Re: Magnifier Driver coil design

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Ward <steve.ward@xxxxxxxxx>

Hi John,

Good catch!  The 46awg is a typo! oops!  Supposed to be 26 awg.

It is the secondary im using at the moment, which i know is good for
11' or so of spark.  The specs on that coil are 8.1"x45" winding of 26
awg for about 2300 turns, topped off with a 36" diameter toroid.

As to your other email, you mention using Antonio's equations.
Antonio mentioned that the optimal magnifier design for a DRSSTC might
not be the same as for a spark gap coil.  I am open to hear what
Antonio has to say about this and if his formulas predict a design
within my limits, then i might just base if off of that.  Its mostly
up in the air still as to a final design.

You mention using very wide diameter coils, even for the extra coil.
What is the reason for this?  Do you see any drawback in having a tall
thin resonator vs a short and fat one?  Part of my goal is to keep the
overall size down, though my current 8" diameter, 4' long secondary
isnt exactly doing that.  I may look at a 10"x36" winding or something
in that ballpark with 26awg most likely.  I dont want to go too short
for fear of destroying the coil or something.... though that would be
kinda cool.

As to the driver coil:  Im somewhat hesitant to go with such thick
wire as 16awg because i dont think i will reach my desired inductance
at a reasonable coil length or diameter.  Its hard to find coil forms
larger than 12.75" here (largest sono-tube available at home depot),
so i was basing my design off of that.  An 18" long winding with 20awg
gives me an inductance in the 40-50mH range. I think that i want to
keep my L2:L3 ratio about 1:3.5 to 1:4, but this is only based on the
fact that it would allow for up to K=.25 overall, if we were to
pretend L2 and L3 were the same coil of wire.  All of my experience
says that DRSSTCs need the high coupling in the .25 range to work
efficiently.

I will have to keep playing with the numbers.

Steve

On 4/18/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: FutureT@xxxxxxx
>
> In a message dated 4/17/05 10:32:28 PM Eastern Daylight Time,
> tesla@xxxxxxxxxx writes:
>
> >Tertiary: 8.1"x45" winding of 46awg with a 36" toroid up top.  L is
> >190mH, loaded Fr is 48khz.  Im going to start off just using my
> >original secondary, since i *know* it will take lots of abuse for
> >producing long sparks.  Will look at shorter windings later when
> >teslathons approach at the end of summer
>
> Steve,
>
> 46awg seems too thin to me.  Is that a typo?  I'd recommend not going
> lower than 28awg, but making the coil maybe 16" diameter or
> so or whatever's needed to get the necessary inductance.
>
> The driver coil could be maybe 16awg or so.
>
> I'm not sure if my recommendations will get your
> frequency low enough.
>
> cheers,
> John Freau
>
>