• Journal of Power Electronics
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• v.16 no.3
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• pp.1087-1096
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• 2016

This paper reports an investigation conducted on two diagnostic methods based on the switching voltage pattern of IGBT open-circuit faults in voltage-source inverters (VSIs). One method was based on the bridge arm pole voltage, and the other was based on bridge arm line voltage. With an additional simple circuit, these two diagnostic methods detected and effectively identified single and multiple open-circuit faults of inverter IGBTs. A comparison of the times for the diagnosis and anti-interference features between these two methods is presented. The diagnostic time of both methods was less than 280ns in the best case. The diagnostic time for the method based on the bridge arm pole voltage was less than that of the method based on the bridge arm line voltage and was 1/2 of the fundamental period in the worst case. An experimental study was carried out to show the effectiveness of and the differences between these two methods.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.3
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• pp.131-139
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• 2001

As increasing the accident of Distribution Transformer (DT), we need to manage them efficiently. In this paper, we discusses with the possibility of the diagnostic technique for distribution transformer using relative ageing rate calculation in this paper. The relative ageing rate of the DT could be calculated from the measured top oil temperature, ambient temperature and load current. In order on apply the proposed diagnostic technique we developed an on line Monitoring and Diagnostic System (MDS) which has hardware and software part. Diagnostic device is developed to measure the state information of DT and to send them with R/F(radio frequency) communication. Host computer monitors and saves the receive data. The database is constructed from the data of distributed DT and it is used for estimating loss-of-life in the MDS.

• Transactions on Electrical and Electronic Materials
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• v.7 no.2
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• pp.90-95
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• 2006

An on-line diagnostic test has been studied and performed for the pumped storage generator/motor. This study aims at reducing the diagnostic cost, minimizing the technical dependency on third party manufactures. Further design of on-line diagnostic system such as shorted-turn of rotor winding, partial discharge (PD) of stator winding and air-gap between stator and rotor for pumped storage generator/motor has been verified. In addition, it needs to be validated on site performance of the developed continuous on-line monitoring system for corresponding tasks for the improvement of the availability & reliability during operation.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1891-1893
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• 2000

In this paper, we studied the diagnostic technique to analyze the deterioration of cast resin transformer using partial discharge detection for on-site application.

• Journal of The Korean Radiological Technologist Association
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• v.25 no.1
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• pp.20-20
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• 1999

Purpose : Cochlear implant poses a contraindication to the magnetic resonance imaging (MRI) process, because MRI generates artifacts, inducing an electrical current and causing device magnetization. CT is relatively expensive and the metal electrodes scat

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.214-216
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• 2001

In this paper, we developed the on-line Diagnostic & Monitoring system of distribution transformers using wireless communication. The Diagnostic system consists of the top oil temperature sensing, ambient temperature sensing. load current sensing, acoustic emission peak-value sensing, acoustic emission pulse counter and wireless communication part. The Monitoring system consists of the communication setting, online monitoring and database construction part. The Diagnostic system send the date acquired from the some sensors of the distribution transformers to the host PC. The Monitoring program of the host PC store the data to database. And the Monitoring system estimates the loss of life from the DB. Thus it could be managed the career and the functional lifetime of the transformer more efficiently than existing methodologies.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.330-332
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• 1997

The absorption coefficient of contrast media was measured region of diagnostic X-ray. Relative values of absorption coefficient was found the largest peak in the range of $60{\sim}70kVp$ for sodium sulfate and 60kVp for iodine. Increasing the thickness of contrast media and patient, the values of absorption coefficient was rising.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.499-499
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• 2008

High voltage transformer of Diagnostic X-ray system has been contributed to wiping out disease to get a good quality images from patients. High voltage transformer of diagnostic X-ray system has been usefully used for diagnostic purpose but if high voltage transformer performances are deteriorated, low quality image will be archived. In this case, operator has to exposure to get a more good quality images. In this case, unexpected radiation could be exposed to patient and it is very harmful to the patient. And I would like to design and make equipment to checkable high voltage transformer performance after that I wish to test and study what it is most influences in radiation output quality.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.863-869
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• 2017

This paper is to enable electrical safety manager to have more objective evaluation on the safety by indicating quantitative values such as life-time and status quotient of daily visual inspection on private electrical equipments. Self-diagnosis table is recommended to apply such a evaluation efficiently according to the characteristics of each electrical equipments, and the managers's determination of the precise inspection, replacement etc. will be also possible through the standard selected by various domestic and foreign data with expert's advise for numerical evaluation. This circumstance will be able to establish the foundation to secure the soundness of electrical equipments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.132-135
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• 1997

The absorption coefficient of contrast media was meassured region of diagnostic radiology. Relative values of absorption coefficient was fecund the largest peak in the range of 60 ∼ 70kVp for sodium sulfate and 60kVp for iodine. Increasing the thickness of contrast media and patient the values of absorption coefficient was rising.