RE: Space winding question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi John,

On 11 Mar 01, at 13:00, Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
> 
> 
> Stan -
> 
> As Terry showed in another post your question can be answered with a
> few manual calculations. However, it is easier to use a TC computer
> program like the JHCTES program. An on-line Ver 3.2 of this program
> can be found at my web site
> 
>    http://home.att-dot-net/~couturejh
> 
> For your question enter in the secondary inputs
>    Rad       6.00
>    Turns     1000
>    TPI       18.5   1000/54  (closewound)
>    Sec term     0
>    Click "Calculate" or "Calculated etc." and the resonant operating
> frequency of 138.67 Khz appears in the upper right corner of the
> screen. To print click on "File - Print".
> 
> For the space wound coil change only the TPI to 16.7 = 1000/60
> Click "Calculate" which gives 140.62 Khz
> 
> Terry's resonant frequencies are slightly different because he used a
> different Medhurst equation for the coil self capacity.
> 
> There is another type of question that is much more difficult for the
> expert to answer but is easily answered by using a computer. The
> question "How many turns would be required on the space wound coil to
> give the same resonant frequency as the closewound coil?" This
> requires an iterative type solution and "many many" repeat manual
> calculations. Several of the variables are changing at the same time
> including the coil inductance, coil self capacity, etc.

That actually depends on whether you maintain the same height and 
diameter or not - i.e. use two different wire gauges leaving all else 
the same.

Regards,
malcolm