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Re: Classic coil



>
>>From Hans.Grimstad-at-maxware.no Sun Dec  1 22:28:46 1996
>Date: Sun, 1 Dec 1996 23:34:05 +0100
>From: Hans.Grimstad-at-maxware.no
>To: tesla-at-pupman-dot-com
>Subject: Classic coil
>
>Hello everyone !
>
>I have been rereading my reprint of Teslas lecture to the Institution of
Electrical 
>Engineers in London. On page 15, he describes a small bipolar coil. Each of
the  
>terminals of the coil is connected to a circle, one is 80 cm in diameter,
the other is 
>30 cm in diameter. During operation of the coil, the discharges between the 
>terminals produce a "luminous sheet" with an area of about 0.43 square
metre. He 
>states that he in earlier experiments, using bigger circles had covered an
area of 
>more than one square metre. 
>This coil has 2 primaries with 96 turns in each, and two secondaries with
260 turns in 
>each. When both the primaries and the secondaries are connected in series,
this 
>gives a ratio of conversion of about 1:2.7.
>
>It seems that a lot of people are designing coils with much bigger
conversion ratios 
>(1:67 for a coil with 1000 windings on the secondary and 15 on the
primary). I would 
>say that Teslas results with this coil are quite impressive. Why the big
secondaries 
>in "modern" coils ? 
>
>
>Hans J|rgen Grimstad
>


Hans,
        I do not believe that Tesla coils 'use' the ratio concept.
I believe it is the product of resonance. In the resonance formula:
                                   1
                RFrequency = ------------------
                              2 * pi * SQRT(L*C)

it is possible to adjust L(inducatnce) and C(capacitance) of the
circuit while still attaining a certain frequency. In the Tesla
coil it is Large C, Small L in the primary while in the secondary
it is Big L, Small C. When both work out to the same resonant
frequency, you have a resonant transformer, as with a Tesla coil
and I dont think turns ratio plays much of a part, if any.

Bob