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Detection of Mechanical Imbalances of Induction Motors with Instantaneous Power Signature Analysis
Kucuker, Ahmet,Bayrak, Mehmet The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.5
Mechanical imbalances are common mechanical faults in induction motors. Vibration monitoring techniques have been widely used for the diagnosis of mechanical faults in induction motors, but electrical detection methods have been preferred in recent years. For many years, researchers have concentrated on the Motor Current Signature Analysis (MCSA). This paper examines the effect of mechanical imbalances to induction machine electrical parameters. Instantaneous Power Signature Analysis (IPSA) technique used to detect these faults. In the paper, a full analysis of the proposed technique is presented, and experimental results for healthy and faulty motors have been shown and discussed.
Numerical analysis of entropy generation in concentric curved annular ducts
Haydar Kucuk 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.9
The entropy generation has been numerically investigated in concentric curved annular square ducts under constant wall temperature boundary condition. The problem has been assumed to be steady, hydrodynamically and thermally fully developed and incompressible laminar flow with constant physical properties. The solutions of discretized equations for continuity, momentum and energy have been obtained by using an elliptic Fortran Program based on the SIMPLE algorithm. Solutions have been achieved for i) Dean numbers ranging from 3.6 to 207.1, ii) Annulus dimension ratios of 5.5, 3.8, 2.9 and 2.36, and iii) Prandtl number of 0.7. In this regard, local entropy generation as well as overall entropy generation in the whole flow field has been analyzed in detail. Moreover, the effects of Dean number and annulus dimension ratio on entropy generation arising from the friction and heat transfer have been investigated. Accordingly, it is concluded that the effect of volumetric entropy generation that is a result of fluid frictional irreversibility can be neglected as compared with volumetric entropy generation due to heat transfer irreversibility. As Dean number increases, the distribution of volumetric entropy generation coming out from the heat transfer irreversibility is formed by the temperature field, which is depending on the curvature.
Detection of Mechanical Imbalances of Induction Motors with Instantaneous Power Signature Analysis
Ahmet Kucuker,Mehmet Bayrak 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.5
Mechanical imbalances are common mechanical faults in induction motors. Vibration monitoring techniques have been widely used for the diagnosis of mechanical faults in induction motors, but electrical detection methods have been preferred in recent years. For many years, researchers have concentrated on the Motor Current Signature Analysis (MCSA). This paper examines the effect of mechanical imbalances to induction machine electrical parameters. Instantaneous Power Signature Analysis (IPSA) technique used to detect these faults. In the paper, a full analysis of the proposed technique is presented, and experimental results for healthy and faulty motors have been shown and discussed.
Effectiveness of Recombinant Human Growth Hormone for Pharyngocutaneous Fistula Closure
Nurten Kucuk,Murat Sari,Ahmet Midi,Ali Cemal Yumusakhuylu,Ozan Findik,Adem Binnetoglu 대한이비인후과학회 2015 Clinical and Experimental Otorhinolaryngology Vol.8 No.4
Objectives. In laryngeal cancer, which comprises 25% of head and neck cancer, chemotherapy has come into prominence with the increase in organ-protective treatments. With such treatment, salvage surgery has increased following recurrence; the incidence of pharyngocutaneous fistula has also increased in both respiratory and digestive system surgery. We investigated the effects of recombinant human growth hormone on pharyngocutaneous fistula closure in Sprague-Dawley rats, based on an increase in amino acid uptake and protein synthesis for wound healing, an increase in mitogenesis, and enhancement of collagen formation by recombinant human growth hormone. Methods. This study was experimental animal study. Forty Sprague-Dawley rats were separated into two groups, and pharyngoesophagotomy was performed. The pharyngoesophagotomy was sutured with vicryl in both groups. Rats in group 1 (control group) received no treatment, while those in group 2 were administered a subcutaneous injection of recombinant human growth hormone daily. On day 14, the pharynx, larynx, and upper oesophagus were excised and examined microscopically. Results. Pharyngocutaneous fistula exhibited better closure macroscopically in the recombinant human growth hormone group. There was a significant difference in collagen formation and epithelisation in the recombinant human growth hormone group compared to the control group. Conclusion. This study is believed to be the first in which the effect of recombinant human growth hormone on pharyngocutaneous fistula closure was evaluated, and the findings suggest the potential of use of growth hormone for treatment of pharyngocutaneous fistula.
Israfil Kucuk,Tahsin Boyraz 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.1
3 mole % yttria stabilized zirconia (YSZ) ceramic and 20 wt. % mullite (M), and 20 wt. % aluminium titanate (AT) reinforcedYSZ ceramic composites were produced using a conventional ceramic production process. After a combined method of wetball milling and dry pressing, these samples were sintered at 1500 oC and 1600 oC for 1hr and 5hrs, respectively. Physicalproperties, microstructural and phase characterizations of the sintered samples were analyzed using Archimedes method, ascanning electron microscope with energy dispersive spectroscopy and X-ray diffraction technique, respectively. Thereafter,micro Vickers and three-point bending tests were performed. The density, relative density and firing shrinkage of the sinteredsamples increased with addition of M and AT and the increased sintering temperature at each time. However, both porosityand loss of water properties determined were inversely proportional to M and AT addition and sintering temperature and timeincrease. An increase in M and AT content influenced the grain morphology as is presented in the microstructures of thecomposites produced thus bringing about a rise in grain size, as well as homogeneity and density in YSZ samples. Promisingresults were observed with the Vickers and bending strength in the mullite reinforced YSZ samples sintered at 1600 oC for 5hrsdue to mullite addition, which provides excellent mechanical features to the YSZ ceramic composites.
Inductance Vector Angle Based Sensorless Speed Estimation in Switched Reluctance Motor Drive
Fuat Kucuk,Hiroki Goto,Hai-Jiao Guo,Osamu Ichinokura 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-
Feedbacks signals of rotor speed and motor torque are essential in most of Switched Reluctance (SR) motor control applications. An SR motor has highly nonlinear characteristics that do not allow to be modeled by simple equations. Hence, the feedback signals can not be mathematically calculated from the model. Instead of calculation, they should be measured or estimated. In Direct Torque Control (DTC) drive, which enables easy control of torque ripple in the SR motor, position sensor is employed to obtain the feedback signals. Position sensor causes DTC drive not only less reliable but also more expensive. Estimation of feedback signals is required in order to eliminate position sensor (or encoder). This paper concerns about sensorless speed estimation under the DTC condition and presents a simple method. The proposed method is based on inductance vector angle. The inductance vector angle is obtained by applying α ? β transformation to the phase inductances. A relay triggers a speed calculation circuit according to its band limits and the inductance vector angle. Inside the circuit, triggering time is kept in a memory until the next triggering. Then, rotor pole pitch is divided by the time difference between two consecutive triggerings. Finally, the estimation circuit outputs the rotor speed. Estimation method is simulated and verified experimentally to show its validity.