FLAW DETECTOR ELECTROMAGNETIC TRANSDUCER Russian patent published in 1997 - IPC

FIELD: nondestructive flaw inspection; flaw inspection of electricity conducting equipment. SUBSTANCE: flaw detector transducer has excitation system in the form of U-shaped magnetic core 1 with winding 2 and metering element 3 arranged symmetrically to effective ends of magnetic core 1 and built up of two differentially connected inductance coils 4,5 and magnetodielectric core 6; inductance coils 4,5 are arranged coaxially and have common effective end. Metering element core 6 is placed coaxially relative to coils 4,5. Core size and its permeability are chosen according to condition ΔL_в/2 < ΔL < 1,5ΔL_в, where ΔL is maximum permissible change in inductance of metering element 3 due to core 6 mounted on its axis; ΔL_в is variation in metering element inductance due to change in its external coil turns by one turn. Size T of effective end of magnetic core 1 in direction perpendicular to line crossing both ends is recommended to be chosen from condition D_н<T, where D_н is outer diameter of metering element 3. Winding 2 of magnetic core 1 is recommended to be uniformly distributed part spaced P > 0,5 D_н from its both ends. Transducer is provided with nonmagnetic metal strip used to protect metering element 3 and magnetic core 1. EFFECT: improved validity of inspection. 5 cl, 2 dwg