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Документ Calculation of the equivalent electrical parameters of the inductor of induction channel furnace with defects in its lining(НТУ "ХПИ", 2018) Podoltsev, O. D.; Zolotaryov, V. M.; Shcherba, M. A.; Belyanin, R. V.The aim of the paper is to determine a quantitative relationship between measured impedance of the inductor and the electrical characteristics of the separated melt circuit parts for the determination of the place of a liquid metal leakage andfor the improvement in such way the diagnostic system of lining state of induction channel furnaces. The study was performed on the basis of the concepts of theoretical electrical engineering, mathematical physics, and mathematical modeling. Using two equivalent electrical circuits of the inductor the analytical expressions and graphical dependencies, which determine a quantitative relationship between the parameters of the separated parts of a liquid-metal circuit and the impedance of the whole inductor measured in practice, for the presence of different lining defects, were found. The method for calculating the increments of equivalent electrical parameters of the inductor as a function of increments of the parameters of the secondary liquid-metal circuit was proposed. It is proved that for small changes (less than 10 %) of the parameters of the liquid-metal circuit, it is expedient to use a linear relationship between its increments and to create the sensitivity matrix, which clearly shows the presence of a strong or weak interrelation between the disturbed values of the parameters of the secondary circuit and the inductor. The use of this technique allows to develop the database for various types of lining defects for a given furnace and on itsbasis to predict the places of a melt leakage and the state of furnace lining owing to periodical measurements of the inductor parameters.Документ Electromechanical transient processes during supply voltage changing in the system of polymer insulation covering of the current-carrying core ofultra high voltage cables(НТУ "ХПИ", 2018) Zolotaryov, V. M.; Shcherba, M. A.; Belyanin, R. V.; Mygushchenko, R. P.; Korzhov, I. M.The article is devoted to the analysis of the electromechanical transient processes in a system of three frequency-controlled electric drives based on asynchronous motors that control current-carrying core motion, as well asto the study of the effect of such processes on the modes applying three-layer polymer insulation to the current-carrying core. The study was conducted based on the concepts of electromechanics, electromagnetic field theory, mathematical physics, mathematical modeling. A mathematical model has been developed to analyze transients in an electromechanical system consisting of three frequency-controlled electric drives providing current-carrying core motion of ultra-high voltage cables in an inclined extrusion line. The coordination of the electromechanical parameters of the system drives has been carried out and the permissible changes in the supply voltage at the limiting mass while moving current-carrying core of ultra-high voltage cables with applied polymer insulation have been estimated. For the first time it is determined that with the limiting mass of the current-carrying core, the electromechanical system allows to stabilize the current-carrying core speed with the required accuracy at short-term decreases in the supply voltage by no more than 27 % of its amplitude value. It is also shown that this system is resistant to short-term increases in voltage by 32 % for 0.2 s. Using the developed model, it is possible to calculate the change in the configuration and speed of the slack current-carrying core when applying polymer insulation, depending on the specific mass of the current-carrying core per unit length, its tension atthe bottom, the torque of the traction motor and the supply voltage to achieve stable operation of the system and accurate working of the set parameters.Документ Comparative analysis of electrical and thermal control of the lining state of induction apparatus of copper wire manufacture(НТУ "ХПИ", 2018) Zolotaryov, V. M.; Shcherba, M. A.; Belyanin, R. V.; Mygushchenko, R. P.; Kropachek, O. Yu.This article is intended to develop a technique for monitoring the lining state of induction channel furnaces for melting oxygen-free copper by monitoring changes in the distribution of thermal fields in their lining and carrying out a comparative analysis of the developed technique with the existing one that controls the electrical resistance of the melting channel of the furnaces. For carrying out the research, the theories of electromagnetic field, thermodynamics, mathematical physics, mathematical modeling based on the finite element method were used. A technique for diagnosing the lining state of the induction channel furnaces for melting oxygen-free copper has been developed, which makes it possible to determine the dislocation and the size of the liquid metal leaks by analyzing the temperature distribution over the body surface both the inductor and the furnace. The connection between the temperature field distribution on the surface of the furnace body and the dislocation and dimensions of the liquid metal leaks in its lining is determined for the first time. Using the proposed technique will allow to conduct more accurate diagnostics of the lining conditions of the induction channel furnaces, as well as to determine the location and size of the liquid metal leaks, creating the basis for predicting the working life of the furnace.