• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.735-736
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• 2008

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, CLR, Back Up Breaker, Making Switch and Excitation Equipment etc. Gradually an allowable tolerance of the short circuit test voltage is become smaller by the standards for short circuit test. The excitation equipment of short circuit generator is very important for test voltage is adjusted by the excitation equipment. Especially the excitation equipment must be possessed character of exactitude, durability and inalterability because some times around 10,000 times opening and closing short circuit test is requested by clint, which must be done within one minute. The purpose of this study for function and operation of the excitation equipment which rated DC voltage is 1,000V, rated DC current is 300A, rated out put is 30kW and type is YNEX 97S-441/609, is to help operation of short circuit generator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.70-75
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• 2014

TMR(triple modular redundant) digital excitation system with simulator is developed for tuning optimal control parameters during commissioning test and coping with system faults rapidly. A new system which mocks up virtual generator, turbine, grid can simulate as if excitation system is connected to a real generator system by setting four switches. The maintenance crew using the simulator is able to test perfectly the phase controller rectifiers, field breaker, sequence relays as well as TMR controller of the excitation system. Commissioning and performance results about the excitation system with simulator is discussed. The trial product was installed and operated at a 500MW thermal power plant after the commissioning test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.842-849
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• 2009

The objective of this study is to investigate design parameters of a tuned liquid column damper(TLCD), which is affected by various excitation amplitudes, through shaking table test. Design parameters of a TLCD are examined based on the equivalent tuned mass damper(TMD) model of a TLCD, in which the nonlinear damping of a TLCD is transposed to equivalent viscous damping. Shaking table test is carried out for a TLCD specimen subjected to harmonic waves with various amplitudes. Transfer functions are ratios of liquid displacement of TLCD and control force produced by a TLCD, respectively, with respect to the acceleration excited by a shaking table. They are derived based on the equivalent TMD model of a TLCD. Then, the variation of design parameters according to the excitation amplitude is examined by comparing analytical transfer functions with experimental ones. Finally, the dissipation energy due to the damping of a TLCD, which is experimentally observed from the shaking table test, is examined according to the excitation amplitude. Comparisons between test results and analytical transfer functions showed that natural frequencies of TLCD and the ratio of the liquid mass in a horizontal column to the total liquid mass does not depend on the excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitudes.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1167-1176
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• 2009

The objective of this study is to investigate design parameters of a tuned liquid column damper(TLCD), which is affected by various excitation amplitude, through shaking table test. Design parameters of a TLCD are examined based on the equivalent tuned mass damper(TMD) model of a TLCD, in which the nonlinear damping of a TLCD is transposed to equivalent viscous damping. Shaking table test is carried out for a TLCD specimen subjected to harmonic waves with various amplitude. Transfer functions are ratios of liquid displacement of TLCD and control force produced by a TLCD, respectively, with respect to the acceleration excited by a shaking table. They are derived based on the equivalent TMD model of a TLCD. Then, the variation of design parameters according to the excitation amplitude is examined by comparing analytical transfer functions with experimental ones. Finally, the dissipation energy due to the damping of a TLCD, which is experimentally observed from the shaking table test, is examined according to the excitation amplitude. Comparisons between test results and analytical transfer functions showed that natural frequencies of TLCD and the ratio of the liquid mass in a horizontal column to the total liquid mass do not depend on the excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitude.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1953-1954
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• 2008

The excitation system for class 1E has been developed to apply to the nuclear power plant emergency diesel generator by utilizing the existing digital excitation system. The additional mission was to evaluate the excitation system of safety. It is the safety analysis of the excitaton system, the verification test, the aging test, the safety requirement test and so on. The verification test is classified of hardware and software part for detail.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.2
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• pp.118-126
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• 2011

The characteristics of the responses obtained in thermosonic tests are investigated in this study to improve the performance of a thermosonic test system. Thermosonic tests are conducted with an acoustic horn with high power capability to investigate the characteristics of the vibration produced in turbine blades with complex geometry. The influences of the excitation signal that is input to the horn and the coupling methods between a clamp and the acoustic horn on the characteristics of the vibration excited in a component are presented. As a result, an excitation method with a fast narrow band chirp test (sweep test) and a stud coupling is proposed as an excitation method for thermosonic testing. This method can be applied to different types of turbine blades and also to other components.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.91-94
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• 1996

A simulation procedure was developed for identifying Yungnam unit 2 excitation model parameters to improve the accuracy of stability simulation of KEPCO. First, generator model parameters are derived by using modified load rejection technique from measured load rejection test. For identifying excitation model parameters, switch was changed from MVR mode to AVR mode in Yungnam unit 2 excitation system instead of applying to a small step to the voltage reference($V_{ref}$) because of saving time and efforts, assuming the test result would show coincided result with applying to a small step to the $V_{ref}$. However, it was found that the response of switching from MVR to AVR is greatly different from it of applying small signal to the $V_{ref}$. A simulation procedure was needed to take into accounts of real AVR component status before and after switching from MVR to AVR. This paper reports the procedure which duplicated the measured response and addresses the merits of this test on conventional AVR step test.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.157-164
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• 2001

This paper performs static and dynamic tests of a multi-leaf spring and a tapered leaf spring to investigate their hysteretic characteristics. In the static test, trapezoidal input load is applied with 0.1Hz excitation frequency and with zero initial loading conditions. In the dynamic test, sinusoidal input load is applied with five excitation amplitudes and three excitation frequencies. In these tests, static and dynamic hysteretic characteristics of the multi-leaf spring and the tapered leaf spring are compared, and, the effects of excitation amplitudes and frequencies on dynamic spring rate are also shown. In this paper, actual vehicle tests are performed to study the effects of hysteretic characteristics of the large-sized truck's handling performance. The multi-leaf spring or the tapered leaf spring is used in the front suspension. The actual vehicle test is performed in a double lane change track with three velocities. Lateral acceleration, yaw rate and roll angle are measured using a gyro-meter located at the mass center of the cab. The test results showed that a large-sized truck with a tapered leaf spring needs to have an additional apparatus such as roll stabilizer bar to increase the roll stabilizer due to hysteretic characteristics.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.453-460
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• 2001

The seismic capacity of columns usually has been tested in uniaxial loading condition. The seismic performance used to be evaluated under the same assumption. Since the real earthquake motion is multi-directional, the effects of multi-directional excitation on the seismic capacity of structures need to be carefully examined. In this paper, a frequency dependent alternate biaxial cyclic loading test is proposed as an evaluation method of seismic capacity under multi-directional excitation. Four test specimens were made and tested to study the degradation of strength, stiffness and ductility under biaxial loading condition. A multi- directional excitation. The capacity is obtained using frequency dependent alternate biaxial cyclic loading test. The orthogonal effect is taken into account by increasing the demand.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.218-221
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• 2004

This Research is to test the running stability of the developed bogie with 350km/h of which conventional speed is faster than Korea TGV 300Km/h. The running stability test has been executed in status of a car with the developed bogie on the roller rigger to adjust similar to the actual condition. And the test has been done in the two rail conditions, i.e. excitation and non-excitation, respectively. Running speed of bogie increased by the roller step by step. In consequence, the developed bogie in the non-excitation has run without any unstable point for 400kn0h. Vibration characteristics of carbody also was within the value specified on the UIC 518.