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Demagnetization using a determined estimated magnetic state

  • US 8,934,210 B1
  • Filed: 06/28/2012
  • Issued: 01/13/2015
  • Est. Priority Date: 06/28/2012
  • Status: Active Grant
First Claim
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1. A method for demagnetizing comprising:

  • a. providing a core positioned within the electromagnetic field generated by a first winding upon application of a first voltage across said first winding;

    b. applying said first voltage across said first winding generating a first electrical current through said first winding until said generated first electrical current is not substantially increasing, thereby determining a saturation current;

    c. after said step of applying said first voltage across said first winding, applying a second voltage across said first winding generating a second electrical current through said first winding until said generated second electrical current is approximately equal to the magnitude of said determined saturation current;

    the polarity of said second voltage opposite of the polarity of said first voltage;

    d. determining, using a processor, a value related to the maximum magnetic flux within said core during said step of applying a second voltage across said first winding using a value relating to the voltage across said first winding and a value relating to said second current;

    e. after said step of applying a second voltage across said first winding, applying a third voltage across said first winding generating a third electrical current through said first winding until said core has a value related to the magnetic flux of the core, the same relation as said determined value related to the maximum magnetic flux, approximately half of said determined value related to the maximum magnetic flux within said core;

    the polarity of said third voltage opposite of the polarity of said second voltage, thereby demagnetizing said core;

    f. said step of applying a second voltage across said first winding comprises applying a second voltage across said first winding;

    said second voltage having a magnitude equal to the magnitude of the first voltage;

    g. said step of determining the a value related to the maximum magnetic flux within said core comprises;

    i. multiplying said determined saturation current by approximately 0.6 determining a two-tau saturation current; and

    ii. during said step of applying a second voltage across said first winding, timing the amount of time for said second electrical current to reach the approximate magnitude of said two-tau saturation current thereby determining a saturation time; and

    h. said step applying a third voltage across said first winding comprising;

    i. determining a half saturation time by dividing said timed two-tau saturation time by two; and

    ii. applying said third voltage across said first winding for said half saturation time.

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