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Article
Publication date: 1 November 2007

Janusz Zięba

This paper introduces two types of textile magnetic elements: mechanical-magnetic and circuital. Textile magnetic cores consist of elementary monofilament magnetic fibres…

Abstract

This paper introduces two types of textile magnetic elements: mechanical-magnetic and circuital. Textile magnetic cores consist of elementary monofilament magnetic fibres. Textile magnetic coils which are composed of a textile carcass, winding (electro-conductive yarn or wire) and magnetic fibres are presented. Textile magnetic elements are mainly textile cores which are the basic elements of textile electromagnetic devices such as sensors, actuators and transformers. Textile sensors are used to measure human physiological parameters such as breathing rhythm and pulse.

One of the most interesting applications of magnetic non-wovens is magnetic shielding. I present macroscopic magneto-mechanical and magnetic models circuital which will possibly be the basis for future mathematical description and simulation procedures of magnetic fibres and textile magnetic cores. The analysis results of transversal and longitudinal magnetic fibres are also presented. The mathematical problem of designing textile magnetic cores with the interlacement of the magnetic fibres is described. A block diagram for simulation models created by the Matlab-Simulink program is presented.

Details

Research Journal of Textile and Apparel, vol. 11 no. 4
Type: Research Article
ISSN: 1560-6074

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Article
Publication date: 21 July 2020

Hongbo Qiu, Xutian Zou and Xiaobin Fan

Owing to the salient pole structure and stator slots of hydro-generator, the air gap magnetic field in the generator is unevenly distributed. High-frequency harmonic…

Abstract

Purpose

Owing to the salient pole structure and stator slots of hydro-generator, the air gap magnetic field in the generator is unevenly distributed. High-frequency harmonic components contained in the inhomogeneous air gap magnetic field will have a negative impact on the generator performance. The purpose of this paper, therefore, is to improve the distribution of air gap magnetic field by using appropriate magnetic slot wedge, thereby improving the generator performance.

Design/methodology/approach

Taking a 24 MW, 10.5 kV bulb tubular turbine generator as an example, the 2 D electromagnetic field model of the generator is established by finite element method. The correctness of the model is verified by comparing the finite element calculation data with the experimental data. The influences of the permeability and thickness of the magnetic slot wedge on the generator performance are studied.

Findings

It is found that the intensity and harmonic content of the air gap magnetic field will change with the permeability of slot wedge and then the performance parameters of the generator will also change nonlinearly. The relationship between the eddy current loss, torque ripple, output voltage and other parameters of the generator and the permeability of slot wedge is confirmed. In addition, the variation of losses and torque with wedge thickness is also obtained.

Originality/value

The influence mechanism of magnetic slot wedge on the performance of hydro-generator is revealed. The presented results give guidelines to selecting suitable magnetic slot wedge to improve generator performance.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 16 November 2021

Wasim Barham, Ammar AL-Maabreh and Omar Latayfeh

The influence of using magnetic water instead of tap water in the mechanical properties of the concrete exposed to elevated temperatures was investigated. Two concrete…

Abstract

Purpose

The influence of using magnetic water instead of tap water in the mechanical properties of the concrete exposed to elevated temperatures was investigated. Two concrete mixes were used and cast with the same ingredients. Tap water was used in the first mix and magnetic water was used in the second mix. A total of 48 specimens were cast and divided as follows: 16 cylinders for the concrete compressive strength test (8 samples for each mix), 16 cylinders for the splitting tensile strength (8 specimens for each mix) and 16 beams to test the influences of magnetized water on the flexural strength of concrete (8 specimens for each mixture). Specimens were exposed to temperatures of (25 °C, 200 °C, 400 °C and 600 °C). The experimental results showed that magnetic water highly affected the mechanical properties of concrete. Specimens cast and curried out with magnetic water show higher compressive strength, splitting tensile strength and flexural strength compared to normal water specimens at all temperatures. The relative strength range between the two types of water used was 110–123% for compressive strength and 110–133% for splitting strength. For the center point loading test, the relative flexural strength range was 118–140%. The use of magnetic water in mixing concrete contribute to a more complete hydration process.

Design/methodology/approach

Experimental study was carried out on two concrete mixes to investigate the effect of magnetic water. Mix#1 used normal water as the mixing water, and Mix#2 used magnetic water instead of normal water. After 28 days, all the samples were taken out of the tank and left to dry for seven days, then they were divided into different groups. Each group was exposed to a different temperature where it was placed in a large oven for two hours. Three different tests were carried out on the samples, these tests were concrete compressive strength, flexural strength and splitting tensile strength.

Findings

Exposure of concrete to high temperatures had a significant influence on concrete mechanical properties. Specimens prepared using magnetic water showed higher compressive strength at all temperature levels. The use of magnetic water in casting and curing concrete can increase the compressive strength by 23%. Specimens prepared using magnetic water show higher splitting tensile strength at all temperatures up to 33%. The use of magnetic water in casting and curing can strengthen and increase concrete resistance to high temperatures, a significant enhancement in flexural strength at all temperatures was found with a value up to 40%.

Originality/value

Previous research proved the advantages of using magnetic water for improving the mechanical properties of concrete under normal conditions. The potential of using magnetic water in the concrete industry in the future requires conducting extensive research to study the behavior of magnetized concrete under severe conditions to which concrete structures may be subjected to. These days, there are attempts to obtain stronger concrete with high resistance to harsh environmental conditions without adding new costly ingredients to its main mixture. No research has been carried out to investigate the effect of magnetic water on the mechanical properties of concrete exposed to elevated temperature. The main objective of this study is to evaluate the effect of using magnetic water on the mechanical properties of hardened concrete subjected to elevated temperature.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

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Article
Publication date: 1 December 2021

Heshan Zhang, YanPeng Wang, Jiying Tuo, Minglei Yang, Ying Ma and Jin Xu

This study aims to accurately calculate the magnetic field distribution, which is a prerequisite for pre-design and optimization of electromagnetic performance. Accurate…

Abstract

Purpose

This study aims to accurately calculate the magnetic field distribution, which is a prerequisite for pre-design and optimization of electromagnetic performance. Accurate calculation of magnetic field distribution is a prerequisite for pre-design and optimization.

Design/methodology/approach

This paper proposes an analytical model of permanent magnet machines with segmented Halbach array (SHA-PMMs) to predict the magnetic field distribution and electromagnetic performance. The field problem is divided into four subdomains, i.e. permanent magnet, air-gap, stator slot and slot opening. The Poisson’s equation or Laplace’s equation of magnetic vector potential for each subdomain is solved. The field’s solution is obtained by applying the boundary conditions. The electromagnetic performances, such as magnetic flux density, unbalanced magnetic force, cogging torque and electromagnetic torque, are analytically predicted. Then, the influence of design parameters on the torque is explored by using the analytical model.

Findings

The finite element analysis and prototype experiments verify the analytical model’s accuracy. Adjusting the design parameters, e.g. segments per pole and air-gap length, can effectively increase the electromagnetic torque and simultaneously reduce the torque ripple.

Originality/value

The main contribution of this paper is to develop an accurate magnetic field analytical model of the SHA-PMMs. It can precisely describe complex topology, e.g. arbitrary segmented Halbach array and semi-closed slots, etc., and can quickly predict the magnetic field distribution and electromagnetic performance simultaneously.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 2014

Heesung Yoon and Chang Seop Koh

The purpose of this paper is to present the vector magnetic properties of the electrical steel sheet and investigate its influences on the magnetic field and iron loss…

Abstract

Purpose

The purpose of this paper is to present the vector magnetic properties of the electrical steel sheet and investigate its influences on the magnetic field and iron loss distributions for the electrical machines.

Design/methodology/approach

The vector magnetic property of the electrical steel sheet is measured by using a two-dimensional single sheet tester and modelled through an E&S vector hysteresis model to be applied to finite element analysis.

Findings

The magnetic field and iron loss distributions are calculated by finite element analysis combined with the E&S vector hysteresis model for the three-phase transformer and induction motor models.

Originality/value

The influences of the vector magnetic property on the electrical machines are verified by comparing with the numerical results from a scalar magnetic property.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 1/2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 July 2019

Mustafa Kadıoğlu and Ertuğrul Durak

The purpose of this study was to examine the effect of the magnetic field to the friction coefficient in the rolling element bearings which exists in electric motors.

Abstract

Purpose

The purpose of this study was to examine the effect of the magnetic field to the friction coefficient in the rolling element bearings which exists in electric motors.

Design/methodology/approach

To achieve this, the test rig was modified to adjust the density of the magnetic flux applied to the rolling ball element bearing. Experiments were carried out in the magnetic field from 0 to 7.5 mTesla at magnetic flux density range from 15, 40 and 65 N constant loads. Also, its rotary speed selected as 100, 200, 400, 800 to 1200 rpm, respectively.

Findings

In the majority of the experiments, it was observed that the magnetic field affected the friction coefficient. This influence reduced the friction coefficient in some experimental conditions and increased in some of them.

Originality/value

In the literature, there are very few studies on the effect of magnetic flux density to the friction coefficient in these rolling element bearings. It has become clear that more studies have been conducted on the effects of the magnetic field and/or electrical current on bearing damages and failures. This aspect is a study with specificity.

Details

Industrial Lubrication and Tribology, vol. 71 no. 10
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 7 August 2019

Ryoko Minehisa, Yasuhito Takahashi, Koji Fujiwara, Norio Takahashi, Masafumi Fujita, Kazuma Tsujikawa and Ken Nagakura

This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the…

Abstract

Purpose

This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the proposed method, the effects of magnetic anisotropy and a space factor on a no-load saturation curve and no-load iron loss of the turbine generator are discussed.

Design/methodology/approach

The proposed method was derived from the combination of the homogenization of microscopic fields in a laminated iron core with the modelling of two-dimensional magnetic properties based on free energy. To verify the validity, the proposed method was applied to a finite-element analysis of a simple ring core model. Finally, a no-load saturation curve and iron loss of the turbine generator was investigated by using the proposed method.

Findings

The computational accuracy of the homogenization method considering magnetic anisotropy is almost the same as that of the detailed modelling of the laminated structure in the magnetic field analysis of the laminated iron core. Furthermore, it is clarified that magnetic anisotropy does not have a large influence on the no-load saturation curve of the turbine generator because of the large air gap. On the other hand, the space factor affects the shape of the no-load saturation curve.

Originality/value

This paper verifies the validity of the homogenization method considering magnetic anisotropy method and elucidates the effects of magnetic anisotropy and a space factor on no-load characteristics of the turbine generator.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 38 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 June 2005

Wlodzimierz Ochonski

To present some new designs of magnetic fluid exclusion seals for rolling bearings and possibility to use them in modern industrial sealing applications.

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Abstract

Purpose

To present some new designs of magnetic fluid exclusion seals for rolling bearings and possibility to use them in modern industrial sealing applications.

Design/methodology/approach

In the paper is given principle of magnetic fluid sealing technology and are presented new designs of magnetic fluid exclusion seals for rolling bearings, such as compact magnetic fluid seals, two‐stages seals being combination of magnetic fluid seal and labyrinth seal or radial lip seal, magnetic fluid seals with “floating” magnetic system. This paper also shows examples of their application in various rotating process equipment.

Findings

Provides information about new designs of bearing seals and gives the main advantages of these seals over other types, such as total tightness, low viscous drag, maintenance‐free service and high reliability.

Originality/value

This paper offers some new designs of high‐performance magnetic fluid exclusion seals for rolling bearings and points their practical applications.

Details

Industrial Lubrication and Tribology, vol. 57 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 24 August 2018

Piotr Jankowski and Miroslaw Woloszyn

The purpose of this paper is to present computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera 3D 18R2…

Abstract

Purpose

The purpose of this paper is to present computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera 3D 18R2 programme. This paper aims to check the magnetic signatures’ numerical calculations precision of objects using the thin plate boundary conditions and analysis of the magnetic signature of ship with a degaussing system and with and without inner devices.

Design/methodology/approach

The ferromagnetic sphere and cube with and without the thin plate boundary condition were compared. The computer results of the magnetic field of a sphere were compared with an analytical solution. A superstructure, decks, hull and bulkheads of a corvette were modeled. An analysis of ship’s magnetic field with consideration of inner ferromagnetic devices and with degaussing system was carried out.

Findings

The results of the analytical and numerical comparative analysis of magnetic field of cube and sphere have shown that the thin plate boundary condition is a good method for analysis of magnetic signatures of thin-walled objects. The computer simulations of the corvette model have shown that for relative magnetic permeability of a few hundred range the influence of inner ferromagnetic devices on the ship’s magnetic signature is negligible. The thin plate boundary condition is also good method for calculation of the ship magnetic signature with degaussing system and for optimization currents of coils.

Originality/value

The calculation time of ship’s magnetic field with the thin plate boundary condition bears resemblance to the ship model with layers of steel.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 4 January 2016

Xiayu Zheng, Yuhua Wang and Dongfang Lu

The purpose of this paper is to model the particle capture of elliptic magnetic matrices for parallel stream type high magnetic separation, which can be a guidance for the…

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Abstract

Purpose

The purpose of this paper is to model the particle capture of elliptic magnetic matrices for parallel stream type high magnetic separation, which can be a guidance for the development of novel elliptic cylinder matrices for high-gradient magnetic separation (HGMS).

Design/methodology/approach

The magnetic field distribution around the elliptic matrices is investigated quantitatively and the magnetic field and gradient were calculated. The motion equations of the magnetic particles around the matrices were derived and the particle capture cross-section of elliptic matrices was studied and was compared with that of the conventional circular matrices.

Findings

Elliptic matrices can present larger particle capture cross-section than the conventional circular matrices and can be a kind of promising matrices to be applied to HGMS.

Originality/value

There is little literature investigating the magnetic characteristics and the particle capture of the elliptic matrices in HGMS, the study is of great significance for the development of novel elliptic magnetic matrices in HGMS.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 1
Type: Research Article
ISSN: 0332-1649

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