• Journal of Drive and Control
• /
• v.14 no.1
• /
• pp.1-7
• /
• 2017

The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.1
• /
• pp.11-17
• /
• 2002

This paper describes on a position detection method for the motors which have repetitive operations using the Algorithmic State Machine(ASM), one of the digital logic design methods. With analyses for the incremental encoder output patterns, state diagram and state table are constructed and a digital circuit which can detect the changing point of direction of motor rotation is designed. To verify the validity of the designed circuit, simulations for all cases in which the direction of motor rotation is changed, are performed. Simulation results show the designed digital circuit can detect the direction of motor rotation accurately for all cases.

• Korean System Dynamics Review
• /
• v.15 no.1
• /
• pp.51-74
• /
• 2014

Despite the high efficiency of nuclear power plant, people in Korea do not give approvals and supports the facilities because the risk of the accidents and incidents. In particular, the low level of safety culture is a crucial mechanism that damages the robustness of the NPP. By considering the various definitions of safety culture and analyzing the major reasons of incidents, the conceptual safety culture model is made by using Causal Loop Diagramming. For sustaining development of nuclear power, social supports, incentives and organizational learning are needed. It also requires the coordination of work schedules and the expansion of human resource for protecting the rules and procedures in NPP. Decommissioning aging nuclear power plants will prevent a serious accident. In order to promote the safety culture, Korea Hydro & Nuclear Power Corporation should disclose more information to the public and promote the internal and external communications.

• Proceedings of the KIEE Conference
• /
• 2004.07e
• /
• pp.27-29
• /
• 2004

This paper presents improved teaching and learning Gill for easily analysis tool of load flow of power system. This GUI includes not only contingency analysis function, but also calculating power loss from transmission line flow. The Gill is friendly for study for power system operation and control because picture provide a better visualizing of relationships between input parameters and effect than a tabula type result. This Gill enables topology and the output data of load flow for line outages to be shown on same picture page. Users can input the system data for power flow on the the picture and can easily see the the result diagram of bus voltage, bus power, line flow. It is also observe the effects of different types of variation of tap, shunt capacitor, loads level, line outages. Proposed Gill has been studied on the Ward-Hale 6-Bus system.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.2
• /
• pp.285-291
• /
• 2017

This paper proposes the use of advanced generator models in the studies of Korean power systems to accurately represent the dynamic behaviors of synchronous generators and thus to achieve a better match between transient stability simulations and reality. In the paper, GENTPF and GENTPJ models are described which have appeared over the last decade in the WECC system. Those advanced models are compared with conventional synchronous generator models such as GENROU and GENSAL, which have been used in dynamic studies of Korean power systems. The advancements are investigated by recognizing the differences in block diagram, saturation modeling, and network interface equations. Simulation comparisons between conventional and advanced models in Korean power systems are then provided. Clear distinctions identified in the simulation results demonstrate the necessity of the use of advanced generator models in Korean power system.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.12
• /
• pp.71-79
• /
• 2013

This paper describes a 12.5 Gb/s low-power receiver design with equalizer adaptation. The receiver adapts to channel and chip process variation by adaptation circuit using sampler and serializer. The adaptation principle is explained. It describes technique receiving ground referenced differential signal of voltage-mode transmitter for low-power. The CTLE(Continuous Time Linear Equalizer) having 17.6 dB peaking gain to remove long tail ISI caused channel with -21 dB attenuation. The voltage margin is 210 mV and the timing margin is 0.75 UI in eye diagram. The receiver consumes 0.87 mW/Gb/s low power in 45 nm CMOS technology.

• Journal of Convergence Society for SMB
• /
• v.2 no.2
• /
• pp.13-19
• /
• 2012

Various quality requirements have increased in developing embedded systems. One of those requirements in mobile embedded system is to reduce energy consumption because of limited power supply. Especially as the complexity of embedded software is increased, the interests of the software energy consumption analysis is also increased. In recent years, some studies has been carried out model-based analysis because it can be able to reflect energy consumption requirements in design phase. In this paper, we proposes a model-based energy analysis technique using SysML parametric diagram. The proposed technique designs software activity model using characteristics of parametric diagram, and then energy consumption value by the execution of the model is derived. Our technique has merit that can perform tradeoffs analysis for energy quality property between different implementations.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.6
• /
• pp.262-270
• /
• 2003

In this paper, the characteristics of single-phase line-start permanent magnet synchronous motor driven by constant voltage are analyzed on d-q axis vector diagram and compared with that of current controlled motor. The coupled method of symmetrical coordinates and d-q axis voltage equation are applied to the analysis method like the analysis of single-phase induction motor. From the result of the analysis, it is seen that motors driven by constant voltage source have effects on not only the amplitude of current and torque but also current and current phase angle, so overall characteristics such as power factor and load angle are affected by circuit parameters. For precise analysis and design of single-phase line-start synchronous motor, its characteristics should be analyzed on d-q axis vector plan in consideration of the variation of circuit parameters.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.752-757
• /
• 2003

The steady stress, modal analysis for the damaged blade was carried out to evaluate the integrity of LP 4 blade row. As a result, 4 dangerous modes for LP blade row were found in the interference diagram and it was confirmed that the nozzle passing frequency has nothing to do with the blade failure. And then the dynamic stress are analysed for the 4 dangerous modes. There are some points far out of maximum allowable stress in the cover and tenon. Therefore the blade is not safe according to the Goodman judgement. So the manufacturer have modified the design of cover and tenon. Until now, the power plant is being operated without special problems.

• Computers and Concrete
• /
• v.14 no.3
• /
• pp.263-277
• /
• 2014

This study investigated four electric field configurations of two-dimensional accelerate lithium migration technique (ALMT), including line-to-line, plane-to-line, contour-to-line and plane-to-plane, and analyzed the ion migration behavior and efficiency. It was found that the free ion distribution diagram and voltage distribution diagram were similar, and ions migrated in the power line direction. The electrode modules were used for the mortar specimen with w/c ratio of 0.5. The effectively processed areas accounted for 14.1%, 39.0%, 49.4% and 51.4% of total area respectively on Day 28. Larger electrode area was more advantageous to ion migration. In addition, it was proved that the two-dimensional electric field could be divided into different equifield line active regions, and regarded as affected by one-dimensional electric field, and the ion migration results in various equifield line active regions were predicted by using the duration analysis method based on the theoretical model of ion migration obtained from one-dimensional test.