Electrical Steels: Fundamentals and basic concepts (Energy Engineering)

✍ Scribed by Anthony Moses, Philip Anderson, Keith Jenkins, Hugh Stanbury

• Publisher: The Institution of Engineering and Technology
• Year: 2019
• Tongue: English
• Leaves: 647
• Category: Library

✦ Synopsis

Electrical steels are critical components of magnetic cores used in applications ranging from large rotating machines, including energy generating equipment, and transformers to small instrument transformers and harmonic filters. Presented over two volumes, this comprehensive handbook provides full coverage of the state-of-the-art in electrical steels.

Volume 1 covers the fundamentals and basic concepts of electrical steels. Topics covered include soft magnetic materials; basic magnetic concepts; magnetic domains, energy minimisation and magnetostriction; methods of observing magnetic domains in electrical steels; electromagnetic induction; fundamentals of a.c. signals; losses and eddy currents in soft magnetic materials; rotational magnetisation and losses; anisotropy of iron and its alloys; magnetic circuits; the effect of mechanical stress on loss, permeability and magnetostriction; magnetic measurements on electrical steels; background to modern electrical steels; production of electrical steels; amorphous and nano-crystalline soft magnetic materials; nickel-iron, cobalt-iron and aluminium-iron alloys; consolidated iron powder and ferrite cores; and temperature and irradiation dependence of magnetic and mechanical properties of soft magnetic materials.

The companion Volume 2 describes performance and outlines applications.

✦ Table of Contents

Title
Copyright
Contents
Acknowledgements
Preface
Common acronyms, symbols and abbreviations used in the text
Introduction to Volume 1
About the authors
Chapter 1 Soft magnetic material
1.1 Range and application of commercial bulk magnetic materials
1.2 Industrially important characteristics of soft magnetic materials
1.3 Families of commercial soft magnetic materials
1.4 Electrical steels
1.5 Global impact of energy wastage in electrical steels
References
Chapter 2 Basic magnetic concepts
2.1 Magnetic fields, flux density and magnetisation
2.2 Units in magnetism
2.3 Dimensional analysis of magnetic quantities
2.4 Crystal planes and directions
References
Chapter 3 Magnetic domains, energy minimisation and magnetostriction
3.1 Magnetic dipole moments and domains
3.2 Weiss theory and molecular field
3.3 Minimisation of free energy
3.4 Domain wall structure and motion
3.5 Domain changes occurring during magnetisation
3.6 Anisotropy energy
3.7 Magnetostatic energy (Ems)
3.8 Fundamentals of magnetostriction
3.9 Magnetoelastic energy (Eme)
3.10 Domain wall energy (Ew)
3.11 Work and energy in the magnetisation process
3.12 Static domain structure with minimum stored energy
3.13 Domain changes occurring during magnetisation
3.14 Energy (Eh) due to an externally applied field
3.15 Effect of an applied field on a domain wall
3.16 Magnetostriction in soft magnetic materials
3.17 The Barkhausen effect
References
Chapter 4 Methods of observing magnetic domains in electrical steels
4.1 Introduction
4.2 Powder techniques
4.3 Optical methods of surface domain observation
4.4 Magnetic force microscope
4.5 Domain visualisation from surface field sensors
4.6 Observation of sub-surface domain features
4.7 Use of magnetic bacteria for domain observation
4.8 Magneto-optical indicator films
4.9 Comparison of methods for observations on electrical steels
References
Chapter 5 Electromagnetic induction
5.1 Faraday’s law
5.2 Lenz’s law
5.3 Expressions for an induced e.m.f.
Reference
Chapter 6 Fundamentals of a.c. signals
6.1 Waveform terminology
6.2 Distortion factor
6.3 Distorted voltages on power systems
6.4 Distorted B or H waveforms due to non-linear magnetisation curves
6.5 Effect of the electric circuit on waveform distortion
6.6 General relationship between harmonics in B and H waveforms
6.7 Calculation of flux density under distorted magnetisation conditions
References
Chapter 7 Losses and eddy currents in soft magnetic materials
7.1 Physical and engineering approaches to magnetic losses
7.2 Energy dissipation derived from the area enclosed by a B–H loop
7.3 Derivation of the dependence of loss on B and H using the Poynting vector theorem
7.4 Hysteresis loss
7.5 Eddy current generation in a rod of conducting material
7.6 Eddy currents in a thin sheet
7.7 Classical eddy current loss
7.8 Separation of losses into eddy current and hysteresis components
7.9 Total loss within a sheet
7.10 Total power loss of a strip expressed in terms of B and H
References
Chapter 8 Rotational magnetisation and losses
8.1 Vector representation of a pure rotating magnetic field
8.2 Rotational flux density
8.3 Torque curves and stored magnetocrystalline energy
8.4 Rotational hysteresis loss
8.5 Magnetic domain structures under rotational magnetisation
8.6 Combined alternating, rotational and d.c. offset magnetisation
8.7 Rotational loss at power frequency
8.8 Magnetostriction under rotational magnetisation
8.9 Three-dimensional magnetisation
References
Chapter 9 Anisotropy of iron and its alloys
9.1 Magnetisation at an angle to a preferred crystal direction
9.2 Magnetisation at angles to an easy direction under a.c. magnetisation
9.3 Effect of strip width on magnetisation direction in anisotropic material
9.4 Effect of stacking method on apparent loss of anisotropic strips cut at angles to an easy axis
References
Chapter 10 Magnetic circuits
10.1 The basic magnetic circuit
10.2 Magnetic reluctance
10.3 Field and flux density distribution in a circular core
10.4 Iron cored solenoid
10.5 Flux density in a magnetic material measured by an enwrapping search coil
10.6 Field and flux density at the interface between two media
10.7 Forces between magnetised laminations
References
Chapter 11 Effect of mechanical stress on loss, permeability and magnetostriction
11.1 Effect of stress on simple magnetic domain structures
11.2 Stress sensitivity derived from domain structures
11.3 Effect of biaxial stress
11.4 Stress sensitivity of GO steel
11.5 Stress sensitivity of NO steel
11.6 Effect of bending stress
11.7 Effect of normal stress
11.8 Effect of stress on components of loss
11.9 Effects of building stresses in electrical machine cores
11.10 Slitting and punching stress in electrical steel
References
Chapter 12 Magnetic measurements on electrical steels
12.1 Introduction
12.2 Effect of sample geometry (toroids, single strips, rings and single sheet)
12.3 Sensing methods
12.4 A.C. magnetic measurements of losses and permeability
12.5 2D and rotational magnetic measurements
12.6 Magnetostriction measurements
12.7 On-line measurements
12.8 The d.c. magnetic measurements
12.9 Surface insulation testing
12.10 Barkhausen noise measurement
References
Chapter 13 Background to modern electrical steels
13.1 History and development of electrical steels
13.2 Metallurgical requirements and control
References
Chapter 14 Production of electrical steels
14.1 Chemical composition
14.2 Hot rolled coil production
14.3 Cold mill processing
14.4 Final property assessment
14.5 Future development
References
Chapter 15 Amorphous and nano-crystalline soft magnetic materials
15.1 Amorphous materials
15.2 Nano-crystalline magnetic materials
15.3 General properties of amorphous and nano-materials
15.4 High silicon micro-crystalline ribbon
15.5 Applications of amorphous and nano-crystalline ribbons
References
Chapter 16 Nickel–iron, cobalt–iron and aluminium–iron alloys
16.1 Introduction
16.2 Iron, cobalt and nickel
16.3 Nickel–iron alloys
16.4 Perminvar
16.5 Cobalt–iron alloys
16.6 Aluminium–iron alloys
16.7 Applications
References
Chapter 17 Consolidated iron powder and ferrite cores
17.1 Background
17.2 Consolidated iron and SiFe powder cores
17.3 Soft ferrites
References
Chapter 18 Temperature and irradiation dependence of magnetic and mechanical properties of soft magnetic materials
18.1 Effects of temperature on structure insensitive magnetic properties
18.2 Effect of temperature on permeability, coercivity and losses
18.3 The d.c. and a.c. properties of silicon steels at elevated temperatures
18.4 Temperature dependencies of magnetic properties of various material
18.5 Modelling high temperature performance
18.6 Magnetic properties at cryogenic temperatures
18.7 Effect of non-uniform temperature gradients in magnetic core laminations
18.8 Effect of irradiation on soft magnetic materials
References
Index