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Re: Transformer



Subject:   Re: Transformer
  Date:    Sun, 18 May 1997 19:02:26 -0800
  From:   roger-at-annex-dot-com
    To:   tesla-at-pupman-dot-com


           Peter,
                  My D.C. coil is powered by two larg domestic microwave
   transformes with the shunts removed.  Each transformer drives a
   voltage dubbler circut resulting in an output of about 4000 volts
   DC per transformer.  The voltage dubblers are configured so that
   the output voltages are opposit each other relative of the
   transformer case ground.
         With both transformers conected "back to back" we now have
   a DC voltage of 8,000 volts.   The power output of this supply
   is only limited by the size of the capacitors in the voltage
   dubblers.  Curently I am using somthing like 4 uf caps and getting
   about 3.5 KVA.
       Now comes the impotant part....  With a DC sorce such as this
   We need inductive ballasting between are 8000 volts DC and the Tesla
   coil circut.  Curently, I use about a dozen microwave oven
   transformers for this.  I conected the secondarys all in series
   and electricaly isolated the cores from each other.  The primarys
   are just left open so these transformers are just serving as
   inductors.
       The amount of ballasting isnt criticall. You can get by with
   less, more might be better.  I plan to experement more with this
   peramitor myself.
             The tesla circut itself is typical for a coil of this
   power leval.  It uses a .04 uf primary cap, about a dozen turns
   on the primary, and the secoundary uses about 800 turns of
   #22 gauge wire on an 8 inch diamitor PVC pipe.  This coil
   must use a rotory gap (I have often wonderd if I added enough
   ballist if I could do away with the rotory)  Thats an experement
   for another day.
        It must be remembered that the capaciors in this circut will
   will remane charged when the coil is turned off. This could be
   dangerus, so I sugest you take precausons to make shure thay
   are discharged befor working on the coil.
         You should be able to scale the DC power sorce up if you
   want a higher power leval, just need more transformers and
   capacitors.  You could even make voltage tripler circuts but
   you would need lots of big capacitors.
             Finaly, you might want to talk to John Freau. He
   Has made some AC coils with microwave oven transformes by
   configuring them in serise.
          Thanks for bearing with me while my spell checker
   is in the shop.
                  Roger Smith