| Project/Area Number |
12450111
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | The University of Tokushima |
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Principal Investigator |
ISAKA Katsuo The University of Tokushima, Faculty of Engineering Professor, 工学部, 教授 (50035630)
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| Co-Investigator(Kenkyū-buntansha) |
HIROYUKI Tarao Takamatsu Narional College, Assistant, 助手 (00321498)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Occupational exposure / ELF / Extremely low frequency / Electromagnetic field / Welding / Students experiment / Magnetic field measurement / Induced Current / 電気溶接 / 磁界 / 電界 / ホール素子 / 電磁界暴露評価 / 磁界波形 / 電力線 / スペーサ点検 / 職場 / 暴露評価 / 電力 / VDT |
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| Research Abstract |
On the basis of the experience of measuring electromagnetic exposures in the occupation sites like electric power, welding, electromagnetic induction heating, railroad and iron steel works, a survey was made of measuring the exposure of 7 students performing experiments in the lab time to magnetic fields. The five of them carried EMDEXII meters and the two EMDEX MATE meters during the lab. They also performed experiments associated with electric power systems. As a result, it has been found that time-weighted average of the exposure exceeds 100 μT for relay and welding experiments.
A novel meter was developed for measuring the AC magnetic field superimposed on DC one that appears at the time of welding using a DC source. Some Hall elements were successfully connected in series to detect and observe such a magnetic field.
In order to reduce the exposure of welders to magnetic fields, several mitigation measures were proposed : (1)A welder should be out of the loop line conductor carrying a welding current, (2)The line conductor should be close enough so that the magnetic fields are cancelled each other. (3)A long line conductor should not be placed in a loop manner on the ground. The impedance method was introduced to evaluate the induced current density in the welder. It is found from the computer simulation that this method is applicable to compare the maximum induced current to the basic restriction specified by ICNIRR.
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