Magnetic Actuators and Sensors

[BOOK DESCRIPTION]

A fully updated, easy-to-read guide on magnetic actuators and sensors The Second Edition of this must-have book for today's engineers includes the latest updates and advances in the field of magnetic actuators and sensors. Magnetic Actuators and Sensors emphasizes computer-aided design techniques-especially magnetic finite element analysis; offers many new sections on topics ranging from magnetic separators to spin valve sensors; and features numerous worked calculations, illustrations, and real-life applications.To aid readers in building solid, fundamental, theoretical background and design know-how, the book provides in-depth coverage in four parts: PART I: MAGNETICS * Introduction * Basic Electromagnetics * Reluctance Method * Finite-Element Method * Magnetic Force * Other Magnetic Performance Parameters PART II: ACTUATORS * Magnetic Actuators Operated by Direct Current * Magnetic Actuators Operated by Alternating Current * Magnetic Actuator Transient Operation PART III: SENSORS * Hall Effect and Magnetoresistive Sensors * Other Magnetic Sensors PART IV: SYSTEMS * Coil Design and Temperature Calculations * Electromagnetic Compatibility * Electromechanical Finite Elements * Electromechanical Analysis Using Systems Models * Coupled Electrohydraulic Analysis Using Systems Models With access to a support website containing downloadable software data files (including MATLAB(R) data files) for verifying design techniques and analytical methods, Magnetic Actuators and Sensors, Second Edition is an exemplary learning tool for practicing engineers and engineering students involved in the design and application of magnetic actuators and sensors.

[TABLE OF CONTENTS]

Preface                                            xi
Preface to the First Edition                       xiii
        List of 66 Examples                        xv
  PART I MAGNETICS                                 1   (92)
    1 Introduction                                 3   (6)
      1.1 Overview of Magnetic Actuators           3   (1)
      1.2 Overview of Magnetic Sensors             4   (1)
      1.3 Actuators and Sensors in Motion          5   (2)
      Control Systems
      1.4 Magnetic Actuators and Sensors in        7   (2)
      Mechatronics
        References                                 8   (1)
    2 Basic Electromagnetics                       9   (24)
      2.1 Vectors                                  9   (5)
        2.1.1 Gradient                             9   (2)
        2.1.2 Divergence                           11  (1)
        2.1.3 Curl                                 11  (3)
      2.2 Ampere's Law                             14  (3)
      2.3 Magnetic Materials                       17  (5)
      2.4 Faraday's Law                            22  (3)
      2.5 Potentials                               25  (3)
      2.6 Maxwell's Equations                      28  (5)
        Problems                                   29  (2)
        References                                 31  (2)
    3 Reluctance Method                            33  (10)
      3.1 Simplifying Ampere's Law                 33  (4)
      3.2 Applications                             37  (3)
      3.3 Fringing Flux                            40  (1)
      3.4 Complex Reluctance                       41  (1)
      3.5 Limitations                              41  (2)
        Problems                                   42  (1)
        References                                 42  (1)
    4 Finite-Element Method                        43  (12)
      4.1 Energy Conservation and Functional       43  (2)
      Minimization
      4.2 Triangular Elements for Magnetostatics   45  (1)
      4.3 Matrix Equation                          46  (3)
      4.4 Finite-Element Models                    49  (6)
        Problems                                   53  (1)
        References                                 53  (2)
    5 Magnetic Force                               55  (24)
      5.1 Magnetic Flux Line Plots                 55  (5)
      5.2 Magnetic Energy                          60  (1)
      5.3 Magnetic Force on Steel                  61  (4)
      5.4 Magnetic Pressure on Steel               65  (1)
      5.5 Lorentz Force                            66  (1)
      5.6 Permanent Magnets                        67  (5)
      5.7 Magnetic Torque                          72  (1)
      5.8 Magnetic Volume Forces on Permeable      73  (6)
      Particles
        Problems                                   75  (1)
        References                                 76  (3)
    6 Other Magnetic Performance Parameters        79  (14)
      6.1 Magnetic Flux and Flux Linkage           79  (3)
        6.1.1 Definition and Evaluation            79  (1)
        6.1.2 Relation to Force and Other          80  (2)
        Parameters
      6.2 Inductance                               82  (4)
        6.2.1 Definition and Evaluation            82  (3)
        6.2.2 Relation to Force and Other          85  (1)
        Parameters
      6.3 Capacitance                              86  (2)
        6.3.1 Definition                           86  (1)
        6.3.2 Relation to Energy and Force         86  (2)
      6.4 Impedance                                88  (5)
        Problems                                   91  (1)
        References                                 91  (2)
  PART II ACTUATORS                                93  (82)
    7 Magnetic Actuators Operated by DC            95  (34)
      7.1 Solenoid Actuators                       95  (11)
        7.1.1 Clapper Armature                     95  (7)
        7.1.2 Plunger Armature                     102 (4)
      7.2 Voice Coil Actuators                     106 (2)
      7.3 Other Actuators Using Coils and          108 (1)
      Permanent Magnets
      7.4 Proportional Actuators                   109 (3)
      7.5 Rotary Actuators                         112 (2)
      7.6 Magnetic Bearings and Couplings          114 (3)
      7.7 Magnetic Separators                      117 (12)
        Problems                                   125 (2)
        Reference                                  127 (2)
    8 Magnetic Actuators Operated by AC            129 (18)
      8.1 Skin Depth                               129 (1)
      8.2 Power Losses in Steel                    130 (5)
        8.2.1 Laminated Steel                      130 (1)
        8.2.2 Equivalent Circuit                   131 (3)
        8.2.3 Solid Steel                          134 (1)
      8.3 Force Pulsations                         135 (4)
        8.3.1 Force with Single AC Coil            135 (2)
        8.3.2 Force with Added Shading Coil        137 (2)
      8.4 Cuts in Steel                            139 (8)
        8.4.1 Special Finite-Element Formulation   139 (1)
        8.4.2 Loss and Reluctance Computations     140 (5)
        Problems                                   145 (1)
        References                                 145 (2)
    9 Magnetic Actuator Transient Operation        147 (28)
      9.1 Basic Timeline                           147 (1)
      9.2 Size, Force, and Acceleration            148 (2)
      9.3 Linear Magnetic Diffusion Times          150 (6)
        9.3.1 Steel Slab Turnon and Turnoff        150 (5)
        9.3.2 Steel Cylinder                       155 (1)
      9.4 Nonlinear Magnetic Infusion Times        156 (8)
        9.4.1 Simple Equation for Steel Slab       156 (1)
        with "Step" B--H
        9.4.2 Transient Finite-Element             157 (4)
        Computations for Steel Slabs
        9.4.3 Simple Equation for Steel            161 (1)
        Cylinder with "Step" B--H
        9.4.4 Transient Finite-Element             161 (3)
        Computations for Steel Cylinders
      9.5 Nonlinear Magnetic Effusion Time         164 (5)
        9.5.1 Planar Effusion in Nonlinear         164 (3)
        Steel Slab
        9.5.2 Axisymmetric Effusion in             167 (2)
        Nonlinear Steel Cylinder
      9.6 Pulse Response of Nonlinear Steel        169 (6)
        Problems                                   171 (3)
        References                                 174 (1)
  PART III SENSORS                                 175 (54)
    10 Hall Effect and Magnetoresistive Sensors    177 (24)
      10.1 Simple Hall Voltage Equation            177 (2)
      10.2 Hall Effect Conductivity Tensor         179 (3)
      10.3 Finite-Element Computation of Hall      182 (8)
      Fields
        10.3.1 Unsymmetric Matrix Equation         182 (1)
        10.3.2 2D Results                          183 (4)
        10.3.3 3D Results                          187 (3)
      10.4 Hall Sensors for Position or Current    190 (3)
        10.4.1 Toothed Wheel Position Sensor       190 (2)
        10.4.2 Position Sensors using Multipole    192 (1)
        Magnets
        10.4.3 Hall Effect Current Sensors         192 (1)
      10.5 Magnetoresistance                       193 (1)
        10.5.1 Classical Magnetoresistance         193 (1)
        10.5.2 Giant Magnetoresistance             193 (1)
        10.5.3 Newer Forms of Magnetoresistance    194 (1)
      10.6 Magnetoresistive Heads for Hard Disk    194 (1)
      Drives
      10.7 Giant Magnetoresistive Spin Valve       195 (6)
      Sensors
        Problems                                   198 (1)
        References                                 198 (3)
    11 Other Magnetic Sensors                      201 (28)
      11.1 Speed Sensors Based on Faraday's Law    201 (2)
      11.2 Inductive Recording Heads               203 (3)
      11.3 Proximity Sensors Using Impedance       206 (4)
        11.3.1 Stationary Eddy Current Sensors     206 (3)
        11.3.2 Moving Eddy Current Sensors         209 (1)
      11.4 Linear Variable Differential            210 (3)
      Transformers
      11.5 Magnetostrictive Sensors                213 (2)
      11.6 Fluxgate Sensors                        215 (4)
      11.7 Chattock Coil Field and Current         219 (3)
      Sensor
      11.8 Squid Magnetometers                     222 (1)
      11.9 Magnetoimpedance and Miniature          223 (1)
      Sensors
      11.10 MEMS Sensors                           224 (5)
        Problems                                   225 (1)
        References                                 226 (3)
  PART IV SYSTEMS                                  229 (130)
    12 Coil Design and Temperature Calculations    231 (18)
      12.1 Wire Size Determination for DC          231 (3)
      Currents
      12.2 Coil Time Constant and Impedance        234 (1)
      12.3 Skin Effects and Proximity Effects      235 (4)
      for AC Currents
      12.4 Finite-Element Computation Of           239 (10)
      Temperatures
        12.4.1 Thermal Conduction                  239 (2)
        12.4.2 Thermal Convection and Thermal      241 (1)
        Radiation
        12.4.3 AC Magnetic Device Cooled by        242 (4)
        Conduction, Convection, and Radiation
        Problems                                   246 (1)
        References                                 246 (3)
    13 Electromagnetic Compatibility               249 (14)
      13.1 Signal-To-Noise Ratio                   249 (1)
      13.2 Shields and Apertures                   250 (5)
      13.3 Test Chambers                           255 (8)
        13.3.1 TEM Transmission Lines              255 (2)
        13.3.2 TEM Cells                           257 (1)
        13.3.3 Triplate Cells                      257 (3)
        Problems                                   260 (1)
        References                                 260 (3)
    14 Electromechanical Finite Elements           263 (26)
      14.1 Electromagnetic Finite-Element          263 (3)
      Matrix Equation
      14.2 0D and 1D Finite Elements for           266 (6)
      Coupling Electric Circuits
      14.3 Structural Finite-Element Matrix        272 (1)
      Equation
      14.4 Force and Motion Computation by Time    273 (2)
      Stepping
      14.5 Typical Electromechanical               275 (14)
      Applications
        14.5.1 DC Solenoid with Slowly Rising      275 (1)
        Current Input
        14.5.2 DC Solenoid with Step Voltage       276 (3)
        Input
        14.5.3 AC Clapper Solenoid Motion and      279 (3)
        Stress
        14.5.4 Transformers with Switches or       282 (2)
        Sensors
        14.5.5 Reciprocating Magnetic Actuators    284 (2)
        Problems                                   286 (1)
        References                                 286 (3)
    15 Electromechanical Analysis Using Systems    289 (38)
    Models
      15.1 Electric Circuit Models of Magnetic     289 (7)
      Devices
        15.1.1 Electric Circuit Software           289 (1)
        Including SPICE
        15.1.2 Simple LR Circuits                  290 (2)
        15.1.3 Tables of Nonlinear Flux Linkage    292 (1)
        and Force
        15.1.4 Analogies for Rigid Armature        293 (1)
        Motion
        15.1.5 Maxwell SPICE Model of Bessho       293 (2)
        Actuator
        15.1.6 Simplorer Model of Bessho           295 (1)
        Actuator
      15.2 VHDL--AMS/Simplorer Models              296 (5)
        15.2.1 VHDL--AMS Standard IEEE Language    296 (1)
        15.2.2 Model of Solenoid Actuator          297 (4)
      15.3 MATLAB/Simulink Models                  301 (6)
        15.3.1 Software                            301 (1)
        15.3.2 MATLAB Model of Voice Coil          302 (5)
        Actuator
      15.4 Including Eddy Current Diffusion        307 (5)
      Using a Resistor
        15.4.1 Resistor for Planar Devices         308 (2)
        15.4.2 Resistor for Axisymmetric Devices   310 (2)
      15.5 Magnetic Actuator Systems for 2D        312 (1)
      Planar Motion
      15.6 Optimizing Magnetic Actuator Systems    313 (14)
        15.6.1 3D Analysis of Fuel Injector        314 (4)
        System
        15.6.2 Analysis of 3D Solenoid for         318 (6)
        Valve Actuation
        Problems                                   324 (1)
        References                                 325 (2)
    16 Coupled Electrohydraulic Analysis Using     327 (32)
    Systems Models
      16.1 Comparing Hydraulics and Magnetics      327 (1)
      16.2 Hydraulic Basics and Electrical         328 (2)
      Analogies
      16.3 Modeling Hydraulic Circuits in Spice    330 (4)
      16.4 Electrohydraulic Models in Spice and    334 (7)
      Simplorer
      16.5 Hydraulic Valves and Cylinders in       341 (7)
      Systems Models
        16.5.1 Valves and Cylinders                341 (2)
        16.5.2 Use in SPICE Systems Models         343 (5)
      16.6 Magnetic Diffusion Resistor in          348 (4)
      Electrohydraulic Models
      16.7 Optimization of an Electrohydraulic     352 (1)
      System
      16.8 Magnetic Actuators for Digital          353 (6)
      Hydraulics
        Problems                                   357 (1)
        References                                 357 (2)
Appendix A Symbols, Dimensions, and Units          359 (2)
Appendix B Nonlinear B--H Curves                   361 (6)
Appendix C Final Answers for Odd-Numbered          367 (4)
Problems
Index                                              371