Re: Top-load-less TC

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

Original poster: "albert hassick by way of Terry Fritz <twftesla-at-qwest-dot-net>" <uncadoc-at-juno-dot-com>


On Sun, 27 May 2001 03:03:51 -0400 albert hassick <uncadoc-at-juno-dot-com>
writes:
> Hi Scott, Barton.  Thanks for your interest!   OK, here goes with my 
> additional specs of the coil you requested.   Secondary:  8" 
> Quickcrete cardboard form, 24" tall, coated internally with two 
> coats of Minwax 'satin polyurethane' and sealed atop that with 
> 'Tiger hair fiberglass resin".  The exterior of the coil received 
> three coats of said poly and was then wound with #18 super motor 
> wire from the local motor shop, it was some kind of isopolyidamide 
> or something motor winding wire and it was the best that there is to 
> be had.  The form was close wound for the first 22" and was then 
> spiraled loosely for the last three turns to reach the top of the 
> form.  I guess about six pounds of wire on the form.  It was then 
> coated with said poly coating until the winding was smooth and free 
> of gaps.  I guess about 6 or seven coats of poly.    Ground wire to
backyard 
> spring:  1/4"od refrigeration tube layed next to a #4 aluminum THW 
> single cable, both terminating in a 1/2" hard copper tube driven 
> into the loose moist clay of a year round natural spring. Primary: 
> Flat, 3/8"od copper tube. 14 turns total, 5/16 max. between 
> turns.  Tuning: variable, dependant upon the use and type of 
> topload, if any.  Tuning can give the same spark length regardless 
> of the size, construction, shape, or composition of the topload.  
> Distance, inner turn of primary to secondary: slightly more than 1". 
>  Length of arc in free air: six to seven feet, and approaching eight 
> feet dependant upon weather. Spark length to grounded object:  four 
> to six feet.  Also, please note: this coil can give the same results 
> if or if not connected to a ground poise for the secondary bottom 
> terminal.    So, what is the verdict?    Al.      
> 
> On Tue, 22 May 2001 18:18:32 -0700 Scott.L.Hanson-at-seagate-dot-com 
> writes:
> > There is nothing in your power supply or tank circuit that is out 
> of 
> > the
> > ordinary, or would seem to have any affect on the secondary. I 
> > suspect that
> > the self-capacitance of your secondary may be providing the 
> largest 
> > effect.
> > 
> > Could you define the following characteristics:
> > 
> >      Secondary:
> >           Form dimensions (wound length, diameter, wall 
> thickness)
> >           Form material (including any coatings)
> >           Winding data (wire diameter, wire type [magnet wire, 
> PVC
> > insulated hookup wire, Kynar insulated wire-wrap wire, etc], 
> > insulation
> > type & thickness, close wound or space wound, overcoating,        
> 
> > single
> > wire or multiple wires paralleled)
> >           Total number of turns (if space wound)
> >           Height of first turn relative to primary
> >           Grounding (ground wire diameter and length, define 
> > connection to
> > "backyard spring")
> > 
> >      Primary:
> >           Type (helical, conical, flat, or ??)
> >           Conductor type
> >           Number of turns used at best tune point
> >           Spacing of turns (center-to-center)
> >           Distance from inner turn to surface of secondary
> > 
> > 
> >      Typical arc length:
> >           Streamers to free air
> >           Arc length to grounded conductor
> > 
> > 
> > Have you measured the primary/secondary coupling factor?
> > 
> > Do you have an oscilloscope available to monitor the ringdown?
> > 
> > 
> > Many older (turn-of-the-century) Tesla coils were  built with only 
> a 
> > small
> > discharge ball at the top of the secondary and performed well. The 
> 
> > addition
> > of a large capacitive top load  has become common over the last 20 
> 
> > years or
> > so as a better understanding of Tesla coil operation has been 
> > gained.
> > Regardless of how well your coil seems to operate now, I am quite 
> 
> > sure that
> > I will perform better if supplied with a topload, and re-tuned to 
> 
> > optimize
> > with the larger top capacitance.
> > 
> > Regards,
> > Scott
> > 
> > 
> > 
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno-dot-com/get/tagj.