Re: [TCML] Greenhorn Coiler

[FutureT@xxxxxxx]

Nicholas,
 
In building a coil, it's good to be aware of certain principles and  concepts.
 
Here are some concepts which may be helpful.
 
1)  Traditional spark gap tesla coils require a high voltage  transformer,
usually about 10kV to 15kV.  For a very small coil 5kV to 7kV is  OK.
These voltages are just a rough guide.  
 
2A)  Large tesla coils which give long sparks require more power  than
small coils which give short sparks.  A powerful coil requires a  powerful
transformer.  Power is determined by the kVA rating of the  transformer.
 
2B)  I use the formula:
 
     spark length (inches) = 1.7*sqrt input power  (watts)
 
to get a general idea of how much power might be needed to 
achieve a particular spark length.  For example to get 42"  sparks
might require roughly 650 watts for an efficient coil.  In many  cases
the sparks may be much shorter for that power level.  
 
3)  It's common to use NST's for small or medium coils.  OBIT's  do
not require oil, thus they are also well suited for beginner's coils, or  for
a small coil project.  MOT's sometimes require oil if they are  subjected to
HV stresses.  NST's and OBIT's are current limited so no  external
ballast is needed (keeps things simple).  
 
The Tesla coil capacitor is very important and must be of the right
type and rated  correctly and of the right electrical size  (capacitance).  
The spark gap is important too.  
 
4)  It's common when starting out to build a small coil first.   Such
a coil is simpler and easier to build.  It permits one to gain  familiarity
with coiling  basics before moving on to larger more dangerous  coils.
 
5)  There are great dangers with coiling.  Of course there are  great
dangers with lawn mowers, gasoline, etc.  However the dangers 
associated with the last items mentioned may be more well known
and better understood by the uninitiated.  
 
6)  Parts for Tesla coil projects can be obtained cheaply using
patience and experience.  
 
7)  It's wise to study and learn about coiling theory rather than  just
building one.
 
8)  Some of what you read at some websites will not be correct.  
 
9)  There are other important factors which I didn't mention  here.
 
Cheers,
John
 
 
In a message dated 6/10/2008 4:54:21 P.M. US Eastern Standard Time,  
ngoble@xxxxxxx writes:

I'm  beginning to plan my first tesla coil.  I've looked through many  
sites over the internet and can't find any concrete information on the  
transformer needed.  I know this is a broad question, but can someone  
please explain the type of transformer that I need.  I don't want to  
buy something that's not going to work on a tesla coil.

I'm leaning  more towards an NST because I've read that the alternative 
needs oil  (OBIT) and that seems like a hassle to deal with.

Here are a few  questions that I have:

1) What size transformer should I get?
2)  What does RMS mean?
3) Is there anything specific that I need to know when  buying a 
transformer?
4) Does anyone have a suggestion as to what I  should get and where I 
could get it?

Thanks

Nicholas  Goble







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