IMPEDANCE VARIABLE EDDY CURRENT FLAW DETECTION STANDARD PROBE

摘要

PURPOSE:To detect a minute flaw with high sensitivity by facilitating the equilibrium of a bridge, by making the impedance of a standard coil variable. CONSTITUTION:An eddy current flaw detection apparatus of a standard comparison system consists of eddy current flaw detection coils 4, 5 for detecting a flaw, a standard coil 3 used so as to form a pair with one of said coils 4, 5 and an AC bridge constituted of said two coils as two arms. An impedance variable probe coil 3 is used as the standard coil and the impedance thereof is changed to be made equal to that of a flaw detection probe to make it possible to easily take equiplibrium. The probe is constituted so that the lower side one of the cores 8 each wound by a coil 9 is fixed to an outer cylinder 7 but the upper side one thereof can be moved up and down by a core moving screw 11.