Re: First run 6.5" coil- odd results? (fwd)

In a message dated 6/6/99 5:45:37 PM Pacific Daylight Time, tesla-at-pupman-dot-com 

>  	Since I'm new to the list, let me introduce myself. My name is Scott, 
>  or "Lugnut" and I am very new to coiling. I wanted a good start, so I made 
>  and bought everything for my coil, except for Xformer...:_( Chances are I 
>  doing something wrong but don't know it. I heard that my results were odd 
> due 
>  to my Xformer, tell me what you think.     
>       Well, here's my stuff:     right now I'm getting 8" sparks maybe 9".
>       secondary-6.5" OD PVC 1/4" thick  wound to 26" 22 or 24 gauge...I 
>  forget...
>   	primary- flat pancake, 1/4" copper tubing spaced 1/4"  
>   				13 turns total.
>   	capactitor- salt water type, 15 totally assorted bottles in a 10 
>        gallon fish tank-no oil and I'm not getting flashover. Probrobly due 
> to 
>        my transformer's lack of power.
>   	Xformer- right now I have a horrble, beat up, but working 4000 volt 
>  -at- 
>        30mA..
>   	Spark gap- 4 gaps at about 1 millimeter each.
>   	There are no bypass caps or safety gaps.
>        Discharg terminal- Use everything from a nail to a 7" sphere. After 
>        tuning, I get the best results from the sphere, about 8" sparks. I 
> have 
>        to use a nail to get sparks to the air, they get about 6" in the 
>  (really 	   	dim, but I can feel, them <ouch!>. 
>   	Problem- I have no real idea if I am doing well or not because nobody 
>        that I've heard of uses the weak transformer that I have. If I buy 
>        12kv-at-30mA NST's, will I get 12x the sparks? That almost sounds 
>  insane... 
>                     12x9! 
>        By the way, I'm 14 and showed my science teacher, she looked at it 
> like 
>        I was doing something wrong...hmmmmm...maybe I am. Please help me 
>   	or even comment on my coil. I even need a name of sorts...you people 
>  are 	the best!
>   Thanks, 
>   Scott

Great project.  I have a coil similar to yours in size.  I think you have two 
main problems.  The first is the salt water caps.  If you can borrow a 
capacitance meter from someone, it would be nice to measure them so we can 
calculate where the best tuning point in the primary would be - to start 
testing with.  I was using a .025 mfd cap and now am using a .050 mfd cap 
with my coil.  I am using two large toroids and you apparently have none so 
your resonant frequency would be higher and allow the use of a smaller 
primary cap - but I suspect your capacitance is too low.

The second problem is the transformer as you suspect.  4000 volts is just too 
low.  Go to a local neon sign shop and explain you are working on a science 
fair project and see if they will donate a couple of 12 kv or 15 kv 30 ma 

Ed Sonderman