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Re: [TCML] Permanent Magnet GDT(?)




> Correct me if I am wrong, but won't running a current of any type
> through windings on a magnet render it non magnetic in short order?
       As I understand it, the answer is:
           that depends.

       To affect, permanently, an existing magnetic field in a
       'permanent' magnet, several things MUST be considered:
           AC or DC and material?
              AC tends to scrub the existing field to zero,
              BUT SEE NEXT ITEM!
              DC can BOOST or BUCK, depending on polarity.
              (and a given material will have a max
              'field per cross sectional area.)
              (see next item: we ain't there.    yet...8)>>)
              Pulsed current: mixes as above.
              MAGNITUDE of current (but see next Item...)
              Small currents will be 'ignored', larger
              can 'rewrite' the mag field in the 'permanent'
              magnet.

           Next Item: MATERIAL
              (finally.... 8)>>)
              The magnitudes of the currents needed affect
              the 'permanent' field above vary with the MATERIAL
              of the permanent magnet.
              And the temperature.  And details of waveform.

        If one gets into the detailed engineering there are pages of
        data, curves, math.  (Its been a while, i never had to 
        go past the edges: but i think whats above is correct.)
        (Ferinstance there is the distinction between permanently
         altering the 'permanent' field and temporarily bucking
         or boosting it...)

        While this is not TC specific, i trust it is closely enuf
        related.

   best
    dwp
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