Re: my email

["Tesla list" <tesla-at-xxxxxxxxxx>]

Original poster: Terry Fritz <twftesla-at-uswest-dot-net>

Hi Simon,

	Thanks for reminding me!  I get like 50 mails a day and sometimes they get
all blurry...

At 02:24 PM 5/1/1999 +1000, you wrote:
>Hiya Terry..
>
>Just wondering if you got my email..
>
>If not, I've attached it to the bottom..
>
>Thnaks again for your help :)
>
>Hi Terry.
>Yes, it is a going to be a static gap, [.·. 17nfd caps]

If you have a sync rotary you can get to 24nF, but with a static gap about
15-17nF is right.

>I still claim ignorance [less and less gradually though :)] when it comes 
>to caps, but I have narrowed it do to
>http://www.arcotronics-dot-com/htm/prod/ec_polyp.htm ... but I'm not exactly 
>sure what type? Any recommendations?

The R73 series.  1500-2000Vdc and around 650VAC.  Values around 0.056uF.
Always metal-film, self-healing, high-voltage, high-current, AC types with
high Dv/Dt.  And ALWAYS polypropylene.  Try to get the largest case size if
there is a choice.

>
>BTW, I'm not actually sure how many caps I should have per string, or how 
>many strings i should have.. I just threw some values in to try and get 
>some feedback.

You want the voltages of each cap to add together to get to the maximum
voltage of you transformer.  that is 22,000 volts in your case.  So 11 of
the 2000 volt types.  You can easily push that number since the caps are
significantly over designed.  I use 10 1600 volt caps with a 15kV
transformer but that is as far as one should push the voltage ratings.  You
will want at least 4 strings of caps.

>
>One last thing, I assume you mean the 17nfd is a per cap value? [Or maybe 
>not, I don't pretend to know :)]

Let's suppose you used 13 0.047uF caps per string.  The value of each cap
gets divide by 13 to give a string capacitance of 0.047 / 13 = 0.00336uF
per string.  13 x 1600 = 20800 volts which is close enough.  Four strings
gives a total capacitance of 4 x 0.00336 = 0.01446uF which is pretty good.
So I would use four strings of 13 caps each to give a 20800 volt 0.01446uF
cap.  There are zillions of combinations but this sounds as good as any.

Hope that helps.

Cheers,

	Terry


>
>Thanks once again.
>
>Simon
>
>
>At 05:31 AM 30/11/2000 -0700, you wrote:
>Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
>Hi Simon,
>
>For a 15kV/60mA tranny, around 24nF may be a better value. 8 caps per
>string seems too few for 1600 volt caps. Remember that a 15kV transformer
>actually has a peak voltage of 15 x 1.414 = 21200 volts.
>
>If you are using a static gap, around 17nF may be about right. A rotary is
>24nF. Really need to know the gap type, voltage/current of the NST, and
>type data on small caps you are thinking of. I am assuming 60Hz too.
>
>http://hot-streamer-dot-com/TeslaCoils/Misc/NSTStudy/NSTStudy.htm
>
>I have a 15kV/60mA coil described at:
>
>http://hot-streamer-dot-com/TeslaCoils/MyCoils/BigCoil/BigCoil.htm
>
>Also,
>
>http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm
>
>Cheers,
>
>Terry
>
>
>
>
>At 04:23 PM 4/30/1999 +1000, you wrote:
> >Heya-
> >
> >thanks for the help..
> >I'm still sorting out the exact specs of my coil, but I'm looking at a coil
> >very [if not identical] to Don's
>[http://www.fwpd-dot-net/dona/tesla/teslacoil.htm]
> >Even though I'm still a little uncertain, it seems that I'm looking at
> >[from results at http://tesla.better-dot-org/mmc_form.cfm]
> >"MMC has 5 string(s) of 8 cap(s) each. Total C is 0.035 and costs $72"
> >[based on caps being $1.8 a pop]
> >
> >Does this sound reasonable? [If I'm using a 15kV tranny it gets matched to
> >about .0134 [multiplying the resonance value by about 2.5]
> >
> >I hope we can sort something.. :)
> >
> >thanks for your help
> >
> >Simon
> >
> >[ps, i live in toowomba, [near brisbane, QLD]
> >
> >
>
>
>