EDDY CURRENT FLAW DETECTOR

摘要

This invention prevents the failure of detection for horizontal and oblique lift-offs in a probe for an eddy current flaw detection test. Two detection coils (2, 2a, 2b) having mutually different diameters are concentrically disposed on the surface of a testpiece (1). These two detection coils (2) are differentially connected to a bridge circuit (3) for picking up a flaw signal. The two detection coils (2) are adjusted so that interlinkage magnetic fluxes generated inside the detection coils (2) by the eddy current become equal. An excitation coil (4) for inducing the eddy current in the testpiece (1) by AC driving is disposed over detection coils (2). The center of the excitation coil (4) is positioned on the center axes of the detection coils (2). An oscillator (5) for applying an AC current to this excitation coil (4) is connected to the coil. <IMAGE>