RE: [TCML] Single ear piglet

["Jim Mora" <wavetuner@xxxxxxxxx>]

Hi David,

Let me see if I am following you. This then RF grounds the inner turn of the
primary, Yes? I know others do this and tie it to the secondary base. So
there is no arc over from the inner turn to the coil lower turn. I seem to
remember something bad about this but can't peg it. I believe this is the
hallmark of an Oudin coil construction.

Is this what you are doing? The return has the advantage of being RF but
what is there is a fault in the transformer... the LV goes to the operator
controls... do we trust the RF ground resistance to mains to blow a breaker
or am I missing something?

Jim Mora
 



-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of David Rieben
Sent: Wednesday, April 22, 2009 4:31 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Single ear piglet

Hi Jim, Gates,

What "I" do with my single eared piggy is hook the
tank's case "return" to the opposite side of the SG/
capacitor form the "ear".. In other words, the tank
case is tied to RF ground. Since my pig is resting on
a plywood base and fastend via its polemunt brackets
to 2x4 cross beams inside of my control panel, I am
able to effectively isolate the RF from the mains ground.
As a matter of fact, there is no direct connection to
mains ground at all with the my piggy, since proper
input hookup leaves the middle LV bushing un-
grounded.

I see you also mentioned  that your transformer's rated
output is 30 kV with 120 volts input. I am assuming
that this is some type of potential transformer as
30 kV seems rather high for typical primary distri-
bution voltage. Also, as Herr Zapp has mentioned,
this is also a very high primary voltage for a typical
Tesla coil circuit and few of even the largest coils run
on primary circuit voltages of this magnitude. List
member Scot "bunnykiller" D. is about the only one
that I can think of off the top of my head that has
succesfully ran ~ 30 kV in a standard, air-insulated Tesla
primary circuit and he can tell you firsthand of the inherent
problems with running voltages this high that H. Zapp has
already mentioned in his posting to this thread. If it's at
all feasble for you, you may wish to consider obtaining
a pole pig with a more typical input voltage (output
voltage, for our use), like 13.2 or 14.4 kV. If it's not
feasable, then I suggest that you talk with "bunnykiller"
to get some insight from his experience. Of course,
one advantage to using a higher primary voltage is that
you can get by with a notably smaller primary capacitor,
capacitance wise, per E = .5 CV (sqrd), where E is the
energy, in Joules, C is the capacitance, in Farads, and V
is the potential, in volts. However, the increased dielectric
requirements for the additional voltage standoff pretty well
render this advantage moot.

David Rieben


----- Original Message ----- 
From: "Jim Mora" <wavetuner@xxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Tuesday, April 21, 2009 7:54 PM
Subject: [TCML] Single ear piglet


> Hi Gates,
>
>
>
> Dr, Resonance does this on all his coils this way. I just set one up to 
> his
> specs and many list member ground one horn in a dual horn. I'll let Dr.
> Resonance advise on this. Generally the inner turn of the primary is
> grounded to the coils RF ground. You need a return path so the pig may be 
> at
> mains ground too, something I don't like much. Filter the nasties!.
>
>
>
> Jim Mora
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla 

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