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Re: BIG coil project



Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi Dr,

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? > > > > > > > > > > >