To provide an eddy current flaw detection apparatus without misjudgments because of a magnetic variation and a lift-off change of a material to be detected.
High pass filters of a first judgment circuit 5 and flaw length count circuits of a second judgment circuit 6 are set by the same number as flaw detection probes 1A-1N. One of excitation circuits 11 is connected to an excitation power source 2 by switch elements 71A-71N, 72A-72N and, a detection coil 12 pairing with the excitation coil 11 is connected to a peak hold circuit set in the preceding stage of the corresponding high pass filter and to the corresponding flaw length judgment circuit. The switch elements 71A-71N, 72A-72N are sequentially changed over, and a short flaw and a long flaw are judged from output signals of flaw detection probes 1A-1N by the first judgment circuit 5 and second judgment circuit 6.
WATANABE HIROYUKI
YANO TAIZO
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