Search results
1 – 10 of 214Zhu Feng, Shaotao Zhi, Lei Guo, Chong Lei and Yong Zhou
This paper aims to investigate magnetic field anneal in micro-patterned Co-based amorphous ribbon on giant magneto-impedance (GMI) effect enhancement.
Abstract
Purpose
This paper aims to investigate magnetic field anneal in micro-patterned Co-based amorphous ribbon on giant magneto-impedance (GMI) effect enhancement.
Design/methodology/approach
The amorphous ribbons were annealed in transverse and longitudinal magnetic field. The influence of different field annealing directions on GMI effect and impedance Z, resistance R and reactance X with a series of line width have been deeply analyzed.
Findings
In comparison with GMI sensors microfabricated by unannealed and transversal field annealed ribbons, GMI sensor which was designed and microfabricated by longitudinal field anneal ribbon performs better. The results can be explained by the domain wall motion and domain rotation during annealing process and the geometric structure of Co-based GMI sensor. In addition, shrinking the line width of GMI sensor can promote GMI effect significantly because of the effect of demagnetizing field, and the optimum GMI ratio is 209.7 per cent in longitudinal field annealed GMI sensor with 200 μm line width.
Originality/value
In conclusion, annealing in longitudinal magnetic field and decreasing line width can enhance GMI effect in micro-patterned Co-based amorphous ribbon.
Details
Keywords
Marcelo R. Pagnola, Mariano Malmoria, Marcelo Barone and Hugo Sirkin
The purpose of this paper is to present a ribbons production route of composition Fe78Si9B13 (%at.) using low cost noncommercial scrap materials to obtain usable magnetic cores by…
Abstract
Purpose
The purpose of this paper is to present a ribbons production route of composition Fe78Si9B13 (%at.) using low cost noncommercial scrap materials to obtain usable magnetic cores by melt spinning technique and their characterization. This way, these may compete with the materials produced by conventional casting processes.
Design/methodology/approach
The methodology is to design a master alloy with scrap different starting compositions, to which Fe is added to get the desired atomic ratio of components. With this starting alloy, using the method of melt spinning, in its variant of chill block melt spinning, are achieved amorphous ribbons with desired soft magnetic behavior. Then these ribbons are thermally treated for achieve nanocrystalline structures to improve the performance in the magnetic cores.
Findings
The result of this paper shows that it is possible to recycle scrap materials, and re-used efficiently as components essential in part of electrical components. This way, these may compete with the materials produced by conventional casting processes.
Research limitations/implications
The limitation of this work to ensure that the scrap materials used is reasonably adequate to accomplish obtaining the master alloy, i.e. having reduced impurities.
Practical implications
The implications are important, because it assures that the components are recyclable and also high-tech in reference to energy saving that involves the production of amorphous and nanocrystalline materials in the electric industry. These products may compete with those produced by conventional casting processes.
Social implications
The social implications lead to awareness in recycling and energy saving as an option for social progress in technology.
Originality/value
The originality of the study is that it takes as a starting point for the final product (ribbon) noncommercial scrap materials of known composition and the obtained results are comparable to those that also are manufactured from the pure elements. The control of impurities is necessary in the production route. This way, these may compete with the materials produced by conventional casting processes. This process achieved a production with lower cost, high efficient energy products and high added value.
Details
Keywords
Marcelo R. Pagnola, Marcelo Barone, Mariano Malmoria and Hugo Sirkin
The purpose of this paper is to present an analysis over own and other authors data related to the process of Chill Block Melt Spinning (CBMS) and propose a model of analysis for…
Abstract
Purpose
The purpose of this paper is to present an analysis over own and other authors data related to the process of Chill Block Melt Spinning (CBMS) and propose a model of analysis for interpreting.
Design/methodology/approach
The methodology used in this work is to present the data analyzed by other authors, organize own data similarly to establish comparison, and established models and propose a possible physical processes interpretation.
Findings
Similarity between own experimental data. with others data reported by other authors, both z/w ratio and the thicknesses of the films produced has been found. This allows us to establish an exponential decay of the parameters studied and possibly link it the Newtonian cooling to which the samples are subjected in its production.
Research limitations/implications
This work is the first model set up to predict dimensions in design process by CBMS as a function of parameters of the ribbon production process.
Practical implications
The prediction of the product dimensions, with adjusting the initial parameters, allows to improve the process of ribbon production, this saves tuning time of the machine and provides certainty in the molten material ejection.
Social implications
The efficient production of magnetic materials lets save efforts in the raw material process preparing in magnetic cores for the energy sector. This, improves production besides benefit society by the final product and the energy savings.
Originality/value
The value of this paper is to propose a model of analysis that allows standardize production parameters, and could even allow the use of these models in computer programs, process simulators in a more effective manner.
Details
Keywords
Bronislaw Tomczuk, Dariusz Koteras and Andrzej Waindok
In a modular transformer with a wounded amorphous core, the authors should make some cutting to limit the eddy currents in its magnetic ribbon. The purpose of this paper is to…
Abstract
Purpose
In a modular transformer with a wounded amorphous core, the authors should make some cutting to limit the eddy currents in its magnetic ribbon. The purpose of this paper is to deal with 3D magnetic field analysis, including the eddy currents induced by varying frequency of power. The influence of the core leg cutting on the power losses values, in the three variants of a one-phase modular transformer structure, has been presented.
Design/methodology/approach
3D field problems including eddy currents of various frequency were analysed using the electrodynamic potentials and V within the finite element method. The wave method and iterative one of the laminated core homogenization, have been employed. The values of the calculated losses have been verified experimentally.
Findings
The reduction of the core losses by axial cutting of the transformer legs is an efficient approach for the loss limitation. The wave method is not acceptable for homogenization of the amorphous core for its operation above 1 kHz. The iterative method is the better way to perform the homogenization.
Research limitations/implications
Due to very thin (less than 50 μm) amorphous ribbon, the unhomogenization of the laminated magnetic core should be performed. Thus, the solid core with equivalent parameters has been assumed for the computer simulations. For the frequencies above 1 kHz, the iterative method should be used to determine the equivalent electrical conductivity of the solid substitute core.
Originality/value
Using the wave method with the electrodynamic similarity laws and assuming the wave penetration depth, the equivalent electrical conductivity of the homogenized core, has been determined. This approach is valid for supply frequencies below 1 kHz. For the higher frequencies the authors had to use the iterative method. It seems to be valid for another cores with amorphous and nanocrystalic ribbons. For the modular amorphous core it is only way to calculate the losses in the solid geometry of the homogenized laminated magnetic circuit.
Details
Keywords
Zhu Feng, Shaotao Zhi, Xuecheng Sun, Lili Yan, Cui Liu and Chong Lei
This paper aims to investigate the influence of structure parameters on giant-magnetoimpedance (GMI) effect measured by non-contact method.
Abstract
Purpose
This paper aims to investigate the influence of structure parameters on giant-magnetoimpedance (GMI) effect measured by non-contact method.
Design/methodology/approach
The GMI sensor contains a Co-based internal magnetic core fabricated by laser cutting and an external solenoid. The influences of magnetic permeability of magnetic core and structure parameters on GMI effect were calculated in theoretical model. The output impedance, resistance, reactance and GMI ratio were measured by non-contact method using impedance analyzer.
Findings
Enhancing external magnetic field intensity can decrease the magnetic permeability of core, which has vital influences on the magnetic property and the output response of GMI sensor. In addition, increasing the width of magnetic core and the number of solenoid turns can increase the maximum GMI ratio. The maximum GMI ratio is 3,230% with core width of 6 mm and solenoid turns of 200.
Originality/value
Comparing with traditional contact-measured GMI sensor, the maximum GMI ratio and the magnetic field sensitivity are improved and the power consumption is decreased in non-contact measured GMI sensor. GMI sensor measured by non-contact method has a wide range of potential applications in ultra-sensitive magnetic field detection.
Details
Keywords
Daniel Ioan, Mihai Rebican and Antal Gasparics
The paper describes an efficient method to extract the B‐H nonlinear characteristic from the experimental flux‐current Φ‐I data obtained using a non‐uniform magnetic field device…
Abstract
The paper describes an efficient method to extract the B‐H nonlinear characteristic from the experimental flux‐current Φ‐I data obtained using a non‐uniform magnetic field device. Both functions are monotonically piecewise linear approximated with the same number of breakpoints. The method was successfully applied to characterize the ribbon core material of a fluxset magnetic field sector. In this case the hysteresis loop and the lumped magnetic circuit were extracted. Comparison with experimental results validates the proposed method.
Details
Keywords
B. Colin, A. Kedous‐Lebouc, C. Chillet and P. Mas
Geometric or magnetic anomalies in the wound magnetic core of a residual current circuit breaker can be responsible of its abnormal tripping. The purpose of this paper is to…
Abstract
Purpose
Geometric or magnetic anomalies in the wound magnetic core of a residual current circuit breaker can be responsible of its abnormal tripping. The purpose of this paper is to analyse the core shape contribution to false residual currents (FRCs).
Design/methodology/approach
To study precisely the core shape contribution, FEM simulations are investigated. First a 2D multilayer geometry is described thanks to linear regions. Then an apparent anisotropic bulk core is developed and validated in 2D and in 3D.
Findings
The air gaps between the magnetic layers develop a shielding effect responsible of the core high sensibility to primary conductors eccentricity. This effect can be easily represented using an anisotropic bulk core model.
Research limitations/implications
The anisotropic material model is basic and has known limitations. Future research should see the development of a new model.
Originality/value
FRCs can considerably disturb operation of residual current device. This paper provides new hypothesis on the origin of theses currents and proposes an anisotropic magnetic material model that simplifies FRC study.
Details
Keywords
Daniel Ioan, Irina Munteanu and Corneliu Popeea
The paper presents an efficient modeling technique for the fluxset magnetic field sensor. Using separate numerical solutions for the electric and magnetic fields, an equivalent…
Abstract
The paper presents an efficient modeling technique for the fluxset magnetic field sensor. Using separate numerical solutions for the electric and magnetic fields, an equivalent SPICE circuit is extracted in the postprocessing phase. The main contribution of the paper is the technique used to model the distributed capacitive effects in insulation between coils, by concentrating them in an “Extended II scheme”, an infinite circuit which is optimally reduced to a finite one. The results are in qualitative agreement with the experimental ones.
Details
Keywords
Brief Particulars of Recently Introduced Materials likely to have Aircraft, Missile or Space Vehicle Applications. A new company known as Mitchell Mouldings Ltd., Middleton Lodge…
Abstract
Brief Particulars of Recently Introduced Materials likely to have Aircraft, Missile or Space Vehicle Applications. A new company known as Mitchell Mouldings Ltd., Middleton Lodge, Easebourne Lane, Midhurst, Sussex, has recently been formed for the encapsulation of components for both industry and commerce.
ICI Organics Division, PO Box 42, Blackley, Manchester M9 3DA, state that their Neramine S dyes are particularly suitable for colouring wood before varnishing, because of their…
Abstract
ICI Organics Division, PO Box 42, Blackley, Manchester M9 3DA, state that their Neramine S dyes are particularly suitable for colouring wood before varnishing, because of their intensity of colour when the powders are dissolved in methyl glycol or ethyl glycol.