• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.19-21
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• 2001

Induction motors are a critical component of many industrial machines and are frequently integrated in commercial equipment. The many economical losses and the deterioration of system reliability might be caused by the failure of induction motors in industrial field. Based on the reliability and cost competitiveness of driving system(motors), the faults detection and diagnosis of system is considered very important factors. In order to perform the faults detection and diagnosis of motors, the vibration monitoring method and motor current signature analysis (MCSA) method are emphasized. In this paper, MCSA method is used for induction motor fault diagnosis. This method analyzes the motor's supply current, since this diagnoses the motor's condition. The diagnostic system is constructed by using LabVIEW of National Instruments.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2222-2224
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• 2002

Induction motors are critical components of many industrial machines and are frequently integrated in commercial equipment. The heavy economical losses and the deterioration of system reliability might be caused by the failure of induction motors in industrial field. Based on the reliability and cost competitiveness of driving system (motors), the faults detection and diagnosis of system is considered very important factors. In order to perform the faults detection and diagnosis of motors, the vibration monitoring method and motor current signature analysis (MCSA) method are emphasized. In this paper, MCSA method are used for induction motor fault diagnosis. This method analyzes the motors supply current. since this diagnoses faults of the motor. The diagnostic algorithm is based on the artificial neural network, and the diagnosis system is programmed by using LabVIEW and MATLAB.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1692-1695
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• 1997

This paper describes the relationship between the various non-destructive parameters and the breakdown voltage for the 17 kV, 300 MVA and the 22 kV, 500 MVA generators stator bars with polyester and epoxy/mica insulation respectively. Also, this study reports the results of an investigation into the factors which can assess the insulation condition of generator stator winding. Furthermore, a new parameter, Partial Discharge Index(PDI), is introduced as the valuable parameter for the assessment of insulation condition. The ratio between partial discharge increment and the stepwise voltage increment from the Discharge Inception Voltage (DIV) at the characteristic or resonant frequency band shows the close relationship between the breakdown voltage and PDI.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.219-230
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• 2010

Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.8
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• pp.770-777
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• 2004

Fouling and cleaning tests are performed for a uniquely designed 7,000 ㎉/hr fluidized bed heat exchanger for exhaust gas heat recovery. Fuel rich condition is maintained in the combustor for a limited time period to generate soot that is to be deposited on the heat transfer surfaces (fouling) and 600 Um glass beads are circulated inside the heat exchanger system for cleaning and enhancing the heat transfer performance. According to the present experimental study, performance degradation mode could be monitored and the effect of particle circulation on the heat transfer improvement could be identified. Through the present study, it is demonstrated that circulating particles contribute not only to the fouling reduction in gas side, but also to the heat transfer enhancement of the unit, while other possible aging factors including water side corrosion seemed to contribute to the accumulated performance deterioration.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1001-1006
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• 2004

Railroad disasters are frequently occurred by man-made causes or natural causes. In general, man-made causes are illegal construction practices, deterioration with the lapse of time and railroad crossing accidents, and natural causes are rainfall. snow, wind, earthquake, etc. Of cause, railroad disasters by man-made causes are prevented from keeping the safety principle, constructing multi-level crossing, securing enough men of ability and financial resources and making a thorough check using equipments with high capacity. And railroad disasters by natural causes are also minimized by construction of disaster prevention facilities, introduction and operation of general disaster prevention system and reasonable train passage control. Therefore, to setup the criterion of train passage control for train safety at railroad bridge under heavy rainfall, risky factors, national and oversea criteria under such circumstances are reviewed and a scheme to setup the criterion is suggested.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.229-234
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• 1997

Recently many concrete structures have been deteriorated due to the corrosion of reinforcing steel caused by chloride attack. The chloride attack causes very rapid and serious deterioration. Therefore, It is necessary for highly reliable method to stop the corrosion. Especially, on damaged concrete, it is difficult to stop the progress of steel corrosion that has already occured in concrete. The indirect method of corrosion protection such as eliminating corrosion factors by coating would be hard to be expected for complete stop of corrosion. In this paper, we applied the cathodic protection to chloride attacked marine concrete structures and verified the effect in addition to application of cathodic protection.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.3
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• pp.351-364
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• 1996

This paper presents on EMQ model which determines an optimal production run length in a deteriorating machine. It is assumed that a machine is subject to a random deterioration from an in-control state to an out-of-control state with on arbitrary distribution and thus producing some proportion of defective items. An optimal production run length and a minimum average cost are derived in each of three deteriorating processes; constant, linearly increasing, and exponentially increasing. The model with repair cost is also analyzed. Several mistakes in previous research are found and discussed. Numerical experiments are carried out to see the behavior of the proposed model depending on the cost factors as well as machine parameters, and some interesting behaviors are observed.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1333-1335
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• 2000

In order to turn on the SCR gate, trigger signal source have to provide appropriate gate current and voltage under the gate rating based on the characteristic of SCR, the nature of load and power. It will be essential design factors such as trigger source impedance, trigger signal occurring, signal time width and turn off conditions. Also minimum gate trigger current is changed with the deterioration of SCR. SCR, which is needed large gate trigger current absolutely, is very important for SCR characteristic test because it causes unstable output in the misfile or makes a trouble to pulse trigger circuits. This paper shows scheme to test the performance of SCR with the precision analyzing mechanism and the changing trend of minimum gate current under the trigger conditions.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.529-534
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• 2003

Within industry induction motors have a broad application area to drive pumps, fans, elevators and electric trains. Sudden failures of such machines can cause the heavy economical losses and the deterioration of system reliability. Based on the reliability and cost competitiveness of driving system (motors), the faults detection and the diagnosis of system are considered very important factors. In order to perform the faults detection and diagnosis of motors, the vibration monitoring method and motor current signature analysis (MCSA) method are emphasized. In this paper, MCSA method are used for induction motor fault diagnosis. This method analyzes the motor's supply current, since this diagnoses faults of the motor. The diagnostic algorithm is based on the principal component analysis(PCA), and the diagnosis system is programmed by using LabVIEW and MATLAB.