Re: BIG coil project

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>


You can do O-scope tuning with both the 0.1 and 0.2 uF caps.  Your objective
is to add enough capacitance in the primary to bring the total turns into
the area of 4-8 turns.  A lot depends on your topload, so experiment with
the scope and sig gen until you reach a happy state of tune, then add 1/2
turn to compensate for the electric field's capacitance (above the sec), and
fire it up.

If you coil is not yet wound you might even consider going to 24 inch dia.
for higher output especially at this high power level.

Have fun!

Dr. Resonance


>
> Yes, I doubt that my coil will be able to compete with your "Big Bruiser"
> but I am hoping to be able to achieve up to 15 foot point-to-point sparks
> with it once it's completed and tuned in. It's interseting that you
suggest
> using the total .2 uFd with both of my .1 uFd caps as Scot D (aka Bunny-
> killer) suggested seriesing the to 14.4 kV pigs for around 30 kV of pri-
> mary voltage and using both of the .1 uFd caps as well, only in series for
a
> .05 uFd @ 100 kV combo. This would still give me the same joules/bang
> as with .2 uFd at  14.4kV and would allow for using more primary turns.
> The resultant increase of primary L should allow for lower gap losses.
> The one big drawback with this is that 30 kV is a real pain in the butt
> to stand off w/out flashover in the primary circuit. Scot can tell you all
> about that, too. So, it's gonna be a somewhat difficult decision to de-
> cide on exactly how I'm going to wire this thing, but I'll probably start
> out with 14.4 kV at .1 uFd and see what kind of sparks that I can get
> from that setup and go from there ;^)
>
> Unfortunately, I don't have an O-scope or a signal generator. I've been
> spending too much of my money on the coil parts themseleves to worry
> about getting the fancy test equipment.... It'll be a lot of trial and
error
> for tuning it in, just like it was all of the times before ;^))
>
> David Rieben
>
>
> ----- Original Message -----
> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Saturday, December 04, 2004 2:55 PM
> Subject: Re: BIG coil project
>
>
>  > Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
>  >
>  >
>  >
>  >
>  > Dave:
>  >
>  > Our Big Bruiser design is similar to the coil you are proposing.  The
only
>  > difference is our 24 inch dia. sec coil.  We used 0.3 uFd with a 9 turn
>  > primary.  We will run at 220 VAC @ 120 Amps (our main breaker rated at
125
>  > Amps).  We plan on trying 0.4 uFd next summer.
>  >
>  > Your coil should run better with 0.2 uFd with the available power you
> have,
>  > but with less wire length, you could get away with 0.1 uFd.  If you
have
> the
>  > extra cap, use it.  Do an O-scope/sig gen tuning to see which value
works
>  > best.  You might get down to 4-5 turns with the 0.2 uFd cap.
>  >
>  > Dr. Resonance
>  >
>  > Resonance Research Corporation
>  > E11870 Shadylane Rd.
>  > Baraboo   WI   53913
>  >
>  >
>  >  >
>  >  > I'm starting to get together some of the basic parts for my biggest
> coil
>  >  > project to date. I have just completed a 12 x 56 toroid made from 4
>  >  > pieces of 12" aluminum flex-duct that each had a compressed length
>  >  > of 24". The secondary is ~897 turns of non-spaced # 17 AWG heavy
>  >  > build, Essex magnet wire, wound on a 12.75" OD form for a total
wind-
>  >  > ing length of 44". It's a little short for the spark length that I'm
>  > shoot-
>  >  > ing for, but with that massive toroid, it should work. Looks like a
> mini-
>  >  > ature Wardencliffe :^) The power transformer will be either a 10 or
a
>  >  > 15 kVA, 14,400 volt pole transformer unit and the control/ ballast
as-
>  >  > sembly is (2) paralleled 1256D powerstats in series with the core of
>  >  > a 225 amp stick welder, set at maximum current. I can get a little
>  >  > over 100 amps current flow if I turn the variacs all the way up (280
>  >  > volts input to either pole pig, that's set for a Jacob's ladder) for
a
>  > short
>  >  > run. I have (2) .1 uFd, 50 kV commercial pulse caps that I can use
>  >  > for the primary cap and I was thinking of starting off with just one
>  >  > (.1 uFd). The primary is 12 turns of 1/2" copper tubing and it sets
>  >  > a 2 to 3" below the plain of the lowest secondary turn. The outer-
>  >  > most primary turn is about 40" in diameter. I will be using a G-10/
>  >  > tungsten rotary gap that I still have yet to aquire. I was wondering
if
>  >  > maybe a few of you guys with the coiling programs could run the
>  >  > numbers and tell me how well this will work and what I could expect
>  >  > as far as spark legth output and where the primary coil would be
> tapped.
>  >  > I was hoping to be able to make up to 15 foot sparks with this setup
>  >  > and I know that R. Hull's Nemesis had a 14" dia x 46" tall secondary
>  >  > with a really large top-load and it made 15 foot sparks. I can't
recall
>  >  > the size of his top-load, but it looked to be in the size range of
my
>  >  > 12 x 56 one. Should I use just one of the .1 uFd caps or both with
>  >  > for .2 uFd with this massive of a top load? Any comments
appreciated.
>  >  >
>  >  > Thanks,
>  >  > David Rieben
>  >  >
>  >  > PS- The bottom of the toroid is only about 6" above the upper-most
>  >  > turn of the secondary, so I don't think that I will need a smaller
> second
>  >  > toroid underneath the big one. What do you guys think?
>  >  >
>  >  >
>  >  >
>  >  >
>  >
>  >
>  >
>
>