Re: 44 inches with 450 watt NST

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

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>


Wow.  44 inches.  That blows the John Freau spark length formula out of the
water.
And to think you did it with a 7.5kV/60mA transformer.

Do you have any pictures of this coil in action???

The Captain



 > I would say that a 44 inch spark with a 450 watt NST is very good output.
 > However, if you want to fool around with the "what if's" you may want to
use
 > the JHCTES Ver 3.3 computer program.
 > This program automatically does the calcs to keep all the parameters in
tune
 > when you make changes. The program is used on line and does not have to be
 > downloaded. Click on
 >
 >     http://www.mgte-dot-com
 >
 > Click on "Tesla" then "JHCTES",
 > Click on the JHCTES Ver 3.3 program at the bottom of the Book page.
 >
 > Start with the following inputs
 >
 > Primary  .0302 uf,  5.5,  0,  4.43
 >
 > Secondary 1.75,  1233 turns,  71.25,  0,  26.4 pf
 >
 > These inputs will give you the outputs you have described, like 176 KHZ,
 > etc. Changing the inputs will give you dozens of other TC combinations.
The
 > TC system will always be in tune with the outputs that are shown by the
 > computer.
 >
 > John Couture
 >
 > -------------------------------
 >
 >
 >
 >
 >
 >
 >
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Friday, March 07, 2003 2:07 PM
 > To: tesla-at-pupman-dot-com
 > Subject: New three TC finished! but i need some help
 >
 >
 > Original poster: "tmoore by way of Terry Fritz <teslalist-at-qwest-dot-net>"
 > <tmoorezz-at-adelphia-dot-net>
 >
 > Hello Everyone,
 >
 >       Well  I finished a new coil, it is a 3in system that runs on a
single
 > depotted 7.5/60 francfomer, it used to be one of the transformers with
 > ground fault protection. I use my new PSU its noting fancy just a variac
 > with a few switches. Well I need some help again I have been trying to
 > figure out were to tap the primary coil by visual observation of streamer
 > length and behavior and it is quiet perplexing. My problem is I think I
 > have to much topload for break out, see when I taped the coil -at- 9.25 with
a
 > break out point it produces long bright strikes to near by pair of metal
 > crutches.  Now when I remove the break out point the tesla coil wont run
 > even at full power, then I need to tap it around 7.5 turns to get any
break
 > out from the toroid, and there are allot streamers that are short(around
1.5
 > feet) very pail, with the break out point I get 40-44 inch sparks
regularly
 > to the crutches. Now Ed Sondermans Tesla Cal says it needs to be taped
 > around 10 turns. I think when I taped it -at- 9.4 or beyond the sparks
 > shortened and then will stop when tapped around 9.6turns. Ok how do you
tune
 > by visual
 > inspection?? Is it in proper tune when the break out is on but there are
 > streams COMING off the toroid on a few random places despite having a
break
 > out point were most of the streamers go, also streamers not quite as
bright
 > when they strike the crutches?? OR is it in tune when streamers only come
 > from the break out point and are slightly more intense when they hit the
 > crutches and slightly more frequently?? I REALLY would appreciate if some
 > one could answer those question and describe exactly how to determine
 > whether the coil is in tune by visual observation of streamers.
 >
 > Here I'll give you a run down of my coils specs.
 >
 > Topload
 > Two toroids made from flexo Al ducting
 > #1=19in wide by 3.375in across for 19.83pF
 > #2=12in wide by3.375in across for 13.35pf
 > So then what's is the total?? Its 33.18pF CORRECT???? That's a question
 > cause am not sure!
 > There spaced aprox .5in away from the top and bottom of each other btw the
 > smaller one is on the bottom.
 >
 > Secondary
 > Length=17.25in wound with 28awg enamled wire
 > Diameter= 3.5in pvc pipe coated with polyurathane
 > L=24.7mH (Measured) That makes it 71.25 turns per inch
 >
 > Primary
 > IND=6.5in
 > OD=15.375in
 > Spaceing=Turns out to be around .29 on average between turns
 > Wire= 0.162in
 > Max turns=10.125 Measured 32uH max but Calculated its 34.2uH i think my
New
 > DMM is off cause the lowest seting is 2mH
 >
 > Capacitor= Maxxwell pulse rated 35KV at 30nF Measued value=30.2nF
 > With a satfey gap set at 0.28125in wich fires ocasonaly
 >
 > Spark Gap
 > Spaced total 0.1875in with 3 gaps and 4 copper pipe peices 2in wide by
 > 1.125in diamither enclosed in a box fabricated from plastic cuting board
 > cooled by a 3in fan
 >
 > Transfromer
 > Depotted Fance modified for matching to the capcitor, Some of the shunts
 > were removed, and i actualy submerged and soaked the tran in semi-gloss
 > polyurathane then let dry several times
 > I out=87.8mA
 > When the tesla coil is runing the amp meter waves backanforth between
 > 8-13amps
 >
 >       Ok i have tryed to figure out were to tap the primary coil by puting
 > figures in to the formula F(KHz)=1/(2*pi*(sqrt(L*C))).  When I put in the
 > numbers for the secondary with out the adding on the self capacitance of
the
 > secondary only the topload I get 176.17KHz secondary resonance, and when I
 > change the figures for the primary coil to match the secondary I used the
 > figures 30.2nF for the tank cap and it would take 27uH to match the
 > secondary.  According to Ed's tesla cal it would take 9.03 turns to get
27uh
 > of inductance, also it says I would need to used a 41nf tank capacitor
witch
 > is not the value of mine, so what is going on?  Also according to Ed's
tesla
 > cal I would need 10.4 turns to match my 30nF capacitor, which is bad cause
I
 > only have 10.1 turns max and when I tap it there it doesn't even resonate
 > and the spark gap wont fire, id have to say it appears to operate best
when
 > tapped from 8.6 turns to 9.25 turns. Is this because of my topload?? Is it
 > too bigg?? or is it that there is some formula to figure out the total
 > capacitance of the two toroids?? Like would it be the average of the
series
 > and parallel values??  So could some one help me!! I would like to have it
 > in perfect tune before trying to maximize the spark length.
 >
 >       Also I was wondering if there is a formula to figure out the voltage
 > need to breakdown across the space in the spark gap, so that I know what
 > voltage the spark gap will fire at regularly. So far this system has been
 > very
 > agreeable and well behaved, there have been no racing sparks or secondary
to
 > primary strikes, and streamer length and power is quite impressive. I have
 > also taken some terrific pictures Ill post some of them in a folder at
 > http://hot-streamer-dot-com/nolan/threeintc/ I really need some help on this
so
 > I appreciate your help greatly. Thanks.
 >
 >
 >
 > Sincerely,
 >
 > Nolan Moore
 >
 >
 >
 >
 >