# Re: first tesla coil

```
well my coil is powered by 12k 30 ma transformer i have 2 - 12.5nf caps in
series
1/( 1/C1 + 1/C2 +........ect) = 6.2nf total capacitance. in mineral oil
my pri is saucer shape 15 turns taped at 13 3/4,
sec is on 3" pvc about 1200 turns of #24 awg
and my gap is 9 series 3/4" copper pipes about 3" in length. gap is .025" (the
thickness of a hacksaw blade)
my torrid is 4"aluminum flex pipe its about 19" diameter. i am currently
getting
17" to 24 inch sparks
:-)
i have some pictures at
http://www.datasync-dot-com/~ignatz/electro/teslacoil/teslacoil.htm

cap specs:
plate
alum flashing 5x7=35sq.in.
# of plates- 24

dialect
Polyethylene
30 mil- consisting of 5, .006" layers of poly
estimated capacitance
13.22nf
measured capacitance is
12.5 nf
below is the formulas i used to construct the caps i made.

EQUATION 1:  PLATE TYPE CAPACITORS

Capacitance (in picofarads) = (0.224 KA / d) (N-1) to convert Pf to Nf you
divide by 1000,
and for Polyethylene  i used 2 for the k.

0.224 x Dielectric Strength x Area of plate
C = -----------------------------------------  x (Number of plates - 1)
distance between plates in inches

hope that helps
art

Tesla List wrote:

> Original Poster: Esondrmn-at-aol-dot-com
>
> In a message dated 9/23/99 4:27:24 AM Pacific Daylight Time, tesla-at-pupman-dot-com
> writes:
>
> >
> >  Hi this is Chester Lowrey I just built my first tesla coil and here
are the
> >  specs:
> >
> >  powersupply:    12kv 30ma NST
> >  cap:    2x 5" by 5" plate cap with 60 insulating layers each ten sheets of
> 4
> >  MIL         polyethylene  immersed in mineral oil. uf ??
> >  sparkgap:       8 coper pipe gaps
> >  primary:        7 turns 1/4 copper pipe 18" diameter flat pancake
> >  secondary:      6" by 24" PVC pipe wound with 24gau copper wire
> >  all conections made with 10gau insulated wire.
> >
> >  from this description what do you think about it's performance? all i can
> >  currently get is 5 inch sparks at the most. my thoughts are that the
> >  transformer isn't big enough.
> >  but would it work better if i use a smaller primary and secondary?
> >  transformers are preatty hard to obtain when you live in hawaii and are
> only
> >  15yrs.  i just built the cap this weekend and was expecting better results
> >  than with my 7 bottles but spark gained 1' at the most
> >
> >          well i would greatly apreaciate any help/comments PS. sowrey about
> >  the spelling hope you dont mind
> >
> Chester,
>
> It sounds like a good project.  I would expect one to two foot sparks with a
> 30 ma transformer.  The coil is probably not in tune.  You need to either
> measure or calculate the capacitance you have and run some calculations to
> see if the current design will allow the primary to be tuned to match the
> secondary frequency.
>
> Ed Sonderman

```