RE: SMALL SPARKS: PLENTY OF POWER- NO TIME

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

On 24 Oct 2005, at 19:43, Tesla list wrote:

> Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
>
> Hi Jeremiah:
>
> I would also suspect that the primary tap may not be optimum.  With a
> 15 turn primary, one can vary 1-2 turns and not see a world of
> difference, but since you say you use only six turns, it may be very
> sensitive to fractional turns.  It looks like it wouldn't be too
> difficult to replace the insulated wire you have with solid bare wire,
> at least temporarily, or ideally 1/4" copper tubing, to permit quick
> and easy tapping at arbitrary points.
>
> It's curious that you've not reported racing sparks.  It's always been
> said that the use of a helical primary will result in too-high
> coupling and racing sparks.  Maybe no one's ever actually tried it?  I
> hope so, yours is very compact!

I've used helical primaries with complete success. I generally shoot
for them being about twice the diameter of the secondary and between
5 to 10% of the height, tending towards the lower of those. That
gives coupling in the 0.1 to 0.15 range.

Malcolm


> I don't think that 20 Amps is at all out of line; I use at least that
> much with my 15/60, and that's with PFC caps.
>
> If you' really need to resolve this in 5 days, a more easily tapped
> primary is my best suggestion.  But as time permits, I would strongly
> suggest using John Freau's electronic phase adjuster.  Without a means
> of varying the phase while the coil is operating, either
> electronically or mechanically, I would imagine that it's extremely
> difficult to know when you've hit the best spot.  Your top load also
> seems somewhat small for the power level you have.  My 15/60 coil does
> well with a 7"x30" toroid, and most folks report that performance
> increases with bigger top loads.
>
> Regards, Gary Lau
> MA, USA
>
>  > Original poster: tesla popp <teslas_lab@xxxxxxxxx>
>  >
>  > I would usually troubly shoot this sort of problem
>  > myself, but I am almost OUT OF TIME!  I have a show to
>  > do in 5 days!
>  >
>  > One of my coils has a BIG problem, It's drawing
>  > 20amps, and making 3.5 foot sparks.  This is VERY BAD.
>  >   I have no idea why it is acting up, but I belive it
>  > might be due to bad coupeling?!  {note: the winding
>  > starts 1" above the bottom winding of the HELICAL
>  > primary}
>  >
>  > Operation of the coil is VERY STEADY, and is NOT
>  > erratic at all.  I am pretty shure I have my SRSG set
>  > where it should be.
>  >
>  > [Note: please trust the specs I am providing]
>  > -The tranny is a 15/120NST "Draws more with my L.T.R.
>  > MMC"
>  > -A 120BPS sallent pole syncronious rotery gap
>  > -Secondary coil 6.25" x 40" 20awg, 1250 turns
>  > -helical primary 12.5" wide, tapped at 6 turns "no
>  > room for a flat spiral primary."
>  > -MMC is .05uF
>  >
>  > note- USE THE PICTURE LINK I HAVE PROVIDED TO SEE WHAT
>  > I AM WORKING WITH.  Any ideas will greatly help!
>  >
>  > http://www.amasingscience.com/teslacoils/images/TWIN_FULL.jpg
>  >
>  > http://www.amasingscience.com/teslacoils/images/TWINBIG_PRI.jpg > >
>  http://www.amasingscience.com/teslacoils/images/TWIN_MMC.jpg > > >
>  Thanks, > Coiler Forever: Jeremiah Popp > > >
>
>
>