Re: Questions.

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

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

Hi Josh,

At 09:57 PM 2/20/2001 -0500, you wrote:
>Hello list.
>I've been on the list for a while and am looking to build a my first coil
> in the near future. I have a few questions:

Cool!

>
>1.  What should be a good target frequency for a coil?  What are the
>pro's and con's of a higher or lower frequency?  What effect does the
>input ac's frequency have?

The AC line frequency is what ever you have :-))  You can't change that,
but it is fine!

Coils run about 250kHz (+-100kHz) and the frequency around that point does
not seem to make much difference at all.

>
>2.  I have found some caps I can get for a relatively good price and
>would like to use them for my coil.  Are these in the right ballpark for
>tesla coils?
>	  .001 UF 10 KV AXIAL CERAMIC DISC CAPACITOR   $ 1.00 each

Capacitors will heat up depending and the RMS current and frequency.  Tesla
coils are super hard if not the hardest applications a poor capacitor can
ever find itself in.  Therefore, only the VERY best will do.  The word
"polypropylene" is essential since that dielectric is the best by an order
of magnitude above the rest.  "oil filled", "high dV/dT", "high current",
"self-healing" are the key words to look for.  The "ceramic" caps will cook
and fry in this service...  You should check out the information at:

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

>
>3.  When demonstrating a coil indoors what do you use for a ground?  Do
>you simply run a wire to outside?

That works good!  Unless there is a cold water pipe or steel building
member near, I would just run a wire through a window.  Electrical safety
is first, and then trying to conduct the RF currents to ground is the key. 

>
>4.  Wouldn't a conical secondary be more efficient than a cylindrical
>one?  One reason being that the magnetic force from the lower wider part
>of the secondary coil would create a higher voltage on the smaller higher
>part.  Know what i'm saying?
>

That, "i" have never figured out... :-))

Cheers,

	Terry


>I think that's all for now.  Thanks,
>
>		-Josh B.
>