Re: [TCML] largest secondary coil you'd drive with an NST

["Jared Dwarshuis" <jdwarshuis@xxxxxxxxx>]

Our latest coil uses 5.5 miles of 23 gauge and it rivals the efficiancy of a
solid state coil.

More wire is better!

Jared Dwarshuis

On Dec 15, 2007 8:34 PM, Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx> wrote:

> Hi David and Jared,
>
> I'm not saying less wire is better and I'm not saying more wire wire is
> better. There is a reason helical air coils favor a 4:1 or 5:1 range for
> spark production and it has everything to do with optimizing the
> impedances of the system as stated previously.
>
> I'm not saying Jared's 12"x48" coil won't do well. It is on the edge of
> starting to get lossy to the point of affecting output and in this case
> I think it would do better with a higher gauge wire size in the 18 to 20
> awg range (for the reasons stated previously). In reading Jared's post,
> a coiler might think "more wire is better, hey, I'll wind 5000 turns of
> 30 awg". Because I disagree with that, I am compelled to state my
> thoughts.
>
> My 13" diameter coil was first wound with an h/d a little over 3:1.
> Experienced coilers on the TCML recommended 5:1. I didn't listen (had
> that PI ratio theory in my head). Well, it worked fine, but only about 3
> to 4 foot leaders. I broke down and added over a foot to the coil
> (something that can be done with sonotube). It did much better with 5 to
> 6 foot leaders now with over a 4:1 h/d. I then upgraded the spark gap
> and hit that 9 foot range. For that coil, those were the two major
> improvements (and they were night and day).
>
> I then got on the kick of higher turn coils. And again, going against
> the TCML recommendations (800 to 1500 turns), I wound a high turn coil
> about 1800 turns (I learn the hard way like everyone else I guess). At
> first I thought the coil was doing well (it worked fine), but after
> enough run time I started paying closer attention to power input and
> realized how inefficient the coil was. It was drawing too much power for
> the spark output, even using a very efficient G10/tungsten rotary. The
> problem was the high turn coil was lossy and a poor impedance match.
>
> It took me a while, but I started to realize the experienced coilers on
> the TCML really do know what their talking about. Theory is always up
> for debate, but their experience is priceless. These days, I pay far
> more attention to their recommendations.
>
> Take care,
> Bart
>
>
>
> David Rieben wrote:
> > Hi Jared,
> >
> > I don't believe Bart was trying to make a "blanket statement"
> > by saying that the less wire you use, the better. He WAS
> > stating that you need to MATCH your coil's specs with the
> > power source. It would be rather foolish to build an Electrum
> > sized coil and run it with an OBIT and a 5 nFd primary C
> > as it would  be to build small 2" x 10" secondary coil w/ #32
> > AWG and try running it with a 25 kVA pig and a 200 nFd
> > primary C! Can you say "meltdown" ;^)
> >
> > David
> >
> > ----- Original Message ----- From: "Jared Dwarshuis"
> > <jdwarshuis@xxxxxxxxx>
> > To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> > Sent: Saturday, December 15, 2007 4:31 AM
> > Subject: Re: [TCML] largest secondary coil you'd drive with an NST
> >
> >
> >> Hi Bart:
> >>
> >> You don't make coils better by using less wire. A coil with no wire
> >> at all
> >> would be the best coil using this line of reasoning.
> >>
> >> Small inductors are more portable but do not yield better performance.
> >>
> >>
> >> Jared Dwarshuis
> >> On Dec 14, 2007 9:40 PM, Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> >> wrote:
> >>
> >>> Hi Jared,
> >>>
> >>> There is of course a max inductance for an h/d ratio for a given wire
> >>> length. I did a personal study of this sometime back.
> >>> http://www.classictesla.com/download/max_L_table.pdf
> >>>
> >>> What not everyone realizes is there is that max inductance is not the
> >>> same for resonant and low frequency inductance.
> >>>
> >>> Your 22g 12"x48" coil would yield 1720 turns. Consider the toroid and
> >>> primary in place and your nearing about 54kHz, so the frequency "is"
> >>> low. But due to the high turns, the proximity losses increases as does
> >>> the dc resistance. DCR is about 86 ohms and ACR is about 177 ohms.
> This
> >>> does add up to a lossy coil in the end. I know from experience because
> >>> I've built one similar except using 24g. I even ran it on pole pig
> >>> power. Sure it will perform if enough power is put to it, but it does
> >>> take more power.
> >>>
> >>> The common h/d recommendation of the 5:1 range is not only considering
> >>> the h/d ratio, but the wire size that fits into that ratio and how
> that
> >>> wire size electrically affects impedance.
> >>>
> >>> A coil should be sized for the energy across the gap and the time
> >>> involved. The transformer of course has to be sized to accommodate the
> >>> power needed for the cap size and charge rate. The later is far
> easier.
> >>>
> >>> Take care,
> >>> Bart
> >>>
> >>> Jared Dwarshuis wrote:
> >>> > For a given length of wire your inductance will be greatest with an
> >>> inductor
> >>> > that has a large diameter and a short height. However if you make
> >>> your
> >>> coil
> >>> > to short you can get problems with flashover from end to end.
> >>> >
> >>> > Wire is reasonably cheap compared to capacitors and NST. Using a
> >>> lot of
> >>> wire
> >>> > is the easiest and cheapest way to increase spark length. I  would
> >>> recommend
> >>> > using 22 gauge on a 12 inch by 4 ft concrete form.This will give a
> >>> nice
> >>> low
> >>> > frequency and if (when) you upgrade to using more NST (or a pole
> pig)
> >>> you
> >>> > will be all set. Finer wire also works and I would not be
> >>> surprised if
> >>> one
> >>> > could drop down to as fine as 28 gauge for a pole pig powered
> >>> coil. But
> >>> fine
> >>> > wire does not seem to survive strikes very well so we use the
> thicker
> >>> stuff
> >>> > as insurance.  (tiny wires are hard to wind, they get crossovers >
> >>> easily)
> >>> > Jared Dwarshuis
> >>> > On Dec 14, 2007 12:47 AM, Tim Meehan <btmeehan@xxxxxxxxx> wrote:
> >>> >
> >>> >
> >>> >> I hate to ask this too - but what is the optimum aspect ratio for a
> >>> >> secondary?  I've run JAVATC, and have built a feeble (but pretty)
> >>> classic
> >>> >> tesla before ... and have read but probably poorly understood a few
> >>> >> papers.
> >>> >> I think that I'm ready to build version two of the static-gap,
> >>> >> NST-powered,
> >>> >> properly filtered and protected coil.  I just want to make sure
> >>> that I
> >>> >> learn
> >>> >> as much as possible before I start purchasing things that probably
> >>> won't
> >>> >> suit my needs.
> >>> >>
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> >
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