DIAGNOSING METHOD FOR ABNORMALITY OF ELECTRIC WIRE

PURPOSE:To detect whether there is any defect at an internal layer or at an external layer, by using two sorts of inspecting coils, and by crossing the while layer section and the external layer section of an electric wire with magnetic flux, to look for the defect. CONSTITUTION:An inspecting coil 1A is supported in a state wound on the longitudinally cracked cylinder of non-magnetic substance, and consists of coils separated from each other at longitudinally cracked sections and connected to each other electrically and mechanically with a connector at the longitudinally cracked sections, and magnetic flux phi is crossed with the whole layer of an electric wire W to be measured. An inspecting coil 1C is a coil wound on a circular-plate-shaped core bent along the peripheral direction of the electric wire W to be measured, and the electric wire W is crossed with the magnetic flux phi mainly near an external layer, along the longitudinal direction of the electric wire W to be measured. First, by using the coil 1A, any defect at the whole layer is looked for, and when any defect is detected, then the section of the defect is looked for by using the coil 1C, and it is discriminated whether the defect is an internal layer defect or an external layer defect.