bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction of force exciting influences to decrease radiation of acoustic noise in synchronous machines
Authors: Schulte Stephan , Hameyer Kay 
Published: August 2007

PurposeThe paper aims to provide an approach to actively decrease the radiation of acoustic noise in synchronous machines.Design/methodology/approachSplitting regular three‐phase windings of synchronous machines into two independent three‐phase systems allows for an active influence of the current waveform if both winding systems are mutually displaced against each other. The harmonics content of each phase‐current varies due to the mutual inductive coupling with participating currents of both systems. Therefore, the ensuing force‐density distribution on the stator teeth varies accordingly. Resulting structure dynamics and furthermore the radiation of relevant harmonics of the acoustic noise are based on the mechanical excitation of considered force‐density distributions.FindingsConfigurations of mutual displacement of phase windings of both winding systems with significant decrease of mechanical deformation and emitted acoustic noise are found. Simulation methods to entirely describe and prove the behavior described are developed.Research limitations/implicationsThe proposed approach is developed for a particular synchronous machine. Other machine types are conceivable for analysis in the same manner. Tools need to be adapted. Universal and reliable statements regarding acoustic behavior depend on the mechanical restraint of the machine and may therefore vary.Practical implicationsActive force‐density distribution is used for the noise reduction of alternators in vehicle applications. Additionally, wind‐power generators are considered for the application of split stator winding systems to actively counteract inhomogeneous force distributions on the rotor, evoked by stalling of the propeller blades during pole passing.Originality/valueActive force‐density modification by stator winding modifications allows for the decrease of noise radiation of electrical machines with rotating‐field windings. Innovative simulation methods developed may now replace prototyping partially.
Analysis of a rotational single sheet tester using 3D finite element model taking into account hysteresis effect
Authors: Leite Jean V. , Benabou Abdelkader , da Silva P.A. , Sadowski N. , Henneron Thomas , Clénet Stéphane , Kuo‐Peng P. , Piriou Francis , Batistela N.J. 
Published: August 2007

PurposeThe magnetic field strength measurement in a rotational single sheet tester (RSST) is quite difficult to achieve. In fact, flux leakage perturbs the field sensors as well as the homogeneity in the sample area. This paper seeks to present a 3D finite element (FE) model of an RSST taking into account a vector hysteresis model. The use of such model allows analyzing with accuracy the magnetic behavior of the system.Design/methodology/approachA vector hysteresis model, which is based on a general vectorization of the scalar Jiles‐Atherton model, is incorporated in a 3D FE code, with vector potential formulation.FindingsThe vector hysteresis model is validated by comparison with rotational experimental results. A good agreement is observed between calculations and measurements.Originality/valueThis paper shows that a classical scalar hysteresis model can be extended to take into account the magnetic vector behaviour and can be included in a 3D FE code. The methodology for the hysteresis including in the FE formulation is shown. This is useful for the design and analysis of an RSST prototype, improving the measurement techniques.
Comparison of different iron core models of three‐phase core‐type transformers
Authors: Dolinar Matjaž , Dolinar Drago , Štumberger Gorazd , Polajžer Boštjan 
Published: August 2007

PurposeThe majority of three‐phase dynamic transformer models used in commercially available electric power system transient simulation programs offer only saturated three‐phase transformer models built from three single‐phase transformer models. This paper sets out to deal with the modelling and transient analysis of a saturated three‐limb core‐type transformer.Design/methodology/approachThree iron core models I‐III are given by the current‐dependent characteristics of flux linkages. In the first model, these characteristics are given by a set of piecewise linear functions, which include saturation. In the second model, the piecewise linear functions are replaced by the measured nonlinear characteristic. The more complex third model is given by a set of measured flux linkage characteristics.FindingsThe behaviour of transformers used in electric power applications depends considerably on the properties of magnetically nonlinear iron core. The best agreement between the calculated and measured results is obtained by use of the most complex iron core model III, which takes into account magnetic cross‐couplings between different limbs, caused by saturation.Research limitations/implicationsMeasurement of the current‐dependent flux linkage characteristics of the 0.4 kV, 3.5 kVA laboratory transformer requires corresponding excitation of windings by three independent linear amplifiers. Current‐dependent flux linkage characteristics of the larger power transformer can be determined either by similar measurement with linear amplifiers of an appropriate power or by extracting them from the calculated magnetic field, which is done by the finite element method.Practical implicationsA three‐phase dynamic transformer model with the obtained iron core model III is suitable for the numerical analysis of nonsymmetric transient states in power systems.Originality/valueThis paper presents a three‐phase dynamic transformer model with an original iron core model III, which accounts for magnetic cross‐couplings between different limbs, caused by saturation.
Numerical model of a thermoelastic actuator solved as a coupled contact problem
Authors: Doležel Ivo , Karban Pavel , Ulrych Bohuš , Pantelyat Mykhailo , Matyukhin Yuriy , Gontarowskiy Pavlo 
Published: August 2007

PurposeThe purpose of this paper is to investigate the parameters and operation characteristics of an actuator working on the principle of thermoelasticity whose structure was designed by the authors.Design/methodology/approachThe mathematical model of the system describes the effects of three physical fields (electromagnetic field, temperature field, and field of mechanical strains and stresses due to thermoelasticity). While the electromagnetic field was solved independently, the thermomechanical task in common with the contact problem was solved in the hard‐coupled formulation. The computations were mostly carried out by own codes.FindingsThis type of actuator is characterized by extremely high forces acting in its dilatation element.Research limitations/implicationsThe parameters of the system may still be improved using a longer field coil and dilatation element. Attention has to be paid, however to the mechanical stability of the system. Another improvement could be achieved by suitably designed cooling of the coil that would allow increasing parameters of the field current (its frequency or amplitude).Practical implicationsThe device is promising for various fixing tasks in the industrial environment.Originality/valueAlthough the methods of numerical processing of particular fields are known, the paper provides an algorithm for their simultaneous solution while respecting the temperature dependencies of the material properties and continuous change of the contact surfaces.
Dynamical analysis for flaw shape identification in non linear eddy current tests
Authors: Cacciola Matteo , Costantino Domenico , Carlo Morabito Francesco , Versaci Mario 
Published: August 2007

PurposeThe paper seeks to propose a specific approach based on Dynamic Analysis and Chaos Theory aiming to emphasize the differences into the eddy current signals obtained by related non‐destructive tests, when the inspected specimens have flaws with different shapes.Design/methodology/approachNon‐linear eddy current analysis is very useful for flaw detection in many in‐service inspections. State‐of‐the‐art technologies allow one to define position and depth of defects, but the shape identification is still an open problem. In this paper, experimental data have been subjected to a dynamical analysis in order to relate the trend of eddy current signals to the shape of analyzed defect.FindingsIn particular, a dynamical reconstruction by means of recurrence plots (RPs) has been carried out in order to detect analogies and differentiations between different eddy current signals. Moreover, cross‐correlation between RPs of a reference benchmark and testing eddy current signals has been applied in order to emphasize a different dynamical behaviour and to detect a particular flaw's shape. In this way, a real‐time algorithm for defect shape classification has been performed.Originality/valueProposed approach is very interesting, and it is an innovation in non‐destructive testing procedures. In fact, the shape identification of a flaw is still an open challenge. The proposed approach, based on dynamic analysis, gives the key to solve this particular ill‐posed problem, by introducing a relation between the eddy current measurements and the shape of defect existing in the inspected specimen. Very interesting preliminary results have been obtained.
Applications of phase‐plane analysis to thyristor modelling
Authors: Paisana Júlio , Abreu Santos H. 
Published: August 2007

PurposeThe aim of this study is to develop a thyristor model based on the general equations of the semiconductors.Design/methodology/approachWithin the theory of the systems, the paper starts with the identification of the regenerative feedback current loop present in the p‐n‐p‐n structures. By using phase‐plane analysis and bifurcation theory, it analyses the stability of the different states of the devices and, at the same time, identifies the different characteristic critical points. The analysis of the non‐homogeneous solutions which can bifurcate from the uniform carrier distributions in the thyristor bases gives a further insight about the nature of the switching process.FindingsA link between the electric bistable characteristics of thyristors and their physical and geometrical properties was found.Practical implicationsThe main implication of this work is the acquisition of a method to implement a thyristor model for circuit analysis purposes where the different model parameters can be extracted from the respective device data sheets by using analytical methods.Originality/valueThe simulation of some particular characteristics of the thyristor by numerical methods has been described in other original works of the authors for the non‐homogeneous case. Here, the search is mainly to apply some of the more important findings of the work to a first‐level lumped thyristor model to be used in circuit analysis applications.
Sensorless control of PMSM drive with state and load torque estimation
Authors: Janiszewski Dariusz , Muszyński Roman 
Published: August 2007

PurposeThe purpose of this paper is to obtain a fully sensorless permanent magnet synchronous motor (PMSM) drive control algorithm used for robot arm drive with load recognition. The paper shows how to use an extended Kalman filter (EKF) instead of sensors of the mechanical quantities as well as how to adapt the model of the PMSM to the filter procedures and aims at the real time application in the field‐oriented control (FOC) structure of the high‐dynamic drive.Design/methodology/approachThe synthesis of the control system is based on the method of the FOC, theory of the EKF and object description in the form of state equation with suitable choice of state vector. The adequate connection of these three methodologies is a core of the approach to design. First, the control algorithm was tested by means of simulation method then the real laboratory plant was built and investigated.FindingsOwing to task‐oriented formulation of the PMSM model, adequate organization of the EKF procedures and suitable choice of covariance matrices the proper control algorithm was obtained. The algorithm can be applied on DSP and gives a good result for the high dynamic drive in spite of the fact that the Kalman procedures are recognized as a time‐consumed solution of the estimation problem.Research limitations/implicationsThe proposed algorithm can be used also in the case of another type of drive, for instance induction motor drive, although the model of the motor has a different formula. A disadvantage of the method is lack of the general rules for choosing the elements of the covariance matrices.Practical implicationsThe presented algorithm is written in open‐programming language. Obtained results may be important for synthesis of robot arm drive, where the information about load forces is needed.Originality/valueThe paper presents an original sensorless vector control of PMSM with load recognition based on EKF. The originality elements are the choice of the covariance matrix elements and the real‐time realisation of the algorithm on the DSP.
Improved direct torque and flux control of induction motor drive
Authors: Sikorski Andrzej , Korzeniewski Marek 
Published: August 2007

PurposeThe aim of the paper is to conduct an analytical study of a new method of induction motor torque and flux direct control with nonlinear controllers.Design/methodology/approachThe method is based on the inverter state predictive determination in order to minimize the torque and flux errors.FindingsThe proposed method allows one to eliminate known DTC disadvantages, i.e. the hexagonal flux shape and nonsinusoidal current at a low motor speed, and also secures a decrease of torque and flux pulsation.Practical implicationsThis new method enables a more precise reproduction of the motor torque and flux command signals, working with the same sampling frequency of the control processor as in the case of the standard DTC method. The decreased torque pulsations cause a decrease of the motor speed pulsation.Originality/valueAn innovative optimal control method is presented. The correctness of the initial assumptions as well as the expected final results have been verified in practice.
Customer service in the Baltic region: an exploratory analysis
Authors: Johnson Carol J. , Grimm Curtis M. , Blome Valdis 
Published: August 2007

PurposeThe goal of this research is to identify which service activities contribute most to customer satisfaction in the technical wholesale industry in the Baltic States.Design/methodology/approachIn order to obtain an understanding of customer service in the countries of Latvia, Lithuania, and Estonia, a mail survey was done to investigate customer service obtained by 184 customers of a large technical wholesale firm doing business in the Baltic States.FindingsThe overall results of this research indicate that in the technical wholesale industry of the Baltic countries customer service contributes to customer satisfaction. Of the six dimensions tested, all of the relationships were in the expected direction. Only one did not contribute significantly to customer satisfaction. In order of importance to customer satisfaction the dimensions are: process quality, product quality, delivery quality, communication, availability and product support.Research limitations/implicationsTo obtain more generalizable results, future research areas should include investigating the model using other firms within the same industry, and testing the model in additional industries within the Baltics. Additional research may include testing the model in other countries in Northern and Central Europe such as the well‐developed Scandinavian countries, and the lesser developed countries of Slovakia, the Czech Republic, and Poland as well as other areas of the world. This model was tested using data from the technical wholesale industry and additional research may focus on testing the model across different industries in different countries as well.Practical implicationsThe results are of relevance to practitioners, in particular for firms expanding to the Baltic area. In addition, anecdotal evidence suggests that the level and number of customer service activities provided by technical services firms in the Baltic area of Northern Europe are based solely on management judgment or practices borrowed from competitors without considering the impact of service provision on customer satisfaction. Instead practitioners should consider the process used to deliver services and products.Originality/valueThis is the first empirical work measuring the impact of customer service dimensions on customer satisfaction using data from the Baltic States.
Building supply chain collaboration: a typology of collaborative approaches
Authors: Whipple Judith M. , Russell Dawn 
Published: August 2007

PurposeThis research aims to examine the characteristics, requirements, benefits, and barriers to various collaborative relationships and proposes a typology of collaborative approaches.Design/methodology/approachThe research discusses insights and observations from exploratory interviews with 21 managers from ten different manufacturers and retailers.FindingsA typology of three types of collaborative approaches (collaborative transaction management; collaborative event management; and collaborative process management) is proposed. The three collaborative approaches are compared and contrasted. Benefits and limitations associated with each type of collaboration are discussed.Practical implicationsManagers can use the typology to assess current collaborations and seek ways to improve current collaborative efforts. Managers can also use the typology to develop collaborative strategies across a broad spectrum of relationships in order to determine which type of collaboration best fits each individual business relationship.Originality/valueThis research extends previous relationship typologies by focusing specifically on collaborative relationships. The research examines various types of collaborative relationships in order to categorize collaborative approaches in a manner useful to academicians and practitioners.
Managing complexity in agile global fashion industry supply chains
Authors: Masson Ron , Iosif Laura , MacKerron Grant , Fernie June 
Published: August 2007

PurposeThe purpose of this paper is to examine the agile supply chain management practices adopted by UK clothing retailers in order to effectively manage the supply of innovative, high‐margin, high‐fashion content product offerings in a complex global environment.Design/methodology/approachA case study approach was adopted examining the whole of the global retail fashion supply chain, from typical UK‐based retailers through to their main production and logistics suppliers based in two low‐cost locations, China and Romania. The cases of the UK retailers were followed by a study tour of China and Romania, where ten cases of fabric and finishing manufacturers, intermediaries and logistic providers were carried out.FindingsMany aspects of accepted risk management and agile practice, such as market sensitivity, postponement activities and collaborative information‐sharing partnerships were apparent in the early product definition and the later product delivery stages of the supply chain. However, the responsibility for supply, including the key aspect of managing the complex supply network, was almost exclusively left to intermediaries located in low‐cost countries. These intermediaries in the main could best achieve agile supply from a significantly underutilized low‐cost country supply network through a traditional adversarial price and lead time auction sourcing process.Research limitations/implicationsWhile the cases considered reflected what seemed to be a typical and widely adopted approach to managing such a supply chain, this may not, of course, be the only approach taken by organisations in the clothing industry.Originality/valueBy examining a whole supply chain associated with agile supply in an important sector, the paper identifies the relative importance of some existing practices and brings into sharper focus those most relevant to this type of supply. The paper also identifies key elements of contemporary supply chain management practice, namely the growing use of global supply for innovative products and the essential and valuable role played by intermediaries in such supply chains.
An analysis of mobile credit card usage intentions
Authors: Amin Hanudin 
Published: August 2007

PurposeMany banks consider mobile‐based technologies have improved the banking services through introduction of new banking facilities. One of the latest facilities developed in this area is the “mobile credit card.” The purpose of this study is to examine the factors that determine intention to use mobile credit card among Malaysia bank customers, as their new way in conducting payment transactions.Design/methodology/approachThe technology acceptance model (TAM) was used as the base model in order to develop the modified version of TAM to better reflect mobile credit card. In the modified model, perceived credibility and the amount of information on mobile credit card were added, in addition to perceived usefulness and perceived ease of use.FindingsResults suggest that perceived usefulness, perceived ease of use, perceived credibility and the amount of information on mobile credit cards are important determinants to predict Malaysia bank customers' intentions to use mobile credit card. Needless to say, the paper is exploratory in nature.Research limitations/implicationsThis study suffers from two limitations. The discussion of these limitations is provided in the last part of this paper.Practical implicationsUseful to Islamic banking institutions planning further mobile credit card services for their customers.Originality/valueExtends the understanding of TAM to newly emerging context of mobile credit.
An empirical study of ERP success evaluations by business and IT managers
Authors: Ifinedo Princely 
Published: August 2007

PurposeThe purpose of this study is to examine how two organizational members, i.e. business and information technology (IT) managers evaluate the success measures of acquired enterprise resource planning (ERP) systems.Design/methodology/approachSurveys were conducted in two Northern European countries – Finland and Estonia.FindingsPrior studies suggest that business and IT managers evaluate organizational‐IT issues, including ERP success evaluations differently. However, this study's data analysis showed that no significant statistical differences exist between the two groups on the six dimensions of ERP success operationalized with the exception of one, i.e. vendor/consultant quality. In brief, both groups seem to have a similar view of ERP success in their respective organizations.Originality/valueDiscusses the implications for practitioners and researchers.
The work values of Chinese project managers
Authors: Song Shi‐Rui , Gale Andrew 
Published: August 2007

PurposeThe purpose of the research is to investigate project managers' work values and the relationship between the work values of project managers and their competence.Design/methodology/approachThis research project is based on a category of work‐related values generated from the literature. The authors conducted a web‐based questionnaire survey on Chinese project managers in The People's Republic of China.FindingsFrom this research it was found that both experienced and novice Chinese project managers share most work values. However, novice and experienced project managers' differ on work values regarding personal career success and project success. Project management knowledge, project manager's personal attitudes and project manager's work values are all important with respect to project management practice.Practical implicationsThe authors recommend that work values are an important dimension in relation to project managers' competence. The understanding of project managers' work values has potential application in the context to competence‐based management development.Originality/valueThis paper furthers understanding on project manager's competence.