• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1810-1815
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• 2000

발전기 회전자와 고정자 사이에 유기되는 전자력은 발전기 운전중 진동 피로 현상을 유발시켜 발전기 수명 저감의 요인이 된다. 특히 고정자 코어부에 비해 기계적 구속력이 비교적 약한 권선 단말부에서의 진동은 냉각수 누수, 권선 마멸등에 의한 2차 사고를 유발시킬수 있다. 따라서 본 논문에서는 국내 발전소에서 운전중인 발전기를 중심으로 수행한 제작사별 고정자 권선의 진동 특성을 비교 분석하였다.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1710-1712
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• 1996

This paper was practiced insulation failure test forcing to accelerate on frequency of 420 HZ. There was manufactured generator stator windings for 500MVA thermal plants and selected accelerating deterioration voltage of 5.5kV/mm for electrical aging. Moreover, so as to verification of this experiments, we carried out modeling analysis due to finite element method using to ANSYS5.0 program for common package and imitated multi-stress aging for analyzing electrical and mechanical stress distribution.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.37-39
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• 2004

This paper deals with the prediction of armature reaction field produced by 3-phase stator windings whose current waveform contains significant harmonics. On the basis of 2-d analytical technics, we derived governing equation and predicted magnetic field distribution according to rotor position. The results of predictions from the analysis are compared with corresponding FE (finite element) analyses.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.50-52
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• 2008

This paper deals with design and characteristics analysis of 600HP class high_speed Permanent synchronous motor. The field equations due to magnet and stator windings are established in terms of vector potential and 2-d polar coordinate system. Back-emf and torque are then derived. The results compared with finite element method and show in good conformity with those obtained from finite element method.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.482-487
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• 1998

Field orientation of rotating field machines is influenced by various machine parameters. Most unpleasant are those parameters which vary during machine operation, such as the stator and rotor resistances. Permanent influences of resistance variation in steady state operation could have serious consequences. Also transitory influences are often disturbing. In this paper a control method for a current-fed synchronous machine is presented in which both permanent and transitory parameter influences are suppressed as much as possible.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.321-324
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• 1998

A single phase induction motor (SPIM) rated in fractional horsepower is widely used in home and industrial equipment: washing machines, fans, refrigerators, etc. In this paper, authors present the experimental results of the SPIM under controlling of currents of main and auxiliary windings by using a one-chip micro stator(OMS). This new starting method is developed to replace the conventional starting device consisted with a mechanical switch and a capacitor. In mentioned method, the soft-starting of SPIM is simply implemented and higher efficiency is obtained in comparison with conventional condenser type SPIM.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.8
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• pp.363-368
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• 2006

This paper presents a new method on reducing commutation torque ripples generated in brushless dc motor drives. In such drives the current ripples are generated by motor inductance in stator windings and the back EMF. The ripples suppression techniques that are practically effective in high speed as well as in low speed regions are rarely found. The proposed method here is based on a strategy that the commutation intervals of the incoming ang the outgoing phases can be equalized by a proper PWM control. The controller is implemented by a 16-bit microprocessor and effectiveness of the proposed control method is verified through experiments.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2089-2092
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• 1999

Partial discharge(PD) tests were performed both when the pumped storage generator(rated 13.8kV and 220MVA) was on-line and off-line. This generator has been equipped with 12 bus coupler sensors in directional mode. PD tests were conducted using partial discharge analyzer(PDA), partial discharge meter(PDM) and digital partial discharge detector. PDA showed that the patterns of the normalized quantity number(NQN) and the partial discharge magnitude are in accord with on-line and off-line. The insulation condition was estimated by diagnostic tests(off-line) such as PD magnitude and dissipation factor.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.865-866
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• 2006

Bearingless Switched Reluctance Motor(SRM) have combined characteristics of SRM and magnetic bearing. Production of radial force for rotor shaft magnetic suspension is explained with differential stator windings. Bearingless SRM is simple structurally because the permanent magnet does not exist and bearing does not take the influence at the environment because it does not exist and has strong torque, and loss of bearing by bearing current has the advantage not to exist. In this paper, a design method of bearingless SRM for suspension power and starting torque is proposed. The design model is implement by maxwell.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1376-1378
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• 1997

Mechanical and electrical properties of mica/epoxy composite materials were investigated by dynamic mechanical analyzer(DMA) and dielectric analysis (DMA). Both modulus and permittivity of sound specimens were higher than those of aged specimens. Two results show that $tan{\delta}$ of sound specimens is lower than that of aged specimens. DMA results showed that glass transition temperatures of sound and aged specimens are observed to be $87.16^{\circ}C$ and $88.38^{\circ}C$, which increases with the increase of aging time.