* Originally By: Kukkonen-at-snakemail.hut.fi
 * Originally To: Richard Quick
 * Originally Re: RE: CAP DESIGN (FWD) (FWD
 * Original Area: UUCPE-Mail

btw: I just acquired a 220V 6A variac.. 

On Sat, 24 Dec 1994, Richard Quick wrote:

> The plastic wedges I was describing earlier give the angle of the
> slope. The slope is linear from the inside turn to the outside turn.
> Each turn of the primary is raised by the same amount.

Oh, it is a straight cone.. Yes, that clears things a great bit..

The angle of 30 degrees is ok with a toroid of 50cm diameter
with the assembly you have described?

> BTW, the pipe we use for primaries here is a "soft" grade of 
> copper, commonly called "refrigerator tubing", it is sold in rolls. 
> The other grade of copper pipe is "hard", it does not bend well,
> and it is sold in straight lengths. 

Yes, and the soft grade is used for household water lines as well - 
as you propably know..

> Yes, I covered this with Mark Conway too. Glass, because of it's
> high RF dissapation factor (high loss) is ideal for construction
> of bypassing capacitors to be placed in the HV feed line to the
> Tesla Tank circuit. 

You used four 3nF 30kV doorknobs in series - will about the
same figures meet my requirements - aka 120kV 750pF ?

If I shall not use a center-tapped x-former - I'll just connect
the bypass-cap in parallel with the secondary, right? and the
same applys for the safety-spark-gap as well?

About the rf-chokes to be placed to the primary circuit to protect
the x-former: I've located a source for big 9,3cm*10,3cm "flatten"
toroid-ferrites that have cross sectional area of 3cm*2,85cm..
Will these do - they are assembled of two U-shaped pieces.. 

Or could I just use a couple of ferrite-rods together? aka many rods
together with the coil wound around the "pile"?

I did locate a possible source for rfi-filters - they have two
models - for 250V 3A and 6A - of which the 6A model would do if 
one just calculates the power needed for the x-former - but should
I use more of them is series (and/or parallel) to get more marginal?
(will they get fried?)

> I did make a modification on this gap later that cut down on the 
> air required yet maintained the un-surpassed performance. I drilled

That's great!

> a hole through the face of both electrodes, and plumbed in the air
> from the back. This method injected two opposing air streams into
> each other right in the center of the gap. The quenching was still
> excellent, but it used only 25% of the air previously required.

What were the dimensions of the drilled holes? I presume that the
holes were parallel with the longitudinal axis of the electrodes
and in the middle of the faces.. 

You mentioned 25 psi in your article - will this do or shall
one need more pressure?

> Thank you, I hope I have been of help!

Yes, your help is extremely useful - If I hath not read your articles
in the first place, I would propably have tried with a really morbid
design that could not have worked and thus given up - but now I
really know what I'm doing (I hope, at least to some extent:)..

ps. Happy New Year in advance! Don't blow yourself up :) 


  Kristian Ukkonen.

pps. I just finished making a compilation of the articles from
fidonet electronics that I had.. I appended all the files into
one huge file and then removed the duplicates.. Now all your
articles are in one nice 600k file that is a lot more handy
than the separate files..

The file is at nic.funet.fi : /pub/sci/electrical/tesla

If you wish to get a copy and can't use ftp - I'll mail you the file,
just ask for it.

___ Blue Wave/QWK v2.12