Values Of Magnetic Flux Research Articles

Critical current characteristics and ampere force distribution of a novel HTS cable with different transposition lengths

Abstract Distribution characteristics of the current, ampere force and magnetic flux density (B [T]) of a novel high temperature superconducting (HTS) cable woven by transposed REBCO tapes under different transposition lengths are proposed, and these characteristics of the cable stacked with 3 REBCO tapes are also carried out in this paper for comparison. The objective is to enhance the current density and the compactness of the HTS tapes combination, and uniform the current, ampere force and magnetic flux density (B [T]) distributions. A 3D finite element model (FEM), based on Maxwell's equations without consideration of the displacement current, is established to describe the state of the system in the liquid nitrogen condition. The distributions characteristics, maximum and minimum values of current, ampere force and magnetic flux density (B [T]) show significant differences in the simulation results between the novel HTS cable woven by 3 transposed REBCO tapes and the cable stacked with 3 REBCO tapes. The simulated results show that the distribution characteristics are improved, with a more uniform distribution characteristic than that of the cable stacked with REBCO tapes. This is due to fully transposed REBCO tapes. In addition, the experimental E-I curve was also reached. The experimental results show that using a shorter transposition length in the cable can improve the critical current. However, A too small transposition length can cause significant damage to the HTS tape, resulting in deformation of the HTS tape and a reduction in the electromagnetic properties of the HTS tape. This affects the critical current of the HTS tape and, ultimately, the critical current of the cable. From the point of view of whether the production process is convenient, meets the requirements of economy and reduces costs, we need to find a suitable transposition length. The measured optimal transposition length is 95 mm for the cable woven by 3 REBCO tapes.
Ethical Compliance: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Comparison study on SMC and grain-oriented laminated steel core for small-size axial flux permanent-magnet synchronous machines

Abstract This study aims to compare the soft magnetic composite (SMC) and grain-oriented (GO) steel stator axial flux permanent-magnet synchronous machine (AFPMSM) in terms of performance and iron losses. Stator cores are manufactured using both materials to perform experimental performance tests. The produced machines are designed for pump propulsion systems in left ventricular assist devices as an application area. The machines are modeled with several analytical equations, and iron losses and performance tests are carried out with AFPMSMs, finite element methods, and experimental setups. Our findings show that the torque density is higher in the GO steel stator AFPMSMs that can produce 15.07 percent more torque. GO steel material experimentally has 20.33 percent less iron loss as SMC material since the loss value per kilogram for SMC material is higher than that for GO steel. In addition, the saturation value of the SMC material is lower than that of the GO material according to the magnetic flux density value.

Increasing the damping properties of the magnetorheological actuator of the vehicle suspension control system

Introduction. In accordance with one of the ways of solving the problem of increasing the smoothness of the vehicles, a controlled suspension is proposed, which is created on the basis of the use of «smart» materials – magnetorheological elastomers, the mechanical properties of which, in particular, damping, can be changed with the help of a controlling magnetic field. This is implemented with the help of the magnetorheological actuator of the suspension control system, which has the form of an elastic bushing of the suspension arm, consisting of several electrically connected in series toroid-like coils (with a core of magnetorheological elastomer). The device is powered by current, the value of which is controlled by the operator, or automatically, depending on the road profile and driving mode. Magnetorheological actuators (elastic bushings) are placed in the holes of the suspension levers instead of standard rubber ones and combined with a controlled current source. Thus, the suspension becomes controllable, which makes it possible to set the necessary vibration damping of the vehicle body to increase its smoothness. Problem. The disadvantage of the previous designs of the magnetorheological actuator is the insufficient amount of the magnetic flux density and the unevenness of its distribution within the elastic bushings. As a result, the damping properties of such controlled suspensions become insufficiently effective, which reduces the possibility of increasing the smoothness of the vehicles. The purpose of the work is to increase the damping properties of the magnetorheological actuator of the vehicle suspension control system, which will increase the control efficiency. The task is to improve the design of the performing magnetorheological device, to carry out calculations and develop a calculation scheme of the study, to determine the average magnetic flux density value and its distribution across the cross-section of the device, to calculate the dependence of the device damping indicator on the magnetic flux density, to compare the damping indicators of the improved device with previously known ones. Methodology. Research tasks were solved on the basis of magnetic field analysis using methods of magnetic field theory and SOLIDWORKS® and FEMM software packages, as well as analysis of the dependence of the damping properties of bushings from magnetorheological elastomers on magnetic flux density. A description of the design and principle of operation of the magnetorheological actuator of the vehicle suspension characteristics control system is given, based on which the calculation scheme was developed. Results. The results of research calculations showed that the average value of magnetic flux density in the proposed design of the device reached 0.85 T, its distribution became fairly uniform, and there were no zones where it was abnormally small. For the first time, the dependence of the damping index on the magnetic flux density of the controlling magnetic field has signs of scientific novelty. It was found that this indicator for the proposed design of the device increased by 22 % compared to previous other designs, which will increase the efficiency of the control system and the smoothness of the vehicle. A positive result was achieved due to the following features of the proposed design of the suspension actuator: the elastic sleeve consists of several coaxially located actuators made of anisotropic magnetorheological elastomer, in which the conglomerates of the ferromagnetic filler during the manufacturing process are located collinear to the direction of the angular deformations of the sleeve and the control magnetic field flux density vector, and the devices have control coils located on their surfaces, which are made of conductive elastic elastomer and electrically connected in a series circuit. Originality. The control method, previous designs and construction of this controlled suspension are protected by patents of Ukraine. Practical value. The direction of further research is to optimize the parameters of the control coils in order to reduce the energy consumption for them and to protect them from overheating. References 20, figures 10.

Effects of External Magnetic Field on Focusing and Energy Distribution of Primary Electrons in an Ion Source

The effect of the applied voltage and magnetic field on the defining slot in focusing and energy distribution of the primary filament electron beam was studied theoretically. In this work, SIMION 8.1 software was used to determine the best operational conditions for focusing and the distribution of the electron beam in the ion source system. Furthermore, the Larmor radius on the slot was calculated in two dimensions for different values of magnetic flux density. The results showed that the values of flux density and slot voltage play an effective role in improving the dimensions of beam spot andenergy distribution in the source. The dimensions of beam spot were reduced by about 71% at voltage value of slot 75 volt and flux density 780 G. In addition; the kinetic energy distribution for electrons were computed at different magnetic flux and obtaining a homogeneous beam energy. The results of this research support the calculations of plasma source designers.

Design and application of optimum toroidal shaped electromagnetic energy harvesters for unmanned aerial vehicles

AbstractThis study presents the design and implementation of electromagnetic energy harvesters for the purpose of charging unmanned aerial vehicles (UAVs) battery. In the study, the designed harvesters are analyzed through finite element method (FEM) simulations. In the FEM analysis, common and self‐inductance values, as well as magnetic flux density values of the harvesters, are calculated at specific current values. Inductance values are also theoretically calculated for comparison. Subsequently, an experimental setup is established to test the designed harvesters. After winding the core, the induced voltage and the power transferred to the load by the harvesters are measured. Curve fitting is performed after the measurements with different load resistances to find the maximum power transferred to the load. Through curve fitting, the maximum power obtained at each current value and at which load resistance this power is harvested are determined. Considering the intention of using the designed cores to charge UAVs and the importance of weight in UAV flight, the weights of each core, both without winding and after winding, are measured, and their costs are calculated. Taking all these criteria into account, the performance of the harvesters is demonstrated, and those among the used cores that are the most suitable for UAVs are identified in the study.

Study of Special Unbalanced Load Modes of New Double-Autotransformer of the Flexible Alternating Current Link

The purpose of the work is study of special asymmetric modes of new three-phase autotransformer device for flexible connection of alternative current power systems. The universal model was developed for the device, containing two autotransformers - the main phase-shifting and the additional regulating autotransformer. The model allows studying both symmetric and almost any asymmetric modes of the considered circuit. It became possible to connect asymmetrically the loads in different phases of the regulating autotransformer, as well as arbitrary connect the regulating autotransformer itself to the hexagon taps. According to the calculated values of currents, voltages and magnetic fluxes of the device the visual vectorial diagrams were constructed for the main and the regulating autotransformer, explaining specific of considered operating modes. It was shown that device’ currents in such modes contain symmetrical components of both zero and negative sequences. Also, at asymmetric connection of the regulating autotransformer, the relative magnetic flux of the legs of the main and regulating autotransformers are asymmetrical, but in main autotransformer their sum is approximately equal to zero and magnetic flux practically does not escape into the surrounding space. Radically different situation is observed in the regulating autotransformer. The significant zero-sequence fluxes arise with the release of significant (about 50%) magnetic flux into the surrounding space. This re-quires special measures to be taken to limit its harmful effects on the operation of the autotransformer.

PENGARUH VARIABEL CELAH UDARA TERHADAP FLUKS MAGNET PADA GENERATOR PERMANEN MAGNETIK AXIAL FLUKS

Generators that use permanent magnets do not require initial excitation to produce voltage. where the generator design is an axial flux type using a ceramic type permanent magnet (NdFeB), and uses two flanking stator rotors. For electricity use, the AC voltage is changed to DC voltage using a rectifier for charging the accumulator. The air gap in an axialflux generator is the distance between the rotor and stator. The air gap is also a place for the magnetic field to move through the coils in the stator which ultimately produces a magnetic flux value which will influence the amount of induced voltage produced. The faster the rotation produced, the greater the voltage produced, but the frequency value will also increase, so that this generator is only limited to 400 rpm rotation, at a frequency value of 50 Hz, producing an effective voltage of ± 22 V with an air gap distance ( δ) is 2 mm, the frequency measurement has an error of 10-20 Hz and an error percentage of 5-10%, with the results of the induced current measurement having the same voltage

MICRO-EDD OF INCONEL 800 USING ELECTROMAGNETIC FIELD

Micro-electro-discharge drilling ([Formula: see text]EDD) is a type of non-traditional machining process used for drilling micro-holes of desired dimensions with a high aspect ratio. But, there are no such research works that could have explained the desired accurate circular shape of micro-holes. The need for a more advanced hybrid machining process to improve the overall efficiency in terms of mainly desired circular shape and radial overcut is evolved. In this research work, an electromagnetic field force-assisted micro-EDM process has been carried out on Inconel 800 with a copper tool of 450[Formula: see text][Formula: see text]m. Experimental results showed that measured metal removal rate and tool wear rate decreased for ascending values of magnetic flux density, peak current and gap voltage, whereas circularity increases linearly with an increase in magnetic flux density and also the effects of magnetic field on circularity of micro-holes on Inconel 800 are more predominant than other parameters.

Study on the Strengthening Effect of Excitation Magnetic Field on Stress-Induced Magnetic Signal of X80 Steels

Weak magnetic excitation stress detection has good engineering application prospects in the pipeline non-destructive testing field. To obtain the quantitative variation law between the excited stress-induced magnetic signal and the axial stress value of X80 steel, an axial tensile experimental test of X80 steel under weak magnetic excitation is conducted in this paper. The enhancing effect of the excitation magnetic field on the sensitivity of stress-induced magnetic signals has been quantitatively analyzed. The results indicate that the value of normal magnetic flux density B z increases by 24 times when the excitation magnetic field reaches 600 A/m. Within the scope of 400 A/m to 700 A/m, the excitation magnetic field of 400 A/m has the best excitation effect on X80 steel.

Initial Design of Free energy magnetic generator (FEMG)

Nowadays, it is essential for some areas that there would be implemented such ways for electricity cost reductions in the areas, equipment durability and minimal technical labour demand maintenance. There are many type of generator that can help to generate the electricity such as steam turbines, gasoline turbines, electrical generators, solar or wind turbines, internal combustion engines, and biogas engines. However, there are many drawbacks of using these generators. One of the major drawbacks of these non-renewable generators are the released of hazardous exhausts into the environment such as carbon dioxide, nitrogen oxide, or any other dangerous exhaust. These will produce air pollution, although it imposes environmental costs through manufacture and construction. One of the well-known energy sufficient generator is the permanent magnet generator. The main aim for this project is to design a Free Energy Magnetic Generator (FEMG) using conventional induced voltage generating principle for industrial and residential appliances. The design will be used JMAG Designer Software from designing and observing the generator. It can be concluded that this generator can give a continuous output power supply due to the capability of the generator to produce high output power with low cogging torque which is 2.1Nm. Perhaps, the maximum value of magnetic flux between coil is 2.1066 while the minimum value is 0.0418.

Calculation of Forces to the High Granularity Calorimeter Stainless Steel Absorber Plates in the CMS Magnetic Field

The general-purpose Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN incorporates a hadronic calorimeter to register the energies of the charged and neutral hadrons produced in proton–proton collisions at the LHC at a center-of-mass energy of 13.6 TeV. This calorimeter is located inside a superconducting solenoid that is 6 m in diameter and 12.5 m in length, generating a central magnetic flux density of 3.8 T. For operating optimally in the high pileup and high radiation environment of the High-Luminosity LHC, the existing CMS endcap calorimeters will be replaced with a new high granularity calorimeter (HGCal) with an electromagnetic section and a hadronic section in each of the two endcaps. The hadronic section of the HGCal will include 44 stainless-steel absorber plates with a relative permeability value well below 1.05. The volume occupied by 22 plates in each endcap is about 21 m3. The calculation of the axial electromagnetic forces acting on the absorber plates is a crucial element in designing the mechanical construction of the device. With a three-dimensional computer model of the CMS magnet, the axial forces on each absorber plate were calculated, and the dependence of forces on the central magnetic flux density value is presented. The method of calculation and the obtained results are discussed.

Effect of The Composition of TiO2 Additives on The Physical and Magnetic Properties Crystal Structure and Microstructure of BaFe12O19 Magnetic Ceramics

<p>In this research, the manufacture of barium hexaferrite (BaFe<sub>12</sub>O<sub>19</sub>) magnetic ceramics and the addition of titanium dioxide (TiO<sub>2</sub>) additives with variations of 0%: 0.3%: 0.6% and 0.9% used the powder metallurgical method. The characterization used in this study is the measurement of density, porosity, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM), and Impulse Magnetizer K-Series. Based on the results of density and porosity measurements, the highest values were 4.95 g/cm3 and 5.45%, respectively. XRD results showed the formation of a BaFe<sub>12</sub>O<sub>19</sub> phase with some impurities at 0% (Fe<sub>2</sub>O<sub>3</sub>), 0.3% and 0.9% (Ti<sub>6</sub>O<sub>11</sub>), and 0.6% (Ti<sub>4</sub>O<sub>7</sub>). The SEM results showed that the morphology of TiO<sub>2</sub>-BaFe<sub>12</sub>O<sub>19</sub> was quite homogeneous, and the size and cavity ranged from 0.5 – 1.5 μm and 0.25 – 0.9 μm, respectively. VSM results show Mr, Ms, Hc, and Bhmax values of 1,489 kG, 3,235 kG, 1,758 kOe, and Bhmax of 0,867 MGOe, respectively. The results of the Impulse Magnetizer K-Series show the maximum and lowest magnetic flux values of 272.65 gauss and 218.10 gauss at 0.6% and 0% variation, respectively.</p>

ПОВЫШЕНИЕ ЭНЕРГОЭФФЕКТИВНОСТИ АСИНХРОННОГО ЭЛЕКТРОПРИВОДА В СЕЛЬСКОМ ХОЗЯЙСТВЕ

The cost of electricity for the electric drive of technological installations is about 40 ... 50% of the total electricity consumed, depending on the type of enterprise. Two principles of control of an asynchronous electric motor are analyzed. Optimum from the point of view of energy efficiency, the scalar law of regulation of the supply voltage amplitude assumes the selection for each fixed value of the supply frequency and load moment of such a value of the voltage amplitude at which the losses in the motor are minimal and the efficiency is maximum. For these purposes, an additional controller is added to the composition of the electric drive, which, when the power frequency changes, corrects the value of the voltage amplitude obtained, according to the basic law, to a small extent, in such a way as to ensure the extremum of efficiency. As an objective function of the extremal controller (a criterion for the energy efficiency of an asynchronous electric motor), the following can be chosen: power losses in the motor based on the current in the stator winding or on the value of the main magnetic flux, maintaining a constant rotor slip, combinations of several parameters. A computer model of a scalar control system with a similar extremal controller, created in the SimInTech software package, is proposed. The use of the proposed regulator allows to increase the efficiency of the electric motor by 1.3 ... 11.2%, the largest increase in efficiency is achieved at a frequency of 20 Hz, and the smallest - at a frequency of 50 Hz. The proposed computer model is universal and allows you to explore various combinations of optimization criteria and algorithms for the extremal controller.

Magnetic flux density analysis of magnetic spring in energy harvester by Hall-Effect sensors and 2D magnetostatic FE model

The paper investigates the magnetic properties and design of energy harvester system including the magnetic spring and vibration generator. The magnetic flux density measurements were conducted by means of Hall-Effect magnetic sensors mounted on the magnetic spring. The amplitude of variable component of the magnetic flux density in the magnetic spring depends on the vibrations frequency resembled by vibration generator. In the magnetic spring, two resonant frequencies at 86 Hz and 110 Hz are identified and the reached maximum amplitude value of magnetic flux density is ∼1mT. To confirm the usefulness of the manufactured magnetic spring, the calculation of the magnetic flux density in 2D axis-symmetric model of vibration generator and magnetic spring has been carried out using the Ansys Maxwell. The results of the simulation are in accordance with the measurements. Through simulation analysis and laboratory measurement tests, a better understanding of the properties of magnetic springs prototype has been achieved.

Unsigned magnetic flux proxy from solar optical intensity spectra

ABSTRACT The photospheric unsigned magnetic flux has been shown to be highly correlated with radial velocity (RV) variations caused by solar surface activity. This activity indicator is therefore a prime candidate to unlock the potential of RV surveys to discover Earth twins orbiting Sun-like stars. We show for the first time how a precise proxy of the unsigned magnetic flux (ΔαB2) can be obtained from Sun-as-a-star intensity spectra by harnessing the magnetic information contained in over 4000 absorption lines in the wavelength range from 380 to 690 nm. This novel activity proxy can thus be obtained from the same spectra from which RVs are routinely extracted. We derived ΔαB2 from 500 randomly selected spectra from the HARPS-N public solar data set, which spans from 2015 to 2018. We compared our estimates with the unsigned magnetic flux values from the Solar Dynamics Observatory (SDO) finding excellent agreement (median absolute deviation: 4.9 per cent). The extracted indicator ΔαB2 correlates with SDO’s unsigned magnetic flux estimates on the solar rotational time-scale (Pearson correlation coefficient 0.67) and on the 3-yr time-scale of our data set (correlation coefficient 0.91). We find correlations of ΔαB2 with the HARPS-N solar RV variations of 0.49 on the rotational time-scale and 0.78 on the 3-yr time-scale. The Pearson correlation of ΔαB2 with the RVs is found to be greater than the correlation of the classical activity indicators with the RVs. For solar-type stars, ΔαB2 therefore represents the best simultaneous activity proxy known to date.

Estimating the longitudinal magnetic field in the chromosphere of quiet-Sun magnetic concentrations

Context. Details of the magnetic field in the quiet-Sun chromosphere are key to our understanding of essential aspects of the solar atmosphere. However, the strength and orientation of this magnetic field have not been thoroughly studied at high spatial resolution. Aims. We aim to determine the longitudinal magnetic field component (B∥) of quiet-Sun regions depending on their size. Methods. We estimated B∥ by applying the weak-field approximation to high-spatial-resolution Ca II 854.2 nm data taken with the Swedish 1 m Solar Telescope. Specifically, we analyzed the estimates inferred for different spectral ranges using the data at the original cadence and temporally integrated signals. Results. The longitudinal magnetic field in each considered plasma structure correlates with its size. Using a spectral range restricted to the line core leads to chromospheric longitudinal fields varying from ∼50 G at the edges to 150–500 G at the center of the structure. These values increase as the spectral range widens due to the photospheric contribution. However, the difference between this contribution and the chromospheric one is not uniform for all structures. Small and medium-sized concentrations show a steeper height gradient in B∥ compared to their chromospheric values, so estimates for wider ranges are less trustworthy. Signal addition does not alleviate this situation as the height gradients in B∥ are consistent with time. Finally, despite the amplified noise levels that deconvolving processes may cause, data restored with the destretching technique show similar results, though are affected by smearing. Conclusions. We obtained B∥ estimates similar to those previously found, except for large concentrations and wide spectral ranges. In addition, we report a correlation between the height variation of B∥ compared to the chromospheric estimates and the concentration size. This correlation affects the difference between the photospheric and chromospheric magnetic flux values and the reliability of the estimates for wider spectral ranges.

Design and studying the effect of Polepiece shape on the magnetic and optical properties of the unipolar lens

The investigation of a study of each design included the calculation of its axial magnetic field the magnetization of the lens in addition to the magnetic flux density using Finite Element Method (FEM) at three different values of current density (σ = 2,4 and 6 A/mm2). So clearest values and behavior have been obtained at the value current density of (2 A/mm2). It is found that the best magnetizing properties, the highest value of magnetic flux and the lowest value of band width of the axial magnetic field strength have been obtained when the pole head shape length was of (1 mm). The effect of current density on the optical properties has been also studied, and it is found that optical properties have been improved also, and chromatic and spherical aberration values have been decreased significantly. Thus, lens was chosen as the best design among the proposed designs.

Implicit iteration calculations using 3D field analyses, to predict the power loss in powder ferromagnets, with their measurement tests

An implicit iterative calculation model with 3D magnetic field analysis has been developed to predict the power losses in the sintered ferromagnetic powders. The integral parameters of the magnetic field such as the losses due to eddy currents and hysteresis ones were calculated for different frequencies and magnetic flux density values. Such prediction of the losses is helpful as the data provided in catalogues is measured for strictly limited ranges of flux density and operation frequency. Moreover, the manufacturers don't give the electrical conductivity and magnetic permeability values of the magnetic cores from the aforesaid materials needed for 3D magnetic field analyses, where ferromagnetic particles cannot be separately included due to enormous computational efforts. The simulated losses in the cores were tested for the magnetically soft composite (SMC) called Somaloy as well as for ferrite cores. A good conformity of the simulated core losses with the measured values was obtained.

Methodology to Generate a Reluctance Network Applied to Permanent Magnet Synchronous Generators

This paper presents a methodology for the generation of a static reluctance network, with magnetomotive sources only in the rotor, applied in the analysis and design of surface mounted permanent magnet synchronous generators. In the analysis stage, this network can provide the magnetic flux in several points of the generator, enabling an estimate of the generator performance. In the design process, on the other hand, it provides the armature linkage flux and hence the induced EMF can be calculated. It is worth mentioning that the proposed methodology makes use of a good discretization level (high number of elements) on the teeth tips and in the air gap of the generator, in order to get better precision on the flux modeling of these regions. The main contribution of this paper is to present the development process of a static reluctance network applied to surface mounted permanent magnets synchronous generators with different dimensions. The proposed model has proved to be robust and flexible as it can be seen in the results. The reluctance network (RN) developed with the proposed methodology presented in this paper shows low variations of the magnetic flux values, when compared with finite element simulations.

Design and Studying the Effect of Inner Bore Diameter of Unipolar Lens

This work investigated the development of magnetic and optical properties and the invention of a previously unused lens. Many new designs have been suggested for a unipolar magnetic lens based on changing the width of the inner bore and fixing the other geometrical parameters of the lens to improve the performance of unipolar magnetic lenses. The investigation of a study of each design included the calculation of its axial magnetic field the magnetization of the lens in addition to the magnetic flux density using Finite Element Method (FEM). it was found that the best magnetizing properties, the highest value of magnetic flux and the lowest value of band width of the axial magnetic field strength have been obtained when the width of the inner cavity was (55 mm). The effect of current density on the optical properties has been also studied, and it was found that the optical properties have been improved also, and the chromatic and spherical aberration values have decreased significantly. Thus, the lens (55 mm) was chosen as the best design among the proposed designs.