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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
writes:
>
> 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
am
>
> 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
dark,
>
> (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
two
>
> 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
out
>
> or even comment on my coil. I even need a name of sorts...you people
> are the best!
>
> Thanks,
> Scott
>
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
transformers.
Ed Sonderman