scholarly journals Determination of electromagnetic properties of steel for prediction of stray losses in power transformers

2015 ◽  
Vol 23 ◽  
pp. 1357-1371 ◽  
Author(s):  
Leonardo STRAC ◽  
Damir ZARKO
2020 ◽  
Vol 35 (2) ◽  
pp. 1048-1057
Author(s):  
Haytham Saeed ◽  
Mariana Kamel ◽  
Abdelrahman Karrar ◽  
Ahmed H. Eltom ◽  
Mark Bowman

2011 ◽  
Vol 492 ◽  
pp. 260-263 ◽  
Author(s):  
Bao Cai Xu ◽  
Jian Jiang Wang ◽  
Rong Xia Duan ◽  
Xing Jian Huo

The hollow ceramic microspheres were prepared by Self-reactive flame spraying method. The structural characteristics and morphology properties of the composite powders were obtained by XRD and SEM. The results show that the obtained particles are hollow ceramic microspheres. The average particle size is about 30μm. An analytical method for the determination of electromagnetic parameters (ε, μ) of materials under test is presented by the analysis of normalized general matrix of equivalent network of coaxial line filled with samples. The analysis of vector network analyzer show that reflectance of hollow composite microspheres could well absorb microwaves in 2-18 GHz. The reflection loss is less than -l0dB in the range of 12.4 to15.2GHz while the minimum reflection loss is -18.5dB at 13.6GHz.


2016 ◽  
Vol 64 (8) ◽  
pp. 3459-3469 ◽  
Author(s):  
Ugur Cem Hasar ◽  
Joaquim Jose Barroso ◽  
Musa Bute ◽  
Abdurrahim Muratoglu ◽  
Mehmet Ertugrul

2018 ◽  
Vol 84 (7) ◽  
pp. 38-41
Author(s):  
V. P. Krylov

Current theories of heterogeneous media consider non-uniform materials as natural and artificially synthesizable structures. Nowadays, synthesis of the non-uniform multicomponent materials with given electrodynamic properties and characterized by magnetic and dielectric permeability, is gaining increasing development. When modeling a multicomponent structure as a uniform material with effective dielectric permeability (ignoring the magnetic properties) using the developed models for the components with known dielectric permeability, the errors arise in calculation of the transmission coefficient of a plane wave through the antenna dome wall. We present a heuristic model based on the laws of optics which is intended for simultaneous determination of the effective magnetic and dielectric permeability of multicomponent material in contrast to known models describing statistically non-uniform media only for one electrodynamic parameter. The electrodynamic model developed for description of the effective magnetic and dielectric permeability of non-uniform material suggests a possibility of characterizing a polarized material with the total dipole moment arising in alternating field and expressing the Brewster angle as a the sum of the polarization angles proportional to volume content the mixture components.


2021 ◽  
Vol 23 (1) ◽  
pp. 33-44
Author(s):  
Evgeny Artamonov ◽  
◽  
Andrey Tveryakov ◽  
Anton Shtin ◽  
◽  
...  

Introduction. Today, under the conditions of sanctions, the Russian Federation, more than ever before, needs the development of energy-saving technologies in various industries. There is no secret that when assigning cutting modes for new materials, tool companies conduct tests for the destruction of replaceable cutting inserts during cutting, the obtained numerical values are published in catalogs. The greatest impact on the life and operability of hard alloy cutting tools is exerted by the physical and mechanical properties of tool materials. Studies have shown that the physical and mechanical properties of tungsten hard alloys in the process of operation, namely in the process of cutting difficult-to-process materials under the influence of high temperatures, vary symmetrically. During the development of the laboratory plant, a literary review was carried out, which showed that at the moment non-destructive testing methods of technological facilities are widely used. Methods of non-destructive testing of technological objects allow conducting studies of the state of material, defects in the structure, internal changes, without samples destroying; this advantage was decisive during the literary review. The object of this study is replaceable cutting hard alloy inserts made of single carbide hard alloy В35 (92%WC+8%Co), tetrahedral in the state of supply. The subject of the study is the relationship between the changes of the magnetic component of the properties of a single-carbide hard alloy В35 (92%WC+8%Co) depending on the effect of high temperatures on it. This study is based on the laws of physics of the division of electrodynamics, as well as well-known non-destructive testing techniques, scientific foundations of material science. All studies are carried out in accredited laboratories of Tyumen Industrial University. The reliability of the obtained data is confirmed by the high correlation of the results of numerical values with the data obtained by the scientific predecessors. Research methodology. The paper shows the developed plant for determination of the maximum operability temperature of replaceable cutting hard-alloy inserts on the basis of study of change of electromagnetic properties. The method of research is given. Tests of the specimen are carried out during heating of replaceable cutting inserts made of tungsten hard alloy B35 (92%WC+8%Co). The heating temperature interval is selected in accordance with the temperature mode of the cutting process in the blade treatment of hard-to-process materials. Thus, heating is carried out in the range from 0 to 1000˚ C. The heating itself is carried out by the flame method manually. Results and discussions. Based on the results of experimental studies, tables of the results are compiled, where, with an interval of 10 °C, the corresponding values of the magnetic field of eddy currents induced in replaceable cutting inserts made of tungsten hard alloy B35 (92 %WC+8 %Co) are indicated. The results of the investigation are obtained to determine the maximum operability temperature of replaceable cutting hard alloy inserts based on the study of the change in electromagnetic properties for the hard alloy B35 (92%WC+8%Co) amounted to 460…730 °C, which corresponds to a cutting speed of 18 m/min during the treatment of the alloy EI867-VD (57 %Ni9 %Mo10 %Cr6 %W4.2 %Al4 %Co). On the basis of persistent tests in factory conditions, it is proved that the developed technique allows determining temperature intervals of maximum operability based on the study of changes in electromagnetic properties (magnetic field of eddy currents arising in replaceable cutting inserts) of hard alloys. These intervals make it possible to assign the most appropriate operating conditions for the cutting tool based on a scientifically sound technique that allows using the maximum tool resource.


2021 ◽  
Vol 14 (1) ◽  
pp. 4-10
Author(s):  
Dmitriy Viharev ◽  
Irina Snit'ko ◽  
A. Tihonov

Methods for calculating the intrinsic and mutual leakage inductances based on the use of the vector potential of the magnetic field are considered, expressions are derived for the quantitative determination of the intrinsic and mutual inductances of the leakage fields, taking into account the geometric features of the coils, conductors and the relative position of the objects under study. The results obtained can be used to determine the parameters of the refined equivalent circuits of power transformers.


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