RE- Re: Bombarder xfmr

Subject:      RE- Re: Bombarder xfmr
       Date:  Fri, 06 Jun 1997 10:28:00 GMT
       From:  robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
         To:  tesla-at-pupman-dot-com

T>      From:  jim.fosse-at-bjt-dot-net (Jim Fosse)
T>>I just acquired a bombarder xfmr and variable choke from a neon shop
T>>that went out of business. It is rated at an output of 30 kV -at- 250
T>>7.5 KW. It is a large open air design with 2 separate windings over
T>>primary. For $200!
 [ ... ]

T>For mild over power use: if it doesn't smell, it's OK. For longer term
T>use: if you can hold your hand on it for 3 seconds (power off please;)
T>it's ok. (engineers, unless you have specific info on THIS xformer, or
T>a better rule of thumb, keep the flames to yourself)

 [ ... ]

        I'm not here to flame -- but maybe warm up the outer edges
        a little ( but I won't make a stink & it's nothing you couldn't
        hold your hand on for 3 seconds):

        I fear the smell/hand test my lead some astray, into
        blown-transformer never-never land.

        In Tesla work, over-driving a transformer, or even not
        over-driving it, can cause over-voltage conditions.  Such
        can cause  =brief=  (sometimes very brief) internal arcing
        which in turn can cause an internal open circuit in a trice
        (which is also very brief).  There would never be any
        opportunity for any touchy-feely (or smelly) nor either
        any external warming to touchy-feel.  (You  did expressly
        state "power" overload in your post, but in Tesla work,
        power can translate to voltage in untoward ways.)

        Only a  =current=  overload is apt to generate any palpable
        heat -- and then only after that heat has had a chance to
        overcome the thermal inertia of the transformer's mass.  In
        the pole-pig mass-class, by the time a transformer fails the 3-
        second touchy-feely externally, it may be about right for
        cooking french-fries internally.

                                - - - - - - - -

        I'm not saying your basic premise is wrong, only a little
        oversimplified -- and apt to be mis-applied by some readers.
        Hey -- I'm the guy who unabashedly advocates wholesale over-
        volting (but not over =powering=) military-spec. transformers,
        so we are both brothers of the Cause.

                                 Just a warm feeling I'm having, in --
                                 Detroit, USA

                                 Robert Michaels