Re: [TCML] Best design for a 15KV 120mA trans?

[Mark Crowley <maccrowley8965@xxxxxxxxx>]

Thanks everyone for all the great input!

I shall move forward with the SRSG design with LTR since I already have most
of the these parts on hand.

Best,

Mark

On Thu, Jan 20, 2011 at 8:24 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:

> In my experience, Bigger is always Better when it comes to secondary size
> and toroids.  I would say that 6" for the secondary is an absolute minimum
> if getting the maximum performance is the goal.  A 24" toroid is,
> unfortunately, rather on the small side for that power level.  For my
> single
> 15/60 & SRSG, I use a 7x30 toroid.  For a 6" secondary, the #27 wire is OK;
> I'd go with the #24 if using something larger.  Basically, you want to
> shoot
> for a 5:1 aspect ratio and 1000-1600 turns, though there's a lot of wiggle
> room here.
>
> While there's no doubt that an SRSG will perform far better than a static
> sucker gap, just understand that if you start out using the static gap,
> converting to an SRSG will require a complete overhaul, as the cap size has
> to increase significantly, and that will affect the primary design, and
> secondary geometry.  When using an SRSG, a cap size less than LTR is simply
> not an option, and needs to be roughly 3X the mains-resonant value, or else
> the safety gaps won't stop firing.  You really need to decide in advance
> what type of gap you want before doing anything else, including designing
> the cap and secondary.  Building an SRSG is not something one can throw
> together quickly.  If you're in a hurry, better start with a sucker gap and
> plan to re-do everything some day in the future.
>
> Regards, Gary Lau
> MA, USA
>
>
>
> On Thu, Jan 20, 2011 at 3:35 PM, Mark Crowley <maccrowley8965@xxxxxxxxx
> >wrote:
>
> > Hello all,
> >
> > My first post and my first question!
> >
> > I recently came into possession of (2) 15 KV non-gfi neon sign
> transformers
> > @ 60 mA each.  I plan to parallel these two together for 120 mA total to
> > feed a large coil.  Although not my first Tesla Coil, it is by far the
> > largest I have undertaken.
> >
> > My question is what would be the optimal secondary size for this?  I've
> > searched the archives here and it looks like 6" to 10" diameter seems to
> be
> > preferred but have also heard 4.5 Inch diameter coils driven as well.  A
> > height to diameter ratio of 4.5:1 seems to be recommended too.   I
> already
> > have two large spools of 27 AWG and 24 AWG high temp wire available so I
> > would like to use those if possible.  I have not purchased the sec form
> > yet.  (I also have a 24 inch diameter toroid available).  I have a large
> > collection of the CD 0.15uF MMC on hand and leaning towards LTR cap with
> a
> > sucker gap or a SRSG  (I've been hoarding parts for both :-) )
> >
> > I've experimented with JAVATC and now at the point were I need a push in
> > the
> > right direction for the secondary/wire size and number of turns.  Any
> > advice?  LTR cap good or go under LTR for this size?
> >
> > Thanks again,
> >
> > Mark
> > _______________________________________________
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> >
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