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Article
Publication date: 21 August 2018

Yingying Wang and Jiansheng Yuan

The theoretical method of converting the magnetic circuit into an electric circuit is mature, but the way to determine the inductances in the electric circuit is not reliable…

Abstract

Purpose

The theoretical method of converting the magnetic circuit into an electric circuit is mature, but the way to determine the inductances in the electric circuit is not reliable, especially for the core working in saturation status, and it is impossible to determine the inductances by the transformer terminal measurements, as the measurement information is not enough to determine a number of inductances. This paper aims to propose an approach of calculating the reluctances.

Design/methodology/approach

In this paper, an approach of calculating the reluctances is proposed based on the numerical simulation of magnetic field in transformer with different values of current excitation. The reluctance of a core segment or air region as a branch of magnetic circuit is obtained by the magnetic energy and magnetic flux. By this way, all the reluctances as function of flux can be determined, and then the inductances can be determined. The reluctances and equivalent electric circuit of three-phase integrative transformer is determined, and its validation is proved in the paper.

Findings

The single phase example shows that the proposed method has a good performances on analysis of the inrush current in deep saturation. The peak value of the inrush current derived from the proposed approach matches well with the results obtained by coupled circuit-FEM analysis, and the difference is about 4.8 per cent. For studies on dual models of single phase transformers, the leakage inductances have important effects on the peak value of the inrush current. The reluctances of three-phase transformer are calculated, and the equivalent circuit simulation results are slightly smaller than the coupled circuit-FEM simulation results.

Originality/value

Approach of calculating the reluctances based on the numerical simulation of magnetic field in transformer is proposed. The magnetic core and air space are divided into several segments, and the reluctance for each segment is calculated based on the energy in the region and the flux of the cross-sectional area. By applying various excitation currents, all the reluctances as function of flux can be determined, and then all the non-linear inductances including the non-linear leakage inductances are obtained. The proposed approach is reliable to determine a number of inductances in the dual electric circuit, especially for deep saturation status.

Details

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

Keywords

Article
Publication date: 1 December 2002

Taewon Suh and Ik‐Whan G. Kwon

This study attempted to empirically test a debatable hypothesis that globalization entails homogenization in consumers’ mind and behavior. Using samples from two countries (USA, n…

6657

Abstract

This study attempted to empirically test a debatable hypothesis that globalization entails homogenization in consumers’ mind and behavior. Using samples from two countries (USA, n = 120 and Korea, n= 128), this study explored a path model centered on consumers’ reluctance to purchase foreign goods. The findings indicated that, in the US sample only, consumer ethnocentrism plays a mediating role between global openness and the reluctance to buy, although it is on the decrease with the increasing level of global openness. Consumer ethnocentrism is still an important factor in determining the magnitude of reluctance to buy a foreign product in both samples, while product judgment also plays an important role, but only in a certain cultural context (i.e. the USA). It is concluded, therefore, that consumers in a different culture, who are different in their attitudes and perceptions, tastes and preferences, and values, are still different even after being exposed to the massive wave of globalization.

Details

International Marketing Review, vol. 19 no. 6
Type: Research Article
ISSN: 0265-1335

Keywords

Article
Publication date: 6 April 2012

John Williams, Cheryl Brown and Anita Springer

The purpose of this paper is to identify reported barriers to benchmarking and strategies to surmount these barriers.

3226

Abstract

Purpose

The purpose of this paper is to identify reported barriers to benchmarking and strategies to surmount these barriers.

Design/methodology/approach

The study is a qualitative meta‐analysis of 32 peer‐reviewed sources from January 2005‐July 2010. The authors sought recently published authoritative information on the topic of benchmarking reluctance to formulate an up‐to‐date framework explaining this phenomenon. Content analysis was used to identify reasons for benchmarking reluctance and ways to overcome reluctance.

Findings

The study concludes that organizational leadership best practices have been found to counter each of the four major benchmarking reluctance concerns: soundness of benchmarking theory/practices; lack of resources for benchmarking; inertia impeding pursuit of new practices; and specific impacts of implementing new practices.

Practical implications

The findings of this literature review may assist leaders to anticipate potential benchmarking barriers and to follow best practices for addressing these impediments.

Originality/value

Given the limited amount of recent literature focused on the topic of benchmarking reluctance, this paper provides valuable resources to help organizations succeed in their benchmarking efforts.

Details

Benchmarking: An International Journal, vol. 19 no. 2
Type: Research Article
ISSN: 1463-5771

Keywords

Article
Publication date: 4 January 2011

Amina Ibala, Ahmed Masmoudi, Glynn Atkinson and Alan G. Jack

This paper aims at the derivation of an accurate reluctance model of a transverse flux permanent magnet machine (TFPM) and its validation by finite element analysis (FEA).

Abstract

Purpose

This paper aims at the derivation of an accurate reluctance model of a transverse flux permanent magnet machine (TFPM) and its validation by finite element analysis (FEA).

Design/methodology/approach

Analytical prediction of the different reluctances in the core, the permanent magnets, and the air. These reluctances characterize the paths of both main and leakage fluxes. Then, a validation of the proposed reluctance model is carried out using FEA. An interesting application of the proposed reluctance consists in the assessment of the TFPM torque production capability.

Findings

The torque yielded by the reluctance model of the TFPM and the one computed using 3D‐FEA are in good agreement. This result is of great importance in so far as the CPU time required for 3D‐FEA computation is much more higher than the one consumed in the resolution of the reluctance model.

Research limitations/implications

Further validation of the results yielded by the proposed reluctance model through their comparison with experimental measurements shall be treated in the future.

Practical implications

The proposed reluctance model is of great interest for the TFPM sizing. It could be useful in the pre‐design procedure of the machine.

Originality/value

The paper proposes a new reluctance model where the leakage fluxes are accurately predicted.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Open Access
Article
Publication date: 1 June 2009

Yassir Semmar

The purpose of this study is to gain a better insight into the reasons that make Qatar University students reluctant to attend professors’ office hours. Factor analysis was first…

Abstract

The purpose of this study is to gain a better insight into the reasons that make Qatar University students reluctant to attend professors’ office hours. Factor analysis was first conducted to reveal the components underlying this reluctance; Multivariate Analysis of Variance (MANOVA) was then employed to analyze the effects of gender, GPA, credit hours completed, year of enrollment, and college/major on those factors. Results indicated that professor's competence and demeanor, course characteristics, students' social skills, attitudes/motivation, time conflict/communication style, students' apprehension as well as their physical/emotional state were all related to their reluctance to attend office hours. Moreover the predictor variables of gender, GPA, and credit hours completed had significant effects on several of those seven reluctance factors.

Details

Learning and Teaching in Higher Education: Gulf Perspectives, vol. 6 no. 1
Type: Research Article
ISSN: 2077-5504

Article
Publication date: 26 August 2014

Jianxin Shen, Dan Shi, Canfei Wang, Peng Li, Kang Wang and Mengjia Jin

The purpose of this paper is to investigate a new cause of torque ripple in interior permanent magnet (IPM) alternating current (AC) motors, which is common but has hardly been…

Abstract

Purpose

The purpose of this paper is to investigate a new cause of torque ripple in interior permanent magnet (IPM) alternating current (AC) motors, which is common but has hardly been studied. The paper also proposes a new method to suppress the total torque ripple.

Design/methodology/approach

Besides the well-known cogging torque and mutual torque ripple, a new ripple which exists in the reluctance torque is found. It is verified with both analytical model and finite element analysis. Also, a novel method is proposed to reduce the reluctance torque ripple, with experimental validation.

Findings

It is usually said that the winding inductances of an IPM AC motor vary sinusoidally with the rotor position, thus, the d-axis and q-axis inductances are constant, whilst the reluctance torque is smooth. However, in most practical motors, the inductances vary irregularly, causing a significant ripple in the reluctance torque. Moreover, in machine design, it is always desirable to suppress the cogging torque as much as possible. However, in this paper, it is proved that the cogging torque can remain and be used to cancel the reluctance torque ripple.

Originality/value

Torque ripple in the IPM AC motors is usually reduced by suppressing the cogging torque and making both back electromotive forces and currents sinusoidal. However, this paper reveals the new cause of the torque ripple due to the irregular variation of winding inductances. Moreover, the paper gives a new method to cancel the reluctance torque ripple with the cogging torque.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 January 2012

Jinhua Du, Deliang Liang and Qingfu Li

The purpose of this paper is to propose a method to estimate the magnetic saturation and end effect of linear switched reluctance machines (LSRMs) with fully pitched winding…

Abstract

Purpose

The purpose of this paper is to propose a method to estimate the magnetic saturation and end effect of linear switched reluctance machines (LSRMs) with fully pitched winding configuration used in the wave energy conversion.

Design/methodology/approach

The magnetic saturation and strong coupling make it very difficult to derive a comprehensive mathematical model for the behavior of the LSRMs. Meanwhile, the various end effects could not be comprehensively considered in the two‐dimensional model which is widely studied. Therefore, the magnetic equivalent circuit model including the three‐dimensional (3‐D) effects is presented in this paper and 3‐D finite element analysis (FEA) is used to validate the mathematical model.

Findings

The results from 3‐D FEA are in good agreement with the numerical simulation, which validates the accuracy of the magnetic equivalent circuit modeling method.

Practical implications

This technique helps one to know the influence exerted by the magnet saturation and end effect of LSRMs and provides a powerful computer‐aided analysis tool. Meanwhile, this modeling method supplies accurate values for the following study of reliable control algorithm.

Originality/value

The paper presents a magnetic equivalent method to estimate the magnetic saturation and end effect of LSRMs with fully pitched winding configuration used in the wave energy conversion.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 14 September 2010

Sławomir Wiak, Anna Firych‐Nowacka and Krzysztof Smółka

The purpose of this paper is to discuss the idea of designing and manufacturing intelligent clothes with magnetic fibres. The main goal of the research is to create the universal…

Abstract

Purpose

The purpose of this paper is to discuss the idea of designing and manufacturing intelligent clothes with magnetic fibres. The main goal of the research is to create the universal generator of computer structural models for whole bundles of magnetic microfibres.

Design/methodology/approach

The paper presents the algorithm of magnetic microfibers computer modelling. It covers both finite element method (FEM) and reluctance network method. This paper deals with creating 3D computer structural models of magnetic microfibres, which could be introduced as the textile magnetic sensors or actuators. Because of very complicated 3D microfibres structure, it is hoped that the quickest possible method can be found to solve the problem.

Findings

The results focus on the methodology presented in the paper which can be implemented in building 3D equivalent B/H curve of the microfibers set by using the field method – combining reluctance network method and FEM. Defining the proper magnetic B/H curves of magnetic fibres will enable the production of smart and resistant clothes.

Originality/value

First, the paper presents the original idea of modelling magnetic microfibres by use of the reluctance network method. So far, there are only measurements characteristics of B/H curve of magnetic microfibres. The paper proposes an innovatory way of determining magnetic microfibres parameters. This universal computer models allows for evaluation of a limiting value of magnetization (magnetic permeability, etc.).

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 24 August 2021

Aybegüm Güngördü Belbağ

The current study builds on social identity theory and realistic conflict theory aims to identify the relationships amongst consumers' ethnocentrism, animosity, discomfort with…

Abstract

Purpose

The current study builds on social identity theory and realistic conflict theory aims to identify the relationships amongst consumers' ethnocentrism, animosity, discomfort with differences – a factor of universal-diverse orientation (UDO) – and reluctance to purchase German (RELG) and French automobiles (RELF) in the Turkish automobile market which is dominated by foreign brands.

Design/methodology/approach

Empirical data were collected via face-to-face surveys from 400 respondents in the emerging market Turkey. Structural equation modelling was employed to examine the direct and indirect effects between the variables.

Findings

The main predictors of the RELG are consumer ethnocentrism, discomfort with differences and economic animosity towards Germany, respectively. Furthermore, RELF in the Turkish market is positively affected by consumer ethnocentrism, war animosity towards France and discomfort with differences, respectively. Discomfort with differences mediates the relationship between consumer ethnocentrism and RELG and RELF.

Practical implications

International collaborations with local manufacturers have huge strategic impacts when establishing reliable relationships with Turkish consumers. Foreign companies can initiate socially responsible projects that will relay the message of similarities between cultures to decrease perceived cultural differences. Highlighting the similarities of Turkish consumers with a foreign company in promotional campaigns will be much beneficial.

Originality/value

Despite there are many studies regarding antecedents and consequences of consumer ethnocentrism, extant research overlooks the effect of animosity on this concept. Additionally, studies examining UDO in the marketing literature are scarce. This paper integrates UDO, consumer ethnocentrism, animosity and reluctance to purchase foreign products in one study.

Details

International Journal of Emerging Markets, vol. 18 no. 9
Type: Research Article
ISSN: 1746-8809

Keywords

Article
Publication date: 1 June 2000

K. Wiak

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines;…

Abstract

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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