The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform

S A Bakar - One of the best experts on this subject based on the ideXlab platform.

  • Minor Hysteresis Loop phenomena in particulate recording media
    Journal of Applied Physics, 2002
    Co-Authors: M M Elhilo, A L Almomnee, S A Bakar
    Abstract:

    In this article measurements of Minor Hysteresis Loops in substituted BaFe powder systems with different particle concentrations have been made. The area of Minor Loop is observed to decrease with decreasing particle concentration. In addition, the variation of magnetization with time along the upper and lower sections of the Minor Loop have also been measured and show an inflection point at particular field points. The field at which the rate of magnetization changes sign is believed to be equal to a positive (magnetizing) local interaction field, i.e., the negative applied field is balanced by a local positive field. These results suggest that Minor Hysteresis Loops originate from interactions driving irreversible changes of magnetization during the cycling process of the magnetic field. Hence the opening of Minor Loops in these systems is governed by the ratio of interaction to anisotropy fields.

Pragasen Pillay - One of the best experts on this subject based on the ideXlab platform.

  • A Hybrid Model for Improved Hysteresis Loss Prediction in Electrical Machines
    IEEE Transactions on Industry Applications, 2014
    Co-Authors: Maged Ibrahim, Pragasen Pillay
    Abstract:

    This paper presents a model for calculating the Hysteresis loss in electrical machines. The model can achieve accurate and computationally efficient Hysteresis loss calculations by utilizing both analytical equations and the Energetic Hysteresis model. The model results are experimentally verified by comparing to a series of Minor Hysteresis Loop measurements. The hybrid model is then implemented to calculate the core losses in a switched reluctance machine using finite-element simulation. The results show that precise machine core loss prediction requires having a model that is capable of calculating the Hysteresis losses under a variety of Minor Hysteresis Loops.

  • The Minor Hysteresis Loop Under Rotating Magnetic Fields in Machine Laminations
    IEEE Transactions on Industry Applications, 2014
    Co-Authors: Natheer Alatawneh, Pragasen Pillay
    Abstract:

    In rotating ac machines, the saturated flux density waveforms contain harmonics, which create Minor Hysteresis Loops. The Minor Hysteresis Loops in machine laminations constitute an additional loss which requires modifications in traditional core loss formulas. This causes a serious challenge in core loss estimation. The task becomes more competitive under rotating magnetic fields, where the Minor Loop behavior has not been investigated yet. This paper highlights the problem of harmonics in rotating fields and its effect on the core loss estimation. In addition, the behavior of Minor Loops under rotating fields is compared with the Minor Loops under pulsating fields. Measurements were carried out on a nonoriented silicon steel sample of M36G29 with different fundamental frequencies of interest to the industry, 60 Hz and 400 Hz, with consideration of the third harmonic at each frequency. A design of magnetizing test fixture based on an electromagnetic Halbach array is used to perform these measurements. Results are presented and discussed.

  • The Minor Hysteresis Loop under rotating magnetic fields in machine laminations
    2013 IEEE Energy Conversion Congress and Exposition, 2013
    Co-Authors: Natheer Alatawneh, Pragasen Pillay
    Abstract:

    In rotating AC machines, the saturated flux density waveforms contain harmonics, which create Minor Hysteresis Loops. The Minor Hysteresis Loop in machine laminations causes a serious challenge in core loss estimation, especially under rotating magnetic fields. This paper highlights the problem of harmonics in rotating field and its effect on the core loss estimation. In addition, the behavior of Minor Loops under rotating fields is compared with the Minor Loops under pulsating fields. Measurements were carried out on a non oriented silicon steel sample of M36G29 with different fundamental frequencies of interest to the industry, 60 Hz and 400 Hz, with consideration of the third harmonic at each frequency. A novel design of magnetizing test fixture based on an electromagnetic Halbach array is used to perform these measurements. Results are presented and discussed.

J. Teillet - One of the best experts on this subject based on the ideXlab platform.

  • Magnetization and magnetostriction studies of TbFeCo/YFeCo multilayers
    Hyperfine Interactions, 2006
    Co-Authors: D. T. Huong Giang, J. Juraszek, J. Teillet
    Abstract:

    Exchange-spring TbFeCo/YFeCo multilayers exhibit interesting magnetic and magnetostrictive properties that are rather promising for application in microsystems. In this paper, we present a study of the effect of the exchange coupling on the magnetic properties of these magnetostrictive multilayers. An exchange bias phenomenon, revealed by a shift of the Minor Hysteresis Loop along the applied field axis, is found as the result of the creation of interfacial domain walls. This effect strongly depends on the magnetic properties of the soft YFeCo layer, and becomes more pronounced at low temperatures due to the enhancement of the magnitude of the exchange coupling between the layers.

S J Greaves - One of the best experts on this subject based on the ideXlab platform.

  • Minor Hysteresis Loop effects in magnetic materials
    Journal of Magnetism and Magnetic Materials, 1994
    Co-Authors: K Ogrady, S J Greaves
    Abstract:

    Abstract In this report we discuss the nature of Minor Hysteresis in ferromagnets. In particular we have examined the formation of Minor Loops in which the magnetisation in the second quadrant is at a higher positive value, as the magnitude of H is increasing in a negative sense, than it is during a reverse sweep back to zero field. This behaviour produces the well known elliptical Minor Loops, or the ‘eye effect’. We have examined in some detail changes in magnetisation on these Minor Loops and we infer that these are changes in the irreversible component of magnetisation. Such changes are anomalous as the sample is maintained in a negative field at all times. We have also observed time dependent changes in magnetisation in which M increases in a positive sense in a negative field. Analysis of this effect shows that it alone is insufficient to account for the eye effect. We discuss the origins of the eye effect in terms of interaction effects in materials and show that this phenomenon can occur in dipolar and exchange coupled materials and may provide a technique for probing local interaction effects.

M M Elhilo - One of the best experts on this subject based on the ideXlab platform.

  • Minor Hysteresis Loop phenomena in particulate recording media
    Journal of Applied Physics, 2002
    Co-Authors: M M Elhilo, A L Almomnee, S A Bakar
    Abstract:

    In this article measurements of Minor Hysteresis Loops in substituted BaFe powder systems with different particle concentrations have been made. The area of Minor Loop is observed to decrease with decreasing particle concentration. In addition, the variation of magnetization with time along the upper and lower sections of the Minor Loop have also been measured and show an inflection point at particular field points. The field at which the rate of magnetization changes sign is believed to be equal to a positive (magnetizing) local interaction field, i.e., the negative applied field is balanced by a local positive field. These results suggest that Minor Hysteresis Loops originate from interactions driving irreversible changes of magnetization during the cycling process of the magnetic field. Hence the opening of Minor Loops in these systems is governed by the ratio of interaction to anisotropy fields.