Detection of Rotor Bar Faults in Field Oriented Controlled Induction Motors

Mehmet Akar 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6

In this study, a new method has been presented for the detection of broken rotor bar (BRB) faults in inverter driven induction motors controlled via Field Oriented Control (FOC). To this end, a FOC controlled induction motor with a BRB fault was modeled using the Matlab/Simulink program. Experiments were carried out using the prepared simulation model at various loads and operating speeds. The motor current and speeds were monitored for healthy, 1, 2 and 3 BRB faults. The Resampling Based Order Tracking Analysis (RB-OTA) method was applied to the monitored signals. The obtained results were compared by using the classic Fast Fourier Transform (FFT) method. When the obtained results were analyzed via the FFT method no information regarding any faults was determined in the run up or run down regions of the motor and the presented method gave very good results. The reliability of the proposed method was validated with experimental results. The main innovative part of this study is that the RB-OTA method was implemented on the induction motor current signal for detecting BRB faults.

Detection of Rotor Bar Faults in Field Oriented Controlled Induction Motors

Akar, Mehmet The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6

In this study, a new method has been presented for the detection of broken rotor bar (BRB) faults in inverter driven induction motors controlled via Field Oriented Control (FOC). To this end, a FOC controlled induction motor with a BRB fault was modeled using the Matlab/Simulink program. Experiments were carried out using the prepared simulation model at various loads and operating speeds. The motor current and speeds were monitored for healthy, 1, 2 and 3 BRB faults. The Resampling Based Order Tracking Analysis (RB-OTA) method was applied to the monitored signals. The obtained results were compared by using the classic Fast Fourier Transform (FFT) method. When the obtained results were analyzed via the FFT method no information regarding any faults was determined in the run up or run down regions of the motor and the presented method gave very good results. The reliability of the proposed method was validated with experimental results. The main innovative part of this study is that the RB-OTA method was implemented on the induction motor current signal for detecting BRB faults.

Sustainable Growth of Turkish Tourism Aector and Slternative Methods in Finance

Mehmet YAZICI,Ayşe YİĞİT ŞAKAR 세계문화관광학회 2011 Conference Proceedings Vol.12 No.-

According to the World Tourism Organization-Tourism Highlights 2011 survey in 2010 World's top destinations Turkey has the seventh most tourists with 27 million visitors and the tenth highest revenue from tourism earning $20 8 billion. In first quarter of 2011 the negative effects of economic and political developments in Eastern Europe North Africa and the Middle East caused early booking cancellations and destination changes in favor of Turkey. If we compare the first quarter of 2011 with the previous year there was an increase of international tourists to Turkey of 17% and an increase in tourism revenues of 28.5% in dollars. Turning this positive trend into a sustainable growth in tourism sector and achieving the goal of 63 million tourists and 86 billion dollars in year 2023 as projected by the Ministry of Culture and Tourism depends on improving alternative methods in sectoral finance and support of medium and long-term investments by the government. The subject of this study is to propose alternative methods for tourism finance in Turkey. The first part of this study discusses the current loan structure of tourism sector; the second part discusses existing tax and incentive schemes; the third part analyzes of the alternative finance methods which are used around in the world; and the last part discusses solution proposals for sustainable growth.

Sustainable Growth of Turkish Tourism Sector and Alternative Methods in Finance

Mehmet YAZICI,Ayş,e Yİ,Ğ,İ,T Ş,AKAR 한국문화관광학회 2011 문화관광연구 Vol.13 No.2

According to the World Tourism Organization-Tourism Highlights 2011 survey in 2010 World’s top destinations, Turkey has the seventh most tourists, with 27 million visitors and the tenth highest revenue from tourism, earning $20,8 billion. In first quarter of 2011 the negative effects of economic and political developments in Eastern Europe, North Africa and the Middle East caused early booking cancellations and destination changes in favor of Turkey. If we compare the first quarter of 2011 with the previous year, there was an increase of international tourists to Turkey of 17%, and an increase in tourism revenues of 28.5% in dollars. Turning this positive trend into a sustainable growth in tourism sector and achieving the goal of 63 million tourists and 86 billion dollars in year 2023 as projected by the Ministry of Culture and Tourism depends on improving alternative methods in sectoral finance and support of medium and long-term investments by the government. The subject of this study is to propose alternative methods for tourism finance in Turkey. The first part of this study discusses the current loan structure of tourism sector; the second part discusses existing tax and incentive schemes; the third part analyzes of the alternative finance methods which are used around in the world; and the last part discusses solution proposals for sustainable growth.

Nuclear energy consumption, nuclear fusion reactors and environmental quality: The case of G7 countries

Nigar Demircan Çakar,Seyfettin Erdogan,Ayfer Gedikli,Mehmet Akif Oncü 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.4

Global climate change brings environmental quality sensitivity, especially in developed countries. Developed countries use non-renewable energy sources intensively both in their own countries and inother countries, they make productions that cause an enormous rate of increase in CO2 emissions andunsustainable environmental costs. This has increased the interest in environmentally friendly alternative energy sources. The aim of this study is to investigate the impact of nuclear energy consumptionand technological innovation on environmental quality in G7 countries using annual data over the period1970e2015. The Panel Threshold Regression Model was used for the analysis. Empirical findings haveindicated that the relationship between nuclear energy consumption and carbon emissions differs according to innovation for nuclear power plants. It was also concluded that nuclear energy consumptionreduces carbon emissions more after a certain level of innovation. This result shows that the increase ininnovative technologies for nuclear power plants not only increases energy efficiency but also contributes positively to environmental quality

Design of Self-Starting Hybrid Axial Flux Permanent Magnet Synchronous Motor Connected Directly to Line

Eker, Mustafa,Akar, Mehmet,Emeksiz, Cem,Dogan, Zafer,Fenercioglu, Ahmet The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

In view of the current state of the reserves of electric energy generated resources and the share of electric motors in electricity consumption, many researches and studies related to efficiency in electric motors are being made. The presented work is related to the Axial Flux Permanent Magnet Synchronous Motor (AF-PMSM), which has recently undergone significant work based on the development of magnet and motor technology. In this study, a novel AF-PMSM was designed analytically through Finite Element Method (FEM) which can be started by connecting to a line such as an asynchronous motor in a transient state and can operate with high efficiency and power factor after synchronization in steady state without the need for an expensive motor drive. According to the obtained FEM results, a design with an efficiency class of IE4 of 5.5 kW shaft power, a 4 poles motor was obtained. As a result, economic calculations indicate that the extra cost of the designed Line start AF-PMSM with respect to the asynchronous motor is rapidly compensated by energy saving due to a more efficient operation, especially constant speed operations. As a result of the analysis obtained, the targeted values are reached. For induction motors and radial flux permanent magnet synchronous motors, a good alternative motor that can operate with high efficiency and power factor has been obtained.

Design of Self-Starting Hybrid Axial Flux Permanent Magnet Synchronous Motor Connected Directly to Line

Mustafa Eker,Mehmet Akar,Cem Emeksiz,Zafer Dogan,Ahmet Fenercioglu 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

In view of the current state of the reserves of electric energy generated resources and the share of electric motors in electricity consumption, many researches and studies related to efficiency in electric motors are being made. The presented work is related to the Axial Flux Permanent Magnet Synchronous Motor (AF-PMSM), which has recently undergone significant work based on the development of magnet and motor technology. In this study, a novel AF-PMSM was designed analytically through Finite Element Method (FEM) which can be started by connecting to a line such as an asynchronous motor in a transient state and can operate with high efficiency and power factor after synchronization in steady state without the need for an expensive motor drive. According to the obtained FEM results, a design with an efficiency class of IE4 of 5.5 kW shaft power, a 4 poles motor was obtained. As a result, economic calculations indicate that the extra cost of the designed Line start AF-PMSM with respect to the asynchronous motor is rapidly compensated by energy saving due to a more efficient operation, especially constant speed operations. As a result of the analysis obtained, the targeted values are reached. For induction motors and radial flux permanent magnet synchronous motors, a good alternative motor that can operate with high efficiency and power factor has been obtained.

Multislice Analysis of Axial Flux Synchronous Reluctance Motor Based on 2d Finite Element Method Linear Model

Emre Gözüaçık,Mustafa Eker,Mehmet Akar 한국자기학회 2023 Journal of Magnetics Vol.28 No.2

This study proposes a solution to improve the analysis time of the Axial Flux Synchronous Reluctance Motor (AF-SynRM) using the Finite Element Method (FEM) using the Finite Element Method (FEM). While accurate results can be achieved through 2D and 3D FEM analyses in the design of electrical machines, the analysis time becomes a significant consideration. The non-axisymmetric structure of the flux path in axial flux motors poses challenges for accurate results in 2D FEM analyses. To overcome this issue, the study uses simulation studies to convert axial flux motors into 2D linear models. In this study, a slice model approach is implemented in the linear structure, and the influence of the number of slices on various motor parameters, such as torque, torque ripple, back-EMF, loss, and efficiency, is analyzed and compared with 3D FEM analyses. Experimental loss and efficiency results are also included in these analyses. This study is the first to simulate an AF-SynRM in the 2D linear model. The accuracy of the results is verified experimentally.

Primary Effusion Lymphoma: An Untrivial Differential Diagnosis for Ascites

Funda Ceran,Yusuf AydIn,Levent Özçakar,Ünsal Han,Mehmet YIldIz 연세대학교의과대학 2009 Yonsei medical journal Vol.50 No.6

A primary effusion lymphoma is a rare type of non-Hodgkin’s lymphoma where serous cavities are involved. Thatcause peritoneal, pleural and pericardial effusions without any lymphadenopathy. They affect immunosuppressive patients with human herpes virus-8 being the suspected etiological agent. The prognosis is usually poor despite treatment. Herein, the case of an immunocompetent patient with ascites and pleural effusion diagnosed as primary effusion lymphoma is presented and discuss the case in the light of the current literature. A primary effusion lymphoma is a rare type of non-Hodgkin’s lymphoma where serous cavities are involved. Thatcause peritoneal, pleural and pericardial effusions without any lymphadenopathy. They affect immunosuppressive patients with human herpes virus-8 being the suspected etiological agent. The prognosis is usually poor despite treatment. Herein, the case of an immunocompetent patient with ascites and pleural effusion diagnosed as primary effusion lymphoma is presented and discuss the case in the light of the current literature.