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Re: Safety gap issues



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