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Aihara S.,Nishi Nippon Electrical Wire and Cable Co. | Shimoji H.,Oita University | Todaka T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita Prefectural Organization for Industry Creation
IEEE Transactions on Magnetics | Year: 2012

This paper presents measured local vector magnetic properties in a transformer type model core made of a laser-scratched grain-oriented electric steel sheet by using a vector-hysteresis (V-H) sensor. The V-H sensor consists of B-needle probes for measurement of the magnetic flux density vector B and double H-coil for measurement of the field strength vector H. The distance between the B-needle probes was shortened to be 2.5 mm and a 2 mm × 2 mm-sized double H-coil was mounted on the sensor head to realize higher resolution. The measurement accuracy of the B-needle probes was confirmed with a spatial probe, which can change the needle distance from 2 mm to 20 mm. The results show that the detailed local two-dimensional vector magnetic properties depending on laser-scratches are measurable with the developed new sensor. © 1965-2012 IEEE.


Kutsukake A.,Oita Prefectural Organization for Industry Creation | Kido Y.,Oita Prefectural Organization for Industry Creation | Ikeda T.,Oita Prefectural Organization for Industry Creation | Kanada T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita University
IEEJ Transactions on Fundamentals and Materials | Year: 2012

The accurate magnetic properties of electrical steel sheets are important to develop high-efficiency electromagnetic devices. Especially, the H-coil method is a useful measurement technique of accurate magnetic field strength in single sheet tester. Therefore, we developed the tester of magnetic properties using the H-coil method, we called it the Stress load type - Single Sheet Tester (S-SST), and a problem was found in the iron loss measurement at high flux density, 1.6T or more. In this paper, it is shown that the cause of this problem is phase difference between induced voltage in H-coil and B-coil. In order that the phase difference make BH loop slightly twisted near the tip point, the iron losses are evaluated low. So, we propose the method of determining of phase correction values, these are measured in the absence of a specimen in the S-SST measurement system, and the phase correction method for induced voltage in a coil. Finally, the ideal results of correction on iron loss of non-oriented electrical steel sheets are shown. The proposed method is effective in calibration of a single sheet tester using the H-coil method. © 2012 The Institute of Electrical Engineers of Japan.


Kanada T.,Oita Prefectural Organization for Industry Creation | Kido Y.,Oita Prefectural Organization for Industry Creation | Kutsukake A.,Oita Prefectural Organization for Industry Creation | Ikeda T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita University
Przeglad Elektrotechniczny | Year: 2011

The measurement is carried under the tensile and compressive stresses on non-oriented electrical steel sheets and amorphous sheet, 100×500mm. They are measured by stress load type SST. The results of magnetic power loss and magnetization curve on NO steel sheet in case of no stress, tensile stress 15MPa and compressive stress 15MPa are shown. It is clear that the effect of tensile stress is not so remarkable, though compressive stress affects the magnetic properties greatly. Three types of amorphous sheet, as cast, annealed and annealed in magnetic field were measured.


Shimoji H.,Oita Prefectural Organization for Industry Creation | Shimoji H.,Oita University | Todaka T.,Oita University | Enokizono M.,Oita University
Przeglad Elektrotechniczny | Year: 2011

The aim of this study is to measure the distribution of core loss in electrical steel sheets by using a thermographic camera. This paper describes the measurement system and method, along with their underlying principles. Measurement problems are investigated, and the measurement accuracy is determined. The iron loss distributions are presented, as measured under various conditions on vector magnetic measurement equipment.


Ueno T.,Oita National College of Technology | Aihara S.,Nishi Nippon Electrical Wire and Cable Co.Ltd | Gotoh Y.,Oita Prefectural Organization for Industry Creation
Materials Science Forum | Year: 2013

Transcranial Magnetic Stimulation (TMS) is a noninvasive method to cause depolarization or hyperpolarization in the neurons of the brain. The recent research has developed a novel magnetic coil that can generate higher magnetic field than a conventional coil and have converging capability, which would require a larger exciting current. In this research, a thyristor as a switching device was used for high current switching. The thyristor is a device of current drive. The current differences of each circuit in parallel connected thyristors were measured by changing gate voltage and gate rise time. The gate drive characteristic of parallel connected thyristors was also confirmed. © (2014) Trans Tech Publications, Switzerland.


Ohnishi O.,University of Miyazaki | Doi T.,Kyushu University | Kurokawa S.,Kyushu University | Takahashi K.,Mitsui Engineering and Shipbuilding Co. | And 3 more authors.
International Journal of Nanomanufacturing | Year: 2014

The present paper deals with the micro drilling into silicon carbide (SiC) with micro polycrystalline diamond (PCD) drills. Micro PCD drills with a nominal diameter of 300 m were fabricated by wire electrodischarge machining and they were used to drill into SiC test pieces with or without ultrasonic vibration. In the drilling test, performance of drilling into SiC was investigated. As the result of the drilling test, it was possible to make holes with good shape under all conditions. Large feed condition led to large chipping around hole entrance, bad surface roughness of hole wall and a shortened tool life. On the other hand, effects of ultrasonic vibration on chipping, surface roughness of hole wall, chip form and tool life were unclear, but the surface appearance of holes drilled with ultrasonic vibration did not seem to be affected so much by increase of feed. © 2014 Inderscience Enterprises Ltd.


Shimoji H.,Oita Prefectural Organization for Industry Creation | Shimoji H.,Oita University | Borkowski B.E.,Oita Prefectural Organization for Industry Creation | Borkowski B.E.,Oita University | And 2 more authors.
IEEE Transactions on Magnetics | Year: 2011

In recent years, high-power electric motors have been mounted on mobile platforms such as electric vehicles. These motors are required to be compact, lightweight, and highly efficient. The reduction of core loss that occurs in electrical steels is an important factor in efficiency. Because core loss is ultimately converted into heat, it can be estimated by measuring the amount of heat generated. Methods for directly measuring the core loss in electrical steel sheets with thermistors and thermocouples have been proposed, but in these methods, many constraints complicate the measurements. In addition, the measurements are not suitable for a large number of sampling points. The aim of this study is to measure the distribution of core loss in electrical steel sheets by using thermography. © 2011 IEEE.


Kutsukake A.,Oita Industrial Research Institute | Kido Y.,Oita Industrial Research Institute | Ikeda T.,Oita Industrial Research Institute | Kanada T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita University
International Journal of Applied Electromagnetics and Mechanics | Year: 2014

A study is carried out based on the evaluation of IEC-standard. Two measurement results on N.O. magnetic steel sheets, one from S-SST (Stress load type single sheet tester developed in our research laboratory), another is from SST based on the IEC standard regulation, are compared and discussed. As a result of the measurements, both magnetization curves coincide mostly, but magnetic power loss determined by IEC method is larger than that achieved by S-SST. The differences between them may be caused by magnetic field strength evaluation for each measurement method, magnetizing current method for IEC-type-SST and H-coil method for S-SST. The effective magnetic path is regulated in IEC but actually this may be variable according to the type of magnetic sheet, the structure of the SST and of applied magnetic field strength. In order to discuss this point, a virtual magnetic path length is introduced by using the applied magnetic field strength. © 2014 - IOS Press and the authors.


Ohnishi O.,Kyushu University | Onikura H.,Kyushu University | Mizue H.,Oita Industrial Research Institute | Kido Y.,Oita Prefectural Organization for Industry Creation | And 2 more authors.
Proceedings of the 10th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2010 | Year: 2010

The present paper deals with the micro drilling into quartz glass with micro polycrystalline diamond drills, hereafter called micro PCD drills. Micro PCD drills with a nominal diameter of 300 μm are fabricated by wire electro-discharge machining, hereafter called wire-EDM. The fabricated drills have various shapes. The fabricated drills are used in the drilling into quartz glass with or without ultrasonic vibration and influences of drill geometry are investigated. As the result, it is found that a certain geometry of drill improves quality of hole entrance and hole wall. © euspen Headquarters.


Shimoji H.,Oita Prefectural Organization for Industry Creation | Borkowski E.B.,Oita Prefectural Organization for Industry Creation | Todaka T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita Prefectural Organization for Industry Creation | And 2 more authors.
Proceedings of the International Conference on Sensing Technology, ICST | Year: 2012

Pulsed high magnetic field generator up to 33T with a long pulsed half-width of 70ms was constructed. Effective fields of coercivity in Nd-Fe-B sintered samples were measured in the pulsed high fields. The measurement errors were estimated experimentally and also by numerical simulations using EMAG. We found errors of coercivity fields of more than 30 % in these samples and discussed on the relationship among the sample insertion gaps in the probe and the systematic errors. © 2012 IEEE.

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