# RE: Space winding question

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

On 15 Mar 01, at 7:53, Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>
>
>
> Malcolm -
>
> You are talking about a different problem. The wire gauge has nothing
> to do with the the spacewound 16.7 TPI as long as the wire gauge is
> not to big. If it is too big the JHCTES Ver 2.3 shows a group of stars
> to indicate to the designer that he has made a mistake in logic (the
> program maker must think of everything)!   The TPI must be coordinated
> with the gauge and the insulation thickness to give an overall
> thickness of
>
>       TPI = Turns / Overall thickness
>
> I believe that this is a problem with Bart's great program as I
> mentioned in another post. I haven't checked this out completely but
> was waiting for Bart's comments. The rest of his program gives the
>
> The coil length is always equal to the TPI times the number of turns.

I think not. Not in a spacewound design.

> This is what makes the special type of problem I mentioned difficult
> for experts using manual calcs (many variables changing at the same
> time). This problem requires many repeat calcs of the type Terry
> showed. For example "With 10 TPI how many spacewound turns of any size
> AWG wire that is not too large will have the resonant frequency of
> 138.67 Khz (same as closewound)? The answer is 1075 turns and the coil
> length is 107.5 inches equals 1075 turns/10 TPI. This is an iterative
> type problem. Can you think of the other iterative type problems that
> the JHCTES can solve easily?

I have no idea as I use a calculator if I have to. It takes less time
than booting a computer.

Regards,
malcolm

> John Couture
>
> ------------------------------------
>
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Sunday, March 11, 2001 2:11 PM
> To: tesla-at-pupman-dot-com
> Subject: RE: Space winding question
>
>
> 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
> >    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
>
>
>
>
>
>
>

```