Secondary Conductor Research Articles

Nonlinear Analytical Modeling of Hybrid-Excitation Double-Sided Linear Eddy-Current Brake

An analytical model could be very useful in the design and analysis of electromagnetic devices. In this paper, a nonlinear analytical model of a hybrid-excitation double-sided linear eddy-current brake is presented. The nonlinear analytical model takes into account leakage flux, higher harmonics, core saturation, and the actual path of eddy currents in the secondary conductor. Therefore, as compared with the conventional analytical model, the accuracy of the nonlinear analytical model is observably improved. Finally, the finite element analysis is employed to confirm the validity of the nonlinear analytical model.

Conductor-Less and Vertically Niched: New Species of the GenusPseudopoda(Araneae: Sparassidae: Heteropodinae) from Myanmar

Material of the genus Pseudopoda Jäger, 2000 from Myanmar is revised. Six new species are described: Pseudopoda tji sp. nov., P. pingu sp. nov., P. bangaga sp. nov., P. wamwo sp. nov., P. martinschuberti sp. nov. (all: male, female; Chin State) and P. huberi sp. nov. (male; Mandalay Region). All species were recorded from elevations above 600 m. All five species from Nat Ma Taung are vertically niched in zones of up to 500 m elevation difference. Moreover, males of all these species lack the conductor of the male palp, four of them exhibit a special glandular appendage in the female internal duct system, as well as a unique reduction of tibial spines in both sexes. A special brush of setae on the distal cymbium is identified as a possible surrogate structure acting as a secondary conductor.

Vector Potential Coil and Transformer

For quantum systems, vector potential plays a very important role [1] but, for classical macroscopic systems, it does not seem to play a very significant role. In this study, we demonstrate a vector-potential coil and a vector-potential transformer that each use a long flexible solenoid wound around a hollow cylinder. These devices generate a curl-free vector potential without magnetic field. In the space within the cylinder where no magnetic field exists, the vector potential is detected by observing a voltage across a secondary conductor that is proportional to the time rate of change of the primary current. Finally, we also present the input-output characteristics of the vector-potential transformer and the transparency properties of the vector potential.

CARACTERIZAÇÃO ANATÔMICA DE FOLHAS E INFLORESCÊNCIAS DE ESPÉCIES DE LAVANDA (LAMIACEAE) UTILIZADAS COMO MEDICINAIS NO BRASIL

Plants of the genus Lavandula denominated communly as lavenders are aromatic originated in Europe, especially from the Mediterranean area and belonging to the Lamiceae group. There is little information about the anatomy of plants of this gender, so we prioritized to identify the anatomical characters of Lavandula angustifolia Mill and Lavandula dentata L. to assist their own identification. For the historical analysis it was performed the middle part of young leaves and inflorescences in full bloom, from transverse sections made freehand with the help of razor and Styrofoam and the help of optical microscope and common digital camera (Olympus SP – 800UZ). It was also performed paradermical scraping with freehand from the abaxial surface of leaves and inflorescences and macerated dried material analysis of these organs. We sought to identify and classify the trichomes, the anatomical characteristics of leaves and inflorescences (flowers and bracts), and the powder of these agencies to compare the results obtained. In the anatomical characters examined, both from fresh material as the macerated material, there were similarities between the two species and morphology of epidermal cells, cuticle, stomata types, and heterogeneous dorsiventral mesophyll, and glandular trichomes in the leaves. L. dentata presents two larger secondary vessels conductors in the middle part of the leaves, while in angustifolia L. these vessels are all identical and with smaller gauges.

Secondary School Choral Conductors’ Self-Reported Beliefs and Behaviors Related to Fundamental Choral Elements and Rehearsal Approaches

Secondary school choral conductors from the United States were invited to complete a 10-minute electronic survey about their choral rehearsal priorities and approaches. Respondents ( N = 239) reported (a) rehearsal priorities on fundamental choral elements (balance/blend, diction, dynamics, intonation, interpretation/musicianship, rhythm, technique, and tone quality), (b) rehearsal approaches (micro–macro/macro–micro), and (c) primary professional development influences. Choral elements most frequently cited as rehearsal priorities were intonation and tone quality. Differences were discovered in rehearsal approaches as a function of teaching experience with those who taught for 10 or more years reporting a macro–micro approach. Observing other conductors/ensembles at conferences and continuing education were primary influences cited. Though there were no statistically significant differences ( p > .05) between high school and middle school choral directors’ choices of rehearsal priorities or approaches, notable discrepancies were found. Implications for the preparation of choral educators are discussed, and recommendations for future research are presented.

Evaluation of Stray Load Losses in Cores and Secondary Conductors of Induction Motor Using Magnetic Field Analysis

To develop further higher efficiency induction motors, the reduction of the stray load losses, which are the increase of loss in the load condition relative to that in no-load test condition, should be investigated by using the magnetic field analysis. However, the calculation of the stray load losses using the magnetic field analysis requires high computation cost due to consideration of the slot harmonics in the flux densities, and the large time constant. In this paper, to evaluate the stray load losses in the cores and the secondary conductors of induction motors using the two-dimensional (2-D) magnetic field analysis within practical computation cost, some useful techniques, to mention a few, the nonconforming technique and the simplified time-periodic explicit error correction method, are introduced. Then, the stray load loss of an actual induction motor without skew is evaluated by the developed 2-D magnetic field analysis. It is shown that the calculated no-load losses are almost the same with the measured one, and the stray load losses in the stator core and secondary conductors due to the harmonic components in the secondary current are large.

History of Power Sources in Endoscopic Surgery

The history of energy sources used in surgery is inextricably linked to the history of electricity. Milestones include identification of safe electrical waveforms that can be used in the human body, patient isolation to prevent alternate-site burns, bipolar energy sources to negate capacitance injuries, laser energy, and the combination vessel sealing devices commonly used today. Engineering efforts to eliminate many of the hazards of electrosurgery are critical to how we practice modern gynecologic surgery. The introduction of bipolar instruments, increasing the safety of monopolar electrosurgery by not using hybrid trocars, and introduction of active shielding of the instruments from stray radiofrequency energy using intelligent secondary conductors have led to the re-emergence of electrosurgery as the universal surgical energy source. The low ongoing costs and the presence of electrosurgical generators in all hospitals readily enables electrosurgery to be the mainstay. Expensive lasers are confined to specialized centers, where they continue to be used, but for a long while filled a gap created by complications of electrosurgery. Sophisticated power sources continue to be introduced and include the ultrasonic scalpel, plasma surgery, and various devices for sealing vessels, all of which have advantages and disadvantages that are recognized as they begin to be subjected to scientific validation in randomized trials.

Calculation and Analysis of the Forces Created by Halbach Permanent-Magnet Electrodynamic Suspension

This paper researches on the levitation and drag forces of Halbach permanent-magnet electrodynamic suspension. First, construct an analytical model to calculate the magnetic field in the air gap and the current in the secondary conductor plate, thus deducing analytical expressions of the levitation and drag forces. Second, establish a 2D and a 3D finite element model, using ANSYS. Finally, at different speeds, from 0 to 250 km/h, compare the forces calculating results through the above three methods. Results generating from the 2D-FEM and the analytical algorithm have less than 3% of relative error, but for having not taken the horizontal components of eddy current in the reaction plate into consideration, thus 10% more than the 3D-FEM calculating results.

Manufacture and Measurement of a Fifty Kilo-Ampere Superconducting Transformer for the ASIPP Conductor Test Facility

To meet the performance test of the International Thermonuclear Experimental Reactor correction coil conductors, a 50-kA superconducting transformer has been manufactured, which allows rating of test samples under different operating conditions at the Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP). This transformer system is made up of two concentric layer-wound superconducting solenoids with the primary inside the secondary. The 50-kA secondary winding consists of 4-turn rectangular cable-in-conduit conductor type. This paper describes the design and manufacture techniques of the 50-kA transformer, including a secondary conductor. The secondary terminal design and manufacture are also discussed. Finally, the first test results of the 50-kA transformer are presented.

A study on the transverse edge effect of an eddy current brake with a solid steel secondary

AbstractThe eddy current brake is a type of braking system used for railway vehicles. Because rail heating is a problem in this type of brakes, they have not been put to practical use in Japan. Therefore we proposed using a linear induction motor (LIM) for dynamic braking in the eddy current brake systems. In this paper, we investigate the transverse edge effect on an eddy current brake using an LIM with the solid steel rail as a secondary conductor. The objectives of this investigation are to clarify the transverse edge effect on a rail and to make it easier to determine the characteristics of such an eddy current brake. We find that the lateral surface of a solid steel rail must be considered as an electromagnetic overhang, and that the transverse edge effect of the rail is approximately the same as that of a simple U‐shaped steel plate or a wide, flat steel plate. These findings enable us to apply a simplified analysis method using a traditional modifying coefficient of the transverse edge effect, but from a new perspective. Because this simplified analysis method can easily evaluate the performance of eddy current brakes, it is useful in the early development stages of such brakes. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Theoretical Study of Induction Pump for Molten Metal Using Rotating Twisted Magnetic Field

In this paper, the electromagnetic field in an induction pump for molten metal using rotating twisted magnetic field is theoretically analyzed. Asymptotic analysis for small magnetic Reynolds number clarifies that temporal mean value of the axial driving force f̅ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> is almost uniform but rather small when the twist ratio ka <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is considerably smaller than 1. On the other hand, when ka <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is larger than 1, f̅ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> near the outer boundary of the secondary conductor is large, whereas f̅ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> around the central axis is very small. Such a nonuniform force is not suitable for driving fluids in the pump. Performance of the pump is estimated when the magnetic Reynolds number is always adjusted to a desired value by automatic control of frequency of power supply. The optimal value of the twist ratio ka <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> for the developed pressure is obtained. The ratio of the stator radius a <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> to the secondary-conductor radius a <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> has to be reduced to a value as small as possible in the hostile thermal environment by the molten metal. When the system is scaled up, the developed pressure is proportional to both a <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and the axial length h of the stator. The estimation results give bases for designing the pump system and required specification of the power supply.

FEM Analysis of Single-Sided Linear Induction Motor with Different Secondary Conductor Structures

several 2-D FEM models of SLIM with different kinds of secondary conductor structures are developed and analyzed based on certain equitable prerequisite. The computed magnetic field of different secondary conductor structures is analyzed, and the research results may give references on the optimization of secondary conductor structure.

The 50 kA Superconducting Transformer for Testing ITER CC Conductors Short Sample

To meet the specification of International Thermonuclear Experimental Reactor (ITER) Correction Coil (CC) conductors, the 50 kA superconducting transformer has been designed which allows rating of conductor samples during different operating conditions at the Institute of Plasma Physics, the Chinese Academy of Sciences (ASIPP). The superconducting transformer consists of two concentric layer-wound superconducting solenoids with the primary inside the secondary. The 50 kA secondary conductor consists of 4 turns of rectangular cable-in-conduit conductor (CICC) type used of the 0.87 mm NbTi superconductor strands. This paper describes the basic principles of superconducting transformer, the designed concept of the 50 kA superconducting transformer.

Investigation of Linear Induction Motor According to Secondary Conductor Structure

This paper presents the analysis of single-sided linear induction motors (SLIMs) for application in various systems demanding direct linear motion. In order to investigate the characteristics of linear induction motors according to secondary conductor structures, five types of secondary slot shape structures, usually used in rotary motors, were set up. The equivalent circuit of a SLIM is proposed and the equivalent parameters are computed. In addition, the characteristics such as the air-gap flux density, thrust, normal force, force ripple, speed response, etc., are analyzed by 2-D FEM with an external circuit, and the results are compared.

Effect of annular secondary conductor in a linear electromagnetic stirrer

This paper presents the variation of average axial force density in the annular secondary conductor of a linear electromagnetic stirrer. Different geometries of secondaries are considered for numerical and experimental validation namely, 1. hollow annular ring, 2. annular ring with a solid cylinder and 3. solid cylinder. Experimental and numerical simulations are performed for a 2-pole in house built 15 kW linear electromagnetic stirrer (EMS). It is observed for a supply current of 200 A at 30 Hz the force densities in the hollow annular ring is 67% higher than the equivalent solid cylinder. The same values are 33% for annular ring with a solid cylinder. Force density variation with supply frequency and current are also reported. Numerical simulations using finite element model are validated with experimental results.

Experimental Study on Induction Motor With Superconducting Secondary Conductors

The authors have studied a superconducting induction motor with Bi-2223/Ag HTS secondary conductors in the rotor. If the superconductor is applied to an induction motor, a higher efficiency and a higher power and a higher starting torque can be expected. The authors remodelled the rotor of a commercial 200 W (4 pole) induction motor and made an experimental HTS induction motor. The cast aluminum in the rotor slots were cut-in by 5 mm in depth and HTS tapes were put in the slots. Thus, the original conventional 200 W induction motor was remodeled to a HTS induction motor. The experimental motor was immersed in a liquid nitrogen bath. And, a no-load test, a locked test, a variable frequency locked test, and a load test of the HTS induction motor were carried out in liquid nitrogen bath. The experimental results are presented together with some theoretical analysis.

Optimal Distribution System Horizon Planning–Part I: Formulation

This paper is the first of a two-part paper on optimal distribution system planning. The horizon distribution planning problem and optimal distribution system model formulation are described. The horizon planning mission is to minimize future costs by determining optimal design parameters given assumptions about the future. Prior work addressed short-range and expansion planning of subsets or combinations of design parameters. The many distribution requirements and associated constraints inhibited an all-inclusive evaluation of total horizon design requirements for the 20+ year period. The proposed model and optimization formulation provides a generalized horizon planning approach and introduce a fully functioning comprehensive horizon planning model using a perspective that encompasses all necessary parameters and constraints. Parameters include: substation and distribution transformer capacities; number, size, and lengths of distribution feeders and secondary conductors; and primary voltage class. Optimal design voltage drops and reliability indices are determined. The horizon planning optimization application is described and solved in the second companion paper using continuous constrained nonlinear programming methods. The application is demonstrated with Snohomish PUD case studies

Field-oriented control scheme for linear induction motor with the end effect

The movement of a linear induction motor (LIM) causes eddy currents in the secondary conductor sheet at the entry and the exit of the primary core. The eddy currents of the sheet tend to resist sudden flux variation, allowing only gradual change along the airgap. Hence, the so-called ‘end effect’ causes not only the losses but also airgap flux profile variation changes depending on the speed. In this work, an equivalent circuit model of LIM is developed following Duncan&apos;s per phase model. It is then transformed into a synchronous reference frame which is aligned with the secondary flux. Also, a field orientation control scheme is developed which accounts for the end effect. The validity of the proposed LIM model is demonstrated by comparing experimental and simulated voltage current relations. With the proposed control scheme, the (secondary) flux-attenuation problem due to the end effect is shown to be resolved in the high-speed range.

THE SPIDER SUBFAMILY AMAUROBIOIDINAE (ARANEAE, ANYPHAENIDAE): A PHYLOGENETIC REVISION AT THE GENERIC LEVEL

A cladistic phylogenetic analysis at generic level of the subfamily Amaurobioidinae is presented. The analysis is based on a dataset of 93 representative species scored for one behavioral and 199 morphological characters. Tree searches were made under equal and implied weights according to homoplasy, and the results were compared in terms of sensitivity to jackknife resampling. Mildest weighting functions produced trees more robust to resampling, and those results were selected as the working phylogenetic hypotheses. Groups of weak support as identified by jackknifing and Bremer indices are in general those that vary in resolution with different character-weighting schemes.Seven outgroup representatives were included (Malenella nana Ramírez, from Malenellinae, and six Anyphaeninae species). In this analysis Anyphaeninae, previously identified as sister group of Amaurobioidinae, is paraphyletic, but forcing its monophyly does not alter the groupings within Amaurobioidinae. The monophyly of the genera is in general well supported, but some particularly conflicting groups are discussed. In contrast, the relationships among genera are in general problematic.Amaurobioidinae is diagnosed by a pronounced indentation at the base of male palpal tegulum, and by a particular male copulatory bulb conformation, with a paramedian apophysis. The subfamily is classified in two tribes (Gayennini and Amaurobioidini); the genus Josa Keyserling, probably sister group to Gayennini, is not assigned to either tribe.The tribe Amaurobioidini is mainly diagnosed by an apical loop of the sperm duct in the male copulatory bulb. It includes 10 genera: Amaurobioides O.P.-Cambridge is restricted to seashores of southern continents. Clubiona chilensis Nicolet, transferred to Amaurobioides, is the first true record of the genus for South America. The male of Axyracrus elegans Simon, three species of Aysenia Tullgren, and three of Coptoprepes Simon are newly described. Four new genera are proposed in Amaurobioidini: Gamakia, Selknamia (described for one new species each), Aysenoides (for three new species), and Negayan (type species Gayenna tridentata Simon, including also Axyracrus coccineus Mello-Leitão, Clubiona paduana Karsch, Gayenna excepta Tullgren, Gayenna exigua Mello-Leitão, and Tomopisthes lebruni Simon). The previously revised genera Acanthoceto Mello-Leitão and Ferrieria Tullgren are also included in the tribe. The basal branch and most intergeneric branches of the tribe have low support values. Amaurobioides and Negayan, however, are relatively well supported.The tribe Gayennini is well defined by a homogeneous conformation of male and female genitalia, with a distinctive secondary conductor and spherical spermathecae. It includes 11 genera: Gayenna Nicolet includes only G. americana Nicolet from Chile and adjacent Argentina. Arachosia O.P.-Cambridge comprises many species previously assigned to Oxysoma. Abuzaida striata Keyserling, Anyphaena oblonga Keyserling, Gayenna proseni Mello-Leitão, Gayenna duplovittata Mello-Leitão, Gayenna bonneti Mello-Leitão, Oxysoma dubium Berland, Oxysoma bifasciatum Mello-Leitão, Oxysoma cubana Banks, Oxysoma polytrichium Mello-Leitão, Phidyle bergi Simon, and Samuza praesignis Keyserling are transferred to Arachosia. The males of Arachosia bergi (Simon), A. honesta Keyserling, and Arachosia praesignis (Keyserling) are newly described. Arachosia is easily recognized by the thick setae on the anterior lateral spinnerets, and it has good support values. A very diverse group of species here assigned to the genus Sanogasta Mello-Leitão is paraphyletic in terms of Arachosia. It includes many of the species formerly placed in Gayenna Nicolet. Anyphaena maculatipes Keyserling, Clubiona maculosa Nicolet, Gayenna paucilineata Mello-Leitão, Gayenna alticola Simon, Gayenna bonariensis Mello-Leitão, Gayenna rufithorax Tullgren, Gayenna x-signata Keyserling, Gayenna approximata Tullgren, Samuza minuta Keyserling, and Tomopisth

Effect of contact resistance between side-bar and secondary conductors in a linear induction motor with a cage-type secondary

A linear induction motor (LIM) with a cage-type secondary has contact resistances between side-bars and secondary conductors due to its own manufacturing process of welding. The finite-element analysis considering the equivalent circuit of the secondary winding is carried out to present the effect of the contact resistance in the LIM. As a result, thrust, normal force, the primary phase current, and the secondary conductor currents of the motor are analyzed for the various contact resistances.