Re: Safety gap issues

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>

YOU SAID:
"A very good equation that works well to find a coils peak output voltage is:

Vt = Vf x SQRT (Cp / (2 x Cs))

Where:

Vt it the peak top voltage
Vf is the spark gap firing voltage
Cp is the primary capacitance
Cs is the effective secondary capacitance
SQRT square root function "

* if i know the distance, can you tell me the sparkgap firing 
voltage? it is 7.5 to 8 mm, at 30MA. 8000v?
* primary capacitance? you mean just the capacitor? 7.8nF (.0078 uF)
* secondary capacitance, with toroid, is 18.6 pF (.0000186 uF)

wtf? that means my coil only makes 117.3KV!!!!?   Cant be true. I wont buy it






> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: Re: Safety gap issues
> Date: Sun, 27 Nov 2005 10:02:21 -0700
>
> Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi,
>
> A very good equation that works well to find a coils peak output voltage is:
>
> Vt = Vf x SQRT (Cp / (2 x Cs))
>
> Where:
>
> Vt it the peak top voltage
> Vf is the spark gap firing voltage
> Cp is the primary capacitance
> Cs is the effective secondary capacitance
> SQRT square root function
>
> This assumes the coil is well tuned and running well without any problems.
> As far as I could ever tell, the size of the toroid really does not 
> affect voltage that much.  But larger toroids do have larger 
> streamers.  I think that is do more to electrostatic field effects 
> rather than higher voltages.
>
> Cheers,
>
>         Terry
>
>
>
> At 05:32 PM 11/26/2005, you wrote:
> > WOW, NICE. According to what you just said, my coil produces an 
> > absolute maximum of 533KV (if  my toroid were perfectly smooth) 
> > Half a million volts seems too much for a mere 14" discharge 
> > average. But, if you say half a million, i'll go with that!  :P
> >
> >
> > > From: "Tesla list" <tesla@xxxxxxxxxx>
> > > To: tesla@xxxxxxxxxx
> > > Subject: Re: Safety gap issues
> > > Date: Sat, 26 Nov 2005 12:51:45 -0700
> > >
> > > Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
> > >
> > > Hi Jim,
> > >
> > > At 08:16 AM 11/26/2005, you wrote:
> > > ...........
> > > > If you want to "estimate" the voltage on your tesla coil from 
> > > > it's physical design, your best bet is to measure the radius of curvature.
> > > > The voltage won't be much higher than the radius of curvature in 
> > > > cm times 30 kV/cm, and will likely be lower (since that's the max 
> > > > voltage for smooth sphere with nothing around it).
> > >
> > > I have noticed that the "breakout voltage" does tend to correspond 
> > > to the radius of curvature and all.  However, the top voltage can 
> > > then go substantially beyond that.  If there is a lot of power behind the arcs.
> > > Then the "breakout loading" is just not enough to hold the voltage down.
> > > So it does not act like say a hard Zener diode, but rather a Zener 
> > > with a big resistor in series with it.
> > >
> > > Cheers,
> > >
> > >         Terry