* Carbons Sent to: Esondrmn-at-aol-dot-com
> From: Esondrmn-at-aol-dot-com
> To: tesla-at-grendel.objinc-dot-com
> Subject: General questions
ES> I am still designing and have some questions:
ES> I have been reading the discussion on rolled capacitors for
ES> the primary. 60 mil polyethylene has been mentioned. Is
ES> this the same material you can buy at the hardware store -
ES> like for covering your windows in the winter? That stuff is
ES> usually clear. I thought someone mentioned it should be
ES> milky white, not clear. Do you buy it from a plastic
60 mil low density polyethylene is thick, tough, milky-white
plastic that is sold almost exclusively by specialists plastics
dealers. This plastic is sold in a common material width of 48
inches wide, and is purchased by the yard or by the entire roll.
This plastic may be cut into three 16 inch wide strips of varying
length to construct rolled capacitors.
ES> Do you use regular aluminum foil like for cooking?
The plate material for these capacitors is commonly sold in
hardware stores here in the 'states' under the name "aluminum
flashing" which is simply rolled sheet aluminum a few mils thick.
The material width used in this project is 14 inches, though
other widths are available. The flashing is usually purchased in
50 foot rolls.
ES> If my calculations are correct, with ten inch wide foil, you
ES> would need 22.3 feet for a .02mf capacitor. Does this sound
ES> about right? This would be three strips of poly (about 14.0
ES> inches wide?) and two strips of foil. All rolled up in a
ES> tight roll. And then what, tie it to keep it tight?
In practice, two plates 102 inches by 14 inches, and two
dielectrics 60 mil x 108 inches x 16 inches, will make one
rolled capacitor with a value around .02 microFarads. This
can vary slightly with the quality and tightness of the
construction. The roll is secured with doubled up 12 inch
nylon wire ties.
ES> This roll then gets submerged in oil in a plastic container?
ES> What is the approximate finished diameter?
The roll will neatly fit inside of an oil tank made out of 6 inch
diameter PVC, thin wall, drain pipe.
ES> I would guess this capacitor will have as much or more
ES> inductance than the primary coil winding.
The self resonate frequency of this capacitor design is about 1.2
megaHertz, which does not interfere much with most coil systems.
Most 4 and 6 inch coil systems (with dischargers) are operating
under 500 kiloHertz. With SOME coil designs these rolled
capacitors could reduce efficiency, but if you have been
following the design theory I have been laying out, you will find
a much greater ratio of inductance in the primary (properly
tapped at 8-12 turns) than you will find in a 8-1/2 foot long
ES> Does anyone know where I can buy only about 2000 ft of #22
ES> double formvar coated magnet wire. My local distributor
ES> wants me to buy 10 lbs. minimum - for about $100.00.
ES> Thanks, Ed Sonderman esondrmn-at-aol-dot-com
Yeah, I think Mark Graalman just posted a source which I saved
to my references file:
Here is a good source for coax cable AND magnet wire, He
carrys in stock sizes from #22 gauge to #10 gauge, and can
order other sizes. He sells by the pound and his prices are
decent. Good quality stuff! Mark Graalman
The Coax Connection:
10 S. Meadow lane
Naperville, Ill. 60564
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12