which disease?

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From:  Esondrmn [SMTP:Esondrmn-at-aol-dot-com]
Sent:  Thursday, March 19, 1998 5:57 PM
To:  tesla-at-pupman-dot-com
Subject:  Re: which disease?

In a message dated 98-03-19 00:18:22 EST, you write:

<<
Dear All, I need some help.

I wound a coil (diam. 4.33", height 33.66") with .35mm wire (AWG 28??)
and a total secundary resistance of approx. 155 ohm. I thought that
these 790 meters from 2290 turns would give me resonance at 94,8 kHz.
Why not???

Everybody talks about 3:1 ratio but that means with 10" diam
->30"height, doesn't it. How do I get 1000 turns in so little height.
Can I take a form with more height??

I now get breakouts (>20") at half of the form, distroying my turns. I
am using a cap wound from 2.5mm thick red plastic (don't know the
material) 2 plates from about 20 cm widht and 7 meters long. Primary is
7.5 turns of .5" copper tube, gap=single .5", toroids vary. Best
sparklength I get (don't understand!!!) with a very small toroid! Supply
is a 10 kv 10kva plate transformer and a variac.

is it wise to build a new coil with 8"diam and what height and number of
turns should it have??? What wirediam??? I am thinking of using wire
used in mainssupply (2.5 mm2). at least is low resistance. What am I
doing wrong?

ARWIN, Holland
>>

Arwin,

I calculate that your secondary should resonate at about 176 khz with no
toroid and about 94 khz with a 30 pf toroid on top.

Your height to diameter ratio is 7.8.  With a 4.33" diameter coil, I would try
to keep this at about 4:1 maximum.  This would be 17.32 " of winding length
and 1,212 turns of wire at about 70 turns per inch.  You could actually make
it a little shorter and still get 900 to 1,000 turns.

If you are getting breakout in the middle of the secondary, your primary must
be tuned to a frequency that is about twice the self resonant frequency of the
secondary.  It sounds like you could cut your existing secondary in half and
be right in the ball park.

Good luck,

Ed Sonderman

```