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Voluminous Eocene gabbros to granites of the Kal-e-Kafi backarc composite intrusion were emplaced prior to the Alpine-Himalayan collision in the central Iranian backarc, but the reasons for precollisional high arc and backarc magmatic productivity (60-53 Ma) are unclear. Diagnostic geochemical signatures are high [K.sub.2]O-Sr contents and successively depleted middle rare earth element (REE) patterns, reflecting a highly metasomatized source and an increasing role for amphibole and garnet (0%-10%) in the relatively younger granites. Release of concealed K-Sr-rich fluids from oceanic fractures and faults during buckling and bulging of a precollisional choking oceanic slab, and melting of phlogopite-bearing lithosphere with subsequent interaction of the melt with lower crustal garnet-amphibolite of a ~40-km-thick crust, can explain the Kai-e-Karl geochemical and isotopic signatures. Gravimetric data indicating a ~39 km present-day backarc crustal thickness are consistent with geochemical results but also imply little if any collisional crustal thickening of the central Iranian Plateau. High Eocene arc-backarc melt flux prior to collision in this region reflects vigorous thermal convection, which may in fact be diagnostic of collisional magmatism, explaining the presence of postcollisional shoshonitic melts in this and other coilisional orogenic settings. Keywords: backarc magmatism, central Iran, Alpine-Himalayan collision, amphibole, crustal thickening.

In order to precisely define the harmonic content of the main flux and stator voltage of an induction motor that is fed by a high-frequency carrier in addition to the normal set of stator voltages, this paper performs the analytical calculation of the zero-sequence components of the air-gap flux and stator voltage. The calculations are made by defining suitable winding functions to derive the self- and mutual inductances and by adopting a new inverse air-gap function to model the variation of the saturation level of the machine produced by the additional magnetomotive force. Analysis of the calculated expressions that are confirmed by experimental tests shows that the proposed analytical technique can be suitably applied to quantify the effects of high-frequency carriers on the air-gap flux and offers useful hints to understand sensorless control mechanisms. Index Terms--High-frequency modeling, induction machine, saturation, sensorless control.

This paper investigates an efficient macroscopic modeling method for laminated iron cores made of grain-oriented silicon steel sheets. Under actual operating conditions, the material exhibits nonlinearity as well as a strong anisotropy resulting in a nonuniform distribution of the iron loss and the flux within each lamination. The presented results, based on a benchmark problem, are helpful in building a finite element model that takes into account the effects of the eddy current, induced by the magnetic field normal to the sheets, on the total iron loss and the distortion of the local magnetic flux in the laminations adjacent to the exciting coils, even though both the total flux inside the entire lamination stack and the source voltage are sinusoidal. Index Terms--Additional iron loss, arbitrary anisotropy, flux inside lamination, modeling of laminated iron core.

The interaction of moving conducting fluids with electric and magnetic fields provides the magnetohydrodynamic (MHD) phenomenon. Based on this principle, MHD pump uses the 'Lorentz force' to move fluid. The railgun channel is one important segment in an electromagnetic launcher (EML). As is known, one of the possible ways to increase the EML efficiency is to segment the working channel. For this purpose, MHD flow study is necessary. It is required to have the knowledge of the flow field and the temperature to design an MHD pump. The purpose of this paper is to investigate the effect of the magnetic flux density and current on the flow and the temperature distribution in an MHD pump. To solve the governing differential equations, a finite-difference-based code is developed and utilized. The temperature and velocity are calculated by solving the energy and the Navier-Stokes equations. Results show a maximum value of velocity for different values of magnetic flux density (B). However, the temperature stays almost constant with magnetic field. In addition, as current increases, the velocity and the temperature increase too. Index Terms--Energy and momentum equations, magnetic flux density, magnetohydrodynamic (MHD) pump.

In order to gain experience in explosive pulsed power and to provide experimental data for modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency (FOI). The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high power pulses for various loads. This paper presents the design of, and tests with, this helical FCG. The generator had an initial inductance of 23 [micro]H and was operated into a load of 0.2 [micro]H. The generator is charged with 0.27 kg of high explosives (PBXN-5). Various types of diagnostics were used to monitor the operation of the generator, including current probes, optical fibers, and piezo gauges. With seed currents of 5.7 and 11.2 kA, final currents of 269 and 436 kA were obtained, corresponding to current amplification factors of 47 and 39. The peak of the current was reached about 30 [micro]s after the time of crowbar. The two generators showed only small losses in terms of 2[pi]-clocking. Using signals from optical fibers, the deflection angle of the armature could be determined to be 10[degrees] in good agreement with hydrodynamic simulations of the detonation process and the detonation velocity to be 8.7 km/s in agreement with tabulated value. Index Terms--Magnetic flux-compression generators (FCGs).

Helical flux compression generators (HFCGs) of a 50-mm form factor have been shown to produce output energies on the order of ten times the seeded value and a typical deposited energy of 3 kJ into a 3-[micro]H inductor. One way to drive a high-power microwave source with an HFCG is by power conditioning, such as an inductive energy storage system (IESS). The output performance of the IESS is contingent upon the opening switch scheme, usually an electroexplosive fuse. Our previous work involving fuse parameter characterization has established a baseline for potential fuse performance. In order to optimize the electroexplosive wire fuse, we have constructed a nonexplosive test bed which simulates the HFCG output with high accuracy. We have designed and implemented a capacitor-based magnetic switching scheme to generate the near-exponential rise of the HFCG. The use of the nonexplosive HFCG test bed will allow the verification of scalability of the fuse parameter model and also allow testing of exotic fuse materials. The nonexplosive test bed has provided a more efficient method for electroexplosive switch development and has allowed us to expand the study of opening switches. We will also discuss the a priori calculated baseline fuse design and compare the experimental results of the gold-wire-material with the silver-wire-material baseline design. With the results presented, an accurate PSpice model applicable to our 45-kA HFCG systems will be available. Index Terms--Electroexplosive switches, flux-compression-generator test bed, fuse, gold, magnetic switches, opening switch, silver.

This paper proposes design and analysis of a new linear motor called flux reversal linear synchronous motor (FRLSM), which is cost effective for long stroke applications. Passive rotor configuration of a typical flux reversal machine (FRM) can be utilized for a linear machine with less permanent magnet (PM). Three different design choices are investigated and compared both in thrust and normal force. The investigation shows extremely low force ripple and good thrust linearity through skewing and three-phase sinusoidal control. Reduced PM configuration generates about 21% higher thrust even with half amount of PM. Index Terms--Finite element method, flux reversal machine, linear synchronous motor.

This paper proposes a control method for eliminating dc magnetic flux from the series transformer of a dynamic voltage restorer. The method is characterized by intentionally injecting no compensating voltage during a one-sixth line cycle (=3.3 ms at 50 Hz). The control method is independent of an initial phase angle of a voltage sag, thus requiring no flux detection. The period, during which no compensating voltage is injected, is one-third as short as that of an existing method. This paper confirms the effectiveness and viability of the proposed method. A 200-V 5-kW laboratory system verifies experimentally that the proposed method brings no dc magnetic flux to the series transformer. Moreover, the proposed method brings a smaller dc voltage drop to the dc load of a three-phase diode rectifier than the existing method does in the same conditions. Index Terms--Compensating voltage, dc magnetic flux, dynamic voltage restorers (DVRs), magnetic saturation, series transformers.

This paper is not intended for firm believers of magnetic reconnection. It calls for attention of the young generation to the following facts: 1) there are a number of unsolved problems such as sunspots, solar flares, and magnetospheric substorms in spite of almost 50 years of effort; 2) one of the reasons for this failure to solve them may be because the guiding principles in understanding those phenomena are not well founded and are misleading; 3) thus, it is encouraged to cast doubt on the leading paradigms and develop new ideas. Index Terms--Coronal mass ejection (CME), magnetic flux ropes, magnetic storms, solar flares, solar-terrestrial physics, sunspots.

A vibrating normal pick-up coil coupled to a superconducting quantum interference device (SQUID) magnetometer as a nondestructive testing system, which enables detection of a cylindrical flaw in an aluminum plate with an excitation field at 40 Hz, is described.

The design of a unique high [T.sub.c] SQUID probe microscope that is combined with a scanning tunneling microscope for investigation of magnetic samples at room temperature in air is presented.

The new exploration of spontaneous symmetry breaking in non-adiabatic phase transitions in Zurek-Kibble (ZK) process mimicked in solid state systems by trapping of magnetic flux quanta, fluxons, in a long annular Josephson tunnel junction quenched through the normal-superconducting transition is reported.

Quantized values of magnetic flux trapped in a superconducting loop enabling a new type of passive shifting elements which could be incorporated into digital Josephson circuits making their design compact is reported.

This paper presents a novel method for analyzing transient magnetic fields in laminated iron cores. It is based on the finite-element method and a newly developed homogenization method is applied to model the lamination effectively. The homogenized constitutive relations, of which the approximation is only applicable to low-frequency problems, are derived analytically, neglecting eddy currents induced by time-varying magnetic fluxes parallel to the lamination. The loss due to the neglected eddy currents is estimated in the postprocessing state utilizing the obtained magnetic field variation. The calculated magnetic field is in good agreement with the measurement for a benchmark problem. It is demonstrated that the homogenized relations can be applied to the low-frequency problems. Index Terms--Anisotropic nonlinear magnetic field analysis, homogenization method, iron loss, laminated iron core.

A series of [Tb.sub.3-x-y][Yb.sub.y][Bi.sub.x][Fe.sub.5][O.sub.12] crystals are grown by the flux method by using [Bi.sub.2][O.sub.3] as main flux and their structure and chemical composition are characterized by using the Faraday rotation (FR) spectra. The results have shown that the Bi-substituted mixed rare-earth iron garnet crystal of [Tb.sub.0.91][Yb.sub.1.38][Bi.sub.0.71][Fe.sub.5][O.sub.12] has a large and stable FR against wavelength variation in the 1.55 [micro]m optical communication band.

A new method to estimate time-varying external forces acting upon a vibrating structure is presented in this paper. The method is developed for a force-calibrating device which is designed to be rigid in the operating frequency band and, therefore, it was believed that simple force-gauges should recover the applied forces. It has been observed that the inertia of the vibrating calibration device distorts the estimated force, even when the excitation is only one-third of the first natural frequency. Unlike traditional methods, the frequency response need not be inverted, alternatively a smoothed, Lagrange multiplier based estimation method is formed. With the proposed method, an electromagnetic excitation device can be calibrated such that the electromagnetic forces can be compared with theoretical estimates. The unique features of the proposed method are: (a) Compensation for inertia forces; (b) incorporation of measured reaction forces in a mixed analytical and experimentally obtained model; (c) possible independence on elastic stiffness forces; and (d) closed form, integral equations. New equations relating the externally applied forces and various measurable physical parameters are established, for example: The dependency upon the air-gap, current, and magnetic flux can be found. [DOI: 10.1115/1.2346699]

The possibility of utilizing hard single-domain magnetic elements with the out-of-plane magnetization at sub- and micrometer scale for the flux biasing of dc superconducting quantum interface devices (SQUIDs) is presented. It is shown that the radius of a Co-Pd magnetic dot can be optimized with a reasonable accuracy, using conventional lithographic techniques, which makes it possible to maximize the zero-field sensitivity of a de SQUID without an external current source.

Generally, a speed servo system of a vector-controlled induction motor has limitations of motor voltage and current. When the speed servo system has a large torque reference, the output of its PI controller is often saturated. In this case, the conventional servo system stops the integral calculation of its PI controller. However, this system often has a large overshoot and/or an oscillated response caused by both a windup phenomenon and phase error on the vector control condition. This paper proposes a new speed servo system considering voltage saturation for the vector-controlled induction motor. The proposed control method compensates the phase error on vector control condition quickly, and always keeps the vector control condition. The experimental results show that the proposed system well regulates the motor speed and the secondary magnetic flux for a large torque reference without a windup phenomenon. Index Terms--Antiwindup algorithm, output saturation, speed servo system.

In order to find an applicable power supply used in electric guns, there have been two types of the magnetic flux compression linear generator (MFCLG) that use the solenoids as the stators. That is to say, a piston armature or a solenoid armature is used within the stator. Although they can amplify the current theoretically, they can only compress the component of the magnetic flux. So their efficiency is low, and there exist some difficulties, which is difficult to solve in terms of the engineering technology. In addition, the use of the solenoid armature leads to the increment of the ineffective part of the solenoid. A kind of the rail stator augmentation MFCLG is presented here. It separates the combustion chamber-cylinder and the generating channel into two independent parts, and with an antirecoil device. The combustion chamber is extended as a cylinder. Within it the piston pushes the stator-armature package to move forward through the connecting rod along the generating channel consisted of the rails. This can compress the magnetic flux to generate the large electric current to be used by electric guns. If we fill the integrated fuel into the combustion chamber, we can realize the successive pulse operation. The separation of the combustion chamber-cylinder and the channel can avoid the high temperature burning gases from entering the channel to cause ablation. The basic mathematic model of this type of the generator is given and its physical properties are analyzed in this paper. It is found that it can compress the magnetic flux perpendicularly and has higher efficiencies for compression and conversion. It can produce large current with sufficient pulse width to supply the electric guns. Besides, a self-excitation method for this type of generator is also put forward, which can omit the seed power source. Instead, it uses the chemical energy that drives and compresses the magnetic flux to generate the electric current to produce the initial seed magnetic flux used by it. Index Terms--Combustion chamber, cylinder, electric generating channel, electric guns, magnetic flux compression, rail stator.

Thermally activated magnetic flux entry into a pickup coil through a flux dam in high-T(sub c) superconducting quantum interference device (SQUID) magnetometer is studied. Numerical simulation shows that circulating current can rapidly decrease much below the critical current and hence can suppress the thermally activated flux entry by using these methods.

The topology optimization of a switched reluctance motor (SRM) excited by magnetic forces is an important issue to minimize the noise and vibration level. In this paper, the magnetic force is computed using the Maxwell stress method and the optimization problem is formulated to minimize the frequency response based on the homogenization design method (HDM). The developed method is applied to the stator of an SRM to minimize the deformation caused by the magnetic harmonic excitation. Numerical simulation shows that this method successfully decreases the vibration level of an SRM. [DOI: 10.1115/1.1467093]

The search for the best configuration of the lightning protection system (LPS) that maximizes the regions inside the building, in which the values of the field are less than the specified threshold levels is an important topic of the LPS design. In this paper, we propose the use of a constrained decision planning tool to optimize the field profile in the regions where the high susceptible equipment will be placed. The induced magnetic flux is evaluated by time-domain simulation. The concepts of 'safe area' and 'connectivity index' are presented and used as measures of this procedure. Index Terms--Electromagnetic compatibility, EMP radiation effects, lightning, time-domain analysis.

A study was conducted to investigate the effective areas, current distributions and inductances of slotted, high-temperature dc superconducting quantum interference devise magnetometers. Results indicate that the magnetometers' inductance, flux and field noise are influenced by the number of slots. For instance, SQUID magnetometers with many slots show low flux noise values.

In recent years, the finite-difference time-domain (FDTD) method has found numerous applications in the field of computational electromagnetics. One of the strengths of the method is the fact that no elaborate grid generation specifying the content of the problem is necessary - the medium is specified by assigning parameters to the regularly spaced cubes. However, this can be a weakness, especially when the interfaces between neighboring media are curved or 'sloped' and do not exactly fit the cubic lattice. Since the E- and H-fields are only calculated at the regular intervals, sharp field discontinuities at the interfaces are often missed. Furthermore, the averaging of the material properties often leads to significant errors. In this paper, a post.processing method is presented, which approximates the correct field behavior at the interfaces by interpolating between the FDTD calculated values, splitting them into the components normal and tangential to the interfaces, and then enforcing the interface conditions for each of these components separately. Index Terms - Averaging of material properties, biological media, curved and 'sloped' interfaces, FDTD method, flux-related fields, interface conditions, layered spheres, linear interpolations, Mie series solutions.

A straightforward and physically motivated derivation of the reciprocity integral in magnetic recording theory is given for the quasi-static limit, where electromagnetic radiation and retardation effects are neglected, but frequency dispersion in the read head from all sources, including eddy currents, is specifically accounted for. This work attempts to correct some errors or misconception on this subject matter that remain in the literature. Index Terms - Flux linkage, frequency dispersion, high frequency read head, reciprocity integral, reciprocity principle.

The absolute abundance patterns of total radiolarian flux data obtained from moored sediment traps placed along the transect at 12, five and two degrees South, two, five and nine degrees North and zero degrees were analyzed using stocks and fluxes of key environmental indicator species. The results indicated that environmental forcing can totally change community composition by retarding the species type that can propagate under mixing and advective conditions. The composition of radiolarian communities can thus be regulated by seasonal to interannual variations in the meridional current.

The design of a rapid-single-flux-quantum autocorrelator which can be utilized in spectrometry was presented. The autocorrelator features 4-GHz input signal bandwidth, double oversampling quantizer and 16-Mb/s-per-channel output rate. The autocorrelator also utilizes an asynchronous architecture which employs dual-rail logic for global propagation and rapid-single-flux-quantum logic for local computation.

A low 1/f flux noise YBa2Cu3O7-x bicrystal dc-superconducting quantum interference device was fabricated using the cylindrical magnetron sputtering method. The experimental values of the magnetic flux-to-voltage transfer parameter obtained were lower than expected. Using wide band reversal electronics, the 1/f noise levels were reduced. Single large magnetometers working at 77 K were also assembled, where a relatively high value of the flux to field transfer factors was achieved.

A global synthesis based on satellite remote sensing was used to investigate the deep water particle flux at sites which satisfy a set of criteria. The results provided a global picture of deep sea particle flux. An 11-fold flux range was found world-wide and polar environments exhibited the wider flux range with the highest and the lowest flux production was found to be linear for non-polar regions at lower levels of primary production. At higher levels, the flux is constant at 3.5 grams per square meter per year.

A 'nutrient model' was introduced into an eddy resolving model of the open ocean. The characteristics of mesoscale dynamical events that cause nitrate flux in the euphotic zone were then analyzed using coupled three-dimensional simulations. The spatial and temporal means of the simulated fields were then used to approximate the integrated annual nitrate flux related to these recurring events. The eddy formation and intensification mechanism were found to be adequate to balance the levels of new production.

The outcome of the deep water particle flux investigation at the European Station for Time-series in the Ocean was compared with the pigment data from historic Coastal Zone Colour Scanner records in the Canary Island to study the difference in the seasonality of particle fluxes. The results revealed that flux maxima takes place one month after the observed occurrence of maxima chlorophyll in surface waters in a primary source region. The particles gathered were composed primarily of mineral particles and carbonate.

Main flux saturation in d-q axis representation of synchronous machines is at present modelled by selecting either all the winding currents or all the winding flux linkages as state-space variables. However, these two available models are just a tiny portion of the complete set of models that can be obtained by selecting other combinations of state-space variables. This paper presents a general procedure for main flux saturation modelling in smooth air-gap synchronous machines, that is applicable for most selections of state-space variables. The method relies on concept of 'generalised flux' and 'generalised inductance', that has recently been successfully applied in modelling of saturated single-cage and double-cage induction machines. The concept is here extended to saturation modelling in smooth air-gap synchronous machines. A number of models, that result from the application of the method for different selections of state-space variables, are presented in detail.

The transient and steady-state mass fluxes were estimated based on partition and diffusion coefficients and compared with fluxes through holes in liner systems under representative field conditions. Stretched high-density polyethylene (HDPE), unstretched very low-density polyethylene (VLDPE), and unstretched poly-vinyl chloride (PVC) had 2.0-2.5, 4.4-5.2, and 8.4-10.8 times greater permeabilities than unstretched HDPE, respectively. The maximum instantaneous mass flux decreased by more than 15 times as the initial aqueous concentration decreased from 100 to 10 mg/L and as the HDPE thickness increased from 0.76 to 2.54 min. The maximum instantaneous mass flux increased by 1.7 times when a HDPE geomembrane was stretched by 5% of its original length. The flux caused by steady-state permeation through the intact geomembrane, which has so far been neglected, was comparable to the flux through the geomembrane with large holes alone but more than three to 34 times greater than the flux through the geomembrane with small holes alone, implying that the permeation through the intact geomembrane may pose serious environmental contamination.

In this paper, we present a voltage input controller for robot manipulators actuated by induction motors. The control is designed to compensate for the nonlinear dynamics associated with the mechanical subsystem and the electrical subsystems while only requiring measurements of link position, link velocity, stator winding currents, and exact model knowledge. Specifically, through the use of nonlinear observers for rotor flux and an observed integrator backstepping approach, we obtain semiglobal uniform ultimately bounded link position tracking. The result is semiglobal in the sense that a control parameter must be made sufficiently large relative to the electromechanical initial conditions in order to guarantee that control singularities are avoided. To provide insight into the design procedure, the controller is first presented for a one-link robot manipulator system. We then extend the controller from the one-degree of freedom system to the multidegree of freedom system. Experimental results are then presented to illustrate the performance of the proposed approach applied to a one-link robot. Finally, simulation results are presented to illustrate the tracking performance for the proposed controller applied to a two-link robot manipulator system.

The power loss of electrical steel sheet given in the data sheets of the steel manufacturers is related to linearly alternating flux conditions, measured with an Epstein frame or a single sheet tester, respectively. In the application of the material in electrical machines, we find large areas with rotational flux conditions, i.e., in the T-joint region of three-phase power transformers or above the stator teeth of three-phase motors and generators. The most general description of the magnetization process in this case is an elliptically rotating flux. The paper outlines the magnetic behavior of steel sheet under these flux conditions, and finally defines a simple method to predict the total power loss under elliptically rotating flux from data measured under linearly alternating and circularly rotating flux conditions only.

A methodology for accurate calculations of shielding factors for quasistatic multilayered magnetic shields is described. 'Transfer relations' for individual layers with specified magnetic permeabilities and electrical conductivities are spliced together in a manner that is analogous to splicing impedances for cascaded sections of transmission line. Specific transfer relations for four layer geometries (planar, cylindrical with transverse fields, cylindrical with axial fields, and spherical) and constraints at source and shielded surfaces for six source-shield configurations involving both externally applied fields and enclosed sources are developed. Limiting cases are extracted for magnetically permeable, nonconducting layers, and for thin, magnetically nonpermeable, conducting layers. Reciprocity conditions are identified for interchanged source and shielded regions in planar, transverse field cylindrical, and spherical geometries. Variations of magnetic field and flux density with position are shown for a specific planar example involving alternating layers of aluminum and steel, with the same total shield thickness occupied by either one or five layer pairs. Simulations with alternating layers of aluminum and steel for the four layer geometries are used to answer questions regarding the effects of material composition, number of layer pairs, and air gaps. An optimal number of layer pairs for a given total shield thickness is identified. Results from simulations where induced currents in the steel layers are neglected are compared with those for simulations with a realistic conductivity value for steel to assess the relative effects of flux shunting and induced current shielding. The effects of introducing air gaps between material layers upon overall shielding factor magnitude are shown.

A minimum airgap flux linkage is required for the self-excitation and stable operation of an isolated induction generator feeding an impedance load. With the aid of bifurcation theory, it is shown that the minimum airgap flux linkage requirement is the value at which the derivative of the magnetizing inductance with respect to the airgap flux linkage is zero. This minimum airgap flux linkage determines the minimum or maximum load impedance and minimum excitation capacitance requirements. This result is demonstrated using single-phase and three-phase induction generators.

Permanent-magnet synchronous machines fed from current-regulated converters feature nearly ideal performance at low-to-moderate speeds. However, as rotor speed increases the back emf rises which results in loss of current regulation and decreased torque. In buried-magnet machine drives, flux weakening is often used to extend the speed range. This paper sets forth a flux-weakening control specifically designed for surface-mounted permanent-magnet machines which is simple and does not require knowledge of the machine or system parameters. The proposed method is demonstrated both experimentally and through the use of computer simulation.

This paper investigates longitudinal and transverse flux linear motor topologies for very high acceleration rate (3-4 g), and high speed (120 km/h), material transport systems which have significant technical and economic potential in flexible manufacturing environments. The general topology under consideration is a double-sided, short-moving-secondary/long-fixed-primary, linear induction motor (LIM). The transport system requirements place severe demands upon the machine topology. In addition to efficient thrust production, the linear machine must be capable of generating large unbalanced normal (i.e., lateral) forces in order to achieve electromagnetic (mechanically passive) steering of vehicles with both straight and curvilinear primaries. Air gap chording and short secondary effects are two additional design complications. Minimization of the primary leakage inductance is necessary not only to minimize inverter ralings but also to maximize the influence of the secondary state on the primary terminal properties for magnetic flux and position/velocity estimation. The orientation of the magnetic flux (i.e., longitudinal versus transverse) has a significant impact upon the above concerns and is thus a major analytical focus of this paper. A hybrid system topology consisting of a longitudinal-flux orientation within straight sections and a transverse-flux orientation within curvilinear sections appears to offer the best of both topologies. The intended contribution of this paper is a detailed comparison of LIM topologies leading to a better design selection for very high performance systems.

A new nonlinear [Pi] model for an induction machine opt rating in magnetic saturation has been developed. It is based on a magnetic circuit model of a rotor-stator tooth pair, with nonlinear reluctance elements representing the saturation in the rotor and in the stator. The model of a tooth pair is extended to a model of the machine by assuming an infinite number of infinitesimal teeth. The model is compatible with the Blondel-Park transformation. Experimental measurements on a wound-rotor machine validate the new model. Operating conditions for optimal efficiency at high torque levels requiring operation in saturation are computed.