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RE: Re:Westinghouse/Bazil (fwd)



---------- Forwarded message ----------
Date: Sat, 22 Feb 1997 22:04:50 GMT
From: Robert Michaels <robert.michaels-at-online.sme-dot-org>
To: mod1-at-poodle.pupman-dot-com
Subject: RE: Re:Westinghouse/Bazil



M>  Shouldn't that be 14,400 / 120(ratio) = 120 volts out??? Boy, I'd
M>love to have a TC power supply that ran on 12 volts...but I guess that
M>would entail a bazillion amps on the line side though... ;-)

M> - brent (bturner-at-apc-dot-net)

        EH?  Huh-What?  Bazillion?  (I guess that must be metric
        measurement).   I'm not sure about the bazillion-system
        but permit me to show you how an American would make the
        calculation:

        In a single-phase, sinusoidal ac system of unit power
        factor (operating in America), the current is given by
        I  in the following equation:

                        I = P/E

        The formula says that the value of current in unit amperes
        is obtained by dividing the power (in watts) by the potential
        difference   E   in volts.

        So --  assume a 1 KW  (i.e. 1 kilowatt or 1000 watt) coil.
        Assume also the ac line powering the 1 KW coil is at a
        potential difference of 120 volts.  Then:

                        I = 1000/120

                        I = 8.333.. amps

        Now, if the voltage were 12 instead of 120, the current
        required would be 10 times as great (trust me):

                        I = 83.333.. amps

         Most ac welding equipment can =easily= achieve such currents.
         The better grade automobile alternators can deliver this
         much current as can nearly all truck alternators -- in
         America.  (Note: the power from an automotive alternator
         (before rectification) is 3-phase ac  (Ah there, Dr. Tesla).

                 So therein lies a methodology for a low-cost
                 portable coil:  An alternator and a lawn-mower
                 engine.  It's possible to single-phase these
                 alternators with relative impunity.

                        - - - - - - -

        Now -- as to how to have a 12 volt Tesla coil:

        =Almost any= Tesla coil that has ever been constructed
        can be run on 12 volts.   The =only= requirement is a step-
        up transformer (or a step-down transformer wired backward
        -- at an appreciable loss of efficiency).  Such a transformer
        would raise the 12 volts to the 120 (or 240) volts required
        for the coil.

        Given the super-abundance of control, signalling, and
        computer applications, used and surplus transformers of this
        ilk are almost in a glut.  New ones are easily purchased
        any day of the week from most any electrical supplies
        dealer catering to the professional trade.

        Yet another work-around is to use an ac arc welder and run
        it backwards, with the 12-volts going in the welder secondary
        and the required 120/240 volts coming out its primary.  This
        would take some fiddling with the taps on the welder and would
        be inefficient.
                               Best wished to everyone there in
                               Bazillia,

                               Robert Michaels - Detroit, USA
                                                 (America)