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EN
Due to speed-dependent centrifugal forces, the support of the torque, static mechanical stress introduced by manufacturing processes the laminated core of rotating electrical machines is exposed to considerable mechanical stress. The resulting stress distribution changes the magnetic properties of the electrical steel. To take this into account, a magnetization model is constituted on the basis of vector magneto-mechanical measurements that include the magnetic permeability as a function of the mechanical stress and the angle between magnetization - and the maximum principal stress direction. Subsequently, the model is integrated into the finite element simulation of a permanent magnet excited synchronous machine at different rotational speeds.
2
Content available remote Achievements in micromagnetic techniques of steel plastic stage evaluation
EN
The investigation of plastic deformation and residual stress by non-destructive methods is a subject of large relevance for the industry. In this article, the difference between plastic and elastic deformation is discussed, as well as their effects on magnetic measurements, as hysteresis curve and Magnetic Barkhausen Noise. The residual stress data can be obtained with magnetic measurements and also by the hole drilling method and x-ray diffraction measurements. The residual stress level obtained by these three different methods is different, because these three techniques evaluate the sample in different depths. Effects of crystallographic texture on residual stress are also discussed. The magnetoelastic term should be included in micromagnetic methods for residual stress evaluation. It is discussed how the micromagnetic energy Hamiltonian should be expressed in order to evaluate elastic deformation. Plastic deformation can be accounted in micromagnetic models as a term that increases the coercive field in soft magnetic materials as the steels are.
EN
Practical implementation of digital feedback (DF) for waveshape control is described in the paper. It is shown that if the system has intrinsically sufficient phase margin then operation of DF can be controlled by changing just the DF gain even though the system gain can vary more than 2 orders of magnitude. Practical tips as well as typical difficulties are also discussed. The provided description should be sufficient to implement DF in any programming language and hardware configuration.
PL
Artykuł opisuje praktyczną implementacją cyfrowego sprzężenia zwrotnego (CSZ). Jeśli system wymuszający ma wystarczający zapas fazy to działanie CSZ może być kontrolowane tylko poprzez zmianę wzmocnienia CSZ nawet jeśli wzmocnienie systemu może się zmnieniać o ponad dwa rzędy wielkości. Podany jest opis praktycznych wskazówek oraz typowych trudności. Zaprezentowany opis CSZ w niniejszym artykule powinien być wystarczający do zaimplementowania CSZ w dowolnym języku programowania i konfiguracji sprzętowej.
EN
In this paper magnetic organic-inorganic hybrid membranes based on EC, PPO polymer matrices and various magnetic powder microparticles were synthesized and studied. Constant pressure permeation technique and the Time Lag method were used to obtain the gas transport coefficients. The mechanical, rheological and magnetic parameters of magnetic hybrid membranes were examined. It was found that their separation and gas transport properties (D, P, S and α) were improved with the decrease in powder particle size and the increase of membrane’s remanence, saturation magnetization and magnetic particle filling. The increase of the magnetic powder addition and a decrease of its granulation improved also mechanical and rheological parameters of the tested membranes. This improvement also had a positive effect on their gas separation properties and their potential usage in the future.
5
Content available remote Local magnetisation of a grain-oriented electrical steel sheet
EN
In the paper, the possibility of measuring fundamental magnetic properties of punched parts of electrical steels by means of nondestructive method and requirements for the measurement area of tested object resulting from its was discussed. Also, experimental results of local magnetisation distribution of the grain-oriented electrical steel sheets area with different width magnetised asymmetrically from one of its surfaces were shown.
PL
W artykule przedstawiono możliwości pomiaru podstawowych wielkości magnetycznych wykrojów blach elektrotechnicznych metodą nieniszczącą oraz wynikające stąd wymagania stawiane obszarowi pomiarowemu badanego obiektu. Przedstawiono również przykładowe wyniki pomiaru rozkładu indukcji na orientowanych blachach elektrotechnicznych o różnej szerokości.
PL
Przedstawiono nową metodę pomiaru podstawowych parametrów rdzenia ferromagnetycznego magnetycznie miękkiego, polegającą na wizualnej ocenie nieliniowych zniekształceń napięcia występującego na cewce wyposażonej w badany rdzeń ferromagnetyczny, w której wymuszany jest przepływ przemiennego prądu sinusoidalnego. Metoda ta umożliwia dynamiczną ocenę dopuszczalnego namagnesowania, będącego iloczynem dopuszczalnego prądu cewki i ilości zwojów, stanowiącego o dopuszczalnym natężeniu pola magnetycznego w rdzeniu oraz jego stałej charakterystycznej AL, proporcjonalnej do względnej przenikalności magnetycznej rdzenia, wyrażającej indukcyjność jednego zwoju.
EN
The paper presents a new method for measuring parameters of a ferromagnetic core, consisting of a visual assessment of non-linear voltage distortions occurring on the coil equipped with tested ferromagnetic core, in which the sinusoidal current flow is forced. This method allows dynamic assessment of acceptable magnetization, which is the product of the permissible coil current and the number of turns, which determine the maximum acceptable intensity of the magnetic field in the core and a constant AL, proportional to the relative permeability of the core, representing the inductance of one coil.
EN
One and two dimensional magnetisation studies of bulk soft magnetic materials have been researched and characterised over the past 100 years. Initially, focus was on dc rotational hysteresis and this has evolved to studies of losses permeability, and magnetostriction, mainly of electrical steels, under controlled complex magnetisation of the type known to locally occur in rotating machine and transformer cores. This paper briefly summarises present knowledge and then some new and unsolved problems of interest or potential industrial importance are reviewed.
PL
Jedno- i dwuosiowe problem magnesowania materiałów magnetycznych miękkich były badane od niemal stu lat. Początkowo koncentrowano się na rotacyjnej histerezie dc i stąd określano takie parametry jak przenikalność, straty czy magnetostrykcję przy magnesowaniu rotacyjnym. Artykuł prezentuje obecny stan wiedzy oraz prognozuje przyszłe kierunki badań w tej dziedzinie.
PL
W artykule zaprezentowane zostały wyniki przeprowadzonej analizy metrologicznej systemu pomiarowego przeznaczonego do pomiarów parametrów materiałów magnetycznych przy bardzo niskich częstotliwościach pola. W analizie zwrócono szczególną uwagę na praktyczne wyznaczenie wartości granicznych błędów torów pomiaru natężenia pola i indukcji magnetycznej wykonanych zgodnie z zaleceniami normatywnymi. Przeanalizowany został również błąd graniczny pomiaru mocy strat w próbce materiału magnetycznego metodą definicyjną opartą o numeryczne planimetrowanie pętli histerezy. W podsumowaniu zestawione zostały wszystkie rozpatrywane źródła błędów w ujęciu procentowym. Pozwala to na porównanie parametrów dokładnościowych systemów stosujących metodę techniczną pomiaru stratności z analizowanym systemem określającym stratność metodą planimetrowania pętli histerezy.
EN
The article concerns the results of a metrological analysis of a measurement system for measuring parameters of magnetic materials at very low frequencies. Particular attention was paid on determining limiting error values of the magnetic field and magnetic induction measurements according to normative recommendations. Limiting error of the measurement of power losses in a sample of magnetic material conducted with the definitive method based on numerical planimetry of the hysteresis loop was also analysed. All analysed error sources have been presented in the summary. This enables the comparison of parameters of system accuracy other methods with the analysed system determining the losses with the hysteresis loops planimetry method.
9
Content available remote AC Magnetic Properties of Electrical Steel Sheet under DC-biased Magnetization
EN
AC magnetic properties of electrical steel sheets are generally evaluated under symmetrical alternating magnetization in the standard magnetic measurement. However, magnetizing conditions of electrical steel sheets in electromagnetic equipments are not always symmetric and alternating magnetization. This paper presents a measuring system for AC magnetic properties of electrical steel sheets under two-dimensional DCbiased magnetization and discusses the properties under DC-biased magnetization.
PL
Warunki magnesowania w urządzeniach elektromagnetycznych nie zawsze są symetryczne. W artykule zaprezentowano system do badania właściwości AC z możliwością podmagnesowania polem DC w obu osiach.
10
Content available remote System pomiaru pola magnetycznego w procesie demagnetyzacji modeli okrętów
PL
Obiekt ferromagnetyczny umieszczony w ziemskim polu magnetycznym ulega namagnesowaniu. Obiekty ferromagnetyczne, którymi są okręty wojenne, powinny podlegać okresowej demagnetyzacji. Demagnetyzacja tak dużego obiektu jest zadaniem złożonym i pracochłonnym. Artykuł przedstawia wybrane problemy związane z budową stanowiska badawczego oraz badaniami nowych metod demagnetyzacji okrętów prowadzonych na modelach. Przedstawiono zautomatyzowany system pomiarowy do badania pola magnetycznego modelu okrętu. Omówiono strukturę i funkcje układu pomiarowego oraz metodę ograniczania błędów wynikających z przemieszczania czujników pomiarowych względem pola magnetycznego. Podano przykładowe wyniki pomiarów.
EN
Ferromagnetic objects have induced and permanent magnetisation. The permanent magnetisation in case of warships has to be decreased by a degaussing process for minimization of the magnetic field of a ship. The degaussing process is a complicated and time-consuming task. The cheapest method of investigation of degaussing process is research on ship models. The measurement system for investigation of the magnetic field of a ship model is presented in this paper. The measurement system is completely automated and allows for efficient measurements. The computer program of this system was carried out in LabVIEW. The structure and functions of the measurement system and the method for decreasing errors connected with the move of magnetic sensors on the platform were discussed. The 3-axis magnetoresistive magnetometers HMR2300 are used in the measurement system. The sensitivity and accuracy of these magnetometers are sufficient enough for measurements of the magnetic field of a ship model. The sequential method of communication between a computer and magnetometers provides approximately simultaneous measurements from all sensors. The result of a degaussing process of the ship model is presented in this paper.
PL
Przedstawiono zastosowanie systemu do pomiaru właściwości magnetycznych materiałów ferromagnetycznych w polach wirujących do pomiaru anizotropii właściwości magnetycznych. Metoda nie wymaga obracania badanego obiektu lub aparatury pomiarowej podczas pomiaru, a jedynie sterowania systemem pomiarowym z poziomu programu operatorskiego.
EN
An application of computerized measuring system designed for measurement of magnetic properties of ferromagnetic materials under rotational fields to measurements of magnetic properties anisotropy is presented. An effective alternative solution for the measurement of magnetic properties in different directions, without the need to shift the sample or measuring apparatus but only by setting of measuring system by application program is proposed.
12
Content available remote Badania pola magnetycznego modelu okrętu podczas demagnetyzacji
PL
Przedstawiono system pomiarowy do badania pola magnetycznego modelu okrętu. System ten będzie wykorzystany przy opracowaniu algorytmów demagnetyzacji okrętów wojennych. Omówiono sposób kompensacji zakłóceń magnetycznych występujących w środowisku.
EN
A measurement system for investigations of the magnetic field of a ship model is presented in the study. The system will be applied in order to work out algorithms for degaussing process of warships. A method of magnetic disturbances compensation occurring in the environment is discussed.
13
Content available remote Badania materiałów magnetycznych w ujęciu Normy
PL
Polska Norma PN-EN 60404-6: Materiały magnetyczne; dopuszcza dwa warianty wymuszania sygnałów sinusoidalnych do badania materiałów magnetycznych. Pierwszym z nich jest sinusoidalne wymuszenie indukcji magnetycznej B, natomiast drugi wariant dopuszcza możliwość wymuszenia sinusoidalnego kształtu natężenia pola H w próbce. W pracy porównano wyniki badań podstawowych parametrów materiałów magnetycznych stosując bądź sinusoidalne wymuszenie indukcji magnetycznej, bądź sinusoidalne wymuszenie natężenia pola.
EN
The Polish Standard allows two variants of sinusoidal signal extortion to investigation of magnetic materials. First of them is sinusoidal extortion of magnetic flux density B while the second variant admits to sinusoidal signal extortion of field intensity H into the tested sample. The essential parameters of the magnetic materials of the test samples to obtain by means of two variants input signal force were compared.
EN
A model-based approach, the Model-View-Interactor Paradigm, for automatic generation of user interfaces in software frameworks for measurement systems is proposed. The Model-View-Interactor Paradigm is focused on the "interaction" typical in a software framework for measurement applications: the final user interacts with the automatic measurement system executing a suitable high-level script previously written by a test engineer. According to the main design goal of frameworks, the proposed approach allows the user interfaces to be separated easily from the application logic for enhancing the flexibility and reusability of the software. As a practical case study, this approach has been applied to the flexible software framework for magnetic measurements at the European Organization for Nuclear research (CERN). In particular, experimental results about the scenario of permeability measurements are reported.
EN
Purpose: The paper presents the results of the investigations concerning the effect of (γ → α') phase transformation on microstructure, magnetic and mechanical properties of austenitic stainless steel grade X5CrNi18-10. Design/methodology/approach: Light microscope examinations, microhardness measurements and static tensile tests were performed in order to reveal microstructure and changes in mechanical properties. The magnetic properties: relative magnetic permeability μ (Maxwell-Wien bridge) and coercive force Hc (permalloy probe) were measured at room temperature. The analysis of the phase composition was carried out on the basis of X-ray investigations. In the qualitative X-ray analysis the comparative method was applied. Findings: It was found that the plastic deformation in cold rolling within the range 10-70% of investigated austenitic Cr-Ni steel induced in its structure a phase transformation of paramagnetic austenite into ferromagnetic martensite. Research limitations/implications: The results of the X-ray quantitative analysis allowed to determine the proportional part of martensite phases α' in the structure of investigated steel in the examined range of cold plastic deformation. Practical implications: A wide range of practical applications of austenitic X5CrNi18-10 steel sheets is warranted by both their high corrosion resistance and high plastic properties, especially in the supersaturated state. Besides, a strong correlation was found between the magnetic properties and the (γ → α') phase transformation. Originality/value: In the course of deformation, the volume fraction of martensite increased at the expense of the amount of austenite resulting in the hardening of the material. In general, a gradual increase of the yield strength results from the strain hardening of the austenite structure and formation of strain-induced martensite.
EN
Magnetic losses have been investigated as a function of frequency in non-oriented steel sheets under alternating and rotational flux. Accurate measurements could be performed over a large induction range, extending up to the approach to saturation, by combining the fieldmetric and thermometric loss measuring methods. It is verified that for both rotational and alternating losses one can apply the concept of loss separation, where the hysteresis, excess, and classical loss components are in a frequency independent relationship.
PL
Artykuł przedstawia analizę strat mocy w funkcji częstotliwości dla nieorientowanej blachy elektrotechnicznej dla przemagnesowania osiowego i obrotowego. Wykonano dokładne pomiary w szerokim zakresie indukcji magnetycznej, sięgającej nasycenia magnetycznego, przy użyciu techniki czujników indukcyjnych oraz termometrycznych. Badania potwierdzają, że zarówno wartości osiowe jak i obrotowe podlegają rozdziałowi strat mocy, w którym komponenty histerezowy, klasyczny wiroprądowy i dodatkowy znajdują się we wzajemnej relacji niezależnej od częstotliwości.
PL
W artykule przedstawiono wyniki pomiarów parametrów próbek materiałów magnetycznych przy zastosowaniu różnych wariantów wymuszenia sygnału magnesującego. Sinusoidalne wymuszenie napięciowe sygnału powoduje sinusoidalne wymuszenie indukcji magnetycznej, co powoduje odkształcenie natężenia pola, natomiast sinusoidalne wymuszenie prądowe sygnału magnesowania powoduje sinusoidalne wymuszenie natężenia pola, co skutkuje odkształceniem indukcji (strumienia magnetycznego). Porównano parametry podstawowych parametrów opisujących właściwości materiałów magnetycznych badanych próbek otrzymane dla dwóch wariantów wymuszeń pola.
EN
The parameters of magnetic materials are determined by both the autonomic measuring stands, i.e. the volt-ampermeter method and the impedances bridges or the computer measuring systems. The sources of signal in measuring system to investigation of magnetic material parameters are alternating current power supplies. However, in automated measuring systems, the final unit of track feeding is power amplifier. It permits to extorting both the proper value of voltage and to supply the tested sample appropriate large current. The Polish Standard allows two variants of sinusoidal signal ex-tortion to investigation of magnetic materials. First of them is sinusoidal extortion of magnetic flux density B while the second variant admits to sinusoidal signal extortion of field intensity H into the tested sample. Extortion from theoretically ideal voltage source signal corresponds to the first option, while in the second variant is necessary ideal current source. In practice, to comply with requirement of the Standard, it is necessary to assure the condition of a much smaller or a much larger internal source impedance in relation to impedance of magnetizing winding of the test sample, respectively to condition of voltage or current extortion. Disposing of either the power supply with well-known internal impedance or the amplifier with well-known output impedance this condition be comply with properly selection of magnetizing winding number of turns. The investigation of magnetic materials of different samples in which was executed either the force of sinusoidal magnetic flux density, which effects the deformation of intensity of the field strength or sinusoidal force of the field strength which causes the deformation of magnetic flux is presented. The essential parameters of the magnetic materials of the test samples to obtain by means of two variants input signal force were compared. The investigations showed distinctness of measurements results of parameters of the same samples by applying the different variants of signal extortions admitted by the Standard.
18
Content available remote A Helmholtz coil for high frequency high field intensity applications
EN
In this work a general introduction to Helmholtz coil is presented and then attention is drawn to the implementation of a wideband (50 kHz) coil for applications requiring high magnetic flux density (up to a few mT) for sensor calibration, immunity tests and exposure of biological specimens. Experimental characterization confirms that field uniformity is quite good: dispersion is within 1.5% and 0.35% inside cubic volumes of 25% and 10% of the coil side respectively for the larger spacing; the measured impedance and the self resonance frequency are in accordance with the proposed simplified model; the magnetic field expanded uncertainty with k=2 is less than 0.5%.
EN
The (Tl0.5Pb0.5)Sr2(Ca0.9Gd0.1)Cu2Oy superconductor has been fabricated by the wet chemical gel technique. The structure of the superconductor was determined as a Tl-1212 tetragonal structure by X-ray diffraction technique. Magnetic properties of the specimen were characterized by measurements of the real and imaginary parts of ac susceptibility in function of the temperature and of the ac applied magnetic field. The peaks of imaginary part of ac susceptibility shifted to lower temperatures upon increasing magnetic field. Taking advantage of the Bean model, the critical current densities of the samples were calculated. The temperature dependences of the critical current were successfully fitted using the powerlaw from thermally activated magnetic flux creep model.
20
Content available remote Some mechanical and magnetic properties of cold rolled X5CrNi18-8 stainless steel
EN
Purpose: The paper analyzes the influence of the degree of cold deformation on the structure forming and changes of mechanical and magnetic properties of cold-rolled sheet on austenitic X5CrNi18-8 stainless steel. Design/methodology/approach: The investigations included observations of the structure on a light microscope, researches of mechanical properties in a static tensile test, microhardness measurements made by Vickers's method and magnetic behaviors determine by used normalized non-destructive testing methods (NDT). The analysis of the phase composition was carried out on the basis of X-ray researches. In the qualitative X-ray analysis the comparative method was applied. Whereas X-ray quantitative phase analysis was carried out by the Averbach Cohen method. Research limitations/implications: The X-ray phase analysis in particular permitted to disclose and identify the main phases on the structure of the investigated steel after its deformation within the range 10%-70%. Moreover results of the X-ray quantitative analysis allowed to determine the proportional part of martensite phases α' in the structure of investigated steel in the examined range of cold plastic deformation. Practical implications: The analysis of the obtained results permits to state that the degree of deformation has a significant influence on the structure, mechanical and magnetic properties of the investigated steel. Besides, it was found that the plastic deformation in cold rolling process of metastable austenitic steel type X5CrNi18-8 induces in its structure a phase transformation paramagnetic austenite into ferromagnetic martensite. Originality/value: plastic deformation in cold rolling process in the austenitic X5CrNi18-8 stainless steel a good correlation was found between changes of the structure and the effects of investigations of the mechanical properties, connected with martensitic α' phases forming. Existing this relation is of essential practical importance for the technology of sheet-metal rolling of austenitic steel.
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