A comparative analysis of the parameters of a rotating magnetic field inductor when using concentric and loop windings

Abstract

Introduction. Three-phase inductors of a rotating magnetic field are used in grinders, separators and stirrers for the technological processing of bulk and liquid substances. This occurs in a cylindrical working chamber under the influence of ferromagnetic elements in the form of pieces of iron wire, which move together with the field. Problem. By analogy with three-phase induction motors, for the stator of inductors a concentric winding is adopted, which is a diametric single-layer winding. When moving from such motors to an inductor, its operating conditions have changed due to the significantly increased non-magnetic space inside the inductor compared to the motor clearances. The difference in the frontal parts of the phase windings has become essential for the electromagnetic parameters and the structure of the magnetic field in the inductor working chamber. Therefore, a loop shortened stator winding, which is symmetrical, can be considered as an alternative to a concentric diametric winding. Goal. The aim of the work is to compare the dimensional and electromagnetic parameters of a rotating magnetic field inductor in two versions of its three-phase winding: concentric single-layer diametrical and loop shortened two-layer. Methodology. Comparison of the windings is carried out through a detailed analysis of the geometrical parameters of their frontal parts, as well as through numerical-field calculations of the electromagnetic parameters of the inductor as a whole and the distribution of the magnetic field in its working chamber. Results. A significant difference in the geometrical parameters of the frontal parts of the two windings under inductor conditions was revealed. The loop version of the winding makes it possible to reduce the length of the winding conductor, its active resistance, as well as the reactance of its frontal dissipation. At the same time the asymmetry of the phase windings is excluded and an increase in the homogeneity of the magnetic field in the inductor working chamber is provided. Originality. The scientific novelty of the work lies in the development of a method of comparative analysis of the windings under the conditions of the rotating magnetic field inductor and in revealing the advantages of a loop shortened winding compared to the used concentric diametric winding. Practical value. The loop shortened stator winding recommended for the inductor will eliminate the asymmetry of its electromagnetic system. Thereby, the quality of its work in the technological processing of different substances is significantly increased due to ensuring the homogeneity of the magnetic field in the working chamber. At the same time, the copper conductor of the winding is still saved, and the efficiency of the inductor is also increased by reducing the power of electrical losses.

Study of the Effect of Magnetic Field on Dispersion of Crushed Portland Cement and Tensile Strength of Cement Stone

“…When ferromagnetic elements interact with each other and the slip bushing, a voltage difference (up to 17 mV) is produced, having intermittence with a frequency of 4...10 microseconds. This leads to an electrolytic effect in electrically conductive media, with up to 15% of the vortex layer's power used for electrolysis and only about 2% of the energy spent on producing a high-frequency magnetic field and acoustic vibrations in the medium [5][6][7][8][9]. The magnetic field induction modulus on the circular current axis at a distance z from its center is determined by the Biot-Savart law:…”

“…To improve the efficiency of the electromagnetic mill, studies have been conducted aimed at tracking the movement of the working medium in the mill [5,6]. To improve the design of the electromagnetic mill so as to reduce energy consumption, various mills design solutions were proposed, mainly to ensure a uniform magnetic field inside the unit's mixing chamber to reduce electric losses [7][8][9][10][11]. However, it should be noted that the effect of the magnetic field on the properties of the material being ground during the operation of the electromagnetic mill has not been studied in the scientific literature.…”