RE: TESLA-COILS ETC.
Subject: RE: TESLA-COILS ETC.
From: richard.quick-at-slug.st-louis.mo.us (Richard Quick)
Date: Sat, 10 Dec 1994 21:53:00 GMT
>Received: from news.starnet-dot-net (wupost.wustl.edu) by csn-dot-net with SMTP id AA19794 (5.65c/IDA-1.4.4 for <chip-at-grendel.objinc-dot-com>); Sat, 10 Dec 1994 19:55:10 -0700
* Original msg to: Kukkonen-at-snakemail.hut.fi
* Carbons sent to: tesla-at-csn-dot-net
Ku> That is fine - can I mail you the converted images as mime-packages
Ku> or can you get them from the ftp-site? (ftp.funet.fi) ?
> I would prefer if they were mailed to me. I am new at this, and do not
> have on-line real-time access to the internet.
Ku> Ok, that is fine.. Can your post-program handle mime-packages?
I am not positive, but I believe it can. If not, would you be willing
to air-mail the data tapes/disks?
> 16cm diameter secondary coil is fine. The coil should be lengthened
> to around 75cm or so, giving an aspect ratio (height to diameter) of
> around 4.5 : 1 for this diameter. Your planned wire diameter is way
> too small. Please check my figures but: I would never wind any coil
> with a wire diameter less than .025 inches which I convert to .635mm.
> I would not use .3mm wire for any coil unless it was for some very
> specific experiment, and the experiment required a tiny coil. Use
> from 900 - 1000 turns (approximate) and a wire diameter closer to
> .635mm or a little larger.
Ku> Ok, then I'll wind a new coil..
I did not know that the coil was already wound. But based on the info
you gave me, I would go ahead and wind another.
Ku> Could I use castable plastic (polyester-based) to insulated the
Ku> secondary? (the plastic is cured by adding methyl-ethyl-ketone (sp?))
Yes this is a pretty good (meaning high Q, low loss) material.
> 8 mm hollow copper tubing is OK, but I would go with 9 - 10 mm
> outside diameter copper tubing for the primary conductor. I figured
> a little closer to 24 cm for the inner diameter. I never wind a
> primary that has less the 15 turns. I would expand the outer diameter
Ku> Should this be flat-spiral or a "cone" like you've described? How
Ku> exactly do you wind the 10mm dia tube to get a nice spiral - is
Ku> there some "easy" trick?
Flat spiral is ok with your smaller toroid. Use an inverse conical
section if you are using a larger toroid. A larger toroid has the
effect of allowing more energy to be processed through a coil. By
increasing the size of the toroid you can tighten up the coupling
between the primary and secondary to increase efficiency, since the
secondary coil will handle more energy. There is no easy way or
"trick" to winding a pipe primary. It usually takes time, and a lot
of elbow grease (work).
> DO NOT USE PVC (Poly-Vinyl-Chloride) for capacitor dielectrics!
Ku> Just guess who bought the pvc before reading your articles :(
Sorry to hear that. Go ahead and use them, but don't expect much.
I would plan on upgrading later.
Ku> What do you think - should I stick to the plate-cap or is a rolled
Ku> one (like what you've described) - is the difference that big?
In a smaller coil (like that we are discussing) a rolled cap and a flat
stacked cap will both perform adequately. As the capacitance required
increases (larger coils) flat caps offer distinct advantages.
Ku> As I haven't been able to find "Al flashing" - can I use .1 mm thick
Ku> copper instead or is there some reason (expect price) to prefer Al?
Ku> (the copper-sheet is 33cm wide).. Copper could be soldered as well to
Ku> get easy connections..
Copper is better than Aluminum, but here the aluminum is readily
available and much cheaper.
> This will start you out. You will want to add a larger toroid, and then
> a larger capacitor ( the .03 ) to bring this coil up to peak performance.
Ku> How big a toroid would that be?
Oh say, from 35 cm to 50 cm wide and, 8 cm to 13 cm high
...Talking about spark gaps.
> It will work, but a series of gaps will work much better and put
> less strain on the capacitor dielectric. I have two, GIF format
> digital image files that detail two very simple, but much better,
> gap designs. The spark gap plans and some good wiring diagrams are
> on my Tesla Archives disk.
Ku> Are the pictures cldndr.gif and airblst.gif?
YES! Those are the gaps! There is a text file for each GIF.
The cylinder gap is ideal for this project.
Ku> Jim Oliver has already mailed me one disk with lots of your
Ku> articles and the pics.. The newest file on the disk was dated
You have pretty much everything then.
> I would try to grab four of the oil-burner xfmrs, and use heavy RF
> choking to protect the high voltage windings.
Ku> About the chokes - toroid cores are dirty expensive - but if I
Ku> were to use "cylinder" cores - will they not be affected by the
Ku> fields around them? (toroid will not, but..)
Position them so that they are "off axis" by 90 degrees from the
primary coil, and set the transformers/chokes away from the coil a
bit. It should not be a problem.
Ku> How big chokes should I use?
I like a "donut" or ring shaped core about 5 cm in diameter and
2.5 cm thick with 15 - 20 turns of insulated wire on them. You may
place several chokes of different sizes in the line to cover a wide
range of frequencies. Some people use air wound, or air core, coils
of wire for RF chokes, but the iron powder chokes really are better.
> A fatter coil tends to be much higher Q, and it also couples better
> with the primary. But too fat and the coil overcouples, the coil
> frequency "splits" and the coil begins to break down electricaly.
Ku> I fully agree with you on this one too - A friend of mine tried
Ku> to run a secondary identical to mine and it got destroyed pretty
Your existing coil may find use if it is employed as a tuned receiver
coil for wireless power transmission experiments. Do not think that
just because it is not a suitable design for a secondary in a 1/4 wave
coil system that the coil itself is useless. In other words, do not
RQ> I leave an extension (or "tail") of wire at the top of the coil.
RQ> I "air wind" this extension up to the toroid. The air wound turns
RQ> are the same diameter as the secondary winding, or slightly
RQ> smaller. The turns (2 - 4 in number) are widely spaced. The wire
RQ> meets the toriod off center, but it may then be brought directly
RQ> in to the center of the toroid for a hard connection. The ideal
RQ> distance from the top of the secondary to the toroid is best
RQ> determined experimentally, the ideal distance and will change
RQ> with power levels and toriod size.
Ku> "center of the toroid" - what do you regard as a toroid - a "donut"
Ku> shape? - in fact, this was interesting in your article about making
Ku> the toroid - do you consider a toroid with a conductive center-plate
Ku> as a "toroid"? (a mathematical toroid does not have a "center-plate")
Well in practice; toriods used in Tesla coiling have conductive plates
inside the center of the ring. These plates usually have a hole in the
center to mount the toroid.
>Ahhh, another person seeking Tesla's "Holy Grail". I will comment.
Ku> No, I'm not seeking on building something to destroy the earth :) -
Ku> I was just rather surprised to find the things about Tesla like
Ku> that with quotations from Tesla himself..
Oh no! I have never met with anyone who desires to destroy the earth!
I simply meant that the devices referred to are the "Holy Grail"
because of the mutitude of very powerful applications that they can
be used for.
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12