| 摘要 |
PROBLEM TO BE SOLVED: To make the phases of flaw signals constant, with respect to flaws in all of directions in an eddy-current flaw detecting probe constituted so that two exciting coils are arranged so as to allow the coil axes of them to cross each other at a right angle and separate exciting power supplies are respectively connected to the exciting coils. SOLUTION: The exciting power supplies EV1 and EV2 which differ in frequencies are connected to the exciting coils 11 and 12 and are arranged so that the coil axes of them may cross each other at right angles, and the frequency of the exciting power supply EV1 is set to f1, while the frequency of the exciting power supply EV2 is set to f2. The detection output of a detection coil separately performs synchronous detection by a reference current, having the same frequency as the exciting power supplies EV1 and EV2 to separately take out flaw signals. The maximum amplitude characteristics of both flaw signals after synchronous detection are indicated by graphs b1 and b2. The phases of both flaw signals after synchronous detection are not changed by the angles of the flaws. COPYRIGHT: (C)2010,JPO&INPIT
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