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The properties of the solid magnetic core of the stator of a slotless torque motor with permanent magnets are considered. It is noted that the solid stator under the conditions of low rotation speed has some advantages over the traditional laminated magnetic circuit. These advantages consist in the cost reduction of the design, its compactness and the low time of production preparation. The mathematical model's assumptions and the input data's limitations are formulated. A model of a static magnetic field with a moving electrically conductive medium is chosen. The two-dimensional model is implemented in the "Magnetic fields" interface of the "COMSOL Multiphysics" software. The maximum torque values were obtained and the optimal number of pole pairs was found. The method of calculating the torque based on eddy current losses in the magnetic medium is used. The decrease in torque with increasing rotor speed is calculated. The correction coefficients of the maximum moment were obtained to correct the results of two-dimensional modelling using a three-dimensional model. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the distribution of effective coercive force (CF) in composite ferromagnetic standard samples assembled from two homogeneous samples with different CF values, abutted to each other. Two types of attachable U-shaped magnetic transducers (MT), which were connected to MA-5 type magnetic analyzer, were used for measurement of effective CF in a closed magnetic circuit. Measurements in an open magnetic circuit were performed using MT of attachable solenoid type, operating by the pole point method (PPM). This MT was connected to a coercimeter-structurescope of IKS-104 type. It is shown that for all MT types the effective CF of composite samples (CS) depends on their position relative to the butt. With MT movement relative to the butt from homogeneous sample with smaller CF to homogeneous sample with larger CF the effective CF increases in the range between CF values of these samples. Quantitatively, the nature of distribution of CS effective CF depends on MT type, its dimensions and type of their orientation relative to the butt for MT of non axisymmetric design. With parallel orientation of the poles of U-shaped MT relative to the butt, the nature of the changes in effective CF is smoother. Presence of a gap between CS parts causes a decrease of effective CF and instability of its values in the butt area. For MT of the same type reduction of their size leads to decrease of effective CF range. For MT of similar size the range of the change in CS effective CF, measured in an open magnetic circuit, is noticeably larger, compared to the one measured in a closed magnetic circuit. Shown is the principal possibility of CS application for metrological support of magnetic structurescopes, as well as for modeling the two-dimensional distribution of CF of ferromagnetic structures, which are characterized by surface inhomogeneity of magnetic parameters. 18 Ref., 1 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

The structure of an electric machine with a rotor, which has three degrees of freedom of rotation (EMTR) and consists of external and internal magnetic circuits, is considered. Between them, in the air gap of a spherical configuration, there is an m-phase rotation winding and a control winding. The excitation of the magnetic field in the EMTR is carried out by means of permanent magnets located on the external magnetic circuit. The scope of application of EMTP in systems of stabilization, observation, tracking, where the rotor performs the function of a gyro-stabilizing element, is outlined. Taking into account the structure of the considered EMTR, the absence of eddy currents in the design and the suitability of the mathematical model of the static magnetic field are substantiated. The calculation of the torque of the EMTR with two- and three-phase rotational windings at different angles of rotor’s inclination relative to the stator axis has been performed. It is shown that the rotation torque of the three-phase winding is 20% higher than that of the two-phase winding. A significant influence of the control winding on the torque of the three-phase winding and approximately the same influence of the two- and three-phase rotation windings on the processional torque with a significant value of the rotor inclination angle are noted. References 7, figures 8, tables 1. [ABSTRACT FROM AUTHOR]

criteria (minimum cost, force to volume ratio and efficiency) and mechanical load parameters are defined in the work. To do this, a computer model was developed, which is based on magnetic and electrical equivalent circuits with lumped parameters. The magnetic circuit of the model is built taking into account the saturation of the magnetic material, magnetic losses and leakage fluxes. The electromagnetic force amplitude of the motor is determined on the basis of the fundamental component of the Fourier series expansion of the air-gap flux density. The mechanical part of the model is constructed using the electromechanical analogy method, according to which, induced armature EMF is represented by a voltage drop on the equivalent mechanical resistance. The problem of choosing the constructional parameters for the given mechanical load characteristics is considered in conjunction with the nonlinear connections of the system and subject to thermal, magnetic and electrical constraints. Using the gradient descent method, the motor parameters were optimized and the most effective designs that meet the selected criteria were determined. References 8, figures 5, tables 2. [ABSTRACT FROM AUTHOR]

The classification is carried out and the characteristics, capabilities and disadvantages of the known methods of programmed correction of the output current of a single-phase primary measuring channel (PMC) of the current are determined. A discretized model of short-circuit current (SCC) is proposed. A method and an algorithm for increasing the accuracy of a threephase current PMC in transient modes of electric power systems (EPS) under the condition of saturation of the magnetic circuits of its phase current transformers have been developed. The reliability of the developed method is confirmed by simulation of the PMC output current under the condition of phase-to-phase short-circuit of phases A and B without correction and with correction of its phase currents. It is shown that the developed method makes it possible to reduce the total error of the PMC in the transient modes of the EES under the condition of saturation of the magnetic circuits of the CT from 70-90% to 6-15%. References 47, figures 6, table 1. [ABSTRACT FROM AUTHOR]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. Constructional improvement of lamellar matrix of polygradient electromagnetic separator, research of magnetic field distribution in working area of matrix and experimental determination of separator efficiency. Methodology. The finite element method implemented in module Magnet of Infolytica software package for analysis of magnetic field distribution in working area of matrix of electromagnetic separator was used. The distribution of magnetic field in a system that contains a current coil as a source of magnetic field is carried out in a three-dimensional formulation. The physical experiment for evaluation of extraction efficiency of ferromagnetic inclusions from loose medium was applied. Findings. An improved design of electromagnetic separator is proposed, for which a security document is received. It is shown that improved design provides a more uniform distribution of local areas of high intensity and heterogeneity of magnetic field in working volume of separator matrix in comparison with basic design. According to results of numerical-field analysis of magnetic field distribution by application of finite element method, it was set that due to constructional improvement of matrix the maximum value of magnetic induction in working interpolar gaps and inhomogeneity degree of magnetic field increased. The results of physical experiment showed that improved design of separator provides an increase of extraction efficiency of metal inclusions in comparison with basic design, first of all, at a low concentration of metal impurities in sample of bulk material. Originality. For improved design of electromagnetic separator, the distribution of magnetic field in magnetic circuit and working area of device is obtained, which made it possible to substantiate its advantages compared to basic version. Practical value. The numerical-field calculations of magnetic field distribution in magnetic circuit and working area of electromagnetic separator received further development, which made it possible to substantiate advantages of improved design of separator compared to basic version. [ABSTRACT FROM AUTHOR]

Purpose. The development of a detailed mathematical model of the system "network - multifunctional converter unit with a photovoltaic battery - load", which will allow for a comprehensive study of the processes in the system with an assessment of the efficiency of the unit. Methodology. Synthesis of the structure of the model and the control system of the unit based on the analysis of processes in electrical circuits using computer simulation. Findings. Dependencies for approximating the current-voltage characteristics of a photovoltaic battery. The use of a standard model of a transformer with magnetic circuit saturation as a nonlinear reactor is proposed. A model for determining power losses in semiconductor switches by the instantaneous values of currents and voltages and their catalog data. Originality. The mathematical model of the photovoltaic battery is improved according to the passport data with the introduction of the dependence of the open circuit voltage on the intensity of solar radiation. The structure of the control system with an internal current control loop and switching external controllers according to the operating modes has been improved: when working with the network in the "day" mode, it is the voltage controller of the photoelectric battery, in the "night" mode it is the inverter input voltage controller; in standalone mode - load voltage controller. There is a justified change in the settings of the current control loop and the modulation frequency in the standalone mode to eliminate the growth of power losses in the switches. Practical value. The obtained solutions are the basis for the design and analysis of indicators of multifunctional converting units for systems with renewable energy sources with improved energy efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machinery & Energetics is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machinery & Energetics is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. Working out of mathematical models of the speed-controlled induction electric drives ensuring joint consideration of transformers, motors and loadings, and also matching reducers and transformers, both in static, and in dynamic regimes for the analysis of their operating characteristics. Methodology. At mathematical modelling are considered functional, mass, dimensional and cost indexes of reducers and transformers that allows observing engineering and economic aspects of speed-controlled induction electric drives. The mathematical models used for examination of the transitive electromagnetic and electromechanical processes, are grounded on systems of nonlinear differential equations with nonlinear coefficients (parameters of equivalent circuits of motors), varying in each operating point, including owing to appearances of saturation of magnetic system and current displacement in a winding of a rotor of an induction motor. For the purpose of raise of level of adequacy of models a magnetic circuit iron, additional and mechanical losses are considered. Results. Modelling of the several speed- controlled induction electric drives, different by components, but working on a loading equal on character, magnitude and a demanded control range is executed. At use of characteristic families including mechanical, at various parameters of regulating on which performances of the load mechanism are superimposed, the adjusting characteristics representing dependences of a modification of electrical, energy and thermal magnitudes from an angular speed of motors are gained. Originality. The offered complex models of speed-controlled induction electric drives with matching reducers and transformers, give the chance to realize well-founded sampling of components of drives. They also can be used as the design models by working out of speed-controlled induction motors. Practical value. Operating characteristics of various speed-controlled induction electric drives are observed and depending on the chosen measure including measure of cost of losses of active energy, sampling of the best alternative of the drive is realized. [ABSTRACT FROM AUTHOR]