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Wyświetlanie 1-15 z 25
Tytuł:
Validation of finite element solutions of nonlinear, periodic eddy current problems
Autorzy:
Plasser, R.
Bíró, O.
Powiązania:
https://bibliotekanauki.pl/articles/140778.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
eddy currents
nonlinear magnetic
finite elements
3-dimensional
Opis:
An industrial application is presented to validate a finite element analysis of 3-dimensional, nonlinear eddy-current problems with periodic excitation. The harmonicbalance method and the fixed-point technique are applied to get the steady state solution using the finite element method. The losses occurring in steel reinforcements underneath a reactor due to induced eddy-currents are computed and compared to measurements.
Źródło:
Archives of Electrical Engineering; 2014, 63, 4; 591-600
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat generation by eddy currents in a shell of superconducting bus-bars for SIS100 particle accelerator at FAIR
Autorzy:
Tomków, Ł.
Trojanowski, S.
Ciszek, M.
Chorowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/141177.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
superconductors
eddy currents
electromagnetic heat generation
particle accelerators
Opis:
Superconducting magnets in the SIS100 particle accelerator require the supply of liquid helium and electric current. Both are transported with by-pass lines designed at Wrocław University of Technology. Bus-bars used to transfer an electric current between the sections of the accelerator will be encased in a steel shell. Eddy currents are expected to appear in the shell during fast-ramp operation of magnets. Heat generation, which should be limited in any cryogenic system, will appear in the shell. In this work the amount of heat generated is assessed depending on the geometry of an assembly of the bus-bars and the shell. Numerical and analytical calculations are described. It was found that heat generation in the shell is relatively small when compared to other sources present in the accelerator and its value strongly depends on the geometry of the shell. The distribution of eddy currents and generated heat for different geometrical options are presented. Based on the results of the calculations the optimal design is proposed.
Źródło:
Archives of Electrical Engineering; 2017, 66, 4; 705-715
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupled wave-equation and eddy-current model for modelling and measuring propagating stress-waves
Autorzy:
Peussa, T.
Belahcen, A.
Powiązania:
https://bibliotekanauki.pl/articles/140923.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coupled model
eddy currents
finite element method
magnetostriction
stress wave
Opis:
The coupling of the propagating stress wave with the eddy current model is presented. The applied stress produces magnetization in the sample that can be measured outside the sample by measuring the resulting magnetic flux density. The stress and flux density measurements are made on a mechanically excited steel bar. The problem is modelled with the finite element method for both the propagating wave and the eddy current. Three aspects are considered: eddy current model using magnetization from the measurements, coupled wave and eddy current models, and coupled different dimensions in the wave model. The measured stress can be reproduced from the measured flux density by modelling. The coupled models work both for stress and flux couplings as well as for the different dimensionality couplings.
Źródło:
Archives of Electrical Engineering; 2015, 64, 2; 215-226
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of end-winding proximity losses in a high-speed PM machine
Autorzy:
Mlot, A.
Lukaniszyn, M.
Korkosz, M.
Powiązania:
https://bibliotekanauki.pl/articles/141443.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
end-winding
permanent magnet motor
eddy-currents losses
proximity losses
Opis:
This paper presents a finite element investigation into the proximity losses in a high-speed permanent magnet (PM) machine for traction applications. A three-dimensional (3D) finite element analysis (FEA) is employed to evaluate and identify the endwinding contribution into the overall winding power loss generated. The study is focused on the end-winding effects that have not been widely reported in the literature. The calculated results confirm that the end-winding copper loss can significantly affect the eddycurrent loss within copper and it should be taken into account to provide reasonable prediction of total losses. Several structures of the end-winding are analyzed and compared in respect to the loss and AC resistance. The results clearly demonstrate that the size of the end-winding has a significant impact on the power loss. The calculated results are validated experimentally on the high-speed permanent magnet synchronous machine (PMSM) prototype for selected various winding arrangements.
Źródło:
Archives of Electrical Engineering; 2016, 65, 2; 249-261
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CPC-based currents’ description in three-phase four-wire systems with asymmetrical and nonsinusoidal waveforms
Autorzy:
Sołjan, Z.
Hołdyński, G.
Zajkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200460.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Currents’ Physical Components (CPC)
power theory
asymmetric voltage
nonsinusoidal waveforms
Opis:
This article aims to explain the capability of describing three-phase systems powered from the source with asymmetrical nonsinusoidal voltage waveforms. Indicating the physical components of the currents associated closely with specific physical phenomena facilitates separating the unbalanced components from the active and reactive ones. All those currents, excluding the active current and the scattered current, contribute to the existing unbalanced and reactive power. This article presents the decomposition of currents based on the Currents’ Physical Components Theory. When decomposing currents, it is assumed that the load is linear and unchanging in time, and the voltage supply is asymmetrical and nonsinusoidal.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 5; 1127-1134
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the number of turns on the performance of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Zhang, Y.
Yang, C.
Yi, R.
Powiązania:
https://bibliotekanauki.pl/articles/200007.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
eddy currents density
losses
PMSM
number of turns
temperature field
Opis:
The current passed by the stator coil of the permanent magnet synchronous motor (PMSM) provides rotating magnetic field, and the number of turns will directly affect the performance of PMSM. In order to analyze its influence on the PMSM performance, a 3 kW, 1500 r/min PMSM is taken as an example, and the 2D transient electromagnetic field model is established. The correctness of the model is verified by comparing the experimental data and calculated data. Firstly, the finite element method (FEM) is used to calculate the electromagnetic field of the PMSM. The performance parameters of the PMSM are obtained. On this basis, the influence of the number of turns on PMSM performance is quantitatively analyzed, including current, no-load back electromotive force (EMF), overload capacity and torque. In addition, the influence of the number of turns on eddy current loss is further studied, and its variation rule is obtained, and the variation mechanism of eddy current loss is revealed. Finally, the temperature field of the PMSM is analyzed by the coupling method of electromagnetic field and temperature field, and the temperature rise law of PMSM is obtained. The analysis of this paper provides reference and practical value for the optimization design of PMSM.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 3; 429-436
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyznaczanie wartości parametrów odkształcenia napięć i prądów z zastosowaniem rejestratora wartości chwilowych przeznaczonego do monitorowania pracy urządzeń odlewniczych
Determination of Deformation Parameters of Voltage and Current Using the Instantaneous Values Recorder Designed for Monitoring of the Operation of Foundry Devices
Autorzy:
Ziółkowski, E.
Smyksy, K.
Fedoryszyn, A.
Brzeziński, M.
Powiązania:
https://bibliotekanauki.pl/articles/381909.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
odkształcenia napięć
odkształcenia prądów
harmoniczne napięć
harmoniczne prądów
układ zasilania
urządzenia odlewnicze
voltages deformations
currents deformations
harmonics voltages
harmonics currents
supply system
foundry machine
Opis:
W artykule opisano dalsze prace związane z rozszerzeniem funkcjonalności rejestratora wartości chwilowych napięć i prądów przeznaczonego do monitorowania pracy urządzeń odlewniczych zasilanych z sieci elektroenergetycznej jedno- lub trójfazowej. W ich ramach opracowano i wdrożono odpowiednie algorytmy obliczeniowe wzbogacające oprogramowanie przyrządu. Do analizy chwilowych przebiegów napięcia i prądu wykorzystano podawane w literaturze syntetyczne wskaźniki charakteryzujące wyżej wymienione przebiegi.
The article describes further work related to the extension of functionality of instantaneous values recorder of voltages and currents designed to monitor of the foundry devices operation. Such devices can be supplied from the single or three-phase power grid. In this framework the appropriate computational algorithms have been developed and implemented. It has enriched the device software. For analysis of instantaneous voltage and current values have been used synthetic indicators characterizing the above-mentioned waveforms (reported in the technical literature).
Źródło:
Archives of Foundry Engineering; 2015, 15, 4 spec.; 163-166
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of inductances and induced currents in cryogenic by-pass line for SIS100 particle accelerator at FAIR
Autorzy:
Tomków, Łukasz
Trojanowski, Stanisław
Ciszek, Marian
Chorowski, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/141153.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
line inductance
mutual inductance
induced currents
superconducting bus-bars
particle accelerators
Opis:
Quality of electric current delivered to the magnets of a particle accelerator is essential for safety and reliability of its operation. Even small discrepancies strongly affect the properties of particle beams. One of the sources of the disturbances is the appearance of induced currents caused by the electromagnetic interactions between the elements of the machine. In this paper the calculations of induced currents in by-pass lines of a SIS100 particle accelerator are presented. In order to find the values of the currents the self-inductances and mutual inductances of the by-pass lines are found. Due to the complex geometry of the line, especially of Ω-shaped dilatations, the numerical approach was employed. The calculations show that the size of induced currents increases with the distance between the cables in an individual bus-bar. The maximum discrepancy of the magnetic field in a dipole magnet is found to be 7.7 μT. The decrease of distance between the cables allows one to obtain a discrepancy of 1.2 μT.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 485-496
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Balancing reactive compensation at three-phase four-wire systems with a sinusoidal and asymmetrical voltage source
Autorzy:
Sołjan, Z.
Hołdyński, G.
Zajkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200474.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
currents' physical components
power theory
asymmetrical voltage supply
balancing reactive compensation
Opis:
The article presents the essentials of reactance compensation of unbalanced loads in three-phase four-wire systems powered by a sinusoidal and asymmetrical voltage source. The whole of compensation and symmetrization is based on the Currents’ Physical Components (CPC) theory. Reactance compensation, i.e. compensation based solely on inductors and capacitors, in four-wire systems requires the device to be included in a star (Y) structure in order to compensate for the reactive current (reactive power) and the current at the neutral conductor caused by zero sequence asymmetry, and for the device in a delta (∆) structure to allow compensation of the reactive current (reactive power) and current, causing asymmetry of the negative sequence.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 71-79
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sediment supply and fluxes in glacial and outwash fjords, Kongsfjorden and Adventfjorden, Svalbard
Autorzy:
Zajączkowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/2051833.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Spitsbergen
subpolar fjords
meltwater
sediment flux
turbidity currents
hypopycnal flow
Źródło:
Polish Polar Research; 2008, 29, 1; 59-72
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The problem of information leak due to parasitic loop currents and voltages in the KLJN secure key exchange scheme
Autorzy:
Melhem, Mutaz Y.
Kish, Laszlo B.
Powiązania:
https://bibliotekanauki.pl/articles/220471.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
unconditional security
key exchange
parasitic loop currents and voltages
information leak
Opis:
The Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme offers unconditional security, however it can approach the perfect security limit only in the case when the practical system’s parameters approach the ideal behavior of its core circuitry. In the case of non-ideal features, non-zero information leak is present. The study of such leaks is important for a proper design of practical KLJN systems and their privacy amplifications in order to eliminate these problems.
Źródło:
Metrology and Measurement Systems; 2019, 26, 1; 37-40
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving sensitivity of residual current transformers to high frequency earth fault currents
Autorzy:
Czapp, S.
Dobrzyński, K.
Klucznik, J.
Lubosny, Z.
Kowalak, R.
Powiązania:
https://bibliotekanauki.pl/articles/141169.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
current transformers
earth fault currents
electric devices
electromagnetic couplings
high frequency
Opis:
For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 485-494
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of GIC effects on core losses in single phase power transformers
Autorzy:
Mousavi, S.A.
Engdahl, G.
Agheb, E.
Powiązania:
https://bibliotekanauki.pl/articles/141321.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transformator energetyczny
prądy indukowane geomagnetycznie
histereza
power transformers
geomagnetically induced currents
hysteresis
Opis:
This paper presents a method for estimation of core losses in banks of single phase power transformers that are subjected to an injected DC current such as geomagnetically induced currents (GIC). The main procedure of the core loss calculation is to obtain a magnetic flux density waveform in both time and location by using a novel algorithm based on 3D FEM inside the core and then to calculate the loss distribution based on loss separation theory. Also, a simple and effective method is proposed for estimation of losses of asymmetric minor loops by using combination of symmetric loops. The effect of DC biasing on core losses in single phase power transformers is investigated and the sensitivity of core type and material is evaluated. the results shows that DC current biasing could increase core losses up to 40 percent or even more.
Źródło:
Archives of Electrical Engineering; 2011, 60, 1; 35-47
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of a Compact 4-shaped Annular Ring Ultra Wideband Antenna Using Characteristic Modes
Autorzy:
Perli, Bhaskara Rao
Rao, A. Maheswara
Powiązania:
https://bibliotekanauki.pl/articles/2055234.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
characteristic modes
multiple-strips
annular-ring
surface currents
UWB antenna
tapered structure
Opis:
This communication proposes a compact 4-shaped monopole annular ring UWB antenna design. The proposed structure contains multiple radiating strips inside the annular ring, in the form of a 4-shaped and a 50Ω microstrip feed line. A tapered structure with a feed point is chosen to achieve wideband characteristics. The proposed model is printed on a low-priced FR4 substrate with a size of 0.180₀ × 0.225₀ (20 × 25mm²). The proposed model achieves a fractional bandwidth of 133.74% in the 2.7 to 13.6 GHz range with S11<-10dB and covers the 3.1-10.6 GHz unlicensed band approved by FCC in 2002 and X-band applications. The antenna exhibits stable and Omni-directional radiation patterns in the operating frequency range. The analysis of the proposed monopole antenna using characteristic modes is performed to obtain a physical understanding of the radiation process occurring on the radiating antenna. The modal significance curves and the modal current distributions are used to analyze the radiating antenna using the first six characteristic modes. The measurement and simulation results show a good agreement.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 2; 229--235
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized DC loop current attack against the KLJN secure key exchange scheme
Autorzy:
Melhem, Mutaz Y.
Kish, Laszlo B.
Powiązania:
https://bibliotekanauki.pl/articles/221184.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
unconditional security
secure key exchange
parasitic loop currents and voltages
information leak
Opis:
A new attack against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system is studied with unknown parasitic DC-voltage sources at both Alice’s and Bob’s ends. This paper is the generalization of our earlier investigation with a single-end parasitic source. Under the assumption that Eve does not know the values of the parasitic sources, a new attack, utilizing the current generated by the parasitic dc-voltage sources, is introduced. The attack is mathematically analyzed and demonstrated by computer simulations. Simple defense methods against the attack are shown. The earlier defense method based solely on the comparison of current/voltage data at Alice’s and Bob’s terminals is useless here since the wire currents and voltages are equal at both ends. However, the more expensive version of the earlier defense method, which is based on in-situ system simulation and comparison with measurements, works efficiently.
Źródło:
Metrology and Measurement Systems; 2019, 26, 4; 607-616
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 25

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