Re: tesla coil urgent help needed

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

Original poster: "Paul Marshall" <klugmann-at-hotmail-dot-com> 

You are making this far too complex. The aspect raito for any secondary 
coil should be no greater than 4.5 to 1. (The winding length on my 4.5" was 
22.5") The primary should have about 12-15 turns of copper tubing. Top load 
the bigger the better. The tank capacitance should be the maximum that your 
transformer can handle. I had a 4.5" diameter coil that got 72" streamers. 
Power input was 2600w.  Tank circuit capacitance was .026 microfarads. I 
used a forced air RQ style gap and the top load was made from 8" diameter 
flexible ducting. the average streamer length was 60". on occasion that hit 
the 72" mark. Happy Coiling.....



Paul S. Marshall





>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: tesla coil urgent help needed
>Date: Tue, 29 Jun 2004 22:00:19 -0600
>
>Original poster: Mddeming-at-aol-dot-com
>
>In a message dated 6/29/04 9:47:47 AM Eastern Daylight Time, 
>tesla-at-pupman-dot-com writes:
>Original poster: "Anthony" <ant17-at-optushome-dot-com.au>
>
>hi guy i really need some help i have made a Tesla coil but i cant get any
>output i can get a bit of a tingle if i touch the secondary my setup is as
>follows
>the transformer is 15kv 30ma nst the
>secondary is 27milihenries with a self capacitance of 4 picofarads the
>primary is a 8 turn spiral primary which has an adjustable tap from turn 1
>to 8 the primary is 46 microhenries  with the tap at turn 8 the primary
>cap  is 4 nf  the spark gap is a richard quick style gag i have tried
>adjusting the primary at different levels but it doesn't seem to make
>difference any i deas
>
>Hi Anthony,
>1) Are the values for the Cs, Ls, Cp and Lp measured or calculated? How 
>was measurement/calcs done?
>2) Are you using any sort of topload? If so, what size?
>3) assuming your figures are accurate,
>
>Fs(res)=1/[2pi*sqrt(LsCs)]=1/6.28*sqrt(27*4*10^-12*10^-3)=10^7/6.28*sqrt(10.8)=10^7/20.65
>Fs(res)=484.3 KHz
>
>Fp(res)=1/[2pi*sqrt(LpCp)] 
>=1/6.28*sqrt(46*4*10^-9*10^-6)=10^7/6.28*sqrt(18.4)=10^7/26.95
>Fp(res)=371 KHz.  Tuning should be close to the point where Lp=27 uH. 
>Without knowing the physical dimensions of your coil, it is not possible 
>to say where on the primary this is.
>
>But, this also means that if your coil has more than 2.8 pf additional 
>capacitance on the secondary, your primary is too small to tune properly. 
>When you touched the secondary, your body added far more than this 
>capacitance throwing it way out of tuning range, which is why you only 
>felt a tingle instead of being zapped. Testing for high voltage with your 
>fingers is a VERY BAD practice.
>
>Much more detail about your coil's physical arrangement is needed to pin 
>down your problem
>ID, OD, No. turns & spacing on primary, height of secondary above plane of 
>primary, secondary dimensions, height above floor, and proximity to other 
>objects all affect the tuning.
>
>Matt D.