Re: Questions??

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: jhowson4@xxxxxxxxxxx 

I tried using the capacitors 2 in series and 3    2's in parallel and 
nada.  Its one of the same problems I had before the spark gap does 
not fire.  There is a little zap (like shorting a 9 volt battery) If 
I tap the electrods together which is easy because of the base. But 
thats about it.

I have not tried increasing the primary turns yet as it is late out 
but there will be time tommorrow i hope.
-------------- Original message --------------
From: "Tesla list" <tesla@xxxxxxxxxx>

> Original poster: Vardan
>
> Hi,
>
> At 08:42 PM 9/3/2006, you wrote:
> >The first thing that everyone should know is that I am a junior in
> >highschool. I ran across the tesla a few years ago and have been
> >obsessed ever since. Unfortunatly 75% of all the money I make goes
> >into collage savings leaving me with not alot to buy parts and
> >such. I really appreciate that people like you are around and are
> >willing to help me. MANY THANKS
> >
> >
> >
> >*The paper that i am refering to i downloaded somewhere online along
> >time ago but since is says information unlimited on teh top i am
> >assuming i t orig ionaly came from here
> >http://www.amazing1.com/tesla.htm
> >I am also assuming that it is the
> >Easy to build table top tesla coil 250,000 volts one
> >Since it also says that on the papers
>
> Cool! They have been selling those plans "forever". I am not
> specifically familiar with this one but it gives me a good idea what
> is up with it. if you search below for "btc3" some info comes up:
>
> http://www.pupman.com/htsearch.html
>
> >
> >
> >*The transformer I am using was bought off ebay for about 20$ It is a
> > 6000v 30ma Neon Sign Transformer
> >someone I was talking to said that it might be centertapped or
> >something and that it could be the problem
>
> Many (most) are center tapped but that should not matter. A nice LTR
> cap size would be 21nF (20.8333..).
&g
t;
> >
> >
> >* dimensions of secondary + number of turns, winding length, and wire
> >size
> > 10 inches tall
> >1 3/4 inches wide
> >#26 magnet wire
> >i have no idea what the length is
>
> #26 wire winds about 58 turns per inch so that is 580 turns. The
> inductance is probably near 2.4mH.
>
> http://hot-streamer.com/temp/FormulasForTeslaCoils.pdf
>
> The coil probably tunes in the 980kHz range with the size top load
> they show. This online JAVA program is very nice.
>
> http://www.classictesla.com/java/javatc.html
>
>
> >
> >I bought the wire at radio shack and had to use 2 small spools to
> >complete it the wires were sanded and were put together but at some
> >point i thought that this was the problem and seperated them. then
> >moved my secondary up about half way . this made a huge
> >(the term huge means that i got an arc out of the magnet wire with
> >out the top load about 3/4 of a cm)
> >
> >
> >* dimensions of primary, number of turns, what sort of wire or
> >conductor used
> >
> >I was using #12 wire at 8 turns with 6 inch diameter
> > but when that did not work i took thick magnet wire and wraped it
> > around electrical tape on the secondary about 24 times. This seemed
> > to work better
> >(i got a small arc instead a a spark)
> >
> >
> >* number and type of capacitors and how connected - series? parallel?
> >20
> >6000v .015mdf
> >Sprague
> >in series
>
> That's a big problem!!! The capacitance is then 15nF / 20 =
> 750pF. You really want three strings with two of those caps in
> series. Or 2 long by 3 wide. The capa citanc e is then 15nF x 3 / 2
> = 22.5nF. Use about a three inch diameter primary and it should tune
> very roughly guessing at 2.7 turns.
>
> So right now your capacitance is 0.75nF and you want it to be about
> 22.5nF or 30 times more!!! that would completely explain way the
> sparks so far are so small.
>
> >
> >At some point i took some glass and 2 4in squares of tin foil and
> >tried that (it worked better but in practical terms not a big 
change at all)
> >
> >* type of spark gap and how constructed
> >2 bolts mounted in lexan or something with a large computer cooling
> >fan sucking are through it the bolts are about .08 mm from each
> >other (which is as far apart as they will go while still allowing a jump)
>
> That is fine.
>
> >
> >At some point i made a small rotary gap to see it it would work
> &g
t;usin g a cd and small wires bend over it and then taped. Then i used
> >brushes to make direct contact with them. This seemed to work alot
> >better and was more consistant than the other gap so I have used 
it ever since.
>
> Best to get the above working first.
>
>
>
> >* nature and dimensions of top terminal.
> >2 small pie tins welded together
> >about 4 inches in diameter 3 inches tall
>
> Cool
>
>
> >*Some pictures of the parts and complete set-up wouldn't hurt either.
> >I dont have a digital camera or anything. But school starts soon so
> >i could ask to borrow one. If you could see it now you would say
> >wow what a piece of junk. I wanted to test it before i made it all
> >nice and such but it is the way it is so i never made it look nice
>
> Not a problem. The primary cap value is the problem. thi s is a
> small high frequency coil which is fine but your 20 caps in series
> has a very low value. You need to use far fewer in series (two to
> get to a comfortable 12000) and then put a few of those strings
> together in parallel to get the value in the 20 - 25nF range..
>
> If all is working, you will get a nice sparks then ;-)))
>
> Cheers,
>
> Terry
>
>
>
>
> >
> >-------------- Original message --------------
> >From: "Tesla list"
> >
> > > Original poster: Gomez Addams
> > >
> > >
> > > On Sep 2, 2006, at 8:23 PM, Tesla list wrote:
> > >
> > > >Original poster: jhowson4@xxxxxxxxxxx
> > > >
> > > >Hello all,
> > > >
> > > >I have a Problem for anyone who is willing to help me. > > > >
> > > >I have been trying get a coil to work decently for some time now
> > > >and have had little success. I admit that I know basically nothing
> > > >in terms of the math and formulas and all the stuff that you
> > > >already know.
> > > >
> > > > I am following instructions to make a coil that runs off a 6000v
> > > >30ma transformer. I have 6000v 0.015mdf capacitors that the paper
> > > >says should work. But in the e nd of all my hard work and little
> > > >understanding i get a spark(not to be confused with an arc or
> > > >anything else that might look cool) out of the top terminal.
> > > >diffidently not what is supposed to happen. (according to the sheet
> > > >that is) What am I doing wrong? transformer issues? capacitor
> > > >issues? coil issu es? wh at? Any help or ideas is greatly appreciated.
> > >
> > > We need a LOT more information than that to know what is going on
> > > with your coil. Such as:
> > >
> > > * dimensions of secondary + number of turns, winding length, and wire
> > > size
> > >
> > > * dimensions of primary, number of turns, what sort of wire or
> > > conductor used
> > >
> > > * number and type of capacitors and how connected - series? parallel?
> > >
> > > * type of spark gap and how constructed
> > >
> > > * nature and dimensions of top terminal.
> > >
> > > Some pictures of the parts and co mplete set-up wouldn't hurt either.
> > >
> > > Is this an oil burner transformer or a neon sign transformer, or what?
> > >
> > > regards,
&g
t; > >
> > > - Bill Lemieux
> > >
> > > .
> > >
> > >
> > >
>
>