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Uniform field generating eddy current testing processing method and apparatus

  • US 4,594,549 A
  • Filed: 05/11/1984
  • Issued: 06/10/1986
  • Est. Priority Date: 05/11/1984
  • Status: Expired due to Fees
First Claim
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1. Apparatus for providing indicia of the surface region characteristics of an electrically conductive article, comprising:

  • two electromagnetic field generating heads in close proximity for creating an area of uniform field in the article under test;

    oscillator means for providing a constant current alternating drive signal to the heads for energization thereof;

    said apparatus characterized by;

    probe means positioned between said heads within the uniform field for providing for each of three orthogonal directions, two probe output signals from the field produced by eddy current in the article exposed to the uniform field, each of said probe output signals manifesting the field strength of the eddy current-produced field in two orthogonal directions at one of two adjacent positions in the third direction;

    first detection means for providing a first signal that represents the magnitude of the phase difference between each prove output signal and the drive signal;

    second detection means for providing a second signal that manifests a characteristic of the magnitude of each output signal;

    said probe means comprising a field pickup coil for providing each probe output signal.

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