ELEKTRONIKA, ENERGETYKA, ELEKTROTECHNIKA ›
PRZEGLĄD ELEKTROTECHNICZNY ›
2011-9b |
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Publikacja: Iron loss analysis of EI-shaped iron-core inductor considering vector magnetic property
Autor: Naoya SODA  Hiroshi ADACHI
We analyze the EI-shaped iron-core inductors with air-gaps by using 2-D finite element analysis considering vector magnetic property. We
can investigate the iron loss distribution in the cores affected by the length of the air-gaps. As a result, we can show the difference of local iron loss
distribution in the inductor cores when the length of the air-gaps is changed. Moreover, it is shown that the iron loss distribution differs from the
maximum flux density distribution.
Streszczenie. Przeanalizowano rdzeń typu EI metopdą elementu skończonego z uwzględnieniem właściwości wektorowych. Zbadano wpływ
wielkości szczeliny. Stwierdzono różny rozkład lokalnej wartości strat zależny od wielkości szczeliny. Ten rozkład styrat zależy też od wielkości
indukcji. (Analiza strat w rdzeniu typu EI z uwzględnieniem właściwości wektorowych)
Keywords: finite element analysis, inductor, iron loss, vector magnetic property.
Słowa kluczowe: analiza pola magnetycznego, straty.
Introduction
The important problems in inductors are high efficiency
and saving energy. The two main types of inductor are aircore
inductors and iron-core inductors. When high
inductance is necessary, the EI-shaped iron-core inductor
with air-gaps as shown in Fig.1 is generally used. In the
case of the EI-shaped iron-core inductor, the inductance is
often changed by an adjustment of the length of the airgaps.
Therefore, from the point of view of saving energy, it
is very important to investigate the iron loss distribution in
the cores when the length of the air-gaps is changed. In
order to investigate the iron loss distribution in the cores,
there are some methods to measure directly the iron loss,
for example, by using the needle probe method [1].
However, when the inductor cores are very small as shown
in Fig. 1, it is impossible to measure the iron loss
distribution in the cores by using the method above.
On the other hand, because the E-core is punched to Eshape
from one gr[...]
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Prenumerata
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3D Stray Field Analysis of Transformer Cores Considering DC-bias
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Edin MULASALIHOVIC Helmut PFÜTZNER Patrick ZANOLIN
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The paper presents experimental analyses of stray field configurations of a 3-phase/3-limb model transformer core. Core-tank interactions
are roughly simulated arranging a steel plate above the core. The paper considers also DC-bias, caused e.g. by geomagnetically induced currents
(GICs). For the determination of stray field distributions B(x,y,z,t) an automatic scanning system was applied, based on the 3D Hall sensor method.
A sensor with four needle contacts was used for non-destructive 2D analyses of local distributions of eddy current fields E(x,y,t) as arising at the
upper and lower surface of the simulated tank material. The results reveal strong increases of stray field through weak bias if arising in a nonbalanced
way. In the tank simulation plate, mainly cross-sectional eddy currents are generated, flowing perpendicular to the limbs as a rough
tendency. Bias yields very strong enhancements of eddy current losses. Above the tank simulation, a considerably strong rest stray field arises. As a
rough tendency, it is directed from one yoke to the other one, however, with complex reconstructions as a function of time. The novel methodology
promises to complement traditionally performed numerical analyses in a effective way.
Streszczenie. Przedstawiono analizę pola rozproszonego w trzyfazowym modelu rdzenia transformatora podmagnesowanego polem DC. Źródłem
takiego pola mogą być na przykład pola geomagnetyczne. Zastosowano automatyczny system skanera wykorzystującego czujnika Halla. Do analizy
pola elektrycznego od prądów wirowych wykorzystano czujniki igłowe. Badania wykazały znaczący wpływ podmagnesowania. Zbiornik symulowano
przy użyciu płytki stalowej. Podmagnesowanie znacząco zwiększało też straty od prądów wirowych. (Analiza 3D pola rozproszonego rdzenia
transformatora podmagnesowanego polem stałym)
Keywords: transformer cores, stray field, eddy current field, dc-magnetization, geo-magnetically induced currents (GICs).
Słowa kluczowe:[...]
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AC Magnetic Properties of Electrical Steel Sheet under DC-biased Magnetization
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Shunji YANASE Masashi UCHIYAMA Suguru ISHIKAWA Yasuo OKAZAKI
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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.
Streszczenie. 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. (Właściwości magnetyczne AC blach elektrotechnicznych
podmagnesowanych polem DC)
Keywords: magnetic measurements, two-dimensional DC-biased magnetization, electrical steel
Słowa kluczowe: pomiary magnetyczne, blachy elektrotechniczne.
Introduction
Electrical steel sheets are widely used as core materials
for electromagnetic equipments, such as transformers and
motors. The AC magnetic properties of electrical steel
sheets are generally evaluated under symmetric alternating
magnetic excitation. In recent years, the driving condition of
the electrical equipments has been diversified according to
development of the power electronics. The equipments may
be driven by AC voltage with DC bias due to the imbalance
of switching time of semiconductor devices. Therefore, the
core material in the equipments is sometimes excited under
AC magnetization with DC bias. The core material is also
magnetized under two-dimensional magnetizing conditions
such as rotational flux magnetization [1]. Typically, we have
dealt with the DC-biased magnetization in the case that the
direction of the DC magnetic induction is the same as the
direction of the AC magnetic induction [2]. However, it is
also important to understand the magnetic properties under
DC-biased [...]
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Analytical inverse model with flexible parameters for dynamic hysteresis loops modelling
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Ivana NOVÁ Ivan ZEMÁNEK
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Analytical inverse model was proposed to find simple mathematical approximation of dynamic hysteresis loops of soft magnetic materials.
It consists of dynamic loop construction from three components by means of mathematical functions. Favourable mimicking coefficients were
searched, which depend on excitation amplitude and frequency. The nature of its behaviour was studied in order to be able to predict the loop
shape. The model was tested for opened specimen of classic silicon electrical steel at sinusoidal excitation, measured by compensation ferrometer.
Streszczenie. Zaproponowano inwersyjny model analityczny do opisu matematycznego dynamicznej pętli histerezy materiałów magnetycznie
miękkich. Model był sprawdzony dla próbki otwartej klasycznej blachy elektrotechnicznej przy sinusoidalnym magnesowaniu. (Analityczny model
inwersyjny pętli histerezy)
Keywords: dynamic hysteresis loop, mathematical modelling, inverse model, analytical approximation
Słowa kluczowe: dynamiczna petal histerezy, modelowanie.
Introduction
Mathematical model based on hysteresis loop
construction from analytical functions and suitable for AC
magnetizing is proposed. It approximates symmetrical
dynamic hysteresis loops and performs reasonably in the
whole range of commonly used excitation.
It is a part of a more complex task - improving the
properties of the measuring device KF9a [1, 2, 3] by means
of simple prediction algorithm implementation. Instead of
the usual B± = f(H) function its inverse H± = f(B) is needed
for calculating magnetic field strength H from magnetic flux
density B because KF9a has B as input variable. Knowing
the rough estimate of material behaviour, the desired goal is
optimum magnetizing parameters setting and measuring
process accelerating.
In the first step, work was focused on suggestion of
suitable analytical functions, which are able to approximate
the shape of the loop successfully. After that, optimum
coefficients [...]
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Assessment of the effect of lift-off on a magnetic flux injection technique for detection of residual curvature in electrical steel
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Jeremy HALL
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A magnetic flux injection technique developed to assess the residual curvature in non-oriented electrical steel strip has been assessed for
its suitability for an on-line application with a study of the effects of lift-off between the pole faces of the magnetising/sensing yoke and strip surface.
It has been found that changes in the lift-off appear to have very little effect on the differences in loss values measured at each of the surfaces which
are correlated to the residual curvature.
Streszczenie. Technika “flux injection" jest niekiedy stosowana do badania materiałów magnetycznych bez możliwości bezpośredniego pomiaru
indukcji. W metodzie tej ważne znaczenie ma kształt nabiegunników rdzenia i ich przyleganie do powierzchni blachy. Zbadano możliwość pomiaru
krzywizny powierzchni blachy. (Ocena efektu uniesienia rdzenia w technice "flux injection" stosowanej do badania krzywizny blachy )
Keywords: Electrical steel, residual curvature, lift-off, power losses.
Słowa kluczowe: blachy elektrotechniczne, straty magnetyczne.
Introduction
Residual curvature can occur in strip steel due to
various causes in the rolling process in which a crosssectional
stress profile in the longitudinal direction leads to
a latent strain in steel laminations. A magnetic flux injection
technique, based on a localised, single sided measurement
of total loss, has been devel[...]
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Calculation and analysis of local magnetic forces in ferrofluids
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Mickaël PETIT Afef KEDOUS-LEBOUC Yvan AVENAS Mansour TAWK Ernesto ARTEGA
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This paper presents a non-exhaustive overview of magnetic force formulations mainly used in ferrohydrodynamics. All of these
formulations give the same global result but the local force density is different from each other. We propose to compare these formulations in order
to highlight which one is the best representation of the local force density. In order to find a reference of local force distribution, computations have
been carried out using the virtual work method on particles surrounded by thin layers of air. The whole particles and air have been homogenized to
create a linear uniform material. Finally, force distributions have been computed and have been compared to the reference calculated by virtual work
method.
Streszczenie. W artykule przedstawiono przegląd metod określania siły magnetycznej w ferrofluidach. W różnych metodach otrzymuje się różne
lokalne wartości siły. W celu weryfikacji metod prze[prowadzono obliczenia numeryczne w których modelowano cząstki otoczone cienką warstwą
powietrza. (Obliczenia i analiza lokalnej wartości siły magnetycznej w ferrofluidach)
Keywords: Ferrofluid, Ferrohydrodynamics, Magnetic force distribution, Magnetic force analytical formulation
Słowa kluczowe: ferrofluidy, siiła magnetyczna.
Introduction
Ferrofluids are colloidal suspensions of coated magnetic
particles. The Brownian movement, due to the natural
convection, is enough to consider them as homogeneous
liquids. Regarding the magnetic properties of nanoparticles,
ferrofluids can be attracted by a magnet. To predict this
movement, local magnetic forces should be evaluated
precisely. Many physical equivalences and analytical
formulas, deriving from magnetostatics, give a good
estimation of the global force applied to a given massive
body when it is submitted to an external magnetic field [1].
Conversely, each equivalence or formula gives a different
distribution of the local forces in the volume or at the
surface of the body. In or[...]
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Characteristic Evaluation of 4mm-square-sized double H-coil
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Shigeru AIHARA Takashi TODAKA Masato ENOKIZONO
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Two-dimensional vector measurement has become popular as an accurate evaluating method, which can measure the relationship
between the magnetic flux density vector B and the magnetic field strength vector H. In order to improve the resolution of the two-dimensional vector
magnetic measurement, 4mm-square-sized double H-coil was manufactured and evaluated with a developed evaluation system, which consists of a
standard solenoid coil and a high-precision turntable. The V-H sensor combined the H-coil with double needles, was applied to measure
distributions of local magnetic characteristics in a model core.
Streszczenie. Cewka tangencjalna H-coil jest powszechnie używana do pomiaru pola magnetycznego w badanej próbce. W pracy opisano
podwójną cewkę H-coil o rozmiarze 4 mm przeznacz\oną do badania pola magnetycznego z dużą rozdzielczością geometryczną. Cewkę taką
sprzężono też z dwoma czujnikami igłowymi do równoczesnego pomiaru indukcji. (Podwójna cewka tangencjalna o rozmarze 4 mm)
Keyword: Two-dimensional vector magnetic measurement, V-H sensor, Needle prove method, Double-H-coil.
Słowa kluczowe: cewka tangencjalna , czujnik igłowy.
Introduction
Rotational magnetic flux distributions in transformer and
motor model cores have so far been measured with crosstype
search coil method [1, 2]. However the search coil
method needs making holes and it affects the magnetic
properties of the electrical steel sheets and the local flux
distributions. Furthermore this method is unsuitable for
measuring flux distributions in a wide region of core
materials because of troublesome task. To overcome this
difficulty, the double needle method [3, 4] has been
employed to measure local flux distributions in the electrical
steel sheets without the insulation coating. This method has
wide application, however it is not possible to make clear
effects of the insulation coating, which is used for producing
tensile stress in some kinds of grain-oriented silicon[...]
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Comparison of Magnetic Field and Iron Loss Models for 2-Dimensional Magnetic Anisotropic Properties
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Kiyoshi WAJIMA Teruyuki TAMAKI
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In numerical analysis of electromagnetic equipment that contains magnetically anisotropic material, the model considering magnetic
anisotropy should be used. In this work, conventionally proposed magnetic field and iron loss models that can take anisotropic magnetic property
into account, are applied to some models to evaluate its accuracy. The two-axis magnetic field model can obtain similar distribution to the magnetic
field by θHB model. Therefore by using BAI iron-loss model with two-axis magnetic field model, relatively accurate iron loss value can be estimated.
Streszczenie. Przy projektowaniu urządzeń magnetycznych z anizotropowym materiałem te właściwości anizotropowe powinny być brane pod
uwagę. W przedstawionej pracy użyto konwencjonalnego HB modelu do obliczeń. Wyniki porównano z modelem kątowym θHB. Sprawdzono także
model BAI. (Porównanie różnych modeli strat przy obliczaniu dwuwymiarowym właściwości anizotropowych)
Keywords: Anisotropy, magnetic field analysis, 2D magnetic property
Słowa kluczowe: anizotropia, analiza pola magnetycznego.
Introduction
The silicon steel sheets are used for the cores of
electrical equipment such as generators, transformers, and
motors [1]. Since the steel sheets have complicated
magnetic properties, such as anisotropy, and non-linearity,
numerical simulation techniques are applied to design
electrical equipments to obtain better performance by taking
full advantage of silicon steel sheets [2]. So far, many
analysis methods are proposed to calculate the magnetic
field and iron loss in electrical equipments made of the
silicon steel sheets [3][4][5]. Especially in case of grainoriented
silicon steel (GO), the model considering magnetic
anisotropy should be used to analyze magnetic field and
iron loss. However, a precise anisotropy model requires
much more computing time and sometimes does not
numerically converge because of the data error caused by
measurement difficulty of 2D mag[...]
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Comparison of Uniaxial and Rotational Magnetostriction of Nonoriented and Grain-oriented Electrical Stee
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Piotr KLIMCZYK Sakda SOMKUN Philip ANDERSON Anthony MOSES
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Surface domain patterns in electrical steel, which appear under rotational magnetisation, were noted to be comparable to those which are
observed under high compressive stress. This paper presents comparison of peak to peak magnetostriction of Epstein strips under high
compression magnetised along rolling and transverse directions, and disc samples under rotational and uniaxial magnetisation with no external
stress applied. Good correlation was found between magnetostriction measurement results obtained in the rolling direction of non-oriented Epstein
strips under high compression and disc samples under rotational magnetisation. Also it was observed that the rotational magnetostriction of grainoriented
electrical steel is greater than its uniaxial value under compressive stress.
Streszczenie. Artykuł prezentuje porównanie magnetostrykcji pasków Epsteina magnesowanych wzdłuż i prostopadle do kierunku walcowania
(podanych naprężeniu) oraz próbek w formie dysku poddanych magnesowaniu osiowemu i rotacyjnemu (bez naprężenia). W przypadku blach
niezorientowanych znaleziono korelację między magnetostrykcją w kierunku walcowania oraz stratami przy magnesowaniu rotacyjnym. W
przypadku blach zorientowanych magnetostrykcja rotacyjna była większa niż jednoosiowa przy naprężeniu próbki. (Porównanie jednoosiowej i
rotacyjnej magnetostrykcji blach elektrotechnicznych zorientowanych i niezorientowanych)
Keywords: magnetostriction measurement, rotational and uniaxial magnetisation, compressive stress.
Słowa kluczowe: pomiar magnetostrykcji, magnesowanie rotacyjne.
I. Introduction
Uniaxial and rotational magnetostriction in magnetic
cores of electrical machines such as transformers and
motors are a potential source of core vibration and acoustic
noise. The magnetic domain structures of electrical steels
under dynamically rotating magnetisation alternate between
well known bar patterns and a more complex distribution at
certain times in the magnetising cy[...]
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Constant dB/dt DC Characterisation Through Digital Control of Magnetic Field
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Philip ANDERSON
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Control over the rate of change of flux density when plotting DC BH loops is of paramount importance when characterising magnetic
materials which exhibit large values of dB/dt for a linear change of applied field. A new method is described which allows constant dB/dt
measurements to be made in a user friendly manner through a small number of iterations of a simple waveform control algorithm. The method was
demonstrated on a grain oriented silicon steel and shown to provide accurate results after 3 iterations of the test algorithm.
Streszczenie. Przy badaniu materiałów magnetycznych przy prądzie stałym szybkość zmian indukcji ma kluczowe znaczenie. Przedstawiono nową
metodę pozwalającą na pomiar i kontrolę wartości dB/dt. Metodę sprawdzono na przykładzie blach zorientowanych i osiągnięto odpowidznią
dokładność już po trzech iteracjach. (Cyfrowa kontrola pola magnetycznego jako metoda utrzymania stałej wartości dB/dt)
Keywords: DC measurements, grain oriented steel, waveform control
Słowa kluczowe: kontrola ksztłtu indukcji, badanie materiałów magnetycznych.
Introduction
The accurate measurement of the DC magnetic
properties of soft and hard ferromagnetic material[...]
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Core loss distribution measurement of electrical steel sheets using a thermographic camera
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Hiroyasu SHIMOJI Takashi TODAKA Masato ENOKIZONO
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The aim of this study is to measure the distribution of core loss in electrical steel sheets by using a thermographic camera. This paper
describes the measurement system and method, along with their underlying principles. Measurement problems are investigated, and the
measurement accuracy is determined. The iron loss distributions are presented, as measured under various conditions on vector magnetic
measurement equipment.
Streszczenie. Zbadano rozkład strat magnetycznych przy wykorzystaniu kamery termograficznej. Przeanalizowano problem pomiarowe i
niepewność pomiaru. Straty mierzono dla różnych warunków magnesowania z uwzględnieniem wartości wektorowych. (Pomiar rozkładu strat
magnetycznych przy wykorzystaniu kamery termograficznej)
Keywords: Core loss, electrical steel, thermographic camera.
Słowa kluczowe: straty magnetyczne, kamera termograficzna.
Introduction
Core loss measurement, along with magnetization
measurement, is one of the typical basic measurements of
electrical steel sheets. The core loss of an electrical
machine is evaluated by loss separation. While the core
loss of the entire machine can be ascertained, it is difficult
to find the distribution of localized core loss. In addition,
questions regarding accuracy of the measurement arise
because the core loss is usually obtained by subtracting
various loss factors from the total loss. Core loss can be
directly measured using a small probe sensor and an H coil;
however, since the measurement covers only localized
areas, there are problems of accuracy and convenience in
deriving the total loss. On the other hand, the core loss is
converted into heat, and the identification of the loss
through the rise in temperature is essential and effective. As
a means of directly measuring the core loss of an electrical
steel sheet, the use of a thermocouple or a thermistor for
measuring the local temperature has been suggested [1-4].
According to these reports, the temperature [...]
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Core loss models in electrical steel sheets with different orientation
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Wojciech A. PLUTA
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Classical core loss models such as two components model or modified Steinmetz model are still popular and used by engineers to loss
prediction in electrical machines. They may carry to increase discrepancy between calculated and measured values. This discrepancy increases with
grain-orientation and with increasing discrepancy from sinusoidal magnetisation conditions. Statistical loss model shows better applicability for loss
calculation however, it requires many measurements in frequency domain what is troublesome. The paper presents the frequency behaviour of
classical and statistical loss models in grain and non-oriented electrical steel sheets.
Streszczenie. Klasyczne modele strat są wciąż popularne i wykorzystywane przez inżynierów do przewidywania strat maszyn elektrycznych. Mogą
one prowadzić do niezgodności pomiędzy obliczonymi i zmierzonymi wartościami strat. Niezgodność wzrasta ze zwiększeniem orientacji ziaren i
odkształceniem od sinusoidalnego kształtu strumienia magnetycznego. Statystyczny model strat wykazuje lepszą stosowalność do obliczenia strat
jednak wymaga czasochłonnych pomiarów w dziedzinie częstotliwości. Artykuł przedstawia właściwości częstotliwościowe klasycznych i
statystycznych modeli strat w zorientowanych i niezorientowanych blachach elektrotechnicznych. (Model strat w blachach elektrotechnicznych o
różnym zorientowaniu)
Keywords: loss modelling, loss components, additional loss.
Słowa kluczowe: modelowanie strat, składowe strat, straty dodatkowe.
Introduction
Electrical steel sheets are used in several stages of
electrical energy transformation from the generators to the
ultimate user. In all of those stages not avoidable heating
generation occurs which is also called generally
‘magnetization loss’. The loss is tolerable in the economics
of electrical power distribution and utilisation. However,
electrical equipment should be designed in a way to keep
the loss at a minimal level.
The physical [...]
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Development of Magnetic After-Effect Setup and Application in the Study of Relaxation Processes in Fe-C, Fe-Cu and Fe-Cr Alloys
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Boris MINOV Milan J. KONSTANTINOVIĆ Luc DUPRÉ
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A magnetic after-effect setup, based on an open magnetic circuit, is developed and presented. The magnetic after-effect experiment aims
to determine the time and temperature dependence of the initial susceptibility, which is obtained by an AC measurement of the mutual inductance.
After sample demagnetization, the change of the time dependent initial susceptibility is measured for particular ferromagnetic materials at a chosen
temperature. The setup is applied for the investigation of relaxation processes of dislocations and carbon atoms in Fe-C, Fe-Cu and Fe-Cr alloys.
Streszczenie. Przedstawiono układ do badania lepkości magnetycznej w obwodach otwartych. Badano początkową susceptancję jako funkcję
temperatury i czasu. Analizowano procesy relaksacyjne w stopach Fe-C, Fe-Cu i Fe-Cr. (System do badania procesów relaksacyjnych w
stopach Fe-C, Fe-Cu i Fe-Cr)
Keywords: magnetic after-effect, initial susceptibility, Fe-based alloys.
Słowa kluczowe: after -fekt - lepkość magnetyczna, początkowa susceptancja.
Introduction
Magnetic relaxation is the relaxation of a magnetic
system to an equilibrium state or steady-state condition as
the magnetic field is changed. The corresponding
measurement technique, also known as Magnetic After-
Effect (MAE) spectroscopy, has been constantly improved
in the last few decades and applied to several pure
ferromagnetic materials and a great number of alloys in
order to obtain detailed information on intrinsic defects,
impurity atoms and their interactions [1]. It is a nondestructive
evaluation technique that belongs to the group
of relaxation techniques which has the great advantage to
be sensitive not only to the mere presence of the lattice
defects - to what most other methods are confined - but, in
addition, to detect defect movements such as local
reorientations or diffusional migration [2].
The MAE is a general term for the following
phenomenon: after demagnetization of the sample under
consideratio[...]
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Dynamics effects on losses due to rotational magnetization
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Damir SABIC Helmut PFÜTZNER Franz HOFBAUER Georgi SHILYASHKI Edin MULASALIHOVIC
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As well known, rotational magnetization (RM) may cause high increases of power losses P in comparison to alternating magnetization
(AM), in particular for highly grain oriented SiFe. So far, it had been assumed that the loss increase is a mere function of shape of the induction
pattern B(t). However, closer investigations reveal that a further impact is given by the angular velocity of the vector B. Compared to low dynamics
as being typical for simulations on RSSTs, high dynamics as being typical for T-joint regions of transformer cores yield further increases of losses.
For elliptic RM, the increases are rather weak and tend to decrease with rising axis ratio a. On the other hand, distinctly increased P arises for
rhombic RM as being typical for transformers. Further increases result for oblique rhombic RM as arising close to overlaps. On the other hand, lower
P is given for the case of DC bias due to the fact that anomalous eddy current losses play a weaker role here.
Streszczenie. Magnesowanie rotacyjne powoduje wzrost trat szczególnie w blachach anizotropowych SiFe. Szczegółowa analiza wykazała że
straty te zależą od szybkości kątowej zmian indukcji. Szczególnie duży wzrost strat obserwuje się dla rombowej zmiany, typowej w rdzeniach
transformatora. Z drugiej strony podmagnesowanie DC zmniejsza wzrost strat przez zmniejszenia strat dodatkowych powodowanych przez prądy
wirowe. (Efekty dynamiczne strat rotacyjnych)
Keywords: grain oriented silicon iron, rotational magnetization, magnetic losses, DC bias, magnetization dynamics.
Słowa kluczowe: blachy elektotechniczne zorientowane, straty, magnesowanie rotacyjne.
1. Introduction
As well known, rotational magnetization (RM) may cause
high increases of power losses P in comparison to
alternating magnetization (AM). Due to high effective anisotropy
this is given especially for highly grain oriented (HGO)
SiFe and even more for scribed highly grain oriented
(SHGO) material. RM proves to be [...]
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Epstein to SST relationship - statistical rather than deterministic
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Johannes SIEVERT Heiko AHLERS
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The relationship between the measurement results of Epstein frame and Single Sheet Tester (SST) method are of increasing interest
since, for technical and economical reasons, manufacturers and users of electrical sheet steel use more and more the SST for grading and quality
control of this material. Besides the systematic deviations between these two methods, there is a considerable statistical component in that
relationship. This paper is to demonstrate this phenomenon on the basis of the statistical characteristics of former international round robin tests and
dispersion characteristics of material production estimated from the internal dispersions within 55 groups of Epstein samples from 9 manufacturers,
each group being constituted of 4 or 5 samples of one grade from one manufacturer. The resulting total dispersion is slightly higher than that of a
previous corresponding study accomplished in one laboratory.
Streszczenie. Zależność między wynikami badań aparatem Epsteina a testerem próbek arkuszowych SST może mieć duże znaczenie praktyczne
ponieważ coraz więcej ośrodków stosuje wymiennie tylko jedną z tych metod. Obok różnic fundamentalnych (zasady fizycznej) ważne sa też
badania statystyczne różnic między tymi metodami. W artykule zaprezentowano międzynarodowe porównania różnych urządzę pomiarowych -
badania wykonywano na różnych rodzajach próbek. Wyniki wskazują że różnice są większe niż w przypadku wcześniej demonstrowanych różnic
między badaniami w jednym laboratorium. (Zależność między wynikami aparatu Epsteina i testera próbek arkuszowych SST)
Keywords: Magnetic Loss Epstein SST
Słowa kluczowe: straty magnetyczne, aparat epsteina, SST.
Introduction
The Epstein method [1] and the Single Sheet Tester
(SST) method [2] are the two standardized methods in force
for the measurement of the magnetic properties of electrical
sheet steel. We confine this consideration to the
independent SST92 (IEC standard published in 1992 [2])
and to [...]
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Evaluation of the Magnetic Properties of the Rotating Machines for the Building Factor Clarification
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Mohachiro OKA Makoto KAWANO Kazunori SHIMADA Takayuki KAI Masato ENOKIZONO
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In order to know how much iron loss of an actual stator core increase in each manufacturing process, we are developing the magnetic
property evaluation method of a rotating machine. In this research, we prepared two kinds of specimens, including piled up five punched electrical
steel sheets that are the shape of the actual stator core and laminated punched electrical steel sheet in the shape of the actual stator core. The
specimen of piled up five punched electrical steel sheets is called a punched specimen and the laminated punched electrical steel sheet is called the
laminated specimen. The magnetic properties were measured using the excitation coil and the search coil that was wound in the back yoke of the
two specimens. This method is called the direct winding method. The evaluated magnetic properties were the iron loss, the coercive force, the
residual magnetic flux density, and the maximum excitation magnetic field strength. The experimental results showed that these measured magnetic
properties clearly depended on the manufacturing process, such as the laminating process. The iron loss was increased by the laminating process
by about 4.7% when the maximum excitation magnetic flux density (Bex) is 1.35 T. In this paper, the influence that the laminating process exerts on
magnetic properties of an actual stator core is reported in detail.
Streszczenie. Zbadano jak zmieniają się straty magnetyczne rdzenia stojana w wyniku procesu produkcji. W tym celu zbadano próbki w kształcie
blach stojana. Badano straty, koercję, indukcję i natężenie pola magnetycznego. Stwierdzono, że parametry te bardzo zależą od procesu produkcji
rdzenia. W wyniku laminowania straty wzrosły o 4.7% przy indukcji 1.35 T. (Ocena zmiany parametrów magnetycznych blach maszyn
elektrycznych w wyniku produkcji rdzenia)
Keywords: rotating machine, stator core, iron loss, coercive force, residual magnetic flux density, silicon steel sheet.
Słowa kluczowe: maszyny elektyryczn[...]
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Evaluations of Iron-based Material Expressed by Magnetic Transfer Function
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Koji YAMADA Jiaolian LUO Hiroyasu SHIMOJI Yasushi NAKAHATA Bartosz E. BORKOWSKI Takashi TODAKA Masato ENOKIZONO
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We have been investigated a basic concept of material constant evaluation using transformer type probes in an a.c. field range
between 20Hz and 200kHz. The probes are consisted of 2 transformers with open magnetic poles attached to the material surface under
estimation and attached to the reference material, respectively. The output voltage of each transformer is connected in series and reverse
to cancel the offset voltage caused by the leakage flux. The analyses are performed by using a.c. magnetic resistance theory of magnetic
circuit. We attained the high sensitivity of conductivity and permeability changes in the material without direct contact as that in d.c.
measurements. The transfer function of material in general was defined by the experimental results of the excitation current of the probe,
operation frequency and the output voltages, independent of the characteristics of the transformer materials.
Streszczenie. Badano koncepcję stałej materiałowej przy badaniu próbki transformatorowej w pasmie 20 Hz do 200 kHz. Próbka składała
się z dwóch otwartych transformatorów, z których jeden przyłożony był doi badanego materiału a drugi do materiału porównawczego.
Wyjścia połączono szeregowo i przeciwsobnie. Określono funkcję przetwarzania umożliwiającą ocenę badanego materiału. (Ocena
materiału ferromagnetycznego wyrażona przez funkcję przetwarzania)
Keywords: NDE, Iron-based material, non-contacting probe, ac magnetic probe, eddy current, permeability
Słowa kluczowe: badania nieniszczące, materiał ferromagnetyczny
Introduction
Iron-based structural materials in general are used in
atomic power stations, where it is very important to detect
the fatigues of the structural material, far before the
collapses in fatal destructions. We have been investigating
the non-destructive evaluations (NDE) of these materials by
using ac magnetic probes with non-contacting method. So
many electrical and magnetic tools of NDE methods have
been develop[...]
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Examination of Magnetic Properties of Several Magnetic Materials at High Temperature
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Masayuki MORISHITA Norio TAKAHASHI Daisuke MIYAGI Masanori NAKANO
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In order to accurately design magnetic devices which are used at high temperature, it is necessary to understand the behaviour of several
magnetic materials at high temperature. In this paper, the magnetic properties of several magnetic materials until Curie temperature are measured. It
is shown that the change of iron loss of rolled steel (SPCC and SS400) with the temperature is more remarkable than that of electrical steel sheet.
Streszczenie. W pracy przedstawiono właściwości magnetyczne niektórych materiałów w wysokiej temperaturze. Zmiana strat blachy walcowanej
SPCC I SS400 jest znacznie większa niż ma to miejsce w przypadku blach elektrotechnicznych. (Badania właściwości magnetycznych
niektórych materiałów magnetycznych w wysokiej temperaturze)
Keywords: high temperature, comparison of magnetic properties, iron loss, specific permeability
Słowa kluczowe: właściwości magnetyczne, straty, wysoka temperature.
Introduction
If the magnetic fields in magnetic devices, which are
used at high temperature, are analyzed using the magnetic
properties at a room temperature (RM), the obtained results
are fairly different from an actual behaviour [1, 2]. In order
to accurately design magnetic devices which are used at
high temperature, it is necessary to understand the
behaviour of several magnetic materials at high
temperature. Although the change of magnetization of
magnetic material measured using a VSM is well reported
[3], the data of magnetic properties, such as B-H curves
and iron loss curves which are indispensable to the precise
magnetic field analysis at high temperature are not familiar.
We have already reported the measurement method of
magnetic properties at high temperature until about 800C
using a ring specimen and discussed the behaviour of the
magnetic properties of electrical steel sheets [4]. However,
it seems that there is no report about the comparison of
magnetic properties of several magnetic materials.
In[...]
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Magnetic Properties of Non-Oriented Electrical Steels under Compressive Stress Normal to Their Surface
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Ken-ichi YAMAMOTO Shunji YANASE
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Magnetic properties of non-oriented electrical steels are measured under a compressive stress up to 28 MPa normal to their surface. It is
shown that the perpendicular stress changes their permeability and magnetic losses along their circumferential direction. The variations in magnetic
properties are discussed in terms of changes in magnetic domains due to the stress.
Streszczenie. Zbadano wpływ naprężeń ściskających na niezorientowane blachy elektrotechniczne. Stosowano naprężenia do 28 MPa normalne do
powierzchni. Stwierdzono że naprężenia prostopadłe powodują zmiany przenikalności i strat w obu kierunkach. (Właściwości magnetyczne blach
elektrotechnicznych niezorientowantych poddanych naprężeniu ściskającemu normalnemu do powierzchni)
Keywords: Electrical steel sheet, Stress effect, compression, magnetic loss
Słowa kluczowe: blachy elektrotechniczne, naprężenia mechaniczne.
Introduction
Electrical steel sheets used in motor cores are subjected
to external stresses in manufacturing process of motors.
Difference in the magnetic properties between before and
after the fabrication is a problem in the design of recent
motors with high performance. The effect of stresses on
strip-shaped non-oriented electrical steels [1, 2], and ringshaped
ones [3, 4] have been studied. These studies have
mainly focused on the stress parallel to the magnetizing
direction, although the stress can be applied in various
directions when electrical steels are used for electrical
machines. There are a few studies on the effect of
compressive stress which is normal to the surface of
electrical steel sheets [5, 6], but more studies are needed to
clarify the magnetizing process of electrical steel sheets
under the perpendicular compressive stress.
In this study, we focused on the effect of a compressive
stress[...]
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Magnetic properties of soft magnetic materials under tensile and compressive stress
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Tsugunori KANADA Yukihito KIDO Akifumi KUTSUKAKE Tetsu IKEDA Masato ENOKIZONO
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The measurement is carried under the tensile and compressive stresses on non-oriented electrical steel sheets and amorphous sheet,
100×500mm. They are measured by stress load type SST. The results of magnetic power loss and magnetization curve on NO steel sheet in case
of no stress, tensile stress 15MPa and compressive stress 15MPa are shown. It is clear that the effect of tensile stress is not so remarkable, though
compressive stress affects the magnetic properties greatly. Three types of amorphous sheet, as cast, annealed and annealed in magnetic field were
measured.
Streszczenie. Przeprowadzono badania wpływu naprężeń na właściwości b lach niezorientowanych SiFe oraz amorficznych. Wykorzystano
urządzenie typu SST - próbka miała rozmiary 100 x 500 mm. Badano straty mocy i krzywą magnesowania. (Właściwości magnetyczne
materiałów magnetycznie miękkich poddanych naprężeniom)
Keywords: tensile and compressive stress, SST, iron loss and magnetization curve
Słowa kluczowe: naprężenia mechaniczne, materiały magnetycznie miękkie.
Introduction
It is important to know the magnetic properties under
applied stresses, because the building factor (the ratio
between the properties of the constructed material which is
affected by the stress and original one) should be
considered. In this case, a single sheet tester (SST) type is
convenient and conventional as one of the measurement
devices. For the measurement of the field strength, one
method is to measure the magnetizing current from the
shunt resistor, as it is made with the Epstein tester, and
another method is to measure it directly by using the H-coil
[1]. The magnetizing current method is simple and
comparatively easy but the effective magnetic path should
be considered. Contrary in case of the H-coil method, the
precise[...]
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Magnetostriction of grain oriented Si-Fe and its domain model
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Satoshi ARAI Masato MIZOKAMI Masao YABUMOTO
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Transformer noise has been drawing more and more attentions recently. One of the main causes of transformer noise is magnetostriction
of grain oriented electrical steel sheets. Magnetostrictions perpendicular to the rolling direction should also be focused in addition to those to the
rolling direction, because magnetic flux flows out of the rolling directions especially around T-joint parts of 3-phase transformers. In this paper,
magnetostrictions of high permeability grain oriented electrical steel sheets to the both directions were measured with a Doppler- vibrometer and
rationalized by magnetic domain models.
Streszczenie. .Szumy generowane przez transformatory są obecnie analizowane coraz bardziej szczegółowo. Głównym ich źródłem jest
magnetostrykcja blach zorientowanych. Magnetostrykcja prostopadła do kierunku walcowania powinna być także brana pod uwagę ponieważ
strumień magnetyczny nie zawsze jest w kierunku walcowania. W artykule przeanalizowano magnetostrykcję blach zorientowanych w obu
kierunkach używając wibrometr Dopplera. (Magnetostrykcja blach anizotropowych SiFe i jej model domenowy)
Keywords: grain oriented electrical steel, magnetostriction, magnetic domain
Słowa kluczowe: blachy anizotropowe, magnetostrykcja, domeny magnetyczne
Introduction
Grain oriented electrical steel sheets (GO) are mainly
used for transformer cores of commercial frequencies, 50Hz
or 60Hz. Most required property for transformers is lower
loss, and GO with lower iron loss have been always sought
for. In addition, recently, smaller transformer noise is
strongly required according to the growing consciousness
on environment, especially for transformers installed in city
neighbors. Magnetostriction of GO is one of the largest
origins of transformer noise and has been measured and
analyzed by many researchers [1-4].
Fig.1. FEM-calculation of flux lines in a 3-phase transformer core.
GO sheets are laminated as the rolling directions, or the
high per[...]
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Measurement of Magnetic Properties of Grain-Oriented Electrical Steel Sheet Using 2D Single Sheet Tester
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Yuki MORI Daisuke MIYAGI Masanori NAKANO Norio TAKAHASHI
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We have already reported the accuracy of measurement of 2D magnetic properties of non-oriented electrical steel sheet using a novel SST.
In this paper, magnetic properties under alternating and rotating magnetic flux of grain-oriented sheet are measured. The accuracy of measurement in
the case of grain-oriented sheet is examined by comparing the measured results using 2D-SST with those using an ordinary SST under alternating
flux excitation. The effect of positioning error of orthogonal B and H coils on measurement accuracy is also discussed.
Streszczenie. Oceniono dokładność badania blachy zorientowanej przy wykorzystaniu testera 2D SST. W celu oceny niepewności wyniki porównano
z rezultatami otrzymanymi przy wykorzystaniu konwencjonalnego testera SST. Przedyskutowano problem błędu pozycjonowania czujników.
(Pomiary właściwości magnetycznych blachy zorientowanej przy użyciu testera 2D SST)
Keywords: grain-oriented electrical steel sheet, alternating magnetic flux, rotating magnetic flux, two-dimensional magnetic properties.
Słowa kluczowe: blacha zorientowana, tester SST.
Introduction
Recently, a miniature and efficient magnetic device is
required. When it is miniaturized, the magnetic flux density
of the magnetic circuit becomes high. Therefore, a precise
measurement at high flux density of electrical steel sheet
that is a main material of magnetic device is important.
Generally, the magnetic properties are measured by using a
single sheet tester (SST), but it can only measure magnetic
properties in one direction. In order to analyze magnetic
characteristics of magnetic devices, it is necessary to
accurately measure magnetic properties of electrical steel
sheet in arbitrary directions [1]. We have already developed
a novel 2D-SST and reported the accuracy of measurement
of 2D magnetic properties of non-oriented electrical steel
sheet [2].
In this paper, magnetic properties of grain-oriented
electrical steel sheet under alternatin[...]
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Measurement of Vector Hysteretic Property of Silicon Steel Sheets at Liquid Nitrogen Temperature
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Masaki MIYAMOTO Tetsuji MATSUO Taketsune NAKAMURA
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This article reports vector magnetic properties of non-oriented silicon steel sheets at the liquid nitrogen temperature of 77 K. The
amplitude of magnetic field decreases at 77 K under alternating and rotational flux conditions when B is large. The iron loss increases at 77 K
because of the increase in eddy-current loss due to the increase in electrical conductivity.
Streszczenie. W artykule przedstawiono badania blachy elektrotechnicznej niezorientowanej w temperaturze ciekłego azotu 77 K. Straty mocy w tej
temperaturze wzrastają na skutek wzrostu prądów wirowych spowodowanego zwiększeniem przewodności elektrycznej. (Badanie histerezy blachy
krzemowej w temperaturze ciekłego azotu)
Keywords: Iron loss, liquid nitrogen temperature, silicon steel, vector magnetic property.
Słowa kluczowe: blachy krzemowe, straty, ciekły azot.
Introduction
A high-temperature superconducting (HTS) induction/
synchronous motor (ISM) [1], [2] achieves high torque
property efficiently over wide speed range. Its rotor and
stator have usual iron-cores whose magnetic properties at
very low temperature greatly affect the motor system
performance.
References [3] and [4] have already reported scalar
magnetic properties of silicon steel sheets at the liquid
nitrogen temperature, which were measured with a compact
single sheet tester (SST). However, accurate simulation of
motor performance requires vector magnetic properties of
silicon steel sheets.
This article reports vector magnetic properties of nonoriented
silicon steel sheets at the liquid nitrogen
temperature, which were measured with a compact
rotational SST (RSST).
HTS Induction/Synchronous Motor
The HTS-ISM [1], [2] possesses both asynchronous and
synchronous torques even though its structure is the same
as the squirrel-cage-type induction motor. It is expected that
the HTS-ISM realizes a gear-less and magnet-less motor
system for elec[...]
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Measurement of vector magnetic property under stress along arbitrary direction in non-oriented electrical steel sheet
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Yuichiro KAI
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Electrical steel sheet in electrical machines is magnetized under alternating and rotating magnetic flux. The vector of magnetic flux
density B and magnetic field strength H are not parallel because B lags H temporally. It is well known that the magnetic property of the electrical
steel sheet is strongly affected by mechanical stress. Therefore, it is important to clarify the relationships between the magnetic property and the
mechanical stress. In this paper, we examine the vector magnetic properties under the alternating and rotating magnetic flux conditions by applying
the mechanical stress at the arbitrary direction.
Streszczenie. W artykule zaprezentowano badania wektora właściwości magnetycznych blachy niezorientowanej poddanej naprężeniom w
dowolnym kierunku. Blachy były magnesowane zarówno w jednej osi jak i rotacyjne. (Pomiary wektora właściwości magnetycznych blachy
niezorientowanej poddanej naprężeniu w dowolnym kierunku)
Keywords: vector magnetic property, mechanical stress, arbitrary direction, magnetic power loss.
Słowa kluczowe: magnesowanie osiowe, magnesowanie rotacyjne, wpływ naprężeń..
Introduction
Developing electrical machines, which have high power
and efficiency requires effective utilization of magnetic
materials. The electrical steel sheet in the actual rotating
machines is magnetized under alternating and rotating
magnetic flux conditions [1]. In addition, the magnetic
properties of the electrical steel sheet are strongly affected
by mechanical stress. Therefore, it is important to know the
magnetic properties under various stress and magnetic flux
conditions in order to utilize for designing the electrical
machine.
Various authors have studied the effect of the stress on
the magnetic property in the electrical steel sheet [2-5].
However, it is difficult to evaluate the relationships between
the stress and the magnetic property under the alternating
and rotating magnetic flux condition by using the
conven[...]
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Measurement techniques for the assessment of materials under complex magnetising conditions
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Philip ANDERSON
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Magnetisation waveforms in many electromagnetic applications exhibit flux density waveforms which are far removed from the sinusoidal
ideal. A test system is described which enables complex flux density waveforms to be controlled. The precautions and additional sources of error
for characterisation under complex magnetisation conditions are outlined. Example results including the effect of introducing high order harmonics
and a simulation of PWM exciting are presented along with examples of the use of a modified superposition of loss technique.
Streszczenie. Kształt krzywej indukcji często odbiega od sinusoidalnego. Przedstawiono system umożliwiający kontrolowanie kształtu przebiegu
indukcji. Przedstawiono przykłady badań materiału magnesowanego przy indukcji zwierającej wyższe harmoniczne oraz PWM. (System do
badania materiałów magnetycznych przy złożonych warunkach magnesowania)
Keywords: AC measurements, complex waveforms, PWM, waveform control
Słowa kluczowe: indukcja, badanie materiałów magnetycznych.
Introduction
The designers and users of electrical machines are
placing increasing demands on the magnetic cores.
Traditionally the electrical steels used in these devices are
characterised under standard conditions with power
frequency sinusoidal magnetisation requiring designers to
over-engineer the magnetic components based on previous
experience.
It is common knowledge that many applications of
electrical steels exhibit flux density waveforms which are far
removed from the sinusoidal ideal.
Power conditioning is of growing importance in electrical
applications ranging from high power and voltage
distribution systems to domestic, commercial and industrial
motor drives. Power electronic converters with strategies
such as pulse width modulation (PWM) techniques are a
flexible means of affecting this control but this is usually
achieved at the expense of waveform quality. There are
substantial uncertainties when motors, transfo[...]
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Possible Future Trends and Research Challenges related to 1 & 2 D Magnetic Properties of Soft Magnetic Materials
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Anthony J MOSES
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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.
Streszczenie. 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. (Trendy i wyzwania w badaniu jednoi
dwuosiowych parametrów materiałów magnetycznie miękkich)
Keywords: rotational losses, Epstein square, magnetic measurements, magnetostriction, electrical steel.
Słowa kluczowe: straty rotacyjne, aparat Epsteina, pomiary magnetyczne, blacha elektrotechniczna..
Introduction
This paper covers the keynote presentation given by the
author at the 1 & 2 DM conference held in Oita in 2010. The
predictions which are implied from the title of the paper are
very subjective and the extent to which they might be
realised depends on many intangibles. Research in this
field is very much driven by emergence of new materials
and industrial trends both of which are difficult to predict.
However the global demand for more efficient energy usage
and conservation is certain to continue and it is this that will
drive the future need for 1 and 2 DM research. It is probable
that demand will increase for measurement of magnetic
properties more directly relevant to operating conditions in
electric[...]
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Spis treści / contents
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Spis treści
01 11 Międzynarodowe Warsztaty na temat Dwuwymiarowych Pomiarów Magnetycznych - Oita 1
02 Johannes SIEVERT - Pomiary magnetyczne dwuwymiarowe - historia i osiągnięcia workshopów 2
03 Anthony J MOSES - Trendy i wyzwania w badaniu jedno- i dwuosiowych parametrów materiałów
magnetycznie miękkich
11
04 Johannes SIEVERT - Zależność między wynikami aparatu Epsteina i testera próbek arkuszowych SST 17
05 Satoshi ARAI, Masato MIZOKAMI, Masao YABUMOTO - Magnetostrykcja blach anizotropowych SiFe i jej
model domenowy
20
06 Kiyoshi WAJIMA, Teruyuki TAMAKI - Porównanie różnych modeli strat przy obliczaniu dwuwymiarowym
właściwości anizotropowych
24
07 Damir SABIC, Helmut PFÜTZNER, Franz HOFBAUER, Georgi SHILYASHKI, Edin MULASALIHOVIC -
Efekty dynamiczne strat rotacyjnych
29
08 Piotr KLIMCZYK, Sakda SOMKUN, Philip ANDERSON, Anthony MOSES - Porównanie jednoosiowej i
rotacyjnej magnetostrykcji blach elektrotechnicznych zorientowanych i niezorientowanych
33
09 Wojciech A. PLUTA - Model strat w blachach elektrotechnicznych o różnym zorientowaniu 37
10 Mohachiro OKA, Makoto KAWANO, Kazunori SHIMADA, Takayuki KAI, Masato ENOKIZONO - Ocena
zmiany parametrów magnetycznych blach maszyn elektrycznych w wyniku produkcji rdzenia
4[...]
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Study of sensor structure for measurement of magnetization characteristics in high pulsed fields
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Yasushi NAKAHATA Bartosz BORKOWSKI Hiroyasu SHIMOJI Koji YAMADA Takashi TODAKA Masato ENOKIZONO
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Permanent magnets, especially Nd-Fe-B magnets are very important engineering elements that are widely used in many applications
such as information, communication, acoustic and medical equipment. Detailed design of electrical and electronics equipment using permanent
magnets, requires precise measurement of magnetization characteristics. It is relatively easy to obtain high field strengths in case of short pulses.
However, our goal is to achieve long pulse and high fields simultaneously. Such experiment conditions imposes certain requirements on excitation
coil construction (taking excitation system energy capabilities into account). Errors influencing the measurements stems from relations between
tested material and pick-up sensor and excitation coil structures. This paper presents the analysis of these relations and their influence on material
properties measurements accuracy and results obtained in comparison of sensors' structures.
Streszczenie. W przypadku badania magnesów często wykorzystuje się pola impulsowe. Celem pracy jest osiągniecie dostatecznie długiego
impulsu o dostatecznie dużej wartości. Wymaga to odpowiedniej konstrukcji cewki magnesującej. W artkule przeanalizowano zależność między
parametrami badanego materiału a parametrami, głównie dokładnością czujnika i cewki magnesującej. (Analiza struktury czujnika
wykorzystywanego przy technice dużych pól impulsowych).
Keywords: high pulsed fields, magnetization characteristics, Nd-Fe-B magnet.
Słowa kluczowe: magnetyczne pola impulsowe, badanie magnesów.
Introduction
The use of permanent magnets in rotators and for
various applications in information and communication,
acoustics, instrumentation, and medicine continues to
increase, and recently applications in automobiles and
large-scale rotators such as wind power generators have
been expanding as a means of achieving higher efficiency.
Although precise measurements of the magnetization
characteristics of the permanent mag[...]
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Two-dimensional magnetic measurements- history and achievements of the workshop
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Johannes SIEVERT
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An exemplary retrospect on two-dimensional metrology applied to electrical sheet steel is presented. First the history of this subject
before the starting of this workshop series is considered, i.e. the time of the mechanical methods of d.c. rotational hysteresis and loss measurements
and of inductive-mechanical methods of a.c. loss measurements. It is followed by the field-metric metrology of a.c. rotational magnetic phenomena.
This method underwent a rapid increase of application due to the fast development of electronics for the excitation and data acquisition of magnetic
field quantities in the 1970s and 1980s. Initiated by this development, the workshop series started shortly after in 1990. Besides the main item of the
workshop, the metrology, the items modelling, theory and applications did enter the scope of the workshop soon. This retrospect focuses on the
metrology of magnetic properties under two-dimensional excitation.
Streszczenie. Przedstawiono retrospekcję badań dwuwymiarowych w dziedzinie blach elektrotechnicznych z uwzględnieniem osiągnięć
workshopów. Początki związane były z metodami mechanicznymi. Następnie wprowadzono metody związane z pomiarem składowych pola
magnetycznego i indukcji. Pomocą był tu rozwój elektroniki umożliwiający łatwą akwizycję wszystkich składowych. W związku z dynamicznym
rozwojem tej dziedziny w latach dziewięćdziesiątych rozpoczęto organizację workshopów poświęconych tym zagadnieniom. Obok pomiarów
zajmowano się też modelowaniem, teorią i zastosowaniem. (Pomiary magnetyczne dwuwymiarowe - historia i osiągnięcia workshopów)
Keywords: Electrical sheet steel, rotational power loss, metrology, historical survey
Słowa kluczowe: blachy elektrotechniczne, straty rotacyjne.
Introduction
Two-dimensional excitation of material is the generic
term for circular rotating excitation in quasi-static (d.c.) or
dynamic (a.c.) mode as well as a.c. dynamic elliptical or
linear excitation in any direction of the sol[...]
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