• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1038-1043
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• 2002

The floating ring journal bearing is attraction for high-speed turbo machinery applications, including turbochargers and aircraft accessory equipment, because it is not only simple and easy to make and to replace in the field but also it seems to have adequate high speed stability characteristics. Therefore, an analysis method of dynamic properties of floating ring journal bearing is presented. The static equilibrium locus of inner film and outer film are calculated by using the impedance description. The equivalent stiffness and damping coefficients of floating ring journal bearing are composed by using the equilibrium of torque between inner film and outer film. Then, a stability analysis of turbocharger shaft system supported with floating ring journal bearing has been performed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.211-217
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• 1998

A disk rotor dynamic analysis program called by DR. DAP is developed for disk drive spindle systems to analyze dynamic characteristics in operation and to estimate the effects of excitation sources. It is applicable to design for stabilization and to select parts of disk drive spindle systems. The disk drive spindle system in this program is modeled as a flexible shaft with multiple flexible disks, which is supported by bearings and driven by electric motor, and its complicated coupled vibration characteristics are analyzed by using a substructure synthesis technique with the assumed-modes method. All the coupled modes of interest can be well predicted by the example of a three disk hard disk drive with the three tuning parameters. It is also shown that, with the introduction of the excitation sources associated with the defects of ball bearing systems, the magnetic unbalance of spindle motor, the program can well predict the stability of the system, i.e., the possibility of resonance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.411-415
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• 2007

The reduction of airborne and structure-borne noise of a shipboard pump for a navel ship is very important because the noise levels of the pump must not exceed criteria such as MIL-STD. In this paper, several practical examples of reducing the noise levels are presented. The examples show that the inadequate rotor-balancing and shaft-alignment results in the increase of the structure-borne noise on all lower mounts. It is also found that the unequal loading on mounts can cause the dramatically increasing the noise levels on certain local positions. Since the piping system arrangement such as valve location, flexible joint, and elbow location affects on the noise measurement, care must be taken to minimize the unnecessary noise from the piping system.

• 한국정보통신학회논문지
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• 제5권7호
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• pp.1308-1313
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• 2001

본 논문은 3상 유도전동기의 파라미터 측정정법과 기동특성을 제시한다. 고정자 권선저항, 구속 및 무부하시험에 의해 측정된 유도전동기 파라미터를 이용하여 전동기의 기동특성을 시뮬레이션 하였다. 또한 유도전동기 축에 스트레인 게이지를 부착하여 기동토크에 대한 특성을 실험으로 확인하고 이를 시뮬레이션 결과와 비교 분석하여 그 타당성을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.380-386
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• 2000

This paper presents the mathematical modelling analysis of Brushless Synchronous Motor(BLSM). The dynamic and the steady state characteristics of BLSM are simulated and analyzed : electromagnetic torque, speed, line voltage, and current. We used mathematical modelling to model of BLSM with sinusoidal back EMF, namely the shaft transformation referencing rotor frame from a, b, c three to produce constant torque like synchronous motor. The experiment result has already similar to compare with simulation result : torque error about 7%, speed error about 5%. The validity of proposed modelling and analysis was confirmed by the experimental result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.733-735
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• 2001

The high temperature superconducting bulk can be used as the bearing of a motor. This paper presents the fabrication and test results of a motor with superconducting bearing using HTS bulks. The bearing used four hexahedron type YBCO bulks. Height, width and depth of the HTS bulk were 10mm, 30mm and 30mm, respectively. Single phase induction motor was used to drive the shaft and solid rotor was adopted for high speed rotation. Test results show the motor with HTS magnetic bearing can rotate silently and smoothly without any contact.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.849-851
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• 2001

This paper presents experimental method of parameter measurement and starting characteristics of 3 phase induction motor. Equivalent circuit parameters measured by DC test, the blocked rotor test, and no load test were used as the input data for computer simulation. Starting characteristics, such as starting current and torque were analyzed through computer simulation by Matlab, and the simulation results were compared with experiment using strain gauge attached on motor shaft. We conform that experimental results are very similar to that of simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.522-526
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• 1994

There are great needs for checking machine operation status precisely in the iron and steel plants. Rotating machines such as pumps, compressors, and motors are the most important objects in the plant maintenance. In this paper back-propagation neural network is utilized in diagnosing rotating machines. Like the finger print or the voice print of human, the abnormal vibrations due to axis misalignment, shaft bending, rotor unbalance, bolt loosening, and faults in gear and bearing have their own spectra. Like the pattern recognition technique, characteristic. feature vectors are obtained from the power spectra of vibration signals. Then we apply the characteristic feature vectors to a back propagation neural net for the weight training and pattern recognition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.264-267
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• 1989

In the vector controlled induction machine drives, mechanical speed sensors such as shaft encoder and resolver have been used. However, the mechanical speed sensors present some problems and restrict the wide applications of high performance AC drives. This paper describes the vector control strategy with the speed estimation algorithm in which motor slip frequency is calculated. Also, the angle deviation of the rotor flux vector is calculated and instaneously compensated to keep the q axis flux zero in the rotationary reference frame.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.321-321
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• 2010

In this paper, we propose a novel type shaft-less ring type ultrasonic motor. A traveling wave rotary type ultrasonic motor is selected as a base model. The newly designed stator has two piezoelectric ceramic rings which are bonded in sandwich shape as traveling wave generator. So, we can expect to produce higher torque. The proposed model has the rotor structure that coupled with the stator provokes the pressure, this model do not install the separate plate any spring device. We used the finite element method to verify the operation principle and to compute the vibration mode of proposed model.