Re: 833 coil

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

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, September 27, 2003 12:07 PM
Subject: Re: 833 coil


 > Original poster: "Steven Ward" <srward16-at-hotmail-dot-com>
 >
 > Notice that the Q of the coil overall will change drastically from using 1
 > tube to using 2 tubes!  In order to truly optimize a single tube coil, you
 > must redesign the tank parameters...likely using a higher impedance.

Without giving it any thought, I would think that you need a lower plate
load impedance, since you've got two tubes in parallel, each one taking half
the load?  I would also assume that the plate C is doubled...

  But,
 > the spark lenght figures Dan mentions sound right on for the tube.  Also,
 > Dan mentions the placement of the coil and spark lenght... this is all too
 > true!  Any time i try to run the VTTC at a thon, its always dissapointing.
 > Im reworking the whole coil now though, so Dan better watch out!  But 32"
 > is outstanding!  How is the tube redness at that level Dan?  And what
 > staccato pulse rate?
 >
 > Steve Ward
 >
 >
 > >From: "Tesla list" <tesla-at-pupman-dot-com>
 > >To: tesla-at-pupman-dot-com
 > >Subject: Re: 833 coil
 > >Date: Sat, 27 Sep 2003 09:10:26 -0600
 > >
 > >Original poster: dhmccauley-at-spacecatlighting-dot-com
 > >
 > >
 > >The John Freau design i am currently using works extremely well and is
well
 > >documented on my page here:
 > >
 > >http://www.spacecatlighting-dot-com/teslacoil12.htm
 > >
 > >Although this design shows paralleled 833 tubes, the design would just
about
 > >identical for a single, triple, quadruple, etc... 833 VTTC.  Just need to
 > >size your filament and plate
 > >transformer accordingly.  10V, 10A Filament transformers are actually
 > >readily available.  I'm not sure why everyone has a difficult time
finding
 > >them.  www.newark-dot-com sells them as
 > >well as many other distributors.  The major filament transformer vendor
now
 > >is Hammond MFG at www.hammondmfg-dot-com  If you go to the website, just look
 > >under distributors and place
 > >your order.  Even if the distributor does not list a specific transformer
 > >explicitly, doesn't mean it doesn't sell them.  I buy all my 10V, 10A
 > >filament transformers from www.newark-dot-com and usually
 > >get them within a day or two of placing my order.  They are about $28.00
 > >each.
 > >
 > >You really don't need a plate transformer.  A MOT will work great,
although
 > >for much shorter durations than a properly rated plate transformer.
Also,
 > >you will want to build yourself a
 > >Stacatto controller (Cathode Pulser) to reduce the average power to the
 > >tubes, ESPECIALLY if you are only using one tube.  This way, you can
still
 > >go for the maximum arc distance, maximize
 > >peak power to the coil, yet reduce average power.
 > >
 > >Those small toroids from John Freau will work just fine.  You really
don't
 > >need a larger toroid as you really aren't building up total voltage on
the
 > >toroid anyways as you typically always use
 > >a break-out point on top of the toroid anyways.  Most VTTCs i've seen use
 > >just a small disk as the topload.
 > >
 > >For a single 833A running with a stacatto controller, i think you could
get
 > >about 12-15" no problem.  After a lot of work and tuning, you could
probably
 > >increase length up to 20".
 > >My maximum spark length so far with my dual 833A coil is 32" which was
done
 > >quite recentlly.  Its very sensitive to tuning and the only place i can
 > >successfully run it at those arc lengths
 > >is in my basement at my mom's house.  Everywhere else, performance is
down
 > >to about 24-26".
 > >
 > >Dan
 > >
 > >
 > >
 > > > Hi,
 > > >
 > > > I recently acquired an 833a tube, and would like to proceed with
making a
 > > > coil.  The only requirement that I want to impose on this project is
 > > > longetivity, even at the expense of spark length.  The goal is to be
able
 > >to
 > > > run for extended periods without worrying about tube damage, allowing
for
 > > > various experimentation.
 > > >
 > > > Due to time constraints, I am hoping plagiarize a working, single tube
 > > > design.  After I have an operational coil, I can then proceed to alter
 > > > parameters to notice their effect.  Also, due to a relative lack of
 > > > knowledge with electronics, I believe that going with an existing
design
 > > > will allow for a better learning experience than continuously fiddling
 > >with
 > > > component values that I know nothing about.  Here goes:
 > > >
 > > > 1)  10v 10A filament transformers seem impossible to find.  Would I be
 > >able
 > > > to use the trans out of a 12 volt battery charger and throttle it back
 > >with
 > > > a variac?  Or, would it be better to use a MOT with the secondary
removed
 > > > and wind a few turns of wire on it like everyone else has done?
 > > >
 > > > 2)  Plate transformers designed to feed an 833 are super expensive and
 > > > heavy.  MOTs again?
 > > >
 > > > 3)  Does anyone have a link with a solid, simple one tube design that
they
 > > > would be willing to share?  It's my understanding that a lot of the
 > > > component values aren't critical, but since I'm the type of person who
has
 > > > to be hands on to learn, they would assist me in getting together a
 > >project
 > > > where results can be seen.
 > > >
 > > > 4)  I have gone thru the archives and done lots of reading on other's
 > > > projects to alleviate you guys from reiterating what has been said
many
 > > > times, as well as making countless visits to Steve W's, John F's, and
 > >others
 > > > websites.  I've read the tube section of my old AARL Handbooks many
times
 > >as
 > > > well, and am getting an understanding on the tube process.  However,
 > > > assembling a project that I know will perform seems to help ease the
 > >mental
 > > > anguish and promote an understanding of what I am doing.
 > > >
 > > > 5)  I've got two of John F's small toroids (2 by 6?).  Will I need
 > >something
 > > > bigger?
 > > >
 > > > 6)  I have to ask:  How much spark can I expect with a durable design?
 > > >
 > > > Thanks for any info,
 > > >
 > > > John Richardson
 > > >
 > > >
 > > >
 > > >
 > > >
 >
 >