• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.861-866
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• 2012

The distance optimizing between coil and magnetic materials never be specified in the magnetic materials acceleration using the coil till now. We can know to be the distance which optimizes when being in the half position about the distance of intercoil by the result of the max point on the Differential calculus. Whether several top and bottom current segment coil structures were made and the steel ball in which the current segment coil structure is the magnetic materials could be accelerated in the optimizing distance or not confirmed. When the coil valley current about the mass of the steel ball was known as the experiment and it was but to be the nose consequently it applied to the magnetic materials and magnetic fluid, the optimal distance was solved between the coil and material.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.210-211
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• 2007

Once high current flows through the vacuum interrupter, eddy current occurs due to the time-varying axial magnetic field caused by the current(AC) and it causes a decrease in axial magnetic field generated by current flowing through coil electrode. but if there are slots on contact electrode it is possible to increase the amplitude of axial magnetic field by reducing the influence of eddy current. there has been many studies about the number of slot of the contact electrode[1][2][3]. In this paper, in addition to these previous results we deal with the influence of the length and width of the slots on axial magnetic field at the mid-gap plane in 4 segment coil type vacuum interrupter by using 3D finite element method software.

• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.41-44
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• 2015

Critical current of high-temperature superconducting (HTS) coil is influenced by its own self magnetic field. Direction and density distribution of the magnetic field around the coil are fixed after the shape of the coil is decided. If the entire part of the HTS tape has homogeneous $I_c$ distribution characteristic, quench would be initiated in fixed location on the coil. However, the actual HTS tape has inhomogeneous $I_c$ distribution along the length. If the $I_c$ distribution of the HTS tape is known, we can expect the spot within the HTS coil that has the highest probability to initiate the quench. In this paper, $I_c$ distribution within the HTS coil under self-field effect is simulated by MATLAB. In the simulation procedure, $I_c$ distribution of the entire part of the HTS tape is assume d to follow Gaussian-distribution by central limit theorem. The HTS coil model is divided into several segments, and the critical current of each segment is calculated based on the-generalized Kim model. Single pancake model is simulated and self-field of HTS coil is calculated by Biot-Savart's law. As a result of simulation, quench-initiating spot in the actual HTS coil can be predicted statistically. And that statistical analysis can help detect or protect the quench of the HTS coil.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.