Characterisation of Soft Magnetic Materials Under Rotational Magnetisation

597 Pages·2018·80.73 MB·English

by  Stanislaw Zurek

Characterisation of Soft
Magnetic Materials Under
Rotational Magnetisation

Characterisation of Soft
Magnetic Materials Under
Rotational Magnetisation
Stanislaw Zurek
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Library of Congress Cataloging-in-Publication Data
Names: Zurek, Stanislaw (Electrical engineer), author.
Title: Characterisation of soft magnetic materials under rotational
magnetisation / Stanislaw Zurek.
Description: Boca Raton : Taylor & Francis, CRC Press, 2017. | Includes
bibliographical references and index.
Identifiers: LCCN 2017033847| ISBN 9781138304369 (hardback : alk. paper) |
ISBN 9780203730126 (ebook)
Subjects: LCSH: Electronics--Materials. | Magnetic materials. |
Magnetization. | Plasticity.
Classification: LCC TK7871.15.M3 Z87 2017 | DDC 620.1/1297--dc23
LC record available at https://lccn.loc.gov/2017033847
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This book is dedicated to the most resourceful, the wisest,
the most hard-working and the bravest person I ever
knew – my mother Janina Żurek who used to say:
We learn our whole life, and we still die stupid.

Contents
Symbols, Acronyms and Abbreviations .................................................................xiii
Preface.....................................................................................................................xxi
Acknowledgements ................................................................................................xxv
Author ..................................................................................................................xxvii
Chapter 1 Introduction ..........................................................................................1
1.1 Brief Introduction to Magnetism ...............................................1
1.2 Magnetic Domains and Domain Walls ...................................10
1.3 Process of Alternating Magnetisation .....................................12
1.4 Soft, Hard and Semi-Hard Magnetic Materials ......................16
1.5 Ferromagnetic Materials Used in Engineering .......................19
1.6 Isotropy and Anisotropy ..........................................................22
1.7 Losses under One-Dimensional Magnetisation.......................27
1.8 Loss Components: Hysteresis, Eddy Currents and Excess .....31
1.9 Practical Importance of Power Loss .......................................37
1.10 Rotational Magnetisation.........................................................38
1.11 Losses under Rotational Magnetisation ..................................39
1.12 Brief History of Rotational Studies .........................................41
Chapter 2 Principles of Rotational Power Measurement ....................................49
2.1 Mechanical ..............................................................................49
2.1.1 Torque Magnetometer – Isotropic Disc Sample .........52
2.1.2 Torque Magnetometer – Anisotropic Sample ............54
2.1.3 Torque Magnetometer – Dynamic Rotation ...............56
2.1.4 Anisometer – Disc Sample .........................................58
2.1.5 Torque Magnetometer – Ring Sample ........................63
2.2 Thermometric (Rate of Temperature Rise) .............................64
2.3 Wattmetric ...............................................................................70
2.3.1 Toroidal Sample..........................................................71
2.3.2 Epstein Frame .............................................................72
2.3.3 Single-Sheet Tester .....................................................74
2.3.4 Single-Strip Tester ......................................................76
2.3.5 Other Wattmetric Methods .........................................76
2.3.6 Rotational Wattmetric Method ...................................77
2.4 Fieldmetric ...............................................................................77
2.4.1 Non-Circular and Non-Rotational 2D
Fieldmetric Measurements .........................................88
2.4.2 Three-Dimensional Fieldmetric Measurements .........91
2.5 Other Measurements Related to Rotational Magnetisation .....92
2.5.1 Magnetic Domain Observation ..................................93
vii
viii Contents
2.5.2 Magnetostriction and Mechanical Stresses ..............102
2.5.3 Barkhausen Noise .....................................................111
Chapter 3 Sensors and Sensing Techniques ......................................................119
3.1 Flux Density Sensors .............................................................119
3.1.1 Induction Coil (B-Coil) ............................................120
3.1.1.1 Analogue Signal Processing .....................123
3.1.1.2 Digital Signal Processing .........................127
3.1.1.3 Practical Implementation ..........................135
3.1.1.4 Practical Difficulties and Measurement
Errors ........................................................138
3.1.2 Needle Probes...........................................................144
3.1.2.1 Signal Processing ......................................150
3.1.2.2 Practical Difficulties .................................151
3.1.3 Indirect B-Coil .........................................................154
3.1.4 Non-Enwrapping B-Coil ..........................................155
3.1.5 Hall Effect and Other Electronic Sensors ................156
3.1.6 Normal B-Coil ..........................................................162
3.1.7 Pin Sensor .................................................................162
3.1.8 Tangential B Sensor ..................................................164
3.1.9 Optical Techniques ...................................................164
3.2 Magnetic Field Strength Sensors ...........................................165
3.2.1 Magnetising Current Sensors ...................................165
3.2.1.1 Shunt Resistor ...........................................166
3.2.1.2 Other Current Sensors ..............................169
3.2.2 Tangential Sensors ....................................................170
3.2.2.1 H-Coil .......................................................171
3.2.2.2 Rogowski–Chattock Potentiometer ..........183
3.2.2.3 Hall Effect Sensor .....................................190
3.2.2.4 Other Sensors of Magnetic Field ..............194
3.3 Temperature Sensors .............................................................195
3.3.1 Thermocouple...........................................................195
3.3.2 Thermistor ................................................................199
3.3.3 Pyrometric Methods .................................................200
3.3.3.1 Infra-Red Thermometer ............................201
3.3.3.2 Thermal Imaging Camera ........................202
3.4 Mechanical Sensors ...............................................................204
3.4.1 Force, Torque and Stress Sensors .............................204
3.4.1.1 Weight .......................................................204
3.4.1.2 Spring ........................................................205
3.4.1.3 Load Cell ..................................................207
3.4.2 Strain Sensors ...........................................................208
3.4.2.1 Resistance Strain Gauge ...........................209
3.4.2.2 Laser Vibrometer ......................................214
3.4.2.3 Accelerometers .........................................215
Contents ix
3.5 Barkhausen Noise Sensors ....................................................217
3.5.1 Magnetic Barkhausen Noise Sensor .........................217
3.5.2 Magneto-Acoustic Sensor ........................................218
3.6 Voltage-Sensing Techniques ..................................................220
3.6.1 Voltmeter ..................................................................221
3.6.2 Data Acquisition Device...........................................224
3.6.3 Oscilloscope .............................................................225
Chapter 4 Measurement Apparatus...................................................................227
4.1 Sample ...................................................................................228
4.1.1 Single Lamination ....................................................231
4.1.2 Multiple Laminations ...............................................233
4.1.3 Bulk Sample .............................................................236
4.1.4 Liquid Sample ..........................................................236
4.1.5 Sample Cutting .........................................................236
4.1.6 Drilling .....................................................................240
4.1.7 Annealing .................................................................241
4.1.8 Polishing ...................................................................242
4.1.9 Sample and Sensor Mounting ..................................243
4.1.10 Coil Winding (for Sensors) .......................................248
4.2 Magnetising Yoke ..................................................................250
4.2.1 Without Yoke ............................................................254
4.2.2 Field Uniformity and Excitation Level .....................255
4.2.3 Yoke for Cross-Shaped Sample ................................257
4.2.4 Yoke for Square Sample ...........................................257
4.2.5 Yoke for Rectangular Sample ...................................258
4.2.6 Yoke for Overhang Sample ......................................258
4.2.7 Yoke for Hexagonal Sample .....................................259
4.2.8 Yoke for Round Sample ............................................260
4.2.9 Shape of Magnetic Poles ..........................................262
4.2.10 Horizontal and Vertical Yoke Arrangements ...........263
4.2.11 Vertical Shielding .....................................................264
4.2.12 Core Materials and Construction .............................267
4.3 Excitation ...............................................................................269
4.3.1 Permanent Magnet ...................................................269
4.3.2 Magnetising Windings .............................................269
4.3.2.1 Voltage Amplitude ....................................270
4.3.2.2 Power Loss ................................................272
4.3.2.3 Coil Winding ............................................275
4.3.3 Power Amplifier .......................................................276
4.3.3.1 Linear Power Amplifier ............................276
4.3.3.2 Digitally Controlled Power Amplifier ......279
4.3.3.3 Voltage-Mode and Current-Mode
Amplifiers .................................................280
4.3.4 Elimination of DC Bias ............................................280