Effective Field in Macroscopic Descriptions of Magnetization Processes

Abstract The concept of mutual interactions between magnetic moments within a ferromagnetic substance, advanced in 1907 by Weiss The paper is focused on the engineering aspects of the "effective field" theory. It is important to stress that the concept could be applied in practical solutions of different magnetic sensors used in mechatronics and nondestructive testing

The Effects of Sheet Thickness and Excitation Frequency on Hysteresis Loops of Non-Oriented Electrical Steel

The paper focuses on modeling the rate dependence of hysteresis loops in conductive magnetic materials. The concept, which was advanced about fifty years ago by Chua, is discussed. It is shown that the viscous-type equation considered by Zirka and co-workers belongs to the class of Chua-type models. The dynamic effects are described with a simple fractional power law. The value of the exponent in the above-mentioned power law may be assessed on the basis of measurements of coercive field strength at different excitation frequencies. To verify the usefulness of the approach, the measurements of hysteresis loops were carried out at several excitation frequencies under standardized conditions for two grades of non-oriented electrical steel. The modeled curves are in a good correspondence with the measured ones. The considered model uses fewer parameters than approaches based on three-term loss separation schemes

Description of anisotropy of magnetic properties for chosen grades of electrical steels

Magnetic properties of electrical steels, either grain-oriented or non-oriented ones, are significantly affected by anisotropy. The paper considers two descriptions for the dependence: power losses versus angle. The first one is based on the theoretical studies on texture from materials science. The other one is purely phenomenological, and based on an equation of ellipse in a rotated coordinate system

Description of anisotropy of magnetic properties for chosen grades of electrical steels

Magnetic properties of electrical steels, either grain-oriented or non-oriented ones, are significantly affected by anisotropy. The paper considers two descriptions for the dependence: power losses versus angle. The first one is based on the theoretical studies on texture from materials science. The other one is purely phenomenological, and based on an equation of ellipse in a rotated coordinate system

Comparison of macroscopic descriptions of magnetization curves

The paper considers a qualitatively different behaviour of two phenomenological hysteresis models. The first one is the widespread Jiles-Atherton description, which is based on the ”effective field” concept. The other model is the proposal by the Brazilian research team GRUCAD. First order reversal curves simulated with the latter formalism do not exhibit negative slopes. This feature is in accordance with the experiment

Verification of Bertotti's loss model for non-standard excitation

© 2019 Polish Academy of Sciences. All rights reserved. This paper focuses on the possibility to use the Bertotti loss theory to describe energy losses in a toroidal core made of grain-oriented steel sheet under non-standard excitation conditions. The temporal Hclas (t) and Hexc (t) dependences are computed using a simple numerical scheme, which may be easily implemented in a spreadsheet

A Simplified Sablik’s Approach to Model the Effect of Compaction Pressure on the Shape of Hysteresis Loops in Soft Magnetic Composite Cores

A novel approach to take into account the effect of compaction pressure on the shape of modeled hysteresis curves of self-developed soft magnetic composite cores is presented. The description relies on the introduction of an additional term in the so-called effective field, which is assumed proportional to the compaction pressure. The proposed model bears some resemblance to the Sablik’s extension of the Jiles–Atherton model, readily used in the studies of the magnetoelastic effect. Verification of the description is carried out using measurement data from self-developed iron-based composite cores

A Study of Temperature-Dependent Hysteresis Curves for a Magnetocaloric Composite Based on La(Fe, Mn, Si)13-H Type Alloys

In the present paper, the effect of temperature on the shape of magnetic hysteresis loops for a magnetocaloric composite core was studied. The composite core, based on La(Fe, Mn, Si)13-H, was set up using three component disks with different Curie temperatures. The magnetic properties of the components and the outcome composite core were determined using a self-developed measurement setup. For the description of hysteresis loops, the phenomenological T(x) model was used. The presented methodology might be useful for the designers of magnetic active regenerators

Time domain analysis of excess loss in electrical steel

© 2019, University of Kragujevac, Faculty of Science. The aim of this paper is to present a comprehensive approach to analyse and interpret power loss in ferromagnetic materials with particular attention devoted to excess power loss. Experimental results obtained with an Epstein frame and toroidal core made of electrical steel are presented in the paper, including quasistatic and dynamic hysteresis loops. According to the time waveforms of the measured magnetic field and magnetic flux density, an instantaneous power loss is calculated for the quasistatic and dynamic case. Moreover, the instantaneous power loss due to eddy current is calculated, as well as the instantaneous excess power loss and excess magnetic field. This excess magnetic field is compared to the excess magnetic field calculated by Bertotti's model. Analysis and discussion of the results obtained is given in the paper

Short-circuit and load operation of single-phase transformer at low frequencies

© 2019, Wydawnictwo SIGMA-NOT. All rights reserved. The aim of this paper is to present experimental results on the short-circuit and load test of the single-phase transformer at low frequencies. The paper gives information on PC based measurement setup and presents the results of measurement of primary and secondary voltages and currents and electric power of the transformer. Also, a proper discussion of the results obtained is given in the paper