Calculation of Windings Differential Inductances of Electrical Devices in Mathematical Models with a Total Magnetic Flux

he article deals with an analysis of magnetic fields of electric machines and electromagnetic devices on the basis of their circuit mathematical models. The magnetic systems of electrical devices in these models are presented in the form of planar nonlinear magnetic circuits with lumped elements. The parameters of these elements are determined on the basis of geometric dimensions taking into account the design features of the devices and the physical parameters of the environment.

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Development of Refined Electromagnetic Models of Reciprocating Electric Generators with Permanent Magnets

ENERGETIKA Proceedings of CIS higher education institutions and power engineering associations ◽

10.21122/1029-7448-2021-64-4-291-302 ◽

2021 ◽

Vol 64 (4) ◽

pp. 291-302

Author(s):

A. B. Menzhinski ◽

A. N. Malashin ◽

P. B. Menzhinski

Keyword(s):

Magnetic Flux ◽

Mathematical Models ◽

Permanent Magnets ◽

Magnetic System ◽

Optimization Problems ◽

Reciprocating Motion ◽

Magnetic Circuits ◽

Electromagnetic Calculation ◽

Electric Generators ◽

Electromagnetic Models

The analysis of scientific papers devoted to the mathematical description of electric generators of reciprocating motion with permanent magnets demonstrated that the proposed mathematical models of this type of generators are based on the theory of magnetic circuits. Such mathematical models are based on a simplified representation of the magnetic system and the magnetic field in the form of a magnetic circuit with corresponding magnetic conductivities. However, unlike traditional rotary type electric machines, electric generators of reciprocating motion have a number of features, the omission of which in mathematical modeling causes the increase of the cost of their creation (due to the duration of the design and experimental refinement of the generators). Therefore, at the initial stages of electromagnetic calculation and solving optimization problems, it is necessary to use adequate mathematical models to improve the accuracy of calculations of the parameters of these generators. For this purpose, a mathematical model based on field theory can be used; however, its main drawback is the complexity of its application for solving optimization problems. In this regard, to improve the accuracy of calculations of the parameters of electric generators of reciprocating motion with permanent magnets, it is proposed to use refining coefficients (coefficients of scattering and buckling of the magnetic flux) in mathematical models based on the theory of magnetic circuits. The authors have developed refined electromagnetic models of electric generators of reciprocating motion with permanent magnets, which make it possible to obtain the main parameters of generators at the initial stages of electromagnetic calculation and when solving optimization problems with acceptable accuracy. A distinctive feature of the refined electromagnetic models of generators is the consideration of the scattering and buckling coefficients of the magnetic flux in the magnetic system that change during the simulation.

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Temperature modes of the contactor contacts during the test for the limiting breaking capacity

E3S Web of Conferences ◽

10.1051/e3sconf/202022001065 ◽

2020 ◽

Vol 220 ◽

pp. 01065

Author(s):

E.G. Egorov ◽

A.G Kulagina ◽

N.Yu. Luiya ◽

R.V. Fedorov ◽

V.N. Pichugin

Keyword(s):

Mathematical Models ◽

Thermionic Emission ◽

Heat Fluxes ◽

Thermal Processes ◽

Theoretical Studies ◽

Ionic Component ◽

Electrical Devices ◽

Calculation Results ◽

Temperature Equalization ◽

Experimental And Theoretical Studies

The processes of electric arc quenching of an electromagnetic contactor during testing for ultimate breaking capacity are considered. The conditions for facilitating the successful arc quenching when turning off the limiting currents are shown: by reducing the phase shift between current and voltage, by reducing the amplitude of the restriking and recovery voltages. The processes of anode heating during arcing (heat saturation mode), after the change of polarity and transition of the current through zero, processes on the cathode in the temperature equalization mode are considered. The mathematical models of cathode thermal processes adressed the heat fluxes of the ionic component and evaporation. The mathematical models of anode thermal processes in the temperature equalization mode took into account the heat fluxes of the ionic component, thermionic emission, and evaporation. The calculations were carried out for the averaged values of thermophysical coefficients for copper, since the arc base moves from the contacts to the contact holders, which are made of copper or its alloys. The calculation results showed that the used mathematical models of thermal processes are appropriate both for the cathode and for the anode. This was confirmed by the results of previously performed and published experimental and theoretical studies of thermal processes at the switching contacts of electrical devices.

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Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

International Astronomical Union Colloquium ◽

10.1017/s0252921100064630 ◽

2000 ◽

Vol 179 ◽

pp. 263-264

Author(s):

K. Sundara Raman ◽

K. B. Ramesh ◽

R. Selvendran ◽

P. S. M. Aleem ◽

K. M. Hiremath

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Magnetic Flux ◽

Ultra Violet ◽

Active Regions ◽

Morphological Properties ◽

Energy Storage And Conversion ◽

The Sun ◽

X Rays ◽

The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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Large-scale Motion of Solar Filaments

International Astronomical Union Colloquium ◽

10.1017/s0252921100064502 ◽

2000 ◽

Vol 179 ◽

pp. 205-208

Author(s):

Pavel Ambrož ◽

Alfred Schroll

Keyword(s):

Magnetic Flux ◽

Proper Motion ◽

Time Scale ◽

Large Scale ◽

Accuracy Of Measurements ◽

Solar Filaments ◽

General Movement ◽

Scale Motion ◽

Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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Solar Filaments as Tracers of Subsurface Processes

International Astronomical Union Colloquium ◽

10.1017/s0252921100064459 ◽

2000 ◽

Vol 179 ◽

pp. 177-183

Author(s):

D. M. Rust

Keyword(s):

Magnetic Fields ◽

Magnetic Flux ◽

Coronal Mass Ejections ◽

Interplanetary Space ◽

Intermediate Stage ◽

Coronal Plasma ◽

Magnetic Helicity ◽

The Sun ◽

New Paradigm ◽

Solar Filaments

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

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Sunspot Groups as Tracers of Sub-Surface Processes

International Astronomical Union Colloquium ◽

10.1017/s0252921100064393 ◽

2000 ◽

Vol 179 ◽

pp. 155-160

Author(s):

M. H. Gokhale

Keyword(s):

Magnetic Flux ◽

Indian Institute ◽

Surface Processes ◽

The Sun ◽

Global And Local ◽

Sunspot Groups

AbstractData on sunspot groups have been quite useful for obtaining clues to several processes on global and local scales within the sun which lead to emergence of toroidal magnetic flux above the sun’s surface. I present here a report on such studies carried out at Indian Institute of Astrophysics during the last decade or so.

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