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Re: What size TC to start with?




From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Sunday, September 14, 1997 9:21 AM
To: 	Tesla List
Subject: 	Re: What size TC to start with?

On Saturday, September 13, 1997 10:18 PM Roth, Leland
[SMTP:webwise-at-johnstown-dot-net] wrote;

> Hello... I've been a subscriber to this list for a few weeks now
> and would like to ask a 'newbie' type of question:
> 
> What size TC to start with?

The smallest you possibly can! Seriously there is an emence amount of
knowledge to be gained working with very small Tesla Coils and 
mistakes are no where near as dangerous!
 
> Well, now the yearn to get back into some HV stuff is at hand. I'm trying to
> decide where to start. I don't just want to make sparks, I want to *learn*-
> I want to be able to summon my math and physics skills that have been dormant
> for so long (although helping my two oldest teens with their math homework
> proves I'm still agile in that department).
> 
> I want to pick something small to start with so I can learn the TC basics-
> try different gaps, primary sizes, positions, secondaries, caps, etc. I've
> just about ruled out the neon sign xformer route for the moment... I'm looking
> at either an oil burner xformer (23ma, 10kV) or maybe even automobile spark
> coil(s) with a suitable driver transistor setup. Once I feel I've really
> learned not just the 'how', but the *why* things work/don't work, then I'll
> look at moving up to higher input currents- neon sign xformer then maybe,
> some day, a 'pole pig'. One step at a time. This effort may take many
> years, but
> I don't really care- I just want to learn.

You certainly have a good attitude Lee! definately start small with 
perhaps an automobile ignition coil driven T.C then advance to an oil
burner ignition transformer then on to either several microwave 
transformers in tandem  or neon sign transformers then cascade 
several neon sign transformers and then you will be ready to consider 
a pole pig. BTW you can even start out with a T.C. driven directly 
off the A.C. mains ie. 120v primary, this is what is done in the 
small vacuum testor tesla coils. Below is an ASCII schematic of a
line voltage "kicker-coil" driven Tesla coil. Please excuse the ASCII 
art!
                                   ___
                                  (___)
                                    )
                                    )
                                    )
                                    )
                                    ) S
                                    )
                  __________________)
               VG ____  _|_         )
                    | | ___C        )P
                   #( |__|__________)
                 C #(    |
                 O #(    |
                 I #(    |
                 L #(    |
                    |    |
                     115V
                      AC

You have an iron core coil (a couple hundred turns of #28 wire) 
connected at one side of it's windings to the line. The other side of 
the coil connects to a vibrating armature almost identical to those 
found on the old induction coils. The stationary contact of the 
interrupter is connected to a 5 turn tesla coil primary P made of 2 
no.20 double cotton coated wires, the other side of the primary is 
connected to the tesla coil secondary S which is very fine wire 
(No.36 - 40) wound on a wooden form 3/4 inch in diameter and 2 1/2 
inches long. the primary also connects to the moving contact of the 
interrupter and there is a oil-paper capacitor C across the vibrating 
spark gap VG. There is an adjusting screw that pushes the moving 
armature of the vibrating spark gap closer to or further away fro the 
stationary contact. This unit should yielded snappy thin bluish white 
sparks about 2 inches in length at the best position of the 
adjustable control (apx. 50KV). BTW if you want to be extra safe 
drive the unit with a 30 watt isolation transformer, you can 
effectively make one out of two 6V 5 amp transformers or the like by 
connecting the two secondaries in parallel and connect one primary to 
the line the other to the coil.  If you want further information on 
"kicker-coil driven Tesla coils see; Thomas Stanley Curtis's "High 
Frequency Apparatus" 1916 (reprinted by Lindsay Publications 1988)in 
chapter VIII "Kicking Coil Apparatus". Note for those of you out 
there that have dificulty getting H.V. transformers, the 
"kicker-coil" arangement is an ideal substitute and I have seen coils 
using them up to the 10 Killowatt range.

			       Sincerely

				\\\|///
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			       (  -at- -at-  )
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			   Alfred A. Skrocki
		  Alfred.Skrocki-at-CyberNetworking-dot-com
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