• Journal of Magnetics
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• v.18 no.4
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• pp.481-486
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• 2013

An electromagnetic launcher (EML) system accelerates and launches a projectile by converting electric energy into kinetic energy. There are two types of EML systems under development: the rail gun and the coil gun. A railgun comprises a pair of parallel conducting rails, along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail, but the high mechanical friction between the projectile and the rail can damage the projectile. A coil gun launches the projectile by the attractive magnetic force of the electromagnetic coil. A higher projectile muzzle velocity needs multiple stages of electromagnetic coils, which makes the coil gun EML system longer. As a result, the installation cost of a coil gun EML system is very high due to the large installation site needed for the EML. We present a coil gun EML system that has a new structure and arrangement for multiple electromagnetic coils to reduce the length of the system. A mathematical model of the proposed coil gun EML system is developed in order to calculate the magnetic field and forces, and to simulate the muzzle velocity of a projectile by driving and switching the electric current into multiple stages of electromagnetic coils. Using the proposed design, the length of the coil gun EML system is shortened by 31% compared with a conventional coil gun system while satisfying a target projectile muzzle velocity of over 100 m/s.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2067-2073
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• 2018

This paper will present the design of a novel-type velocity-controllable electromagnetic coil launcher (EMCL). By studying the influence of initial capacitor voltage on the velocity of an EMCL, the launcher voltage can be set to precisely adjust the velocity of projectile launching. The simulation of voltage and velocity in relation to time is obtained by Maxwell software. The experimental data show that for the launch accuracy to be achievable, the actual precision is 2%. Because of the excellent performance of Velocity-controllable EMCL, it can replace the air gun and applied to split Hopkinson pressure bar (SHPB).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3455-3459
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• 2014

This paper reports the design and experiments for a high drive force of projectile in a coil gun system. Currently, the coil gun has been studied to apply an electromagnetic launcher. A coil gun launches a projectile by the attractive magnetic force of the electromagnetic coil. The drive force of projectile is proportional to the magnetic force generated by the electromagnetic coil. The current affects the life of the coil and the current limit exists. Therefore, the coil gun design, which does not exceed the current limit and the magnetic forces are at the maximum, is required. For this purpose, this study calculated the magnetic flux density and forces of the coil gun system and determined the current limit of the coil using the Onderdonk's equation. Based on the design result, a prototype was manufactured and an experiment was conducted to measure the muzzle velocity of the projectile. The fired projectile was analyzed using a CCD camera, and the muzzle velocity was 21m/s. In addition, a comparison of the experimental value and analysis value using commercial electromagnetic analysis software MAXWELL revealed an error of approximately 9.5%.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.402-404
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• 2006

Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이며 그 종류에는 레일건과 코일건이 있다 본 논문에서는 소형, 경량의 발사체를 추진, 가속시키기 위한 솔레노이드형 EML을 설계, 제작하여 시험 발사하고 그 특성을 분석하였다. 개발된 EML은 소형이기 때문에 launcher의 직경이 작아 자기장을 한 지점으로 집중시키는 장치가 필요없고, 전기에너지를 줄이기 위한 별도의 시스템이 필요하지 않으며, 솔레노이드의 형태와 발사체의 위치, 스위칭 시간에 의해 발사체의 추진력과 속도를 조절할 수 있는 장점이 있었다.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.74-82
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• 2013

This paper deals with a single stage coilgun which is a variety of EML(ElectroMagnetic Launcher) and can be applied to launching a small satellite. We propose a mathematical and physical model in order to design a single stage coilgun and study physical characteristics related to design parameters. A proposed mathematical and physical model is verified by electromagnetic FEM software FEMM 4.2.

• Journal of Magnetics
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• v.20 no.3
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• pp.322-329
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• 2015

This paper presents a new overlapped coilgun configuration to launch medium weight projectiles. The proposed configuration consists of a two-stage coilgun with overlapped coil covers with spacing between them. The theoretical operation of a multi-stage coilgun is introduced, and a transient simulation was conducted for projectile motion through the launcher by using a commercial transient finite element software, ANSOFT MAXWELL. The excitation circuit design for each coilgun is reported, and the results indicate that the overlapped configuration increased the exit velocity relative to a non-overlapped configuration. Different configurations in terms of the optimum length and switching time were attempted for the proposed structure, and all of these cases exhibited an increase in the exit velocity. The exit velocity tends to increase by 27.2% relative to that of a non-overlapped coilgun of the same length.