[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Finally joined
Hi Joe. Welcome! Now, about your cap setup, You say 22 of the 500pf
caps wired in series parallel. I see that you have therefore a set of 11
series stacked caps, of which each series double set will give you 250pf.
Then these 11 ganged cap sets will be wired in parallel, that should
give you about 2750pf or .0027mf. I am not really good at math, but I
think I applied the capacitance formula to your cap bank properly. I
think you need more tank capacitance to get a longer streamer from your
secondary. If, indeed you have a 15/60 neon. Anyway, if you get more
capacitance in your tank circuit, you will then see that you will be able
to tune your primary to a shorter length(meaning less turns). As far as
the ungrounded secondary. I think you should be very careful in your
apartment, since you may incur the wrath of your neighbors if you
generate interference on their A/V equipment. A pitchfork in the butt
would cut your coiling short, not to mention tar and feathering! And as
you strive for more power and longer arcs, it would be wise to use a
grounding source on your coil. As far as spark length with or without
the secondary being grounded, this is what I have found: I have a
dedicated Tesla ground in the backyard(a 10' piece of 1/2" copper type
'L' water pipe, set in a damp area near a natural spring). It did not
seem to affect streamer length if the ground was coupled or not.
However, I keep an old 19" color tv set on at all times while I run my
coil so I can observe the interference on the screen. With the ground
disconnected I will generate more noise into the tv, which shows up as
washed out lines on the picture. So be very careful. There is nothing
like a good ground from a safety standpoint! A proper ground will also
protect you and your coil in the event of a catastrophic short. Please,
Safety First! Fires and electrocution are no fun. Also, a Tesla coil
generating arcs is a fearsome sight indeed to the eyes of the
uninitiated! Everyone runs away from mine when I fire it! Al.
On Wed, 13 Sep 2000 21:02:15 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: jduva-at-baytechnologies-dot-net
>
> Well, to answer John Freau's query, I'll dump out some info on my
> current
> coil. It's powered by a 15kV 60ma (I *think*..) neon, a cap bank of
> 22
> 500pf 30kV DC ceramite doorknob caps in parallel for .011 uf at
> 30kV. The
> spark gap consists of 7 copper pipe couplings spaced 1/16" apart
> each...mostly. Coincidentally, I also built my gap at 2am, and it
> shows.
> The primary is .25" copper tubing spaced 25." apart, all tacked into
> place
> on un-sealed 2' square plywood using 25' coax tack/holder jobs.
> Can't
> remember what they're actually called at the moment, but there are
> plenty of
> nice pointy nail ends poking through the bottom of the plywood.
> Good stuff.
> I'll replace all of that as soon as I win the lottery. The inner
> turn is
> 5.5" in diameter with a total of 13 turns, tapped between turns 10
> and 11,
> usually. The secondary is wound on 4" PVC that has been baked and
> sealed
> with polyurethane with 3 coats on the inside, 8 coats on the
> outside, all
> allowed to dry for at least 8 hours before the next coat. It is
> wound with
> 26-gauge magnet wire one inch from the bottom, 17" of ~980 turns and
> two
> inches left on the top with two spaced turns . It's capped with
> plexiglas
> and currently has a 4"x16" toroid placed on top of a 3"x8" toroid.
> both
> made with flexible aluminum ducting. The top toroid has the ducting
> wrapped
> around two electric stove burner drip trays. When epoxied bottom to
> bottom,
> the edges are about 2.5" inches apart and make for a great channel
> to set
> the ducting into. As it sits now, I can only get a maximum of about
> 24-26"
> out of it into the air. One 3' arc to ground, but that's never been
> repeated. most are 18"-20" streamers.
> With some improvements to the gap, primary layout, higher voltage
> capacitors, maybe even a new secondary, and toroid(s), what should I
> be
> expecting to the output? I've seen people claiming 40" streamers
> from 15kV
> 60ma input, but I'm nowhere close to that. Oh...one more thing.
> The
> secondary isn't grounded, as I live 3 floors up in an apartment
> complex.
> The grounding tab of the secondary rests comfortably on the copper
> tubing
> going to the first turn on my primary under the plywood board.
> Wasn't
> planning on this, but so far it's working out. I'd like to change
> that in
> the future as well, but it was a pleasant surprise to find that
> corona was
> coming from the top of the secondary with no toroid in place when I
> first
> tested out the tank circuit with the new caps. Turns out that the
> secondary
> was feeding off of the primary, but I didn't see it at the time.
> The NST
> hasn't died yet, so right now, I just keep my distance and get used
> to all
> of the experiences of a tesla coil. Whew...enough out of me.
> -Joe
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, September 13, 2000 12:28 PM
> To: tesla-at-pupman-dot-com
> Subject: RE: Finally joined
>
>
> Original poster: "Ted Rosenberg" <Ted.Rosenberg-at-radioshack-dot-com>
>
> Joe: Welcome.
> I started my first coil last January and finally got first light
> Sept 3.
> During this last 9 mo or so, I talked about not much else (Oh,
> there's an
> election this year?) or how hot it was last night in my garage
> (usually
> 105-110).
> I have discovered that researching, designing, and building that
> first coil
> is an effort that demands 150% concentration almost 24/7.
> I designed my spark gap at 2AM. Couldn't sleep.
> But the whole thing worked right from the first moment I cranked up
> the
> Variac.
> And as for viewing...you are right. I'm finding that civilians can't
> get
> enough viewing time.
> You'll have fun and learn a bunch too.
>
> Safety First
>
> Ted Rosenberg (Ft Worth TX)
> Geek Group Member #1030
> www.thegeekgroup-dot-org
> Because the Geek shall inherit the Earth!
>
> --------------------------
> Subject: Finally joined
>
>
> Original poster: jduva-at-baytechnologies-dot-net
>
> Hello all! I finally joined up with the listserv and I just wanted
> to say
> hi and introduce myself. My name is Joe and I'm currently in
> Maryland,
> working on improving my first coil. I hope to get to know
> everybody, as
> I've worn out everybody I know so far with the tesla coil stuff. At
> least
> they all like to watch it. ;) Take care.
> -Joe
>
>
>
>
>