• Title/Summary/Keyword: Magnetic Field of Ship

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Prediction for Underwater Static Magnetic Field Signature Generated by Hull and Internal Structure for Ferromagnetic Ship (강자성 함정 선체 및 내부 장비에 의한 수중 정자기장 신호 예측)

  • Yang, Chang-Seob;Chung, Hyun-Ju;Ju, Hye-Sun;Jeon, Jae-Jin
    • Journal of the Korean Magnetics Society
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    • v.21 no.5
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    • pp.167-173
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    • 2011
  • Underwater static magnetic field signature for the naval ship has been widely used as the detonating source of the influence mine system because it is possible to make an accurate target detection in the near field although the magnetic field falls off relatively fast with distance in comparison with the underwater radiated noise signal. In this paper, we describe the prediction results about the underwater static magnetic field by the ferromagnetic hull, the internal structures and the main on-board equipment for the target vessel using the commercial FEM software. Also we analyze the degaussing effectiveness for the target vessel through the degaussing coils arrangement.

Development of Electronic Compass using Magnetic Sensors (자기 센서를 이용한 전자 컴퍼스 개발)

  • Hong, Chang-Hyun;Kim, Young-Chul;Chong, Kil-To
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.2
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    • pp.118-124
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    • 2008
  • Recently fishing industry is interested in efficiency and automation to acquire the international competitive power of national fishing industry. As an automation device of fishing boat, there are electric compasses using GPS and terrestrial magnetic sensor. Electric compass can be minimum size, high effectiveness with keeping the characteristic of a magnetic compass. This can be used a heading angle sensor to construct auto-navigation system in a small size ship. This paper develop electronic compass system that has serial output signal in NMEA 0183 and demonstrates the possibility of the electronics compass in navigation system for a small sized ship.

A study on the Electromagnetic Environment for the Navigation Device and Propulsion Device in Ship (선내 항해통신장비 및 추진장비에 대한 전자파환경 연구)

  • Cho, Hyung-Rae;Choi, Gi-Do;Kim, Jong-Woo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.15 no.1
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    • pp.87-94
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    • 2016
  • Although studies and investments on electro-magnetic fields in terrestrial areas are being conducted, they are not applied to a ship. Especially ship is consist of Top Side, Bridge, and Engine Room. Top Side is mounted Antenna and radar. Bridge is mounted navigation and navigation equipment that have a safe voyage. Finally, Engine Room is mounted switchboard and this is used to ship propulsion system. Therefore the purpose of this paper is for suggesting optimized standard to apply to marine environment through analyzing electromagnetic wave environment in ship. For this, we were measured EMF in Hanbada ship in Korea Maritime and Ocean University and we compared and analyzed to measured values in Korea standards and international standards. Consequently, Engine Room of ship for the identified that there are limits to apply. The proposed results of this research will be expected to utilize for establishing standard a plan for EMF in ship.

Indirect Fault Detection Method for an Onboard Degaussing Coil System Exploiting Underwater Magnetic Signals

  • Jeung, Giwoo;Choi, Nak-Sun;Yang, Chang-Seob;Chung, Hyun-Ju;Kim, Dong-Hun
    • Journal of Magnetics
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    • v.19 no.1
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    • pp.72-77
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    • 2014
  • This paper proposes an indirect fault detection method for an onboard degaussing coil system, installed to reduce the underwater magnetic field from the ferromagnetic hull. The method utilizes underwater field signals measured at specific magnetic treatment facilities instead of using time-consuming numerical field solutions in a three-dimensional space. An equivalent magnetic charge model combined with a material sensitivity formula is adopted to predict fault coil locations. The purpose of the proposed method is to yield reliable data on the location and type of a coil breakdown even without information on individual degaussing coils, such as dimension, location and number of turns. Under several fault conditions, the method is tested with a model ship equipped with 20 degaussing coils.

Analysis of mechanical characteristics of superconducting field coil for 17 MW class high temperature superconducting synchronous motor

  • Kim, J.H.;Park, S.I.;Im, S.H.;Kim, H.M.
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.3
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    • pp.13-19
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    • 2013
  • Superconducting field coils using a high-temperature superconducting (HTS) wires with high current density generate high magnetic field of 2 to 5 [T] and electromagnetic force (Lorentz force) acting on the superconducting field coils also become a very strong from the point of view of a mechanical characteristics. Because mechanical stress caused by these powerful electromagnetic force is one of the factors which worsens the critical current performance and structural characteristics of HTS wire, the mechanical stress analysis should be performed when designing the superconducting field coils. In this paper, as part of structural design of superconducting field coils for 17 MW class superconducting ship propulsion motor, mechanical stress acting on the superconducting field coils was analyzed and structural safety was also determined by the coupling analysis system that is consists of commercial electromagnetic field analysis program and structural analysis program.

Empirical model of over-all ship's magnetism (총체적 선체현장의 실험모델)

  • 박길현;정태권;이상집
    • Journal of the Korean Institute of Navigation
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    • v.13 no.3
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    • pp.1-20
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    • 1989
  • In order to provide a basic information to locate the sensor of remote-indicating magnetic compass onboard, an empirical model for the over-all ship's magnetism was developed based on the periodicity of the observed magnetic field around the vessels. The values of model parameters were determined by least-square method and optimum numbers of them were fixed using Akaike's information criterion theory, and also an approximation method to determine parameter was proposed based on the symmetrical characteristic of observed data versus ship's length. The confidence level of the newly developed models was tested by analysis of variance method. The agreement between the modelled and real values was found to be remarkably accurate.

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Conceptual Design of a 5 MW HTS Motor (5 MW 고온초전도 모터 설계)

  • Baik, S.K.;Kwon, Y.K.;Kim, H.M.;Lee, J.D.;Kim, Y.C.;Park, H.J.;Kwon, W.S.;Park, G.S.
    • Progress in Superconductivity and Cryogenics
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    • v.10 no.3
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    • pp.36-42
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    • 2008
  • The superconducting motor shows several advantages such as smaller size and higher efficiency against conventional motor especially utilized in ship propulsion application. However, this size reduction merit appears in large capacity more than several MW. We are going to develop a 5MW class synchronous motor with rotating High-Temperature Superconducting (HTS) coil. that is aimed to be utilized for ship propulsion so it has very low-speed, The ship propulsion motor must generate very high electromagnetic torque instead of low-speed. Therefore. the rotor (field) coils need very large magnetic flux that results in large amount of expensive HTS conductor for the field coil. In this paper a 5MW HTS motor for ship propulsion is considered to be designed with construction cost reduced via HTS field coil cost reduction because HTS conductor cost is critical factor in the construction cost of HTS motor. In order to reduce the HTS conductor amount. iron-cored rotor types are considered. so several cases with iron-core are compared one another and with an air-core case.

Demagnetization to Induce Vertical Magnetization in a Military Vessel (함정에 수직자화를 부여하기 위한 탈자)

  • Kim, Young-Hak
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.1109-1112
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    • 2015
  • A milatary ship without degaussing coil has a vertical magnetization to compensate magnetization induced by the vertical magnetic field component of earth magnetic field during demagnetization process. Flash D is very useful to acquire vertical magnetization. However this is hard to predict vertical magnetization. This experiment was investicated on another method, which used the only vertical bias magentic field. The specimens were prepared by thin Zn coated steel sheet with a thickness of 0.15mm. The shapes of 3 specimes was rectangular, triangular and circular cylinders. These shapes were corresponded to the shapes of bow, mid and stern of a vessel. Through FEM analysis, the difference of magnetic signatures for these specimens was recognized and the residual magnetization curve was measured. magnetic field was generated by a solenoid coil and magnetic signature was measured by a magnetic field sensor. A linearity between a vertical bias magnetic field and a vertical manetzation existed and the vertical magnetization of a miltary vessel was predicted by the linearity.

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A Study on Actuation Probability of Underwater Weapon Based on Magnetic Field (Magnetic Field 기반 수중무기체계 발화확률에 관한 연구)

  • Lim, Byeong-Seon;Hong, Sung-Pyo;Kim, Young-Kil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.5
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    • pp.1253-1258
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    • 2013
  • This Paper deals with detection and defense methods for underwater weapons because there are so many dangers of underwater weapons not only in the war period but also in the peace time. Underwater mines are the representative strategic arms. The sensors and target detection methods, threat elimination method of mines included in this paper. Among the various sensors of mine, we use the magnetometor for target detection method in the simulation and execute the analysis of magnetic field of detected target ships. It will be also provided that effectiveness of target detection, sweeping method of mine, tactics of mine planning and mine sweeping and so on.

Verification of Optimum Degaussing Technique through the Mock-up Test of a Ship (축소 함정을 이용한 최적 소자기법 검증)

  • Kim, Dong-Wook;Choi, Nak-Sun;Kim, Dong-Hun;Yang, Chang-Seob;Chung, Hyun-Ju
    • Journal of the Korean Magnetics Society
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    • v.24 no.4
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    • pp.107-113
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    • 2014
  • In this paper, a optimum degaussing technique, which can minimize an underwater magnetic field anomaly generated by the ferromagnetic hull, was verified through the mock-up test of a ship. To predict degaussing field signals due to the degaussing coils installed in a ship, individual coil effects were measured. Exploiting the linearity of coil effects and analytical sensitivity formula, optimum degaussing current values fed to individual coils were decided. To identify degaussing performance of the proposed method, the obtained degaussing currents were applied to the coils. Then the field anomaly signals were measured and analyzed before and after degaussing. Experimental results show the magnitude of the field signal after degaussing is reduced up to 95% of that before degaussing.