• Journal of Power Electronics
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• v.17 no.4
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• pp.972-982
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• 2017

The Park's vector of stator current is a popular technique for the detection of induction motor faults. While the detection of the faulty condition using the Park's vector technique is easy, the classification of different types of faults is intricate. This problem is overcome by the Multiple Park's Vector (MPV) approach proposed in this paper. In this technique, the characteristic fault frequency component (CFFC) of stator winding faults, rotor winding faults, unbalanced voltage and bearing faults are extracted from three phase stator currents. Due to constructional asymmetry, under the healthy condition these characteristic fault frequency components are unbalanced. In order to balanced them, a correction factor is added to the characteristic fault frequency components of three phase stator currents. Therefore, the Park's vector pattern under the healthy condition is circular in shape. This pattern is considered as a reference pattern under the healthy condition. According to the fault condition, the amplitude and phase of characteristic faults frequency components changes. Thus, the pattern of the Park's vector changes. By monitoring the variation in multiple Park's vector patterns, the type of fault and its severity level is identified. In the proposed technique, the diagnosis of faults is immune to the effects of unbalanced voltage and multiple faults. This technique is verified on a 7.5 hp three phase wound rotor induction motor (WRIM). The experimental analysis is verified by simulation results.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2326-2333
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• 2015

Stator turn faults in permanent magnet synchronous motors (PMSMs) are more dangerous than those in induction motors (IMs) because of the presence of spinning rotor magnets that can be turned off at will. Condition monitoring and fault detection and diagnosis of the PMSM have been receiving a growing amount of attention among scientists and engineers in the past few years. The aim of this study is to propose a new detection technique of stator winding faults in a three-phase PMSM. This technique is based on the image analysis and recognition of the stator current Concordia patterns, and will allow the identification of turn faults in the stator winding as well as its correspondent fault index severity. A test bench of a vector controlled PMSM motor behaviors under short circuited turn in two phases stator windings has been built. Some experimental results of the phase to phase short circuits have been performed for diagnosis purpose.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.184-192
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• 2012

The torque and unbalanced magnetic forces in permanent magnet machines are resultants of the tangential, axial and normal magnetic forces, respectively. Those are in general influenced by pole-teeth-winding configuration. A study of the torque and unbalanced magnetic forces of a small flux concentrating permanent magnet transverse flux machine (FCPM-TFM) in segmented compact structure is presented in this paper. By using FLUX3D software from Cedrat, Maxwell stress tensor has been solved. Finite element (FE-) magneto static study followed by transient analysis has been conducted to investigate the influence of unsymmetrical winding pattern, in respect to the rotor, on the performance of the FCPM-TFM. Calculating the magnetic field components in the air gap has required an introduction of a 2D grid in the middle of the air gap, whereby good estimations of the forces are obtained. In this machine, the axial magnetic forces reveal relatively higher amplitudes compared to the normal forces. Practical results of a prototype motor are demonstrated through the analysis.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1997-1999
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• 2004

In this paper, a novel method has been proposed by use of HY-Pockels sensor for the detection of PD in GITR(Gas Insulated Transformer) in order to improve reliability and to overcome the shortcomings of other techniques which are currently employed. For this work, different types of the test specimen, simulating the winding of the real GITR, have been designed and fabricated to generate the PD. And then, the detection of PD has been realized by conventional methods according to IEC 270 and also the proposed novel sensor as well. Afterwards, their results are well compared to understand the correlation between the nature of the defects in the winding and their PD pattern.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.65-73
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• 2007

Pattern classification of single and multiple discharge sources was applied using a wavelet image signal method in which a feature extraction was applied using a hidden sub-image. A feature extracting method that used vertical and horizontal images using an MSD method was applied to an averaging process for the scale of pulses for the phase. A feature extracting process for the preprocessing of the input of a neural network was performed using an inverse transformation of the horizontal, vertical, and diagonal sub-images. A back propagation algorithm in a neural network was used to classify defective signals. An algorithm for wavelet image processing was developed. In addition, the defective signal was classified using the extracted value that was quantified for the input of a neural network.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.67-70
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• 2010

Spandex yarn requires a twisting process during winding and unwinding processes at the textile industry. The air-twist nozzle is widely used as part of the winding and unwinding. This paper describes computational approach to design the geometry of the air-twist nozzle. The nozzle has circular yarn-channel and the air-inlet which is perpendicularly connected to the yarn-channel with yarn-loading slit. The air-inlet of the nozzle is designed while measurements of the yarn-channel are fixed. The airflow inside the air-twist nozzle is simulated by using Computational Fluid Dynamic model. The Ansys CFX was used to perform steady simulations of the airflow for the air-twisting process. The vortical structure and the airflow pattern such as velocity streamline, vorticity, velocity of the air-twist nozzle are discussed. Computational results are compared with experimental results in this paper.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1846-1849
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• 2002

A shorted-turn test was performed at the Sininchon combined cycle power plant on gas turbine generators. The test was conducted using a permanent flux probe and on-line diagnosis system. The flux probe installed in the generator air gap senses the field winding slot leakage flux and produces a voltage proportional to the rate of change of the flux. This pattern of flux variation is a signature unique to each field winding. We have also applied a voltage waveform analysis technique that can identify the pole location, slot number and number of shorted-turn with each slot.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1721-1724
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• 1998

A shorted-turn test was performed at the Pyungtaek combined cycle power plant on gas. turbine generator #4. The test was conducted using a permanent flux probe and digital oscilloscope. The flux probe installed in the generator air gap, senses the field winding slot leakage flux and produces a voltage proportional to the rate of change of the flux. This pattern of flux variation is a signature unique to each field winding. We have also applied a waveform analysis technique that can identify the pole location, slot number, and number of shorted-Turns with each slot.

• 연구논문집
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• s.30
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• pp.129-135
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• 2000

Double boss type composite pressure bottles have been developed widely but single boss type had not because there are some difficulty in technical point. In this paper a research was performed to develop composite pressure vessel in conjunction with design, fabrication, and test. Fiber pattern and angles were decided by CADFIL software and they are [liner/$15^{\circ}$/$15^{\circ}$/$90^{\circ}$/$18^{\circ}$/$90^{\circ}$/$21^{\circ}$/$21^{\circ}$/$90^{\circ}$]. Fabrication of bottles was done by AEA's 5-axis filament winding machine. During fabrication fiber optic sensor were embedded to measure were behavior of structure at the applied internal pressure. Even though satisfied test results were not obtained, the experimental set-up of fiber optics showed the possibility for the application of filament wound vessels. However, the conventional strain and fabrication of single boss composite bottles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.395-398
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• 2000

In this study mechanical and environment ability of FRP pole for a distribution line about high strength and good insulation properties. The basic filament winding process creates a helical winding pattern. In mechanical analysis of splice with mechanical fastened joint it is important to evaluate a critical load of faster having maximum stress. It is also present a result of several examples to compare this with analytical one. On repair design this finite element method will be used as basis. The influence of environmental factors, such as elevated temperatures, high humidity, and corrosive fluids, and ultraviolet(UV) rays, upon the performance of polymeric matrix composite is of concern in many applications.