Superconducting Levitation: Applications to Bearing and Magnetic Transportation

✍ Scribed by Francis C. Moon

• Publisher: Wiley-VCH
• Year: 1994
• Tongue: English
• Leaves: 315
• Edition: 1
• Category: Library

✦ Synopsis

Presents the fundamental principles governing levitation of material bodies by magnetic fields without too much formal theory. Defines the technology of magnetic bearings, especially those based on superconductivity, and demonstrates the key roles that magnetics, mechanics and dynamics play in the complete understanding of magnetic levitation and its bearings. Features extensive figures and photos of Mag-Lev devices and summarizes recent U.S. research studies in an effort to regain the lead in Mag-Lev technologies.

✦ Table of Contents

SUPERCONDUCTING LEVITATION
CONTENTS
PREFACE
1 INTRODUCTION TO MAGNETIC LEVITATION
1-1 Introduction
1-2 Magnetic Levitation Systems
Active Magnetic Bearings Versus Passive Superconducting Bearings
1-3 Stability and Levitation
Earnshaw’s Theorem
1-4 Magnetic Fields and Forces
Induced Magnetic Forces
Magnetic Stiffness
Magnetic Stresses
1-5 Bearings and Levitation
Active Magnetic Bearings Using Normal Conductors
Passive Superconducting Bearings
1-6 Magnetically Levitated Vehicles
2 PRINCIPLES OF MAGNETICS
2-1 Basic Laws of Electromagnetism
Magnetic Stresses
Nondimensional Groups
Maxwell’s Equations
Low-Frequency Electromagnetics
Electromagnetic Constitutive Relations
Stationary Media
Moving Media
2-2 Magnetic Forces
Dipole-Dipole Forces
Special Cases
Current-Current Forces
Current-Filament-Magnetized-Body Forces
Body-Field Forces
Magnetic Dipole-Field Forces
Current-Field Forces
The Magnetic Stress Method
2-3 Magnetic Stiffness
Magnetic Stiffness and Magnetic Energy
Nonlinear Effects
2-4 Magnetic Materials and Magnetic Circuits
Magnetization Properties
Domains
Magnetic Circuits
Demagnetization
Forces on Magnetized Materials (J = 0)
3 SUPERCONDUCTING MATERIALS
3-1 The Phenomena of Superconductivity
Zero Resistance
Flux Exclusion
Flux Vortex Structures-Type I and Type II Superconductors
Critical Current
Flux Quantization
Penetration Depth
3-2 Review of Theory
3-3 Low-Temperature Superconducting Materials
3-4 High-Temperature Superconducting Materials
Cuprates-Crystal Structure
Cuprates-Superconducting Properties
Critical Currents
Thin Films
Wires and Tapes
Fullerenes
3-5 Processing of Bulk Superconductors
3-6 Magnetization and Levitation Forces
3-7 Superconducting Permanent Magnets
Flux Creep
4 PRINCIPLES OF SUPERCONDUCTING BEARINGS
4-1 Introduction
Conventional Bearings
Magnetic Bearing Systems
Levitation with Permanent Magnets
4-2 Active Electromagnetic Bearings
Stiffness of Active Bearings
4-3 Passive Superconducting Bearings
Magnetic Forces
Bearing Pressure
4-4 Characterization of Levitation Forces in High-Tc Materials
Levitation Force Hysteresis
Levitation Force-Distance Relation
Magnetic Stiffness
Suspension or Attractive Forces
Magnetic Damping
Lateral Magnetic Drag Force
Rotary Drag Torque
Low-Temperature Levitation of High-Tc Superconductors
Levitation Force Versus Magnetic Field
Force Creep
Material Processing and Levitation
Levitation Forces-Thickness Effect
Levitation Forces in Thin-Film Superconductors
5 DYNAMICS OF MAGNETICALLY LEVITATED SYSTEMS
5-1 Introduction
Literature Review
5-2 Equations of Motion
Newton-Euler Equations of Motion
Lagrange’s Equations for Magnetic Systems
The Inductance Method
Linear Stability Analysis
5 -3 Single Degree of Freedom Dynamics
Natural Frequencies of Levitated Bodies
Vibration of a Persistent-Current Superconducting Mag-Lev Coil
Levitated Superconducting Ring
5-4 Dynamics of a Spinning Levitated Superconductor
5 -5 Negative Damping Due to Eddy Currents
5-6 Dynamics of Mag-Lev Vehicles
Lateral-Yaw Oscillation in Mag-Lev Vehicles
5-7 Active Controlled Levitation Dynamics
5-8 Nonlinear Dynamics and Chaos in Levitated Bodies
Vertical Heave Dynamics of a Mag-Lev Vehicle
Chaotic Lateral Vibrations of a YBCO Magnetic Bearing
6 APPLICATIONS OF SUPERCONDUCTING BEARINGS
6-1 Introduction
Early Application: Superconducting Gyro
6-2 Rotary Motion Bearings
Cryomachine Applications
Energy and Momentum Storage
6-3 Linear Motion Bearings
6-4 Vibration Damping and Isolation
7 MAGNETIC LEVITATION TRANSPORTATION
7-1 Introduction
High-speed Wheel-Rail Systems
7-2 Principal Levitation Schemes
EML-Ferromagnetic Rail
EDL-Continuous-Sheet Track
EDL-Ladder Track
EDL-Discrete Coil Track
EDL-Null-Flux Guideway
7-3 Mag-Lev Design Concepts
Earlier Mag-Lev Research and Prototypes
New Design Concepts
National Mag-Lev Initiative
The Magneplane
Superconducting Electromagnetic Levitation System
New U.S. EDL Designs
7-4 Technical Issues
Technical Issues in Magnetic Transportation
Aerodynamic Forces
Grade-Climbing Capability
Guideway Banking and Turns
Propulsion Power
Vehicle-Guideway Interaction
Noise
7-5 Technical Impact of High-Tc Superconductors on Mag-Lev
Cryostat Design
Thermal Stability
Smaller Magnet Design
Mag-Lev with Superconducting Permanent Magnets
Hybrid Ferromagnetic-Superconducting Mag-Lev
7-6 The Future of Mag-Lev
REFERENCES
AUTHOR INDEX
SUBJECT INDEX