Re: Classic coil

To: tesla-at-pupman-dot-com
Subject: Re: Classic coil
From: Richard Hull <hullr-at-whitlock-dot-com>
Date: Sun, 26 Mar 2000 21:29:01 -0800
Tesla List wrote:
> 
> >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 am late getting to this message and have not read all replies, but here 
goes.

In a resonance system the tranfomation ratio doesn't hold as you have 
computed.  We get much more out of the system than those simple ratios 
might imply.

Next, modern coils are going for spark.  Spark is a function of secondary 
inductance.  Tesla's demo system was not a hot performer.  Tesla also 
used very tight coupling in his early systems of the early 1890s and this 
would hurt their performance.  He learned this as he progressed towards 
his 1899 super system.

Richard Hull, TCBOR