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Magnetics, IEEE Transactions on

Issue 1  Part 1 • Date Jan. 2003

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Displaying Results 1 - 25 of 103
  • 11th Symposium on Electromagnetic Launch (EML) Technology [Covers & ToC]

    Publication Year: 2003
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  • Electric launch science and technology in the United States

    Publication Year: 2003 , Page(s): 11 - 17
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB) |  | HTML iconHTML  

    For electromagnetic launchers, most of the effort is directed toward improved computational tools, exploitation of these tools for detailed understanding of transient electrodynamic phenomena, novel diagnostics, and experiments to resolve remaining critical issues such as transition from solid to arc contacts in railguns, improved computational techniques for pulsed power systems, and application of these tools to design new high-energy pulsed-power sources. New methods of testing and determining the critical properties of advanced materials, such as composites, are being developed to enable these materials to be evaluated in extreme thermal and electromechanical environments. Additionally, the U.S. Navy is also in the process of initiating hypervelocity electromagnetic launch efforts for extremely long-range artillery systems employing high-G novel projectiles. Other applications of electric launch technology, such as hypervelocity powder deposition and electromagnetic gun launch to space, continue to offer new and interesting opportunities. View full abstract»

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  • U.K. electric gun national overview

    Publication Year: 2003 , Page(s): 18 - 21
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    This paper reviews the electric gun research carried out in the U.K. since the last Electromagnetic Launch Symposium in 2000. Both electromagnetic (EM) and electrothermal-chemical (ETC) guns are covered, ranging from fundamental small- and medium-scale studies through to evaluation of the technologies at full scale. EM gun research has continued at large caliber (90 mm) with a combination of base push and midride integrated sabot-armature designs. Data for use in launcher and launch package design has been sought through the development of in-bore instrumentation. Lightweight launcher concepts have been generated and analyzed using techniques including finite-element analysis. ETC gun research has continued to focus on assessing the viability of using the technology to improve the performance of 155-mm indirect fire gun systems. In parallel, work is underway to explore the use of the technology for direct fire systems. Significant progress has been made toward a better understanding of the fundamental science of capillary plasma generators, plasma ignition, the propagation of plasma into the combustion chamber, and its interaction with the propellant. View full abstract»

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  • Overview of ETC research in Korea

    Publication Year: 2003 , Page(s): 22 - 23
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB) |  | HTML iconHTML  

    In late 2000, an experimental 30-mm electrothermal-chemical (ETC) gun, a data acquisition system, and a 2.4-MJ pulse-forming network (PFN) consisting of eight 300-kJ modules were constructed, and serious research projects were started. During the past years, basic studies on the effect of the electric pulse in the process of ignition and propulsion of the gun have been done. Two types of ammunition, an exploding wire cartridge and a capillary plasma injector cartridge, were used in the experiments. The load resistance should be estimated well in order to deliver electric energies into the combustion chamber as a desired form in time. For that purpose, there has been an effort to model the load resistance of the ETC gun, which shows the dependence on the pressure of the combustion chamber. A study on a capillary plasma itself is also an important topic and is now in the beginning stage of research using spectroscopic diagnostics. The capillary plasma discharged in the open air provides useful information through the comparison with that discharged in the ETC gun. In the development and operation of the PFN, some problematic characteristics such as a high-voltage surge leading to a destruction of crowbar diodes occurred. A countermeasure was presented to solve the problem. High-current switches are also being studied. Vacuum rotary arc gap switch, pseudospark switch, triggered vacuum switch, and inverse-pinch switch are being studied for better and reliable operations. The ETC program in Korea is currently concentrating on the detailed investigation on the interaction of a plasma with propellants. View full abstract»

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  • Overview of the electric launch activities at the French-German Research Institute of Saint-Louis (ISL)

    Publication Year: 2003 , Page(s): 24 - 28
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (641 KB) |  | HTML iconHTML  

    An overview of the Research Institute of Saint-Louis (ISL) activities and program on electric guns is presented. Experimental and/or numerical results for the railgun, electrothermal-chemical (ETC) guns, and pulse-forming networks (PFNs) are reported. The ISL railguns are supplied by fast-discharge capacitors and use projectiles provided with metallic brush armatures. Velocities up to about 2000 m/s are reached without any arcing. The 10-MJ distributed energy storage railgun facility PEGASUS has proved to have an overall efficiency over 30%. Velocities of 2300 m/s have been achieved with this facility, the projectile masses ranging from 350 to 650 g. The energy storage of the facility consists of 200 PFN units of 50 kJ equipped with semiconductor switches. The objective of the ETC program is to ignite a high-loading-density solid propellant (SP) with small electrical energy and power. Some recent ISL studies have determined the minimum energy and power levels needed to ignite the powder of a 20-mm, a 60-mm, and a 120-mm gun by means of a plasma. Tests with a 20-mm gun allowed the ignition of an SP with a loading density of 1.3 g/cm/sup 3/. The studies of high-power semiconductor switches have led to the development and construction of a thyristor with a blocking voltage of 11 kV and a crowbar diode with a blocking voltage of 12 kV. A fast semiconductor switch developed by ISL and Asea Brown Bovery Semiconductor Company with a highly interdigitated gate has an excellent turn-on capability with current rates dI/dt>15 kA//spl mu/s. First studies on solid-state opening switches demonstrated the possibility of switching off a current of about 20 kA. A steerable electromagnetic launcher based on pancake coils is studied as an active armor system. The launcher is fed by capacitor modules characterized by peak currents of 120 kA and current rates of about 2.5 kA//spl mu/s. Experimental tests have demonstrated that the trajectory can be selected in the range of /spl plusmn/- 5/spl deg/ with an angle error less than /spl plusmn/0.5/spl deg/. Protection elements are ejected at a velocity of about 245 m/s with an overall efficiency of 25%. View full abstract»

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  • Results of recent research on electromagnetic launch technology in Russia

    Publication Year: 2003 , Page(s): 29 - 34
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (361 KB) |  | HTML iconHTML  

    This paper presents the most important research results obtained during the past two years and the main prospects for the electromagnetic, electrodischarge, and electrothermo-chemical (ETC) launch technologies. This research has been focused on the development and improvement of electric launchers. Pulsed-power supplies and technological aspects have also been studied. Among the most interesting results are the design of a combined electrodischarge accelerator, results of studies of a high-current electric discharge in superdense hydrogen at initial particle concentrations of up to 4/spl times/10/sup 22/ cm/sup -3/ at the Institute of Problems of Electrophysics of Russian Academy of Sciences (IPE RAS), and results of integrated studies of rail launchers performed at the TRINITI, Lavrent'ev Institute of Hydrodynamics, High-Temperature Institute, and Ioffe Physico-Technical Institute. Much attention has been given to promising types of propellant for ETC launchers and methods of their ignition. These investigations have been performed at the Institute of Applied Mathematics and Mechanics, Tomsk State University. Research aimed at improving characteristics of important element of pulsed-power sources - high-current switches - has been conducted at the All-Russian Electrotechnical Institute and at the Ioffe Physico-Technical Institute. View full abstract»

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  • National overview of the German ETC program

    Publication Year: 2003 , Page(s): 35 - 38
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (627 KB) |  | HTML iconHTML  

    Today's investigations on electrothermal-chemical (ETC) guns concentrate on different methods of electrothermal plasma ignition technologies to be combined with ETC tailored propellants and their charge designs. It is the goal to obtain increased gun performance in terms of muzzle energy, muzzle velocity, and temperature compensation of the propellants. In the German ETC program, governmental agencies, research institutes, and industry are involved to investigate proper ETC technologies to be applied in large-caliber guns. Basic investigations as well as large-caliber firing demonstrations are included in the program. It is the goal of the current ETC phase to demonstrate muzzle energies up to 15 MJ out of a 120-mm smooth-bore gun barrel under operating conditions. This paper gives an overview of the program structure and briefly addresses the content of the subprograms performed in institutes as well as of the industrial investigations. View full abstract»

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  • Widely developing electric launch technology in China

    Publication Year: 2003 , Page(s): 39 - 41
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (287 KB) |  | HTML iconHTML  

    It can be seen from the 20 abstracts submitted to the 11th Electromagnetic Launch (EML) Technology Symposium by five Chinese departments, that China is developing extensive electric launch technology. At least four Chinese ministries support the experimental research on electrothermal launch technology, electromagnetic rail launch technology, coil launch technology, and reconnection launch technology, respectively. There is also research being done on the electric armor and electromagnetic pumping technologies that are correlative with the electric launch technology. Some other ministries have established various foundations to support the theoretical research on electric launches. In addition, international cooperation in science and technology is under way. For example, we are currently doing cooperative experimental research on the electromagnetic launch with some foreign experts, and coauthoring a book titled Physics of Electric Launch (English version). China emphasizes the cultivation of successors on the electric launch technology. Since the first Peter Kemmy Memorial Student Scholarship was awarded to a Chinese young scholar in 1998, more universities have begun to offer courses in electric launch technology for undergraduates as well as for Master's and Ph.D. degree students. Furthermore, some postdoctoral researchers are researching electric launch technology in their theses. To organize and unite national researchers on electric launch technology, encourage more people to enter the field, and stimulate further development, recently we have initiated to establish the "China Electromagnetic Launch Society." The establishment of the Society makes it convenient for us to accept the lead of the international EML Permanent Committee, and to offer an opportunity of academic exchange and cooperation from home and abroad. View full abstract»

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  • Magnetic blow-off in armature transition

    Publication Year: 2003 , Page(s): 42 - 46
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB) |  | HTML iconHTML  

    Magnetic blow-off forces play an important role in arcing and failure of electrical joints and contacts in electrical systems under high current fault conditions. Magnetic blow-off forces arise from concentration of current in the contact interface and tend to blow the contacts apart, causing separation and arcing. Simple models have been developed to predict the magnitude of these forces and permit the design of joints and contacts that can successfully resist the forces. In this paper, the role of magnetic blow-off in railgun armature contacts is explored. It is shown that magnetic blow-off forces are important and may be the final step in a series of events that ultimately leads to transition. Models that predict the conditions under which blow-off will occur are developed, and supporting experimental data is described. View full abstract»

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  • A survey of armature transition mechanisms

    Publication Year: 2003 , Page(s): 47 - 51
    Cited by:  Papers (53)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (323 KB) |  | HTML iconHTML  

    Over the last two decades, several mechanisms of armature transition have been postulated. Each mechanism has been subjected to experimental and analytic examination with the objective of "explaining" transition. However, no single mechanism has emerged as the consensus cause of transition. In this paper, we take the position that all the mechanisms that have been identified, and perhaps others which have not yet been, contribute to and may be mutually influenced by those processes leading to the onset of transition. Our inability to correlate transition with a single mechanism, or model, results from the multiplicity of mechanisms at work. We examine all the mechanisms identified to date, suggest several additional ones, and explore a more complex transition world in which each transition event is potentially caused by a different mechanism or combination of mechanisms. With this picture, control of transition requires that we control all of the mechanisms which can result in transition, not just one. View full abstract»

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  • Why "C" armatures work (and why they don't!)

    Publication Year: 2003 , Page(s): 52 - 55
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (341 KB) |  | HTML iconHTML  

    While plasma armatures perform well at high velocities, they have severe effects on railguns at the shot start position. Solid armatures overcome this factor but perform less well as velocities increase. Many types of solid armature have been tried, including metal fibers and magnetic obturator types, but the classic "C" type remains the armature of choice for high-velocity projectile launches. The recovery of fired armatures at the Kirkcudbright range has allowed many of these ideas to be formulated. This paper looks at what happens to "C" types, explains the basic processes occurring as the armature gains velocity, and identifies the limitations of this design. It offers suggestions for improving performance, including materials and design options, with outline results in some areas, and offers some design characteristics to be considered with this classic armature shape. Comparison with alternative armature concepts is briefly made so as to present an overall view. View full abstract»

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  • Why solid armatures fail and how they can be improved

    Publication Year: 2003 , Page(s): 56 - 61
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    Failure of electromagnetic launch (EML) solid armatures can be caused by various mechanisms, but a critical performance limit is due to arcing at the rail/armature contact surface above the transition velocity. A previous theoretical transition model based on velocity skin effect and current wave (VSE/CW) phenomena is reviewed and further data of the changing current distribution at the contact surface is derived as the vaporization current wave moves forward until the arcing transition occurs. This VSE/CW model predicts experimental transition velocities with reasonable accuracy over a wide range of parameters (bore size from 15 to 90 mm). To achieve the required contact pressure distribution with the optimum contact region geometry, monolithic armatures are considered to be necessary, which is consistent with the highest transition velocities being achieved with such aluminum alloy armatures. Possible improvements in the performance of solid armatures are evaluated for monolithic armatures with copper rails by optimizing armature geometry, dimensions, contact pressure distribution, and the use of resistive contact region materials. An increase of >40% in transition velocity to >2.5 km/s is predicted above reported experimental results. View full abstract»

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  • An optimized double ramp integrated launch package design for railguns

    Publication Year: 2003 , Page(s): 62 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (367 KB) |  | HTML iconHTML  

    The need to evolve and make more efficient design tools for use in complex railgun system trade studies has led to an enhanced design for a fully integrated hybrid metal contact launch package for railguns. During work on two successful railgun projects at The University of Texas at Austin Center for Electromechanics (UT-CEM), an algorithm was designed which has produced what appears to be a strong design candidate for an aluminum double ramp integrated launch package (ILP). Using only four user inputs, the code produces railgun bore configurations (simple or augmented) and detailed ILPs which minimize the energy requirements for the compulsator. The output design gives useful mass fractions very close to the pinnacle of what is possible without more extensive use of composites. This paper describes the design process used to optimize the railgun bore and ILP. Included is an advanced concept generated by the algorithm along with a detailed three-dimensional structural analysis of the ILP based upon a current profile that is relevant for high-performance applications. View full abstract»

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  • Electrodynamics of the current melt-wave erosion boundary in a conducting half-space

    Publication Year: 2003 , Page(s): 66 - 71
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB) |  | HTML iconHTML  

    An analytic model of the current melt wave in a one-dimensional stationary conductor has been developed to gain insight into the complex problem of melt-wave erosion contact wear in railgun armatures. Unlike two-dimensional models with motion, in which the dominant driving mechanism for the erosion front is current concentration from the velocity skin effect, in one dimension, the driving mechanism is a concentration of current caused by the electrodynamics at the melt-wave erosion boundary. Specifically, as molten material is ejected, current is driven into the remaining solid material at the interface, resulting in a local concentration of current and joule heating at the interface. We derive an expression for the velocity of the melt-wave front in one dimension, and assess the importance of this effect by comparing the erosion speed we obtain with erosion speeds predicted by previous models. The comparison suggests that the electrodynamics of the moving melt-wave boundary has an insignificant effect on melt-wave erosion in solid armature railguns, and as such can be justifiably neglected. View full abstract»

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  • Effect of geometry change on the current density distribution in C-shaped armatures

    Publication Year: 2003 , Page(s): 72 - 75
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (874 KB) |  | HTML iconHTML  

    High-current densities in the armature of an electromagnetic launcher can lead to high local temperature and consequent loss of strength and even melting and erosion. In this paper, we examine if the peak current density distribution can be made more uniform by altering the armature geometry. Finite-element analyses using Electromechanical Analysis Program in Three Dimensions (EMAP3D) showed how the current is distributed in a baseline C-shaped armature. By curving surface edges and strategically adding and subtracting material from the original armature, a new model was constructed that had a better current density distribution. Thus, altering the armature design could lead to reduced possibility of transition in the electromagnetic gun. View full abstract»

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  • Transition in brush armatures

    Publication Year: 2003 , Page(s): 76 - 81
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (731 KB) |  | HTML iconHTML  

    The use of metal fiber brush armatures incorporated in sabots made of insulating low-density materials in distributed energy storage (DES) railguns requires the avoidance of permanent high-current plasma arcs (contact transition). The resulting plasma might damage the sabot and may also lead to the malfunction of the DES system. In order to determine critical parameters concerning the transition of brush armatures, a series of experiments was performed using the ISL-EMA3 railgun (DES, 3 m, 15/spl times/30 mm/sup 2/, 620 kJ). The maximum muzzle velocity obtained during these experiments was about 1200 m/s. A qualitative model of brush-rail contact, assuming that contact transition is mainly due to mass loss of brushes, is presented. The mechanisms causing mass loss were investigated. It could be shown that joule heating is primarily limiting brush armature performance, while friction is not negligible. View full abstract»

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  • Analysis of physical effects on the electrode surfaces in rail launchers

    Publication Year: 2003 , Page(s): 82 - 85
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2280 KB) |  | HTML iconHTML  

    This paper analyzes some physical effects that occur on the electrode surface in plasma-armature rail launchers when the linear current density is higher than the critical value. The melt on the electrode surface is found to be unstable. An analysis of the possible development of a number of instabilities showed that under experimental conditions, Rayleigh-Taylor and Kelvin-Helmholtz instabilities and magnetohydrodynamic instabilities due to the interaction of the current with the self-magnetic field can develop over times much smaller than the discharge time. As a result, the electrode material can enter the plasma armature, thus limiting projectile velocity. X-ray recording of the electrode surface confirmed the presence of small-scale inhomogeneity and ejection of the electrode material from the surface. Under certain conditions, the emergence of conducting metal jets from the electrode surface was detected. View full abstract»

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  • Progress on developing the "magnetic obturator," a novel railgun armature

    Publication Year: 2003 , Page(s): 86 - 91
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB) |  | HTML iconHTML  

    The "magnetic obturator" is an armature concept developed by IAP Research in the late 1980s. Advantages of the magnetic obturator include lower mass than conventional "C-type" railgun armatures (approaching the theoretical minimum mass), compatibility with mid-drive sabots, and the potential for nontransitioning operation. The Institute for Advanced Technology (IAT) at The University of Texas at Austin began testing magnetic obturators in 1997. Our tests showed that magnetic obturators can operate very well, but not yet as reliably as C-type armatures. This paper discusses experiments conducted to understand and resolve several recurrent problems that include difficulties associated with start-up, high contact pressures leading to local yielding of copper rails, and susceptibility to develop intermittent arcing contact before transition. This paper reports our progress in addressing these three areas and presents recommendations for further research. View full abstract»

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  • Experiments to assess structural loads during solid armature contact transition

    Publication Year: 2003 , Page(s): 92 - 96
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1199 KB) |  | HTML iconHTML  

    The objective of the work is to characterize the force developed at the rail-armature interface during contact transition. Solid armatures were accelerated up to 2.5 km/s, with peak currents on the order of 1 MA. The armature contacts were allowed to naturally transition, an event that typically occurred on the decaying portion of the current pulse. Deflections of unsupported steel rods launched with an armature were measured from flash X-ray images taken at muzzle exit. In-bore X-rays were used on a few tests to refine the time at which the maximum rod deflection occurred. The highest velocity tests provided further data on armature deformation. In addition to the experiments, a coupled electromagnetic-structural dynamics code was used to compute the rod and armature deformations based on a range of assumed pressure profiles at the rail-armature interface and under a variety of boundary conditions. Reasonable agreement between the calculations and experiment was obtained with an interface pressure of approximately 550 MPa (80 ksi) applied over the smallest mesh area available at the leading edge of the front contact (25 kN). In future work, this load can then be used as input to structural mechanics calculations to further increase the survivability of hypervelocity long-rod penetrators. View full abstract»

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  • Reduction in fluctuation of the accelerating force in linear induction launchers

    Publication Year: 2003 , Page(s): 97 - 102
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (463 KB) |  | HTML iconHTML  

    In a linear induction launcher, both the barrel and the projectile are of finite length. This causes the force-displacement curve to have a jagged shape. The reasons are: the barrel is partitioned into sections; end effects are present; dc components exist in the input currents; and the drive coils are of finite width. The first three factors were dealt with in our previous publications. This paper describes how to improve the performance of a four-section linear induction coil launcher, powered by synchronous generators, by redesigning the drive coils so that they may be fed by a five-phase source rather than the customary three. The paper presents the drive-coil design criteria, the reasoning behind the selection of the firing sequence for each of the four sections, and the improved accelerating force curve. View full abstract»

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  • Analysis of the performance of a combined coil-rail launcher

    Publication Year: 2003 , Page(s): 103 - 107
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    An electromagnetic system that operates both as a rail and as a coil launcher is proposed, and its performance is analyzed. The device has a composite stator that consists of two rails properly slotted in order to allow the presence of a system of coils. The armature consists of a conductive slab sliding between the rails. Another system of slots is present in the armature where a system of short-circuited coils is placed. A source of constant voltage is connected to the rails and the current flowing in the armature through the sliding contacts produces a thrust force on it. If a proper system of currents able to produce a traveling wave of flux density in the region between the rails is used to feed the barrels, the induced currents that flow in the armature's short-circuited coils produce a further thrust force on the armature itself. The analysis of the behavior of this launcher is performed via a computer code based on an integral formulation and a tool that analyzes the phenomena related to the velocity skin effect; the interactions between the two systems of currents on the armature and the currents on the stator (rails and barrels) are investigated. The thermal behavior of the device has been taken into account by a simple adiabatic model since the short operating time allows one to neglect heat diffusion in the conductive parts of the system. A comparison between the velocities, respectively obtained by separately feeding rails and coils and the system with the combined feeding, has been performed. Preliminary results of the analysis show that this device, because of the presence of two systems of thrust forces acting on the armature, can be successfully used in the acceleration of heavy masses at relatively high velocities, the maximum achievable speed being limited by thermal and mechanical stresses. View full abstract»

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  • Helicoidal electromagnetic field for coilgun armature stabilization

    Publication Year: 2003 , Page(s): 108 - 111
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    In this paper, stabilization of an induction type coilgun inside the bore armature is considered. The projectile moves with a helicoidal motion and such a movement is obtained using a double-fed induction launcher furnished of two coils: the main one generates a traveling magnetic field providing, as a consequence, the axial motion, while the other one produces a rotating magnetic field that is responsible for the rotation. The aim of this work is to investigate the effects of the interference between the traveling and rotating magnetic fields on the in-bore armature stability. View full abstract»

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  • Prediction and verification of electromagnetic forces in helical coil launchers

    Publication Year: 2003 , Page(s): 112 - 115
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (426 KB) |  | HTML iconHTML  

    Calculating the circuital parameters and electromagnetic force production between two coupled coils is critical when modeling helical coil launchers (HCLs). Computer tools that calculate the self inductance, mutual inductance, and inductance gradient of a coupled-coil pair are developed for the PSpice circuit simulator. The inductance values and gradient are used to model a short (16.3-mm length), small-bore (19.4-mm diameter) HCL. The HCL is constructed in the laboratory and its performance is measured. The HCL accelerated nominal 16-g projectiles up to 170 m/s using a 6-kJ capacitive energy store. The highest overall electric-to-kinetic conversion efficiency was 5.4%. Comparisons are made between the theoretical and experimentally measured launcher parameters. In general, there is good agreement between the predicted and measured HCL parameters. View full abstract»

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  • Research on the relation between the propulsive force and magnetic system of the coil launcher based on the mechanism of hybrid switched reluctance motor

    Publication Year: 2003 , Page(s): 116 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (263 KB) |  | HTML iconHTML  

    In this paper, the structure and principle of a coil launcher based on the mechanism of a hybrid switched-reluctance motor are introduced. The magnetic system model of the coil launcher is established. The influence of various parts of the system on the propulsive force is analyzed and calculated. Tested results are given. The relative values of various parts of the magnetic circuit are recommended to achieve maximum propulsive force, which provides the foundation for the manufacture of a prototype launcher. View full abstract»

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  • Field analysis in tubular coilguns by wavelet transform

    Publication Year: 2003 , Page(s): 120 - 124
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (374 KB) |  | HTML iconHTML  

    In this paper, a new method for the field analysis in tubular coilguns by wavelets on the interval and equivalence theorem is proposed. By adopting the equivalence theorem, the computational domain is restricted to the conductive region while expanding the space variables by wavelets on the interval. We obtain a storage of the unknowns in a matrix form instead of the usual vector form yielding a savings of memory storage and CPU times. The solution is then obtained by a standard time-stepping method. View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics publishes research in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage.

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Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology