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Article
Publication date: 1 April 1995

J. Wagner, D. Maga and R. Ort‐Šnep

In spite of our previous results, where we have investigated the simplified 2D model, we would like to present our results coming out from real motor geometry. We use the Finite…

34

Abstract

In spite of our previous results, where we have investigated the simplified 2D model, we would like to present our results coming out from real motor geometry. We use the Finite Element Method to solve the magnetic field of real cross‐section of hightorque stepping motor. This point of view allows us to investigate the multiphase (2 phase) supply. We are able to supply the motor with different current amplitude in each phase and with different polarity as well. The simplified model was used for slot and tooth shapes and sizes design optimisation, air‐gap width optimisation with reaching the maximal possible torque. Now we are going to verify these results and compare them to our latest ones. The comparison will be made by showing the magnetic field layout in the motor (with different current supply) in different stator‐rotor position. We will present tables and figures of some important variables, necessary for torque computation. We will compare these variables in the simplified and in the real motor. Then, on the base of the magnetic field solution, we will show the possible ways of rotor torque computation.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 June 1998

D. Maga and J. Wagner

A prototype of a special electrical machine ‐ double statored switched reluctance motor ‐ has been developed which produces a very high static and dynamic torque. Possible ways of…

331

Abstract

A prototype of a special electrical machine ‐ double statored switched reluctance motor ‐ has been developed which produces a very high static and dynamic torque. Possible ways of measuring the machine are presented. The basic parameters of the model are described. Results are compared to those obtained by computer design. A difference between computed and measured results is discussed.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 1994

Dipl Ing. Juraj Wagner, PhD assoc prof, Dušan Maga, Renata Führichová, Dipl Ing Roman Guba and Jozef Opaterný

In our contribution we deal with the optimization of the magnetic circuit design of the high torque step motor by numerical solution of the motor magnetic field (the Finite…

27

Abstract

In our contribution we deal with the optimization of the magnetic circuit design of the high torque step motor by numerical solution of the motor magnetic field (the Finite Elements Method — FEM) and with the solution of some electrical parameters of this motor and we introduce the methodology of optimization of the motor size from the parameters dependant.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 1994

Juraj Wagner, Vltězslav Hájek, Renata Führichová, Dušan Maga, Dipl Ing Roman Guba and Dipl Ing Jozef Opaterný

The analysis of the magnetic field and computation of the leakage magnetic flux is important for optimum design of the motor, especially for the small machines on low voltage…

60

Abstract

The analysis of the magnetic field and computation of the leakage magnetic flux is important for optimum design of the motor, especially for the small machines on low voltage loaded from the accumulator battery. In our contribution we analyzed the computation of the leakage magnetic field and flux by means of analytical, respective numerical methods (Finite Elements Method — FEM).

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 March 2018

Eduardo Parra-López and José Alberto Martínez-González

The purpose of this study is to synthesize the published works about tourism in the island. Island destinations, especially smaller ones, suffer the negative effects of tourism…

1904

Abstract

Purpose

The purpose of this study is to synthesize the published works about tourism in the island. Island destinations, especially smaller ones, suffer the negative effects of tourism more than other destinations. This is because of the characteristics of island destinations and the negative impacts arising from their inadequate management by different stakeholders. For these reasons, and conversely because tourism favors the social and economic development of islands, there has been a great deal of research published on insular tourism in the literature at a global level. Despite the number of studies carried out from different approaches, none have synthesized this scientific production. Thus, the main contribution of this paper is the use of a bibliometric and descriptive approach to carry out a thorough review of studies published on tourist development in island destinations.

Design/methodology/approach

The authors use a bibliometric and descriptive approach to carry out a comprehensive review of the published studies on tourism development in island destinations in the past decade with special emphasis on the items analyzed, places of analysis and scientific journals that have addressed this topic.

Findings

The results of the analysis of the literature show the interest of the study of tourism in island destinations. This interest is partly due to the attraction that tourists have for this type of destinations and the need to promote their sustainable management as tourism destinations (Cusick, 2009, Hall, 2011, Cave and Brown, 2012, López, Orgaz, Marmolejo and Alector, 2016). In addition, tourism in island destinations constitutes an opportunity for economic development and benefits both the local population and its visitors (Fabinyi, 2010; Porter et al., 2015).

Research limitations/implications

The main limitation of this paper is the great diversity of tourist destinations made up of islands, the complex nature of these destinations and tourism and the quantity and diversity of research carried out into them. This aspect has already been highlighted by other authors and makes it complex to determine which research should be included or excluded in this review.

Practical implications

Importantly, the results allow researchers and decision-makers to identify the main areas of interest in the study of island tourism and the reasons for this interest. They also indicate new areas of interest and in-depth studies. Thus, professionals have a map that shows the most relevant factors in tourism development for this type of destination and the variables that, both from a positive and a negative point of view, influence its development.

Social implications

This research shows that the main areas of interest is island destination are the quality of life of the local community, stakeholder collaboration, sustainability, diversification and seasonality, marketing, consumer behavior/perception and segmentation, planning of tourism activity, information and technology, competitiveness and efficiency.

Originality/value

As evidenced by the amount of research carried out, there is a great deal of interest in tourism in island destinations. This interest arises from the specific characteristics and the interest of tourists themselves in this type of destination, as well as from the negative impacts and opportunities generated by island tourism. Nevertheless, the number of references obtained for tourism in island destinations (N = 949) represents only 0.2 per cent of the total number of studies referring to only “island” in the SCOPUS consultation (339,607 studies). Thus, one of the contributions of this paper has been to highlight the need to continue studying and reviewing in greater depth research on insular tourism.

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Tourism Review, vol. 73 no. 2
Type: Research Article
ISSN: 1660-5373

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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;…

929

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.

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

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Available. Content available
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Publication date: 10 June 2024

Neven Šerić, Ivana Kursan Milaković and Ivan Peronja

Free Access. Free Access

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Specialised Tourism Products
Type: Book
ISBN: 978-1-83549-408-0

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Article
Publication date: 5 January 2015

Belli Zoubida and Mohamed Rachid Mekideche

Reducing eddy current losses in magnets of electrical machines can be obtained by means of several techniques. The magnet segmentation is the most popular one. It imposes the…

237

Abstract

Purpose

Reducing eddy current losses in magnets of electrical machines can be obtained by means of several techniques. The magnet segmentation is the most popular one. It imposes the least restrictions on machine performances. This paper investigates the effectiveness of the magnet circumferential segmentation technique to reduce these undesirable losses. The full and partial magnet segmentation are both studied for a frequency range from few Hz to a dozen of kHz. To increase the efficiency of these techniques to reduce losses for any working frequency, an optimization strategy based on coupling of finite elements analysis and genetic algorithm is applied. The purpose of this paper is to define the parameters of the total and partial segmentation that can ensure the best reduction of eddy current losses.

Design/methodology/approach

First, a model to analyze eddy current losses is presented. Second, the effectiveness of full and partial magnet circumferential segmentation to reduce eddy loss is studied for a range of frequencies from few Hz to a dozen of kHz. To achieve these purposes a 2-D finite element model is developed under MATLAB environment. In a third step of the work, an optimization process is applied to adjust the segmentation design parameters for best reduction of eddy current losses in case of surface mounted permanent magnets synchronous machine.

Findings

In case of the skin effect operating, both full and partial magnet segmentations can lead to eddy current losses increases. Such deviations of magnet segmentation techniques can be avoided by an appropriate choice of their design parameters.

Originality/value

Few works are dedicated to investigate partial magnet segmentation for eddy current losses reduction. This paper studied the effectiveness and behaviour of partial segmentation for different frequency ranges. To avoid eventual anomalies related to the skin effect an optimization process based on the association of the finite elements analysis to genetic algorithm method is adopted.

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COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 February 1974

B.W. Rooks, K.O. Okpere and R.H.M. Cheng

The use of industrial robots in the advanced countries of the world is growing. Whilst generally the concept of a robot is taken as a highly versatile human‐like device the term…

36

Abstract

The use of industrial robots in the advanced countries of the world is growing. Whilst generally the concept of a robot is taken as a highly versatile human‐like device the term also extends to include much simpler devices of the pick‐and‐place type with a fixed sequence of events and these form by far the largest proportion of the world's robot population. Whilst they lack versatility in themselves they often form part of a much more complex automatic system in which some degree of flexibility is required. In addition they must operate at their optimum rate whilst being fail‐safe in operation. The design of a suitable control system to meet such demands particularly when a number of such devices and the primary process machinery have to be interlinked can be solved with the aid of sequential switching theory.

Details

Industrial Robot: An International Journal, vol. 1 no. 2
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 14 August 2007

Damijan Miljavec and Bogomir Zidarič

This study aims to calculate eddy current losses in permanent magnets of BLDC machine in the generator mode of operation with no‐load.

986

Abstract

Purpose

This study aims to calculate eddy current losses in permanent magnets of BLDC machine in the generator mode of operation with no‐load.

Design/methodology/approach

Stator slot openings and special design of the stator poles cause changes in the magnetic flux density changes in permanent magnets. The stator windings are not connected to an outer source and no currents flow in them. The induced eddy currents in permanent magnets are dependent solely on the stator geometry. Analytical approach to calculate the eddy current density distribution in permanent magnets is based on known distribution of magnetic flux density in the air‐gap of BLDC. The magnetic flux density distribution is obtained from magneto‐static finite element model of BLDC. For verification of analytical approach the eddy current density distribution in permanent magnets is also calculated by magneto‐transient finite element model of BLDC.

Findings

The eddy current losses in PM obtained with the FEM indicate additional heating of the BLDC machine at high rotational speeds even when it operates at no load. When some special stator designs (the side of the air gap) are needed, the losses in PMs and their heating increase.

Research limitations/implications

To get more precise results, the proposed analytical method for eddy current losses calculation in PM should be further analyzed. More geometric parameters of the BLDC design should be introduced to analytical formulations, especially those which affect variations in reluctance.

Practical implications

When some special stator designs (the side of the air gap) are needed, the losses in PMs should be observed. This is particularly recommended at higher rotation velocities. Any kind of magnetic flux density change induces eddy currents and together with them also power losses. These losses give rise to additional heating of PM. With this, the temperature‐dependent working characteristic of PM (second quadrant of the B‐H curve) moves toward the coordinate origin point. The overall machine performance is reduced. The presented work gives the view about happenings in permanent magnets regarding induced eddy current losses. It is a useful tool for fast estimation and reduction of eddy current losses in PM due to stator geometry.

Originality/value

The value of the paper is the closed view about happenings in permanent magnets regarding induced eddy currents and the calculation of eddy current losses in rotor permanent magnets of BLDC due to stator design. The originality is in the analytical approach to calculate the eddy current losses based only on known magneto‐static flux density distribution in air‐gap of BLDC.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 4
Type: Research Article
ISSN: 0332-1649

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