Re: My First Tesla Coil

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

Original poster: Kreso Bukvic <kreso.bukvic-at-kc.htnet.hr> 

Well let me help as much i can. You encountered some beginners mistake, that
happened to me also and i still didnot know about TCML ;-).

You do not want more than 2-4 thousand turns. 1000 turns is the value that
all coilers use. Primary and secondary do not need to be insulated one from
each another, just make sure you use the right distance from the secondary
to primary. Use arround 12 turns on primary.

Really cool so much MOTS, and i have to buy a new MO to get a MOT :-(. Yep
bigger ones are better ( more power ). As the "legend" says they were
producing 4 kV mots also, but they discontinued them. Maybe you got the 4 KV
ones? Best MOT supply is the twin MOT with the voltage doubler ( you will
ned 2 MO caps and 2 MO diodes). Go to www.hot-streamer-dot-com and go on the
page of Gregs garage you will find instructions how to build this PSU. The
capacitors will act as current limiter.

Mylar caps wont do good, but you could try them i used them on a really
small coil and they performed good, but on big power they will go in smoke
in seconds. They are not good for this use. MO capacitor are also not good
for TC work. I think they are also mylar. HV ceramic capacitors - some used
them but they are also not suitable for this use. I suggest using a MAXWELL
capacitors there are four going for ~70 bucks ( by piece) now on ebay. These
are great capacitors ( 35 kV 30 nF). Or you could build one of those
overrated MMC but it wont last long a run or two. MMC will be good if you
desing it good, for twin MOT PSU you would need :

12000 V x 1.414 =16968 V peak
If im right one cap can take (GG caps) 500 VAC.
16968V/500V=33.936 caps. So 35 caps for a nice MMC.
150 nF / 35 = 4.28 nF
30 nF / 4.28 = 7
7 strings x 35 capacitors= 245 capacitors to get 30 nF
245 x 3 = 735 $. As you see this is very unefficient capacitor, and
expensive too if you want it last.So use maxwells insted or bucket cap but
this last one is not too good( heavy, bulky,messy, much looses).

Well thats all for now

Best Regards

Kreso Bukvic

PS. is i understood you have alot of electronic components from your repair,
build a SSTC instead.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, May 14, 2004 12:21 AM
Subject: My First Tesla Coil


 > Original poster: "Chris Fanjoy" <zappyman-at-hotmail-dot-com>
 >
 >    I've wanted to build one of these for several years now, but just never
 > got around to it. But finally, I'm now ready to build my first coil!
 > Although I have spent years in electronics (mostly repairing TV's etc),
the
 > principles involved in Tesla coils are still not completely within my
 > grasp. That's why I'm asking for your help.
 >    I received the main ingredient in the mail today - a 10 lb spool of #27
 > AWG magnet wire. Upon seeing the immense size of the spool, I now realize
 > that I have more wire than I'll probably ever need! Not a problem though,
 > since an associate of mine also wishes to build a coil, and I'll probably
 > just share some with him. As for the other materials - high voltage
 > transformers, capacitors, large-diameter copper wire, etc - I have a large
 > stock of these items that I've collected, from the years I've spent
 > repairing consumer electronics.
 >    I've got quite a mouthful of questions, but I'll try to summarize them
 > as briefly as possible:
 >
 > Consideration #1 : Number of coil turns / turns ratio
 >
 >    Most info I've collected from the web, suggests winding about 2-4
 > thousand turns of 20-24 AWG magnet wire, for the secondary of the coil.
The
 > primary should be about 20-25 turns of heavier (<14 AWG) copper wire. Is
it
 > theoretically possible, to use a turns radio of 1:100 (say, primary=10
 > turns and secondary =1000 turns), to multiply the input voltage by 100x?
 > (assuming 100% efficiency, obviously it will be much lower in real life).
 > Secondly, how does one determine the proper number of turns? And finally,
 > can the primary and secondary windings be isolated from each other by
 > putting a larger-diameter piece of PVC pipe between them? (to prevent
arcing)
 >
 > Consideration #2 : High Voltage Transformer
 >
 >    Since I have literally dozens of old MOT's in my parts pile, it goes
 > without saying that this will be what I use. My first question is, are the
 > older (bigger) ones better? Size might be a consideration depending on the
 > enclosure I built this stuff into. And also, is it possible to use two
 > transformers (primaries wired in parallel, secondaries in series) in order
 > to get twice as much voltage to feed to the spark gap/capacitor? Since two
 > MOT's would draw more than 15 amps from the wall, some kind of current
 > limiting would be needed (custom-wound inductor?)
 >
 > Consideration #3 : Tank Capacitor
 >
 >    It seems that everyone uses a tank cap comprised of dozens, or
hundreds,
 > of small HV caps to get the required value and voltage. I have a fair
 > number of mylar caps (mostly from 70's and 80's color TV's) which may do
 > the job, but I'm wondering if microwave oven capacitors would work. I have
 > dozens of em', and most have values of 0.7 - 1.0 uF at up to 2400VAC -
 > each! Only thing is, they have bleeder resistors (typically 10meg-ohms
 > each) and might not withstand high operationg frequencies. And what about
 > high-voltage ceramic capacitors, are these any good?
 >
 >    Maybe that's enough questions for now. It will take some time to
 > assemble all the components, and work out the design. I look forward to
any
 > advice you may have.
 >
 >
 >
 >