Bezkorovaynyy V. Improving the noise immunity of fluxgate flaw detectors to interference's magnetic fields

The object of study - the signal forming process in the magnetic system of ferroprobe at the high magnetic field interference. The purpose of research - increasing of noise resistance of ferroprobe flaw detector to control defects discontinuity of products with an uneven surface by using of the magnetic measuring elements in magnetic system, that provide the selection of the magnetic field defect. Methods of research: based on the calculation of the static magnetic field in the nonlinear medium by numerical method of the vector integral equation and the calculation of the magnetic field in the ferromagnetic rods by using of the reciprocity theorem of K.M. Polivanova. Theoretical and practical results: methods of experimental estimation of the magnetic intensity in the ferroprobe cores induced by the defect and field interference. Theoretical and practical results: the appropriate software for the automated processing of research results is created; ferroprobe flaw detector which has a high selectivity to the magnetic interference fields, minimum number of windings and increased conversion ratio is developed. Scientific novelty: improved mathematical model of the magnetization vector field in a nonlinear ferromagnetic medium, that provides the calculation of the magnetic field of the defect and its surroundings with the uneven surface of the controlled product and allows to design the structure of the magnetic flux gate with high selectivity; the magnetic flux gate system consisting of two ferromagnetic ferroprobes with jumpers included in the differential circuit, that provides the selection of the signal generated by a defect (patent of Ukraine for utility model № 99978) is proposed for the first time and its theoretical principles are justified; the method of the transfer function for the bridge circuit of the flux gate with U-shaped core operating in the parametric resonance mode, has given the further development. Degree of implementation: the results of the thesis work are introduced in OJSC "HC Luganskteplovoz" in controlling the non-smooth surfaces of ferromagnetic bodies, in particular, for monitoring undercarriage components of rail transport; in the form of methods of calculation of static magnetic fields, algorithms and software system are introduced in the educational process of "Electromechanics" department of EUVDNU (East Ukrainian Volodymyr Dahl National University). Scope - instrumentation, engineering and metal industry, flux-gate non-destructive testing, scientific research institutes and educational process.