Re: Primary construction

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "kayaker" <kayaker-at-sbcglobal-dot-net> 

Hello All:-)

Does anyone remmeber the post from last week. Ballasting variacs with
torids. I deleted that post by mistake. Help! Please. Many thanks.

Doug,

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, September 24, 2003 6:58 AM
Subject: Re: Primary construction


 > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
 >
 > Hi MCP,
 >
 > Tesla list wrote:
 >
 > >Original poster: The MCP <ejkeever-at-comcast-dot-net>
 > >Oh... Well, there's nothing special about the primary wire either. The
 > >connection to the caps is a fat red wire, with 1 or 2 mm of stranded wire
in
 > >the middle. The primary coil is around 22 gauge wire, nothing special. It
 > >starts getting slightly warm after 20 seconds.
 >
 > All losses end up as heat, so that is telling you something right there.
 > Need to get heavier gauge wire. I personally would go with #18 or larger.
 >
 > >The topload, I mentioned, is the remainder of wire coming off the
secondary.
 > >It's roughly 6 inches long, wound around a 3/8" dowel rod as a form,
coming
 > >out to 7 or 8 turns. It seems to give the same results as the original
copper
 > >tube topload (1/2" pipe, ~2" diameter)
 >
 > Ok. I'd try a larger topload. Any old thing would do. It would be nice to
 > form a toroid shape if possible, but really, even a pepsi can would
 > suffice. If pepsi can, try a primary about 3.2 turns range within a 2.2"
 > botttom to top height. Set can upright on top of coil.
 >
 > >However, although people are telling me this thing is in fact in tune, I
still
 > >get absolutely no sparks exceeding 3 inches - ever. Do I need to connect
the
 > >bottom of the secondary to a spike hammered into the ground? Do I need to
use
 > >a "real" topload?
 >
 > Couldn't hurt. Also, I've mentioned this in a past post and just noticed
it
 > again. Your coupling coefficent is low at 0.065. This will result in
 > smaller sparks. If you were to place the primary center to the secondary,
 > you "still have a low coefficient" at 0.085. This is the maximum you can
 > possibly obtain without winding a primary coil closer to the secondary.
 > This is probably the area I would work on along with the topload and
 > primary size. I would go to larger primary wire also for the reason that
 > #22 will not only heat up, but it will also be prone to pri to sec arcs
 > (unwanted arcs) if you were to get too close. Increasing the primary
 > diameter would increase the radius of curvature and in so doing, increase
 > the voltage of arcover, thus allowing for a decrease in proximity between
 > coils (needed to increase the coupling coefficient). Try to get k at least
 > to 0.12 and then adjust coupling up or down by raising and lowering the
 > primary (or secondary, whichever is easiest for your coil).
 >
 > As coupling increases, the coil may want to arc out of the top of the
 > secondary. At that point, it's time to decrease coupling until it stops. A
 > pepsi can won't do well at shielding the top of the secondary, so you may
 > not be able to run as high a k as you would like. If you can build a
toroid
 > out of something (again, anything will do), the shape of the toroid
 > provides excellent sheilding and helps relieve the top terminal stress. At
 > this point, you would have to double your coupling to even get to this
point.
 >
 > All these types of adjustments/modifications are all part of the fun to
 > make the coil more efficient at producing longer sparks for a given input.
 >
 > Take care,
 > Bart
 >
 >
 >
 > >On Saturday 20 September 2003 09:19 am, Tesla list wrote:
 > > > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
 > > >
 > > > Hi MCP,
 > > >
 > > > Nice when you get things like that! But, the #32 is secondary wire. I
was
 > > > curious about the primary wire and topload.
 > > >
 > > > Take care,
 > > > Bart
 > > >
 > > > Tesla list wrote:
 > > > >Original poster: The MCP <ejkeever-at-comcast-dot-net>
 > > > >Well, the wire I'm using is an interesting story... I got 8 rolls of
#32
 > > > > gauge from mpja-dot-com to be used to wind a *load* of small
electromagnets
 > > > > in an attempt to build a maglev. I ended up using, um... 2 of them.
So
 > > > > I've got about 3 miles of wire, and I wanted to build a tesla coil!
And
 > > > > I've *still* got almost all the wire I started with...
 > > > >
 > > > >Having this huge amount of wire available was one of the things that
made
 > > > > me consider making little "play-thing" size tesla coils.
 > > > >
 > > > >On Friday 19 September 2003 06:47 am, Tesla list wrote:
 > > > > > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
 > > > > >
 > > > > > Hi MCP,
 > > > > >
 > > > > > 2 turns sounds about right with a slight topload (maybe a point or
your
 > > > > > coiled wire?). Could you do us a favor and give more info as to
the
 > > > > > wire type used for the primary? We are still not clear on what
your
 > > > > > actually using. The topload would also be much needed data. This
type
 > > > > > of data seems to be very limited from coilers (full specs with
center
 > > > > > heights).
 > > > > >
 > > > > > Both John C. and I truly enjoy crosschecking against the programs.
We
 > > > > > love doing it or we wouldn't. Your coil is pretty cool to run
through
 > >Msnip...........
 > >
 > >
 > >
 > >
 >
 >
 >