• Journal of Magnetics
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• v.14 no.2
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• pp.97-100
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• 2009

A new eddy current testing probe was developed to separate the eddy current signal distortion caused by permeability variation clusters and ordinary defects created in steam generator tubes. Signal processing circuits were inserted into the probe to increase the signal-to-noise ratio and allow digital signal transmission. The new probe could measure and separate the magnetic phases created in the steam generator tubes in the operating environment of a nuclear power plant. Furthermore, the new eddy current testing probe can measure the defects in steam generator tubes as rapidly as a bobbin probe with enhanced testing speed and reliability of defect detection.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.613-614
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.477-478
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• 2009

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.311-318
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• 2006

Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. Tn this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.288-289
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• 2004

The performance of the InGaAs/InP avalanche photodidodes operated in Geiger-mode was investigated for 1550nm wavelengths at room temperature. We find the optimal operating points where the high quantum detection efficiency and low dark current are achieved. For the optical pulse detection, the gated-mode is used to reduce the dark current.

• International Journal of Railway
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• v.1 no.3
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• pp.94-98
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• 2008

Static inverters are essential devices onboard of rolling stock. State-of-the-art static inverters have an impact on both rail infrastructure and vehicle maintenance due to their new topology with new features. The paper describes two important aspects as examples of new features available in state-of-the-art static inverters: active input current control and the effects on the rail infrastructure as well as the detection of the state of charge and the state of health of batteries to simplify vehicle maintenance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.995-1000
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• 2017

In this paper, we present an electrical arc detection algorithm using the mash-up analysis technique which is the core technology for the autonomous electrical safety management system(AESMS) of the multi-unit dwellings. The mash-up analysis technique analyzes the voltage, load current, zero phase current data simultaneously to judge arc faults. In order to develop the arc fault detection algorithm, the characteristics of series arc and parallel arc were analyzed. Also, we propose the mash-up analysis technique that analyzes waveforms of voltage, load current, and zero phase current at the same time. The arc fault detection algorithm was developed using the mash-up analysis technique. The developed algorithm can prevent electrical disasters in an effective way through accident prediction, and it will be used as a basic technology to introduce an autonomous electrical safety management system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1303-1310
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• 2016

The track circuit carries out a train detection using a electrical closed loop, and incidentally it detects the rail rupture using the track circuit current flowing rail. However, in the case of the axle counter or the Radio based train control system, it requires a new way for detecting the rail rupture because of not using the track circuit. To solve this problem, it periodically checks non-steady state of rail by the track inspection car. but real-time detection of the rail rupture is impossible. Therefore, this paper analyzed feasibility to realize a real-time detection of rail rupture by using the return current.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.404-413
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• 2006

Induction motors are the workhorse of our industry because of their versatility and robustness. The diagnosis of mechanical load and power transmission system failures is usually carried out through mechanical signals such as vibration signatures, acoustic emissions, motor speed envelope. The motor faults including mechanical rotor imbalances, broken rotor bar, bearing failure and eccentricities problems are reflected in electric, electromagnetic and mechanical quantities. The recent research has been directed toward electrical monitoring of the motor with emphasis on inspecting the stator current of the motor, The stator current spectrum has been widely used for fault detection in induction motor systems. The motor current signature analysis is the useful technique to assess machine electrical condition. This paper describes the motor condition detected by the current signatures Paralleled with vibration signatures analysis of induction motors with the roller bearing and the journal bearing type for large vertical pumps in power plant as examples to discuss for motor fault detection and diagnosis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1149-1154
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• 2017

In this paper, we propose a sensorless multi-function controller applicable for deep well water pumps using current detection method. The proposed system overcomes various drawbacks of existing sensored system and additional features like Over current protection function due to overload, Under current protection function for idling at low water level and Relay function for starting single phase motors and acts as a level indicator to detect water lever in real time by the current detection method. A prototype of the multi-function controller system is designed and all of its functions are tested in the laboratory. The application of the proposed controller ensures reduction in the power consumption and maintenance cost in the facilities like water and septic tanks, drainage and waste water system, oil and chemical tanks where deep well pumps are used.