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# Re: Coil Specs

```Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ben,

For a 9/30 NST, the resonant capacitor size is 8.842nF (0.008842uF).  An LTR
size is around 12nF.

The "peak" voltage from your 9000 volt transformer is the rated RMS voltage
(9000) multiplied by the square root of two.  9000 x SQRT(2) = 12728 volts.

Lets say we get a bunch of Geek group caps at 100nF 2000 volts each.  "I" would
try for the LTR range in the 11 to 12 nF range.  I am going off the chart at:

http://hot-streamer-dot-com/TeslaCoils/Misc/NSTStudy/9-30.gif

100nF / 9 = 11.1nF which would be fine.  9 caps gives a voltage of 18,000 volts
which is also fine.

We should check the current which MMCCalc will do:

--------------------------------------------
MMC Calculator  Ver. 2.2   9/12/2000  Terry Fritz
Transformer voltage =  9000
Transformer current =  .03
Firing voltage =  12727.89
Fo =  200000
Break rate =  120
Thermal dissipation constant =  33
Individual cap value =  .0000001

Strings  Caps/Str  Capacitance  Voltage   Temp C    Cost              I Arms
1        9         11.11        18000     2.84   16.20  :-))  :-))  2.44
--------------------------------------------------------------------
2       18         11.11        36000     0.71   64.80  :-))  :-))  2.44
2       19         10.53        38000     0.64   68.40  :-))  :-))  2.31
---------------------------------------------------------------------

2.44 amps which a well within the capacitors range.

So I would say to get 9 of the 0.1uF 2000 volt caps from Chris.  That would run
you \$16.20.  If you want a 8.8nF cap then get 11 of them.  I think Sam used the
very high voltage caps because that is what he had on hand.

A variac is a super usefull thing to have.  It makes tuning and such far
easier.

Hopefully this is what you wanted to know.

Cheers,

Terry

At 04:35 PM 5/29/2001 -0500, you wrote:
>
>
> Secondary:
>     Diameter- 42mm
>     Wire- 29AWG
>     Turns- 885
>     Inducyance- 4.98mH
>     Reson. Frq- 1.150MHz
> Primary:
>     Inner Diameter- 6.6cm
>     Outer Diameter-24.6cm
>     Wire Dia.- 5mm copper
>     Inductance(at 7) .007Mh
> Gap:
>     Static
>     10 sections of 10x2cm copper tubing
> Caps:
>     -To be determined
>     Desired Qualities-
>     Voltage-50kv(copying, let me know if this is resonable)
>     uF- .0088
> Top Load:
>     Capacitance- 8.85pF
>     Diameter- 5.5cm
>     Crossection- 20cm
> PowerSupply:
>     Output(volts)- 9KV
>     Current- 30mA
> *How useful is a voltage controller?
>
> These are the specs(approxiamtly) of the coil I will be constructing. All
> useful data is extremly appreciated. I need a little help with caps at the
> moment. Check out
> <http://www.powerlabs-dot-org/coil2.htm>http://www.powerlabs-dot-org/coil2.htm to see
> what my design is based on. I have the MMC calculator but it is not working
> for some reason. It gives no output of data, only takes everyting I will feed
> it :)
>
> Thanks,
> Ben
>
>
>

```