxxx>
Sent: Friday, May 28, 2010 3:57 PM
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Toroid Shielding
> By "electrostatic field control" Dr. Resonance means the electrostatic field has no points of concentration where the toroid and the secondary are joined. He is not saying that the electrostatic field is controlling or moving the streamers once they are initiated.
>
> So why are there no points of electric field concentration near the top of the secondary coil?
>
> The large, smooth, conducting surface of the toroid creates an equipotential volume at the top of the secondary. So the very top of the secondary coil and the immediately surrounding air are at similar potential(voltage). The electrostatic stress between the top of the coil and the air immediately surrounding it is therefore reduced (controlled). This reduces the chance of breakdown occurring at the top of the secondary.
>
> It is useful to think of electrical potential (voltage) as a contour map, the contour lines being equipotential lines though not equiheight (altitude) lines as on maps.
>
>
> The streamers are not pushed or deflected at all, they simply do not originate from the area connecting the top of the secondary to the toroid because this is a low electrical stress area. The streamers originate from the area with the greatest electrical
> stress. Returning to the analogy with the contour maps, this would be the area on the map with the steepest slope. The large toroid smooths the slope around the top of the secondary.
>
> Break out points (sharp bumps or wires) on the toroid provide a point of increased electrical stress, i.e. a steeper slope.
>
> /*If you are still reading and not bored by this stage*/
>
> One example the electric field strength between two concentric circles as a function or the radius r of the smaller sphere
>
> Er = UR/r(R-r)
>
> U = voltage/potential difference between the spheres
> R = Radius of big outer sphere
> r = radius of small inner sphere
>
> You can see that as the inner radius becomes smaller the electric field strength at its surface increases. Increasing the inner spheres radius reduces/ controls the electric field strength.
>
> /*And if you are still reading after all this*/
>
> Look up "stress cone" for another example of electrostatic field control.
>
> -Feanor
>
>
>
>
> ________________________________
> From: Phil Tuck <phil@xxxxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Fri, May 28, 2010 5:33:46 PM
> Subject: Re: [TCML] Toroid Shielding
>
> Yes, I know what it is called. How though does the effect manifest itself on a tesla coil?
>
> Does the overall width of the toroid create a vertically descending field that pushes or deflects the streamers away? This field diminishing in effect the further down the coil it travels. So in effect, if it could be seen, it would appear as an inverted cone with the base of the cone being the same as the overall diameter of the toroid?
>
> A bit like this: http://hvtesla.com/temp_images/img004.jpg
>
> Phil
> --------------------------------------------------
> From: "DC Cox" <resonance@xxxxxxxxxxxx>
> Sent: Friday, May 28, 2010 2:30 AM
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Subject: Re: [TCML] Toroid Shielding
>
>> electrostatic field control.
>>
>> Dr. Resonance
>>
>>
>>
>>
>>
>> On Thu, May 27, 2010 at 4:20 PM, Phil Tuck <phil@xxxxxxxxxxx> wrote:
>>
>>> Hello,
>>> How is the shielding that we know that the toroid provides to the top of
>>> the secondary actually achieved? Is it by creating a field that is able to
>>> 'push' the streamers away from the top part of the secondary ?
>>> The 'Green Monster' coil of Dave Rieben (
>>> http://www.youtube.com/watch?v=H3pfStBx2qY ) which has a 12.5" sec and a
>>> 56" major x 12" minor diameter toroid, is a good example.
>>> The streamers of that coil in particular, clearly have a pronounced curved
>>> quality to them on their ground strikes. Could this be a direct result of
>>> the extra shielding that his relatively wide [sec diameter X 4.5] toroid
>>> provides? They appear that initially they curve away from the top of the
>>> secondary before they continue on downwards to their strikes.
>>>
>>> Phil
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
> Regards
> Phil Tuck
>
> www.hvtesla.com
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
>
>
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
Regards
Phil Tuck
www.hvtesla.com
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla