• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.56-65
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• 1999

The relationship of the winding process variables and the mechanical properties of filament wound composites is investigated experimentally. The winding process variables considered are the fiber tensions and the fiber ends. The filament wound ring specimens are fabricated using 3-axis controlled filament winding machine. Two types of carbon fibers, TZ-507 and IZ-40, are used as reinforcements and epoxy for filament winding is used as resin. During the winding process, the fiber tensions are varied from 0.5kgf to 3.0kgf, and the number of the fiber ends are varied from 1 to 6. The fiber volume fractions and the void contents for the ring specimens are measured through the resin digestion. The mechanical properties of the ring specimens are also evaluated by the split disk test. The test results show that the winding process variables affect the fiber volume fractions and the void contents of the ring specimens, which result in the variation of the tensile properties of the ring specimens. Therefore, suitable winding process variables should be applied to maximize the structural performance and the productivity for filament wound structures.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.80-82
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• 2008

고전압 가스차단기용 조작기로 개발된 전자석 조작기(EMFA)는 크기에 비해 큰 힘을 낼 수 있고 긴 스트로크를 갖는 장점으로 다양한 차단기에 적용이 시도되고 있다. 특히 기증차단기(ACB)와 배선용 차단기(MCCB) 등 저압 차단기를 구동하기 위한 연구가 진행중이다. 그러나 적용할 차단기의 전압 등급이 낮아짐에 따라 조작기의 크기 또한 작아져야 하며, 설계 및 해석시 고려해야 할 요소 또한 달라진다. 특히 조작기의 두께가 얇아지면서 코일의 엔드와인딩(end-winding)에 의한 영향이 상대적으로 커지게 되는데, 본 논문에서는 전자석 조작기의 동작 특성 해석시 엔드와인딩 인덕턴스를 고려한 2차원 해석을 시도하였다. 엔드와인딩 형상은 원형으로 가정하였고, 동작 특성 해석에는 유한요소법과 시간차분법을 적용하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.7
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• pp.928-938
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• 1997

The end winding is an important part in induction motor for thermal analysis. But there is little information on the heat transfer coefficient of that surfaces because of geometrical complexity. So our experimental object is to know the heat transfer coefficient of end winding and find the optimum design parameter of rotor fan. Carbon coated papers were used for a uniform heat generating surfaces which were easy to fabricate. The experiments of some parameters were performed as varying rotation speed of rotor fan. We obtained the local and average Nusselt number of the end winding surfaces by correcting radiation and conduction losses errors. The results showed that the average Nusselt number increased with rotor fan blade number and width but decreased with end winding length. However, the increasing limits existed in the case of rotor fan width and blade number. So optimum design value were obtained for rotor fan width and blade numbers.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.148-153
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• 2004

This paper represents that parts of a large generator operating in 1000 MW are affected by centrifugal forces due to high-speed rotation in 3600 rpm and 3D FEM Analyses are required to obtained the structural reliability of the generator. From these results, one would know the weakest locations and the stress distributions. The fatigue life is calculated in order to grasp the remaining life of generator. 2D and 3D analyses are performed to calculate stresses of the generator rotor and the retaining ring. From 2D results, we find the SCF at the slot and sub-slot of the rotor. 3D analysis is applied at the end part of generator rotor, which represents complex geometry, and rotor and retaining ring shrink thermally. With these results, designers of rotor and retaining ring can compare with the results of design code and verify the stress distributions of generator rotor and retaining ring, and then calculate the remaining life from the low-cycle fatigue data.