Re: what capacitor for TC...other newbie questions

["Tesla list" <tesla-at-pupman-dot-com>]

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

Hi Mike,

Welcome to the list :-)

Many of us are using "MMC capacitors" that are made of many smaller
capacitors.  See:

http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm

They are pretty easy to make and can be far cheaper than commercial caps.
Be sure to check into this.  the cap will have to easily handle about 10
amps RMS at say 200kHz.  It needs special high current construction so as
not to fail due to the high RF currents.

With a 15/60 transformer and a static (as opposed to a rotary) gap.  You
will want a capacitor value in the 15-20nF range.  The cap should be about
30kV for a commercial cap but an MMC can be 20kV since they are tough.  Be
sure to use saftey spark gaps to protect the NST and caps from overvoltage.

Spark gaps can be from very simple pipe sections to sync rotary gaps:

http://people.ne.mediaone-dot-net/lau/tesla/RQGap.htm
http://hot-streamer-dot-com/TeslaCoils/Misc/terrygap.jpg
http://hot-streamer-dot-com/TeslaCoils/MyCoils/SmallCoil/small_gap1.jpg

There is also the air "vortex" style gap that people really like.

http://people.ne.mediaone-dot-net/lau/tesla/vortexgap.htm

Lots of choices for spark gaps... 

28ga wire has about 73 turns per inch so 35 inches will give ~2500 turns
which is sort of high.  24ga "may" be a bit better choice but 28 will work.
 However, be sure your primary circuit can tune the coil.  You may need
some extra turns on the primary...  There are computer programs an "us" to
help you with all that if you need.

Hope this helps.

Cheers,

	Terry


At 04:20 PM 7/5/2001 -0700, you wrote:
>hello all,
>my name is mike secord, i have recently joined the
>tesla list, and would like very much to attempt to
>build a coil, i plan on using a polycarbonate hollow
>rod, 5in OD-36in long, 28ga magnet wire, a france
>15000v/60ma nst, my primary will be constructed from
>.375in OD soft copper tubing (30 deg conical). i have
>asssembled these materials so far,but i still need a
>spark gap controller, and a capacitor bank. i saw the
>web site for capacitor industries:
>http://www.capacitorindustries-dot-com/materials.htm
>rather than construct my own, i think i would rather
>purchase something, i just don't know what to order
>from the site....any suggestions? i also could use
>some advice regarding a spark gap... thank you all
>
>mike
>
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