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RE- Test of 6" coil



Subject:      RE- Test of 6" coil
       Date:  Fri, 30 May 1997 16:45:15 GMT
       From:  robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
         To:  tesla-at-pupman-dot-com


        I don't know if it's proper netiquette to respond to my own
        response, but there's an additional item I'd like to add to
        my proposed capacitor FAQ:

                        - - - - - - - - - - -

        It is utterly  =crucial=  to operate any oil-filled capacitor
        in the correct orientation:  righsideup, upsidedown, or
        sideways.   The better capacitors have an arrow or wording
        either stenciled or stamped on the case to indicate operating
        orientation.  Else (sorry about this), you'll just have to
        read the manufacturer's spec. sheets or application notes.

        IMHO -- It's not a good idea to even store oil-filled capacitors
        in the wrong orientation for protracted periods, but that's just
        my gut feeling.

                                =Still=  charged-up, in --
                                Detroit, USA

                                Robert Michaels



->         Hate to make you the target of my ire, Ed (especially you),
->         but I see this same foggy-bottomed thinking again, and again
->         (and again!) on This List:

->         -- If a capacitor is rated "X-volts, ac" that is r.m.s. volts
->            and  =not=  peak volts!   So your 20,000-v. capacitor is
->            good for 14,144-v.  ( that's 20,000/1.414 ) -- but not
->            quite.

->         -- Capacitor manufacturers have  =forever=  played fast and
->            loose with voltage specs.  It is therefore  =essential=
->            to de-rate mfg'rs. specs. before applying any capacitor.
->            (One sees the same thing in other areas of industry --
->            auto makers' horsepower specs., for instance.)

->                 With this in mind, any working engineer would not
->                 apply the above capacitor at any voltage, over, say
->                 10,000-v r.m.s.   The difference between 14,144
->                 and 10,000 is a very necessary safety factor.

->                         |  At  =best=  the spec. plate voltage  |
->                         |  of a capacitor should be take as its |
->                         |  never-to-be-exceeded  voltage, not   |
->                         |  its day-in/day-out working voltage!  |


->         -- In a Tesla circuit, rife with inductance and sparking,
->            there are certain to be transient voltage spikes which
->            rise well above the normal ac peak.

->                  With this in mind, your capacitor probably should
->                  not be used in any Tesla circuit over, say,
->                  5,000-v ac.   This done, your capacitor would have
->                  probably lived forever  (all right, for quite some
->                  years).

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