Investigation on the shaft voltage generation of large synchronous turboalternators

2020 ◽  
Vol 39 (5) ◽  
pp. 1145-1156
Author(s):  
Kevin Darques ◽  
Abdelmounaïm Tounzi ◽  
Yvonnick Le-menach ◽  
Karim Beddek
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Short Circuit ◽  
Element Model ◽  
Stator Winding ◽  
Content Type ◽  
Voltage Generation ◽  
The Impact ◽  
Investigation Process ◽  
Circulating Currents

Purpose This paper aims to go deeper on the analysis of the shaft voltage of large turbogenerators. The main interest of this study is the investigation process developed. Design/methodology/approach The analysis of the shaft voltage because of several defects is based on a two-dimensional (2D) finite element modeling. This 2D finite element model is used to determine the shaft voltage because of eccentricities or rotor short-circuit. Findings Dynamic eccentricities and rotor short circuit do not have an inherent impact on the shaft voltage. Circulating currents in the stator winding because of defects impact the shaft voltage. Originality/value The original value of this paper is the investigation process developed. This study proposes to quantify the impact of a smooth stator and then to explore the contribution of the real stator winding on the shaft voltage.

Detection and Analysis of Stator Winding Inter-Turn Short Circuit Fault in Permanent Magnet Linear Synchronous Motor

2012 ◽  
Vol 529 ◽  
pp. 322-326
Author(s):  
Cai Xia Gao ◽  
Chen Hao ◽  
Yue Bing Zhao
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Short Circuit ◽  
Element Model ◽  
Synchronous Motor ◽  
Stator Winding ◽  
Element Analysis ◽  
Harmonic Content ◽  
Linear Synchronous Motor ◽  
Short Circuit Fault

A two-dimensional finite element model of PMLSM is build based on the finite element analysis software Magnet to research the diagnosis of stator winding inter-turn short circuit fault in PMLSM. The velocity, thrust, the stator current performance curve are obtained by simulation using Magnet when PMLSM is normal and under different extent inter-turn short circuit fault, the harmonic content of speed and thrust are analyzed using Matlab / Simulink , the conclusion that the thrust of the harmonic content is used as the Permanent Magnet Linear Synchronous Motor (PMLSM) stator inter-turn short circuit fault feature is proposed , which provided a basis for detection of stator winding inter-turn short circuit fault in PMLSM.

Detection of time-varying inter-turn short-circuit in a squirrel cage induction machine by means of generalized regression neural network

2017 ◽  
Vol 36 (1) ◽  
pp. 289-297 ◽  
Author(s):  
Wojciech Pietrowski
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Multilayer Perceptron ◽  
Short Circuit ◽  
Electrical Machines ◽  
General Regression Neural Network ◽  
Stator Winding ◽  
Time Varying ◽  
Content Type ◽  
Phase Current

Purpose Diagnostics of electrical machines is a very important task. The purpose of this paper is the presentation of coupling three numerical techniques, a finite element analysis, a signal analysis and an artificial neural network, in diagnostics of electrical machines. The study focused on detection of a time-varying inter-turn short-circuit in a stator winding of induction motor. Design/methodology/approach A finite element method is widely used for the calculation of phase current waveforms of induction machines. In the presented results, a time-varying inter-turn short-circuit of stator winding has been taken into account in the elaborated field-circuit model of machine. One of the time-varying short-circuit symptoms is a time-varying resistance of shorted circuit and consequently the waveform of phase current. A general regression neural network (GRNN) has been elaborated to find a number of shorted turns on the basis of fast Fourier transform (FFT) of phase current. The input vector of GRNN has been built on the basis of the FFT of phase current waveform. The output vector has been built upon the values of resistance of shorted circuit for respective values of shorted turns. The performance of the GRNN was compared with that of the multilayer perceptron neural network. Findings The GRNN can contribute to better detection of the time-varying inter-turn short-circuit in stator winding than the multilayer perceptron neural network. Originality/value It is argued that the proposed method based on FFT of phase current and GRNN is capable to detect a time-varying inter-turn short-circuit. The GRNN can be used in a health monitoring system as an inference module.

Study of staff who have been alleged perpetrators in adult protection cases

2014 ◽  
Vol 16 (2) ◽  
pp. 120-128
Author(s):  
Mel Walford ◽  
Andy Kaye ◽  
Mick Collins
Keyword(s):  
Design Methodology ◽  
Structured Interviews ◽  
Content Type ◽  
Protection Policy ◽  
The Impact ◽  
Vulnerable Adults ◽  
Investigation Process ◽  
Voluntary Basis ◽  
Practical Implications ◽  
Adult Protection

Purpose – The protection of vulnerable adults from abuse is paramount for those working in adult protection. However, staff supporting vulnerable adults who are alleged to have abused them can feel very vulnerable and their needs must also be taken into account. The purpose of this paper is to consider the impact of adult protection investigations from the experiences of people who have been identified as alleged perpetrators in adult protection cases in order to identify improvements in practice. Design/methodology/approach – This limited study used qualitative semi-structured interviews to collect data that reflected views of the issues and experiences of participants. Findings – This study shows that expectations set out in the Wales Interim Policy and Procedures document under “support for alleged perpetrators” do not match with the experience of those who took part in this study. The experience of some alleged perpetrators is that the investigation process can be protracted, they may be left isolated with little or no information and feel very vulnerable. Research limitations/implications – A limitation of this study was the small number of participants who were interviewed and the selection and bias. Participation was on a voluntary basis and the participants were self-selecting. The participants were all paid staff. Vulnerable adults who had been identified as alleged abusers were excluded from the study on the premise that their experiences were likely to be quite different. Practical implications – It is vital that alleged perpetrators are not themselves abused by the process. The findings from this study should be used to develop recommendations to improve practice. Originality/value – The effects on staff who have been investigated as alleged abusers under adult protection policy and procedures has been under-researched. This study will make a contribution to addressing this.

Investigating the attack angle of squeegees with different geometries

2018 ◽  
Vol 30 (2) ◽  
pp. 112-117 ◽  
Author(s):  
Oliver Krammer ◽  
László Jakab ◽  
Balazs Illes ◽  
David Bušek ◽  
Ivana Beshajová Pelikánová
Keyword(s):  
Finite Element ◽  
Numerical Modelling ◽  
Finite Element Modelling ◽  
Design Methodology ◽  
Element Model ◽  
Attack Angle ◽  
Initial Angle ◽  
Stencil Printing ◽  
Content Type ◽  
Steel Aisi

Purpose The attack angle of stencil printing squeegees with different geometries was analysed using finite element modelling. Design/methodology/approach A finite element model (FEM) was developed to determine the attack angle during the stencil printing. The material properties of the squeegee were included in the model according to the parameters of steel AISI 4340, and the model was validated by experimental measurements. Two geometric parameters were investigated; two different unloaded angles (45° and 60°) and four overhang sizes of the squeegee (6, 15, 20 and 25 mm). Findings It was found that the deflection of the blade is nearly homogenous along the length of the squeegee. This implies that the attack angle does not change significantly along the squeegee length. The results showed significant differences between the initial and the attack angle. For example, the angle of the squeegee with 15 mm overhang size and with 60° initial angle decreased by more than 5° for a specific squeegee force of 0.3 N/mm; resulting in an attack angle of 53.4°. Originality/value The attack angle during the printing is considerably lower than the initial angle as a result of the printing force. The papers, which were dealing with the numerical modelling of the stencil printing presumed that the squeegees were having their initial angle. This could have led to invalid numerical results. Therefore, we decided to investigate the attack angle during stencil printing for squeegees with different initial geometries to enhance the numerical modelling of stencil printing.

Crash simulation of fuselage section in the rebound process and the secondary-impact process

2020 ◽  
Vol 92 (8) ◽  
pp. 1245-1256
Author(s):  
Zibo Jin ◽  
Daochun Li ◽  
Jinwu Xiang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Structural Vibration ◽  
Dynamic Simulations ◽  
Content Type ◽  
Secondary Impact ◽  
Impact Process ◽  
Impact Surface ◽  
The Impact

Purpose This paper aims to investigate the rebound process and the secondary-impact process of the fuselage section that occurs in the actual crash events. Design/methodology/approach A full-scale three-dimensional finite element model of the fuselage section was developed to carry out the dynamic simulations. The rebound process was simulated by removing the impact surface at a certain point, while the secondary-impact process was simulated by striking the impact surface against the fuselage bottom after the first impact. Findings For the rebound process, the fuselage structure restores deformation due to the springback of the fuselage bottom, and it results in structural vibration of the fuselage section. For the secondary-impact process, the fuselage deformation is similar with that of the single impact process, indicating that the intermittent impact loading has little influence on the overall deformation of the fuselage section. The strut failure is the determining factor to the acceleration responses for both the rebound process and the secondary-impact process. Practical implications The rebound process and the secondary-impact process, which is difficult to study by experiments, was investigated by finite element simulations. The structure deformations and acceleration responses were obtained, and they can provide guidance for the crashworthy design of fuselage structures. Originality/value This research first investigated the rebound process and the secondary-impact process of the fuselage section. The absence of the ground load and the secondary-impact was simulated by controlling the impact surface, which is a new simulating method and has not been used in the previous research.

Agricultural aircraft wing slat tolerance for bird strike

2017 ◽  
Vol 89 (4) ◽  
pp. 590-598 ◽  
Author(s):  
Adam Deskiewicz ◽  
Rafał Perz
Keyword(s):  
Finite Element ◽  
Impact Velocity ◽  
Structural Response ◽  
Element Model ◽  
Bird Strike ◽  
Element Analysis ◽  
Content Type ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
The Impact

Purpose The aim of this study is to assess and describe possible consequences of a bird strike on a Polish-designed PZL-106 Kruk agricultural aircraft. Due to its susceptibility to such events, a wing slat has been chosen for analysis. Design/methodology/approach Smooth particle hydrodynamics (SPH) formulation has been used for generation of the bird finite element model. The simulations were performed by the LS-Dyna explicit finite element analysis software. Several test cases have been analysed with differing parameters such as impact velocity, initial velocity vector direction, place of impact and bird mass. Findings Results of this study reveal that the structure remains safe after an impact at the velocity of 25 m/s. The influence of bird mass on slat damage is clearly observable when the impact velocity rises to 60 m/s. Another important finding was that in each case where the part did not withstand the applied load, it was the lug where first failure occurred. Some of the analysed cases indicated the possibility a consequent wing box damage. Practical implications This finding provides the manufacturer an important insight into the behaviour of the slat and suggests that more detailed analysis of the current lug design might improve the safety of the structure. Originality/value Even though similar analyses have been performed, they tended to focus on large transport aircraft components. This investigation will enhance our understanding of structural response of small, low-speed aircraft to a bird impact, which is a realistic scenario for the chosen case of an agricultural plane.

Thermomechanical fatigue lifetime evaluation of solder joints in power semiconductors using a novel energy based modeling

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Buen Zhang ◽  
Noor H. Jabarullah ◽  
Ayad F. Alkaim ◽  
Svetlana Danshina ◽  
Irina V. Krasnopevtseva ◽  
...  
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Model Simulation ◽  
Experimental Tests ◽  
Element Model ◽  
Lifetime Estimation ◽  
Fatigue Lifetime ◽  
Content Type ◽  
Power Semiconductors ◽  
Finite Element Model Simulation

Purpose This paper aims to establish a more accurate model for lifetime estimation. Design/methodology/approach Finite element model simulation and experimental tests are used to enhance the lifetime prediction model of the solder joint. Findings A more precise model was found. Originality/value It is confirmed that the paper is original.

The effects of materialism on consumer evaluation of sustainable synthetic (lab-grown) products

2020 ◽  
Vol 37 (5) ◽  
pp. 579-590
Author(s):  
Jessica Keech ◽  
Maureen Morrin ◽  
Jeffrey Steven Podoshen
Keyword(s):  
Design Methodology ◽  
Socially Responsible ◽  
Content Type ◽  
Consumer Evaluation ◽  
Positioning Strategy ◽  
Consumer Markets ◽  
The Future ◽  
Promotion Strategies ◽  
Alternative Sources ◽  
The Impact

Purpose The increasing desire of consumers for socially responsible luxury products combined with fluctuating supplies in consumer markets are leading various industries to seek alternative sources to be able to meet the needs of its customers. One possible solution that may meet the demands of the future is lab-grown products. Because these products confer multiple benefits, this study aims to investigate the most effective ways to appeal to consumers by aligning the benefits of the products with their values as marketers seek to find effective promotion for these items. Design/methodology/approach We examine the effectiveness of an ethical positioning strategy for two types of luxury lab-grown (synthetic) products among high versus low materialism consumers in three experiments. Findings Findings suggest that a positioning strategy stressing product ethicality is more effective for low materialism consumers, whereas the strategy is less effective, and may even backfire, for high materialism consumers. The impact on social status consumers perceive from a lab-grown product explains why this effect occurs among low materialism consumers. Therefore, marketers should take caution and use specific appeals for different segments based on values such as consumers’ materialism levels. Originality/value If lab-grown products represent the wave of the future, it is important to understand how consumers will respond to this emerging technology and how promotion strategies may enhance their evaluation.

Embedding employability within higher education for the profession of policing

2019 ◽  
Vol 9 (3) ◽  
pp. 319-328
Author(s):  
Ian Pepper ◽  
Ruth McGrath
Keyword(s):  
Higher Education ◽  
Design Methodology ◽  
Research Study ◽  
Longitudinal Research ◽  
Evidence Base ◽  
Content Type ◽  
Educational Provision ◽  
Professional Body ◽  
The Impact ◽  
Practical Implications

Purpose The purpose of this paper is to evaluate the impact of an employability module, the College of Policing Certificate in Knowledge of Policing (CKP), on students’ career aspirations, their confidence and wish to join the police along with the appropriateness of the module. This will inform the implementation of employability as part of the College of Policing-managed Police Education Qualifications Framework (PEQF). Design/methodology/approach A three-year longitudinal research study used mixed methods across four points in time to evaluate the impact on students studying the employability module. Findings The research suggests that the employability-focussed CKP was useful as an introduction to policing, it developed interest in the police and enhanced the confidence of learners applying to join. Lessons learnt from the CKP should be considered during the implementation of the PEQF. Research limitations/implications The ability to generalise findings across different groups is limited as other influences may impact on a learner’s confidence and employability. However, the implications for the PEQF curriculum are worthy of consideration. Practical implications As the police service moves towards standardised higher educational provision and evolution of policing as a profession, lessons can be learnt from the CKP with regards to the future employability of graduates. Originality/value Enhancing the employability evidence base, focussing on policing, the research identified aspects which may impact on graduates completing a degree mapped to the PEQF. The research is therefore of value to higher education and the professional body for policing.

Gated communities in Ankara: are they a tool of social segregation?

2017 ◽  
Vol 10 (5) ◽  
pp. 687-702
Author(s):  
Leyla Alkan-Gökler
Keyword(s):  
Socioeconomic Status ◽  
Design Methodology ◽  
Gated Communities ◽  
Content Type ◽  
Positive View ◽  
Social Segregation ◽  
Show Evidence ◽  
Local Residents ◽  
Almost All ◽  
The Impact

Purpose Gated communities, surrounded by walls or fences, have emerged as a new trend in almost all cities in Turkey, and are homogenous in terms of the socioeconomic status of their occupants. Within these communities, several facilities and services are provided that are available only to the residents, with restrictions on access from the outside, and this has led to criticisms of social segregation. This study aims to analyze the impact of these communities on social segregation in Ankara, through two different surveys aimed at investigating the attitudes of the residents of local neighborhoods and gated communities toward each other. Design/methodology/approach This paper analyzes how the process of gating has affected social segregation in Ankara through two separate surveys: with the residents of gated communities and with the residents of local neighborhoods around these gated communities. Findings The study revealed that the residents of gated communities tended to have a positive view of the residents of local neighborhoods. In contrast, the responses of the local residents show evidence of feelings of social segregation, based on the presence of the high walls, fences and guards that are in place to keep them out of the community. Originality/value This study shows that, although segregation from the rest of the society is not the main reason for gating, the emergence of gated communities in Ankara leads inevitably to a socially and economically segregated city in which local residents feel excluded from these gated areas.

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