• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.113-122
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• 2018

A hydraulic breaker is an attachment of an excavator, and it crushes stones. Recently, research to reduce the impact and noise of breakers are ongoing. In this paper, a method to improve the upper, lower, and side dampers, which act as insulation for the attenuation of vibration during breaker operation, is studied through testing and simulation. To obtain the nonlinear material constants required for the simulation, the biaxial tensile test was performed with urethane, which is a material used for dampers. The existing parts and the improved parts were compared and evaluated using the LS-DYNA program. As a result, 50% of the equivalent stress was reduced in the bracket body of the hydraulic breaker, and the equivalent stress of the side damper was also decreased. We verified that the fatigue conditions were satisfied by performing a fatigue analysis.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.917-918
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• 2007

The former earth leakage breaker is operating by total leakage current which is the vector-sum of resistive leakage current and capacitive leakage current. However, the electric disaster like the electric shock and fire is caused mainly by resistive leakage current. Therefore, the earth leakage breaker is ideal when it is operating by resistive leakage current. In this paper, the theory for finding the component of resistive leakage current from total leakage current is suggested and it is embodied to actual circuit. The resistive leakage current can be found by integrating the total leakage current during half cycle of line voltage. Thus, we can simply find resistive leakage current by using OP-AMP integrators, and we can confirm that the resistive leakage current is computed exactly from total leakage current obtained by resistive leakage current and capacitive leakage current. The results that the earth leakage breaker is operating within regular interrupt time are verified when the former earth leakage breaker's controller circuit is replaced by the proposed controller circuit.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.201-206
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• 2019

The flooding and overtopping due to unexpected large ocean wave may occur serious problems to environments and structures. Generally fixed wave breakers and several structures were installed to prevent such damages, however, they may affect to environments and charted path of ships badly. In this regard, new type of initial wave breaker was investigated in both of experimentally and numerically. For the experiments, conceptual devices were built by authors with stereo vision system. The moving particle semi-implicit method was adopted for simulation. It is revealed that the initial wave breaker reduce the damages from ocean waves by energy dissipated earlier. Furthermore, the effects of position of the initial wave breaker was also considered.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.32-37
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• 2021

To realize a zero-energy building, a technology that minimizes the energy loss due to thermal bridges by preventing their formation is emerging as an important design factor. In this study, we develop a thermal bridge breaker to prevent thermal bridging in a metal panel roof and attempt to analyze the effects of its application. To this end, we fabricated a thermal bridge breaker and analyzed it in terms of its strength and heat-transfer characteristics, in addition to conducting a load simulation. The thermal bridge prevention effect of the developed thermal bridge breaker improved the insulation performance of the metal panel roof, and the results of a cooling/heating peak load simulation performed by applying the heat transmission resistance test results to a building proved the existence of this effect.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.338-347
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• 1995

Equations of motion and continuity equations of a hydraulic breaker are derived. Hydraulic pressures are defined with 6 state variables corresponding to 6 control volumes. Impact analysis procedure of the piston and chisel is developed based on the finite element nodal displacement description. Computer simulation is performed with given design parameters and the results are compared with experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.70-76
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• 2003

In this study, the hydraulic breaker system was analyzed and simulated using. The simulation result was certified comparing with the experimental result. From the parametric analysis, the effects of each factor were revealed. Through the simulation with varying parameters, the method to reduce the return line pressure fluctuation was presented.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.92-94
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• 1999

This paper describes the interruption techniques of HVDC circuit breaker which adapts inverse current injection method. A representative circuit configuration of this type of HVDC circuit breaker is presented and its operational mechanism and timing diagrams are investigated.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.222-225
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• 2003

In this paper the performance of the high speed circuit breaker with fault current detector is described. The operating mechanism of circuit breaker in use is a magnetic actuator and a fault current detector is based on the DSP and A/D converter. The results show that 3-cycle is enough to interrupt the fault current and the more speed up performance is expected with on-going project.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.902-904
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• 2007

A $SF_6$ gas circuit breakers are widely used for short circuit current interruption in EHV or UHV power system. During a $SF_6$ gas circuit breaker development, Simplified synthetic testing facility is used. This paper shows how simplified synthetic testing facility is used for a SF6 gas circuit breaker development.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.290-291
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• 2010

도통손실이 작고 경제적인 SCR을 이용하여 마이크로그리드에 적용이 가능한 25 [kVA]급 SSCB(Solid-State Circuit Breaker)를 설계하였다. 시뮬레이션을 통하여 3상 단락 사고시의 SSCB 동작특성을 살펴보았고 계통의 용량에 따른 커패시터의 설계값을 제시하였다.