Magnetic Leakage Field inside and outside a Slot on the Cylindrical Surface of a Disc caused by the Threading-Bar Technique

摘要

According to the distribution of the magnetic field caused by the threading - barrntechnique and the magnetization law of magnetic medium, the analytic expressions for thernlinear magnetic charge density along the edge of slot on the cylindrical surface of arndisc and the magnetic leakage field of the slot have been given in this paper. Theirrndigital magnitudes and spatial distribution have also been calculated and plotted. Theserntheoretical results approximately conform to the classical experiment of magneticrnparticle inspection.rnFor theoretical explanation of the experimental result about the magnetic leakage fieldrninside and outside a slot on cylindrical surface of a disc at circumferentialrnmagnetization (Fig.1～Fig.3)[1], the author preliminarily analyzed this problem severalrnyears ago with a model, in which the direct electric current flows through the disc, andrnthe obtained theoretical curves very well conform to the experimental result tendencyrn[2]. Now this classical experiment will be investigated from the viewpoint of alternatingrnmagnetization by the threading - bar technique.