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Path: utzoo!mnetor!seismo!columbia!rutgers!dayton!ems!A60!lee
From: lee@A60.UUCP (G. Lee)
Newsgroups: sci.electronics
Subject: Re: Tesla Coil
Message-ID: <823@A60.UUCP>
Date: Tue, 9-Dec-86 08:09:51 EST
Article-I.D.: A60.823
Posted: Tue Dec  9 08:09:51 1986
Date-Received: Wed, 10-Dec-86 04:41:30 EST
References: <4815@reed.UUCP>
Reply-To: lee@A60.UUCP (G. Lee)
Organization: Sperry Corporation - Roseville, MN
Lines: 66
Keywords: frustration

In article <4815@reed.UUCP> shadow@reed.UUCP (Matthew Giger) writes:
>
>	Does anyone out there know much about tesla coils?  They are a
>type of oscillation transformer and the primaries and secondaries have
>to resonate at certain frequencies to be effective.  The few books I
>-- 
>				Matt Giger
>				tektronix!reed!shadow


  A friend of mine and I build a tesla coil last spring with great results.
The basic idea is make a air core transformer with MANY fine secondary windings
and a few heavy primary windings.

  The materials you will need are:
    1. A neon transformer with as high a power output as you can get. ( Mine
        was about one kilowatt or something like that)
    2. A few feet of wire about the size of 110vac house wire ( I never was very
         good with gages of wire ) 
    3. LOTS of fine enamel coated wire to make the seconary coil
    4. Two carriage bolts to make the spack gap.

    To make the secondary coil we used a cardboard tube about seven inches
    in diameter and eight feet tall.  Starting at one end wrap the fine enamel
    wire around the tube till you get to the top and attach it to a nail mounted    on the end of the tube. when wrapping the wire done NOT overlap the wire.
    The wire wrapping should form a smooth layer over the tube.  Coat this
    wrapped tube with varnish to help prevent arcing. 
    The primary coil is much easier.  It consists of about 5 or 6 turns of the
    110vac size wire around the base end (none nail end) of the secondary coil.
    The primary turns should be spaced about eight inches out from the secondary
    coil with something VERY INSULATING between them.
    Making the spark gap was done using two carriage bolts and a ceramic cheese
    crock ( Any kind of insulation and durable container should do).
    We drilled a hole through each side of the jar and mounted the bolts through
    these holes leaving about a one inch gap between the ends of the bolts in 
    the jar.  
     
    Now to connect it all together...
    Connect one end of the neon sign transformer output to one end of the
    spark gap. connect the other end of the spark gap to one end of the
    primary coil. connect the other end of the primary coil back to the other
    output terminal of the neon sign transformer. connect the base end of 
    the secondary coil to the side of the primary coil not connected to the
    spark gap.

    If I haven't forgotten anything it should be ready to fire (pun
    intended) up. You should hear the spark gap crackling, if not,
    UNPLUG it and move the ends of the carriage bolts together and try
    it again.  If all goes well things should start working, at least a little.
    try to draw a arc off the nail on the top of the secondary using a broom 
    stick with a nail stuck into the end.
    If things aren't working so well, try changing the number of turns in the
    primary.  If things are working well you'll have arcs flying everywhere.
    
    At our coils prime, we had it throwing foot and a half arcs into thin air
    off the nail on the top of the seconday coil ( along with small arc 
    jumping off everything else).
    The more you reduce the extrainious arcing the better the whole thing will
    work.
    
     Good luck and BE CAREFUL
                         Gene Lee
      
-- 
Gene Lee           UUCP: ...ihnp4!{meccts,dayton,rosevax}!ems!A60!lee
Sperry Corporation     ATT:  (612) 635-6334