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Re: Fine Tuning a Spark Gap
to: Bill, Mike
The caps work well because the surface area is very large and the
interconnection surface area is also very large. In the proposed sparkgap
he was not proposing a large surface area for the alum. conductors hence
the degrading of the peak currents. Take a standard medium size system and
measure the peak currents and output currents for yourself using different
materials. We have and there is a substantial difference. The potential
is only slightly lower but the sparks are much less bright than with copper
and other better conductors. Alum. is only tolerable at 60 Hz for power
line work and not very suitable at RF frequencies. Yes, coils will work
and hemi's will run on small 4 bbls but the tradeoff is loss, loss, loss.
Why use alum. if more efficient materials are available at similar cost?
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Fine Tuning a Spark Gap
> Date: Thursday, October 29, 1998 11:24 AM
>
> Original Poster: "Wysock, William C." <Wysock-at-courier8.aero-dot-org>
>
>
> To Mike, D.C., All.
>
> I have to agree with Mike's statement below. If one has an aluminum
> conductor in a (Tesla coil) tank circuit, that is of sufficient surface
> area,
> I see little (if any) degredation in the performance of the circuit.
People
> have been using aluminum rectangular strip for flat spriral primary
> inductances, for many years, with very good success. Moreover, if
> aluminum is so poor a conductor at radio frequencies, then how come
> all the commercial capacitor manufactures use this material in their
> extended foil construction? The high end polypropylene capacitors
> using this foil exhibit very low ESR and ESL numbers, and very high
> Q's.
>
> Of course, the conductivity of aluminum is not as good as copper.
> In coil designs where every precious joule of input energy must be
> conserved (at any cost,) then clearly, copper is the superior choice.
>
> Granted, you wouldn't want to use aluminum wire for a secondary
> inductance, but where a primary inductance is concerned (typically
> say less then 100-150 feet in length and a strip width of say, 2",) I
> know of a number of very effective and efficient coils that have been
> built, using this material. One common trick has been to use 4 to 5
> strips of equal width, and sandwich them together, then wind the
> flat spiral. Using this method, each individual strip had a thckness
> of around 0.020 to 0.030"; therefore a composit thickness of 0.100" to
> 0.150".
>
> Bill Wysock.
> --------------------------------------------
> Tesla Technology Research
>
> ----------
> From: Tesla List
> To: Tesla List
> Subject: Re: Fine Tuning a Spark Gap
> Date: Thursday, October 29, 1998 7:59AM
>
> Original Poster: Hollmike-at-aol-dot-com
>
> In a message dated 10/28/98 9:43:43 PM Mountain Standard Time,
> tesla-at-pupman-dot-com writes:
>
> >
> > Mike,
> > What I've heard has been from this list. Aluminum at RF frequencies is
a
> > poor
> > choice for a conductor. The conductance is affected by the frequency
and
> > the Q of
> > the conductor drops. That's what I meant by RF suppression. I didn't
mean
> > the
> > frequency was suppressed.
> > Bart
> >
>
> I didn't think that the frequency could be suppressed as mentioned in
your
> last sentence. I am not sure I can agree with the statement that
aluminum
> is
> a poor conductor at TC frequencies. Chip uses a primary made from a
strip
> of
> aluminum(about two inches wide) cut from a roll of flashing. His coil
does
> quite nicely with it. Perhaps it would do even better with a copper
strip
> of
> identical size, but as far as I can tell, aluminum works just fine.
Maybe
> this is simply due to the large surface area of the conductor. Whatever
the
> case, I wouldn't hesitate to use a similar design.
> Mike
>
>