• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.2 s.119
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• pp.177-184
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• 2007

The purpose of this study is to investigate experimentally the characteristics of rotational, radial, and axial vibration for helical gears with different contact ratios. For this purpose, the gear box is specially designed and manufactured. Two helical gears with different face widths and reduction ratios are investigated. The gear vibration in each direction is measured by accelerometers attached to the gear body. Rotational vibration is the highest and radial vibration is the lowest in the gear frequencies. While the increase of rotational speed increases gear vibration, it does not always increase with torque. It is not also linearly related to the contact ratio. In addition, axial vibration is not proportional to rotational vibration.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.13-16
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• 2001

This paper describes the problems associated with the use of PWM ASDs to drive induction motors. A major effect of harmonic voltages and currents in induction motors is increased heating due to iron and copper losses at harmonic frequencies. The harmonic components thus affect the motor efficiency, and can also affect the torque developed. In order to investigate the effect of harmonics which is caused by using of nonlinear load at the low voltage system, we fixed up simple load model and measured the voltage and current. Measurement. results show that additional operation of linear load at the parallel bus in using nonlinear load such as ASD is helpful to the reduction of harmonic current.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.52-58
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• 2017

Graphene oxide (GO)/carboxylated styrene-butadiene rubber (XSBR) nanocomposites with various contents of GO were prepared by a latex compounding method. It has been confirmed that the functional groups of GO and the hydrogen bonds between GO and XSBR are existed. It can be seen that the scorch time ($t_{s2}$), which is the measurement of incipient vulcanization of rubber, showed a delay after the addition of GO. Field emission scanning electron microscopy was employed to confirm the uniform dispersion of filler in the matrix. Indeed, with increasing fillers loading, the torque, tensile strength, thermal stability and crosslink density of obtained nanocomposites were improved. These results were correlated to the better dispersion of fillers through the rubber matrix.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.982-990
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• 1994

In this paper, we consider feedback-kinearizing control of brushless dc motors which have been increasingly used in high-performance servo applications, We completely characterize the whole class of the feedback controllers that enable the brushless dc motors to behave like linear systems but without torque ripple. The whole class of the feedback-linearizing controllers is characterized in the explicit form which contains a function to be chosen freely. The previously known controllers correspond to either the particular ones in our whole class of the feedback-Linearzing controllers or their truncated Fourier expansions. This free function can be used to achieve other control objectives as well as linear dynamic characteristics. Furthermore, our feedback-linearizing controllers can be easily determined from the measurement data of back EMF.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.474-482
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• 1992

This paper describes the speed control system of an induction type ac servomotor drive on the vector control basis of slip frequency and constant secondary flux control for a quick torque response. The system is composed of a digital controller using a SCB-V50 microprocessor and a PWM inverter with power MOSFETs for high speed switching. And, for the measurement of actual instantaneous currents, MDCS A070-051 hall sensors are employed. The rising time of step responce by this system through the test of a 600[W] ac servomotor is 30[ms]. Overall experimental result shows that the drive performance of the system is similar to that of a separately excited armature current control of a dc motior.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.409-411
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• 2007

This paper deals with an automatic tuning method of the notch filter to suppress oscillations in a permanent magnet linear synchronous motor(PMLSM) drive. First, it saves automatically the reference torque-component current when oscillations are detected. Then the oscillation frequency of the saved data is calculated by using the fast Fourier transform(FFT) algorithm. And also the Hanning function is used to reduce the leakage components due to the aperiodic measurement data. Finally, the proposed method tunes the notch filter to suppress oscillations. Experimental results on the test rig show the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.988-990
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• 2003

Disk type Single Phase SRM(Switched Reluctance Motor) can be used axial and radial direction magnetic flux. Therefore, the energy density per unit of volume is high and the axis can be shorter than that of any other motor. In this paper, the flux-linkage was measured according as rotor positions of disk type single phase SRM, which is designed and fabricated in previous studies. From the measured data, we got the magnetization curves, inductance profile, co-energy and torque. Also, we compared the value of the measurement with the value of analysis through 3D FEM simulation.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.101-104
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• 2004

동력 및 전등 전열용으로 사용하는 3상 4선식 저압배전시스템에서는 전원측 및 부하측에 연결된 전력사용기기의 영향으로 전압불평형이 발생한다. 전압불평형을 줄이기 위해 설계 및 사용시 부하의 분배를 최적화시키고 있지만, 사용조건과 운전패턴에 따라 완전한 전압평형을 유지하기는 매우 어렵다. 이와 같이 3상 4선식 배전시스템에서 전압불평형은 몇 배의 전류불평형으로 이어져 유도전동기의 경우에 기기의 손실 및 소음증가, 토크 및 속도의 감소와 더불어 비선형 기기의 경우에 고조파의 증가에도 영향을 미칠 수 있다. 전압불평형의 변화에 따라 토크 및 속도의 변동이 발생할 경우 정밀제어나 일정한 속도를 요구하는 설비에서는 심각한 문제를 발생할 수 있다. 따라서 본 연구에서는 전압불평형율에 따라 유도전동기의 토크 및 각속도 특성변화를 측정 분석 하였다.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.36-38
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• 2001

A neutron controls a nuclear fission in the core of a reactor. Drive system for in-core neutron detector is an equipment that drives the detector and cable to survey neutron flux in the reactor. The drive system introduced by this paper was designed for mock-up system and fabricated to drive two drivers that having a different function. The system consists of a driver assembly, a power transmission part, and cable storage part. And there is a control panel that contains PLC and inverter. This paper is going to introduce the design and certify the operation status of completed system by control panal. And we conducted the test for torque measurement.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.1
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• pp.45-51
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• 2002

In this paper are presented dynamic modeling and path-tracking of differential drive wheeled-mobile robots(WMRs) having the limited drive-torques. Instantaneously coincident coordinate system, force/torque propagation and Newton's equilibrium law are used to induce the dynamic model. When drive-torques generated by inverse dynamics exceed the limitation, we make wheeled-mobile robots follow the reference path by modifying the planned reference trajectory with time-scaling method. The controller is introduced to compensate for error owing to modeling uncertainty and measurement noise. And simulation results prove that method proposed by this paper is efficient.