Re: Air Caps

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

Original poster: "Marry Krutsch by way of Terry Fritz <twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>

Hi Terry.

	I'm pretty sure that the plate cap is the only primary cap.  The last
time I examined the coil closely, I didn't see any other obvious part
that could be a capacitor.  I remember that the power supply was a 9/30
neon, and the secondary was 4" in diameter by 4.5 or so feet tall.  The
primary is helical, about 1 foot across, and about 8 inches high.  I
can't remember how many turns.  By "intense arcs", I mean that they were
very thick.  They didn't look like VTTC arcs, and were not particularly
bright.  It sure was loud though! :-).  I will check with him about the
coil, but it may be a while.  The problem is, he was my high school
physics teacher, and I haven't talked to him in about a year.  I will
see what I can do.

	What do you mean when you say that the coil may be working as a loosly
coupled transformer?  I thought that's what a TC is.  Please explain
(I'm new to this).

Winston



Tesla list wrote:
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi Winston,
> 
> Can you check into this?  If those plates are the only capacitor for his
> coil, that would be very unusual!  There may be a hidden cap inside, with
> this air cap used for demonstrations or to show the theory better.  I know
> of no 5 foot coils that only use 20pF of primary capacitance but if someone
> has one that works we should figure out how!
> 
> It is possible the coil is working more as a loosely couple transformer
> too.  "intense arcs" would suggest that.  Be interested to get more details.
> 
> Cheers,
> 
>         Terry
> 
> At 10:22 PM 2/14/2002 -0800, you wrote:
> >Hi Terry, Cory!
> >
> >       My physics teacher has a coil about 5 feet tall that puts out INTENSE
> >2.5 foot sparks (no toroid, uses a bolt as a top terminal), using a 20
> >pF primary cap (if my calculations are correct).  Two 18 by 18 inch
> >plates 3.5 inches apart, with air as the dielectric.  It puts out so
> >many sparks per cycle that it looks like the thing is on fire.
> >
> >Winston
> >