Electromagnetic nondestructive testing of articles made from conducting metals and with defects of any orientation, applicable to shapes with relatively high surface area/thickness ratio

摘要

Two exciting coils (2,3) are wound on a core (1) so their axes are orthogonal. The coils carry currents which have the same frequency and phase but may be varied in size to vary the orientation of the resulting field. A matrix (4) of search coils or magnetic field sensors detects the response of the core and the presence of a defect whatever its orientation