Re: Best Primary Coil

Subject:     Re: Best Primary Coil
      Date:  Thu, 24 Apr 1997 21:32:16 -0700
      From:  Gary Weaver <gweaver-at-earthlink-dot-net>
        To:  Tesla List <tesla-at-pupman-dot-com>

Tesla List wrote:
> Subject:  RE: Best Primary Coil
>   Date:   Wed, 23 Apr 97 06:27:44 UT
>   From:   "William Noble" <William_B_Noble-at-msn-dot-com>
>     To:   "Tesla List" <tesla-at-pupman-dot-com>
> that's an amazing set of tests and very interesting results - but it
> brings to
> mind another primary configuration that I think would potentially act
> like
> your 15 deg coil but without the slant - it seems from your notes that
> the
> secondary likes to have the outer turns of the primary closer to it
> rather
> than farther away (at least that's the conclusion I draw from the
> experiments
> with spacing).  two possible configurations of fairly flat coils could
> do
> this.  You describe a 16 turn primary, so what do you think would happen
> with
> the following 2 configurations??
> 1. a two layer X8 turn flat pancake coil - start at the outside, spiral
> in for
> 8 turns, then raise up an inch and spiral back out another 8 turns. 

This is an interesting idea I have not thought of.  I did try 2
primaries one 
on top of the other.  One was flat wound and the other one on top was 30 
degree.  I used 2 seperate power supplies for each primary.  One was 12K
ma and the other was 15K 30 ma.  It worked but it makes more sence to me
use just one primary coil and one power supply.  You idea is
Connect both primaries in series and it will work and it should couple
better than a single layer flat primary.  It will probably act a little
a vertical wound primary.  I experemented with vertical wound primaries
and gave them up.  They over couple very easy and have a critical
Vertical primary coils have a very small operation window and if
anything in 
the circuit is changed much the TC drastically over couples or under

> guess
> if I were doing this I'd wind it on either side of an acrylic sheet.
> This
> would get the turns closer to the secondary without raising them up any.
> 2. hybrid coil that is flat for say 8 turns and then a helical coil for
> the
> remainder.
> Your data sure suggests that imaginary coil #1 above would be a good
> one.
> I'd try this but I have a lot of really obvious things to do before I
> have an
> even moderatly plausible coil to play with (like make a bigger capacitor
> and a
> better gap)
> -----Original Message-----
> From:   Tesla List
> Sent:   Monday, April 21, 1997 9:24 PM
> To:     tesla-at-poodle.pupman-dot-com
> Subject:        Best Primary Coil
> Subject:  Best Primary Coil
>   Date:   Mon, 21 Apr 1997 13:49:29 -0700
>   From:   Gary Weaver <gweaver-at-earthlink-dot-net>
>     To:   tesla-at-pupman-dot-com
> For several months I have been building and testing primary coils.
> [Bill]  snip
> 1/4" TUBING PRIMARY FLAT WOUND.  The coils tested here are all made with
> 1/4" copper tubing.  All coils are flat
> wound.  The only thing that changes in this test is the spacing between
> turns.  I made coils with .250, .375, .500 and .625
> inches between turns.  The inside diameter of all the coils are the
> same.  All coils have 16 turns.  I tested each primary coil one
> at a time and did not change any thing else in the circuit.  Then I
> retested the primary coils changing things one at a time.  In
> every test the tighter wound primary coil works the best.  The .500
> coils works better than the .625 coil.  The .375 coil works
> better than the .500  or the .625 coil. The .250 coil works better than
> all the other coils.  Again the tight wound coil is the best.
> [Bill]  snip
> Gary Weaver