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Electrical Contacts, 2nd Edition

Book Description

Covering the theory, application, and testing of contact materials, Electrical Contacts: Principles and Applications, Second Edition introduces a thorough discussion on making electric contact and contact interface conduction; presents a general outline of, and measurement techniques for, important corrosion mechanisms; considers the results of contact wear when plug-in connections are made and broken; investigates the effect of thin noble metal plating on electronic connections; and relates crucial considerations for making high- and low-power contact joints. It examines contact use in switching devices, including the interruption of AC and DC circuits with currents in the range 10mA to 100kA and circuits up to 1000V, and describes arc formation between open contacts and between opening contacts. Arcing effects on contacts such as erosion, welding, and contamination are also addressed.

Containing nearly 3,000 references, tables, equations, figures, drawings, and photographs, the book provides practical examples encompassing everything from electronic circuits to high power circuits, or microamperes to mega amperes. The new edition:

  • Reflects the latest advances in electrical contact science and technology
  • Examines current research on contact corrosion, materials, and switching
  • Includes updates and revisions in each chapter, as well as up-to-date references and new figures and examples throughout
  • Delivers three new chapters on the effects of dust contamination, electronic sensing for switching systems, and contact phenomena for micro-electronic systems (MEMS) applications

With contributions from recognized experts in the field, Electrical Contacts: Principles and Applications, Second Edition assists practicing scientists and engineers in the prevention of costly system failures, as well as offers a comprehensive introduction to the subject for technology graduate students, by expanding their knowledge of electrical contact phenomena.

Table of Contents

  1. Cover
  2. Half Title
  3. Title Page
  4. Copyright Page
  5. Table of Contents
  6. Preface to the Second Edition
  7. Preface to the First Edition
  8. Introduction
  9. Editor
  10. Contributors
  11. Part I Contact Interface Conduction
    1. 1. Electrical Contact Resistance: Fundamental Principles
      1. 1.1 Introduction
      2. 1.2 Electrical Constriction Resistance
        1. 1.2.1 Circular a-spots
        2. 1.2.2 Non-Circular and Ring a-Spots
        3. 1.2.3 Multiple Contact Spots
        4. 1.2.4 Effect of the Shape of Contact Asperity on Constriction Resistance
      3. 1.3 Effect of Surface Films on Constriction and Contact Resistance
        1. 1.3.1 Electrically Conductive Layers on an Insulated Substrate
          1. 1.3.1.1 Calculation of Spreading Resistance in a Thin Film
        2. 1.3.2 Electrically Conducting Layers on a Conducting Substrate
          1. 1.3.2.1 Electrically Conducting Layers and Thin Contaminant Films
        3. 1.3.3 Growth of Intermetallic Layers
        4. 1.3.4 Possible Effect of Electromigration on Intermetallic Growth Rates
        5. 1.3.5 Electrically Insulating or Weakly Conducting Films
          1. 1.3.5.1 Growth Rate and Electrical Resistivity of Oxides of Selected Contact Materials
        6. 1.3.6 Fritting of Electrically Insulating Surface Films
      4. 1.4 Temperature of an Electrically Heated a-Spot
        1. 1.4.1 Voltage–Temperature Relation
        2. 1.4.2 Voltage–Temperature Relation with Temperature-Dependent Electrical Resistivity and Thermal Conductivity
        3. 1.4.3 The Wiedemann–Franz Law
        4. 1.4.4 Temperature Distribution in the Vicinity of an a-Spot
        5. 1.4.5 Deviation of the Voltage–Temperature Relation in an Assymetric Contact
          1. 1.4.5.1 Case I: Two Metals in Contact
          2. 1.4.5.2 Case II: A Metal in Contact with a Non-metal
        6. 1.4.6 Special Considerations on the “Melting” Voltage in Electrical Contacts
      5. 1.5 Mechanics of a-Spot Formation
        1. 1.5.1 Smooth Interfaces
        2. 1.5.2 Rough Interfaces
      6. 1.6 Breakdown of Classical Electrical Contact Theory in Small Contact Spots
        1. 1.6.1 Electrical Conduction in Small a-Spots
          1. 1.6.1.1 Contact Resistance
          2. 1.6.1.2 Joule Heat Flow through a-Spots
        2. 1.6.2 Observations of Breakdown of Classical Electrical Contact Theory in Aluminum Contacts
          1. 1.6.2.1 Experimental Data on Aluminum
        3. 1.6.3 Observations of Breakdown of Classical Electrical Contact Theory in Gold Contacts
        4. 1.6.4 Observations of Breakdown of Classical Electrical Contact Theory in Tin Contacts
      7. 1.7 Constriction Resistance at High Frequencies
        1. 1.7.1 Skin Depth and Constriction Resistance
        2. 1.7.2 Evaluation of Constriction Resistance at High Frequencies
        3. 1.7.3 Constriction versus Connection Resistance at High Frequencies
      8. 1.8 Summary
      9. Acknowledgments
      10. References
    2. 2. Introduction to Contact Tarnishing and Corrosion
      1. 2.1 Introduction
      2. 2.2 Corrosion Rates
      3. 2.3 Corrosive Gases
      4. 2.4 Types of Corrosion
        1. 2.4.1 Dry Corrosion
        2. 2.4.2 Galvanic Corrosion
        3. 2.4.3 Pore Corrosion
        4. 2.4.4 Creep Corrosion
        5. 2.4.5 Metallic Electromigration
        6. 2.4.6 Stress Corrosion Cracking
        7. 2.4.7 Contacts under Mineral Oil
      5. 2.5 Gas Concentrations in the Atmosphere
      6. 2.6 Measurements
        1. 2.6.1 Weight Gain Measurement
        2. 2.6.2 Visual Inspection
        3. 2.6.3 Cathodic Reduction
        4. 2.6.4 Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM/EDAX)
        5. 2.6.5 X-Ray Photoelectron Spectroscopy (XPS)
        6. 2.6.6 Other Techniques
        7. 2.6.7 Contact Resistance Measurements
      7. 2.7 Mixed Flow Gas Laboratory Testing
      8. 2.8 Electronic Connectors
        1. 2.8.1 Background
        2. 2.8.2 MFG Test Results
      9. 2.9 Power Connectors
      10. 2.10 Other Considerations
      11. Acknowledgments
      12. References
    3. 3. Gas Corrosion
      1. 3.1 Introduction
        1. 3.1.1 Scope
        2. 3.1.2 Background
      2. 3.2 The Field Environments for Electrical Contacts
        1. 3.2.1 Environmental Variables
        2. 3.2.2 Corrosion Rates
          1. 3.2.2.1 Copper and Silver
          2. 3.2.2.2 Other Metals
          3. 3.2.2.3 Film Effects
          4. 3.2.2.4 Shielding Effects
        3. 3.2.3 Reactivity Distributions
          1. 3.2.3.1 Severity versus Performance
          2. 3.2.3.2 Environmental Classes
          3. 3.2.3.3 Specifications
        4. 3.2.4 Corrosion Mechanisms
          1. 3.2.4.1 Silver
          2. 3.2.4.2 Copper
          3. 3.2.4.3 Nickel
          4. 3.2.4.4 Tin
          5. 3.2.4.5 Porous Gold Coatings
          6. 3.2.4.6 Pore Corrosion
          7. 3.2.4.7 Corrosion Product Creep
      3. 3.3 Laboratory Accelerated Testing
        1. 3.3.1 Objectives
        2. 3.3.2 Definition of Acceleration Factor
        3. 3.3.3 Historical Background
        4. 3.3.4 Single-Gas Corrosion Effects
          1. 3.3.4.1 Hydrogen Sulfide
          2. 3.3.4.2 Sulfur Dioxide (SO2)
          3. 3.3.4.3 Nitrogen Dioxide (NO2)
          4. 3.3.4.4 Chlorine
          5. 3.3.4.5 Mixed-Gas Sulfur Environments
          6. 3.3.4.6 Humidity
          7. 3.3.4.7 Temperature
          8. 3.3.4.8 Gas Flow Effects
        5. 3.3.5 Mixed-Gas Environments
          1. 3.3.5.1 Test Systems
          2. 3.3.5.2 Monitoring Reactivity
        6. 3.3.6 Test Applications
          1. 3.3.6.1 Electronic Connectors
          2. 3.3.6.2 Mated versus Unmated Exposures
          3. 3.3.6.3 Other Considerations
      4. 3.4 Lubrication and Inhibition of Corrosion
      5. Acknowledgment
      6. References
    4. 4. Effect of Dust Contamination on Electrical Contacts
      1. 4.1 Introduction
        1. 4.1.1 Background
        2. 4.1.2 The Importance of the Dust Problem
        3. 4.1.3 The Complexity of the Problem
        4. 4.1.4 The Purpose of the Studies
      2. 4.2 Dusty Environment and Dust Composition
        1. 4.2.1 The Source of Dust
        2. 4.2.2 The Collection of the Dust Particles for Testing
        3. 4.2.3 The Shape of the Dust Particles
        4. 4.2.4 The Identification of the Inorganic Materials
        5. 4.2.5 The Organic Materials in Dust
        6. 4.2.6 The Water Soluble Salts in Dust
      3. 4.3 The Characteristics of Dust Particles
        1. 4.3.1 The Electrical Behavior
          1. 4.3.1.1 Measurement of the Electric Charge
          2. 4.3.1.2 The Electrostatic Attracting Force on the Particle
        2. 4.3.2 Mechanical Behavior
          1. 4.3.2.1 Load Effect
          2. 4.3.2.2 For Stationary Contacts
          3. 4.3.2.3 For Sliding Contacts
          4. 4.3.2.4 The Effect of Lubricants Coated on Contact Surface
          5. 4.3.2.5 Sliding Contacts on Lubricated and Dusty Contacts
          6. 4.3.2.6 Fretting (Micro Motion) on Lubricated and Dusty Contacts
        3. 4.3.3 Chemical Behavior
          1. 4.3.3.1 Dust Particles Create Pores
          2. 4.3.3.2 Corrosion Appears as a Result of Dusty Water Solutions
          3. 4.3.3.3 Indoor Exposure Results
          4. 4.3.3.4 Construction of the Corrosion Stain
          5. 4.3.3.5 Fretting Experiments on Dust Corroded Coupon Surfaces…209
      4. 4.4 Application Conditions in Dusty Environment
        1. 4.4.1 Explanation of the Special Features
          1. 4.4.1.1 Covered by Accumulated Small Particles
          2. 4.4.1.2 Accumulative Particles Caused by Micro Motion
          3. 4.4.1.3 High and Erratic Contact Resistance
          4. 4.4.1.4 The Element of Si Causes High Contact Resistance
          5. 4.4.1.5 Organics Act as Adhesives
          6. 4.4.1.6 Corrosion Products Trap the Dust Particles
          7. 4.4.1.7 Difference Between Short Life and Longer Life Contacts
          8. 4.4.1.8 Large Pieces of “Stepping Stones”
          9. 4.4.1.9 The Performance of Failed Mobile Phones
        2. 4.4.2 Other Examples
      5. 4.5 Theoretical Analysis of Connector Contact Failure due to the Dust
        1. 4.5.1 Two Micro Worlds in Contact
          1. 4.5.1.1 Particles Get into the Contact Interface
        2. 4.5.2 “Preliminary Attachment”
          1. 4.5.2.1 Adhesive Effect
          2. 4.5.2.2 Trapping Effect of Corrosion Products
        3. 4.5.3 Contact Failure Mechanism
          1. 4.5.3.1 Single Particle and Ideal Model
          2. 4.5.3.2 Complicated Model – Number of Particles and Morphology of Contact Pairs
        4. 4.5.4 Micro Movement
          1. 4.5.4.1 Contact Failure
      6. 4.6 Future Work
        1. 4.6.1 Dust Test for Connectors
        2. 4.6.2 Suggestion of the Dust Test
        3. 4.6.3 Minimizing the Dust Problem
          1. 4.6.3.1 Cleaning the Samples
      7. References
  12. Part II Nonarcing Contacts
    1. 5. Power Connectors
      1. 5.1 Introduction
      2. 5.2 Types of Power Connectors
        1. 5.2.1 Plug-and-Socket Connectors
        2. 5.2.2 Wire Connectors
        3. 5.2.3 Bolted Connectors
        4. 5.2.4 Insulation Piercing Connectors
      3. 5.3 Properties of Conductor and Connector Materials
        1. 5.3.1 Definition of Conductor and Connector Systems
        2. 5.3.2 Factors Affecting Conductivity
          1. 5.3.2.1 Effect of Temperature
          2. 5.3.2.2 Effect of Lattice Imperfections
          3. 5.3.2.3 Magnetoresistance
          4. 5.3.2.4 Skin Effect
        3. 5.3.3 Conductor Materials
          1. 5.3.3.1 Copper and Copper Alloys
          2. 5.3.3.2 Aluminum and Its Alloys
        4. 5.3.4 Materials for Connector Systems
          1. 5.3.4.1 Pure Metals and Alloys
        5. 5.3.5 Electroplating and Cladding
      4. 5.4 Parameters Affecting Performance of Power Connections
        1. 5.4.1 Factors Affecting Reliability of Power Connections
        2. 5.4.2 Contact Area
        3. 5.4.3 Plastic Deformation
        4. 5.4.4 Elastic Deformation
        5. 5.4.5 Plated Contacts
        6. 5.4.6 Oxidation
        7. 5.4.7 Corrosion
          1. 5.4.7.1 Atmospheric Corrosion
          2. 5.4.7.2 Localized Corrosion
          3. 5.4.7.3 Crevice Corrosion
          4. 5.4.7.4 Pitting Corrosion
          5. 5.4.7.5 Pore Corrosion
          6. 5.4.7.6 Creep Corrosion
        8. 5.4.8 Dust Corrosion
        9. 5.4.9 Galvanic Corrosion
        10. 5.4.10 Thermal Expansion
        11. 5.4.11 Fretting
          1. 5.4.11.1 Factors Affecting Fretting
          2. 5.4.11.2 Mechanisms of Fretting
          3. 5.4.11.3 Examples of Fretting Damage in Power Connections
          4. 5.4.11.4 Compression Connectors
          5. 5.4.11.5 Bus-Stab Contacts
          6. 5.4.11.6 Plug-In Connectors
          7. 5.4.11.7 Bolted Connections
          8. 5.4.11.8 Fretting in Aluminum Connections
          9. 5.4.11.9 Effect of Electrical Current
          10. 5.4.11.10 Fretting in Coatings (Platings)
          11. 5.4.11.11 Fretting in Circuit Breaker Contact Materials
        12. 5.4.12 Intermetallic Compounds
        13. 5.4.13 Intermetallics in Copper–Tin Systems
          1. 5.4.13.1 Example of Intermetallics Formation in Power Connections
        14. 5.4.14 Stress Relaxation and Creep
        15. 5.4.15 Nature of the Effect of Electric Current
        16. 5.4.16 Effect of Electric Current on Stress Relaxation
        17. 5.4.17 Creep
      5. 5.5 Palliative Measures
        1. 5.5.1 Contact Area
        2. 5.5.2 Contact Pressure
        3. 5.5.3 Mechanical Contact Device
        4. 5.5.4 Disc-Spring (Belleville) Washers
        5. 5.5.5 Wedge Connectors
        6. 5.5.6 Automatic Splices
        7. 5.5.7 Dead-end Connectors
        8. 5.5.8 Shape-Memory Alloy Connector Devices
        9. 5.5.9 Coating (Plating)
        10. 5.5.10 Lubrication—Contact Aid Compounds
        11. 5.5.11 Bimetallic Inserts
        12. 5.5.12 Transition Washers
        13. 5.5.13 Multilam Contact Elements
        14. 5.5.14 Welded Connections
          1. 5.5.14.1 Thermite (Exothermic) Welding
          2. 5.5.14.2 Friction Welding
          3. 5.5.14.3 Explosion Welding
          4. 5.5.14.4 Resistance Welding
          5. 5.5.14.5 Resistance Brazing
        15. 5.5.15 Connector Design
          1. 5.5.15.1 Fired Wedge-Connectors
          2. 5.5.15.2 Stepped Deep Indentation Connectors
      6. 5.6 Connector Degradation
        1. 5.6.1 Economical Consequences of Contact Deterioration
        2. 5.6.2 Power Quality
      7. 5.7 Prognostic Models
        1. 5.7.1 Prognostic Model 1 for Contact Remaining Life
        2. 5.7.2 Prognostic Model 2 for Contact Remaining Life
        3. 5.7.3 Physical Model
      8. 5.8 Shape-Memory Alloys (SMA)
        1. 5.8.1 Origin of Shape-Memory Effect
          1. 5.8.1.1 One-Way Memory Effect
          2. 5.8.1.2 Two-Way Memory Effect
        2. 5.8.2 Applications of SMA in Power Connections
        3. 5.8.3 Electrical Connections
        4. 5.8.4 Temperature Indicators
      9. 5.9 Metal Foam Materials
        1. 5.9.1 Aluminum Foam Materials
          1. 5.9.1.1 Electrical and Thermal Properties of Foam Materials
          2. 5.9.1.2 Power Connection Applications
        2. 5.9.2 Copper Foam Materials
          1. 5.9.2.1 Applications of Copper Foam Materials
        3. 5.9.3 Silver Foam Materials
      10. 5.10 Installation of Power Connections
        1. 5.10.1 Examples of Improper Installations
      11. 5.11 Accelerated Current-Cycling Tests (Standards)
        1. 5.11.1 Present Current-Cycling Tests
      12. References
    2. 6. Low-Power Commercial, Automotive, and Appliance Connections
      1. 6.1 Introduction
      2. 6.2 Connectors
        1. 6.2.1 Functional Requirements
        2. 6.2.2 Types of Connectors
        3. 6.2.3 Mechanical Considerations
      3. 6.3 Contact Terminals
        1. 6.3.1 Contact Physics
        2. 6.3.2 Terminal Types
        3. 6.3.3 Other Electrical Contact Parameters
      4. 6.4 Degradation of Connector Contact
        1. 6.4.1 Surface Films
        2. 6.4.2 Fretting Corrosion of Tin–Plated Contacts
        3. 6.4.3 Examples of Contact Failures
          1. 6.4.3.1 Automotive Position Sensor Connector
          2. 6.4.3.2 Fuel Injector Connector
          3. 6.4.3.3 Glowing Contacts
          4. 6.4.3.4 Electrolytic Corrosion
          5. 6.4.3.5 Incompatible Plating and Low Contact Force
      5. 6.5 Automotive Connector Contacts
        1. 6.5.1 Vehicle Conditions
        2. 6.5.2 High Power Connectors for Electric and Hybrid Vehicles
        3. 6.5.3 Aluminum Wiring Connections
        4. 6.5.4 Connections for High-Vibration Environment
      6. 6.6 Summay
      7. References
    3. 7. Tribology of Electronic Connectors: Contact Sliding Wear, Fretting, and Lubrication
      1. 7.1 Introduction
      2. 7.2 Sliding Wear
        1. 7.2.1 Early Studies
        2. 7.2.2 Adhesion
          1. 7.2.2.1 “Wiping” Contaminant from Contact Surfaces
          2. 7.2.2.2 Mild and Severe
          3. 7.2.2.3 Prow Formation
          4. 7.2.2.4 Rider Wear
          5. 7.2.2.5 Gold Platings: Intrinsic Polymers and Junction Growth
          6. 7.2.2.6 Electroless Gold Plating
        3. 7.2.3 Abrasion
        4. 7.2.4 Brittle Fracture
        5. 7.2.5 Delamination and Subsurface Wear
        6. 7.2.6 Effect of Underplate and Substrate
          1. 7.2.6.1 Hardness
          2. 7.2.6.2 Roughness
        7. 7.2.7 Electrodeposited Gold: Relationship of Wear to Underplate Hardness
          1. 7.2.7.1 Hardener Metal Content
        8. 7.2.8 Clad Metals
        9. 7.2.9 Tin and Tin–Lead Alloys
        10. 7.2.10 Silver
      3. 7.3 Fretting
        1. 7.3.1 Background
        2. 7.3.2 Fretting Regimes
        3. 7.3.3 Static versus Dynamic Contact Resistance
        4. 7.3.4 Field and Laboratory Testing Methodologies
          1. 7.3.4.1 Generation of Fretting Displacement
          2. 7.3.4.2 Determination of Contact Resistance
        5. 7.3.5 Materials Studies
          1. 7.3.5.1 Apparatus
          2. 7.3.5.2 Metals Having Little or No Film-Forming Tendency
          3. 7.3.5.3 Non-Noble Metals/Fretting Corrosion
          4. 7.3.5.4 Frictional Polymer-Forming Metals
          5. 7.3.5.5 Dissimilar Metals on Mating Contacts
        6. 7.3.6 Wear-Out Phenomena
          1. 7.3.6.1 Gold-Based Systems
          2. 7.3.6.2 Palladium-Based Systems
          3. 7.3.6.3 Tin and Tin–Lead Alloy Systems
          4. 7.3.6.4 Role of Underplate and Substrate
        7. 7.3.7 Parametric Studies
          1. 7.3.7.1 Cycle Rate
          2. 7.3.7.2 Wipe Distance
          3. 7.3.7.3 Force
        8. 7.3.8 Environmental Effects
        9. 7.3.9 Thermal
        10. 7.3.10 Effect of Current
        11. 7.3.11 Surface Finish and Contact Geometry
        12. 7.3.12 Material Transfer, Wear, Film Formation, and Contact Resistance
          1. 7.3.12.1 Summary of Physical Processes
      4. 7.4 Lubrication
        1. 7.4.1 Introduction
        2. 7.4.2 Metallic Films
          1. 7.4.2.1 Principles of Metallic Film Lubrication
          2. 7.4.2.2 Sliding and Wiping Contacts
          3. 7.4.2.3 Fretting Contacts
        3. 7.4.3 Fluid Lubricants
          1. 7.4.3.1 Background
          2. 7.4.3.2 Some Fundamental Properties of Lubricants
          3. 7.4.3.3 Requirements
          4. 7.4.3.4 Types of Fluid Lubricants: A Sliding Contact Investigation
          5. 7.4.3.5 Control of Fretting Degradation
        4. 7.4.4 Grafted and Self-Assembled Lubricant Layers
        5. 7.4.5 Greases and Solid Lubricants
          1. 7.4.5.1 Greases
          2. 7.4.5.2 Solids
        6. 7.4.6 Lubricant Durability
        7. 7.4.7 Other Considerations
      5. References
    4. 8. Materials, Coatings, and Platings
      1. 8.1 Introduction
        1. 8.1.1 Scope
        2. 8.1.2 Requirements of Contact Finishes and Coatings
        3. 8.1.3 Terminology
      2. 8.2 Metallic Finishes
        1. 8.2.1 Wrought Metals
        2. 8.2.2 Electrodeposits and Electroless Deposits
          1. 8.2.2.1 Thickness of Platings
          2. 8.2.2.2 Plating Hardness
          3. 8.2.2.3 Classification of Platings
        3. 8.2.3 Contact Finishes Produced by Non-Chemical Methods
        4. 8.2.4 Metal-in-Elastomer Materials
        5. 8.2.5 Overview
      3. 8.3 Properties Related to Porosity
        1. 8.3.1 Origins of Porosity
        2. 8.3.2 Tests of Porosity
        3. 8.3.3 Relationships between Porosity, Thickness of Finish, and Substrate Roughness
        4. 8.3.4 Effect of Underplatings, Flash Coatings, and Strikes on the Porosity of Electrodeposits
        5. 8.3.5 Reduction in the Chemical Reactivity of Finishes by the Use of Underplates
      4. 8.4 Metallurgical and Structural Properties
        1. 8.4.1 Thermal Diffusion
        2. 8.4.2 Intermetallics
        3. 8.4.3 Tin Whiskers
        4. 8.4.4 Silver Whiskers
      5. 8.5 Physical and Mechanical Properties
        1. 8.5.1 Characteristics of Layered Systems
          1. 8.5.1.1 Hardness
          2. 8.5.1.2 Contact Resistance
        2. 8.5.2 Topography
      6. Acknowledgement
      7. References
  13. Part III The Electric Arc and Switching Device Technology
    1. 9. The Arc and Interruption
      1. 9.1 Introduction
      2. 9.2 The Fourth State of Matter
      3. 9.3 Establishing an Arc
        1. 9.3.1 Long-Gap Gas Breakdown
        2. 9.3.2 Vacuum Breakdown and Short-Gap Breakdown
        3. 9.3.3 The Volt–Current Characteristics of Separated Contacts
      4. 9.4 The Formation of the Electric Arc
        1. 9.4.1 The Formation of the Electric Arc during Contact Closing
        2. 9.4.2 The Formation of the Electric Arc during Contact Opening
      5. 9.5 The Arc in Air at Atmospheric Pressure
        1. 9.5.1 The Arc Column
        2. 9.5.2 The Cathode Region
        3. 9.5.3 The Anode Region
        4. 9.5.4 The Minimum Arc Current and the Minimum Arc Voltage
        5. 9.5.5 Arc Volt–Ampere Characteristics
      6. 9.6 The Arc in Vacuum
        1. 9.6.1 The Diffuse Vacuum Arc
        2. 9.6.2 The Columnar Vacuum Arc
        3. 9.6.3 The Vacuum Arc in the Presence of a Transverse Magnetic Field
        4. 9.6.4 The Vacuum Arc in the Presence of an Axial Magnetic Field
      7. 9.7 Arc Interruption
        1. 9.7.1 Arc Interruption in Alternating Current Circuits
          1. 9.7.1.1 Stage 1 - Instantaneous Dielectric Recovery
          2. 9.7.1.2 Stage 2 - Decay of the Arc Plasma and Dielectric Reignition
          3. 9.7.1.3 Thermal Reignition
        2. 9.7.2 Arc Interruption in Direct Current Circuits
        3. 9.7.3 Vacuum Arc Interruption in Alternating Circuits
        4. 9.7.4 Arc interruption of Alternating Circuits: Current Limiting
        5. 9.7.5 Interruption of Low Frequency and High Frequency Power Circuits
        6. 9.7.6 Interruption of Megahertz and Gigahertz Electronic Circuits
      8. Acknowledgments
      9. References
    2. 10. The Consequences of Arcing
      1. 10.1 Introduction
      2. 10.2 Arcing Time
        1. 10.2.1 Arcing Time in an AC Circuit
        2. 10.2.2 Arcing Time in a DC Circuit
        3. 10.2.3 Activation of the Contact
        4. 10.2.4 Arcing Time in Very Low-Current DC Circuits: Showering Arcs
      3. 10.3 Arc Erosion of Electrical Contacts
        1. 10.3.1 Erosion on Make and Erosion on Break
        2. 10.3.2 The Effect of Arc Current
        3. 10.3.3 The Effect of Contact Size
        4. 10.3.4 Determination of Contact Size in AC Operation
        5. 10.3.5 Erosion of Contacts in Low-Current DC Circuits
        6. 10.3.6 Erosion of Contacts in Low-Current AC Circuits
      4. 10.4 Blow-Off Force
        1. 10.4.1 Butt Contacts
      5. 10.5 Contact Welding
        1. 10.5.1 Welding of Closed Contacts
        2. 10.5.2 Welding during Contact Closure
        3. 10.5.3 Welding as Contacts Open
      6. 10.6 Changes in the Contact Surface as a Result of Arcing
        1. 10.6.1 Silver–Based Contacts
        2. 10.6.2 Silver–Refractory Metal Contacts
        3. 10.6.3 Other Ambient Effects on the Arcing Contact Surface: Formation of Silica and Carbon and Contact Activation
      7. Acknowledgments
      8. References
    3. 11. Reed Switches
      1. 11.1 Principles and Design of the Reed Switch
        1. 11.1.1 Pull-In Characteristics of a Reed Switch
        2. 11.1.2 Drop-Out Characteristics of a Reed Switch
        3. 11.1.3 Magnet Drive Characteristics of a Reed Switch
          1. 11.1.3.1 X–Y Characteristic H (Horizontal)
          2. 11.1.3.2 X–Z Characteristic H (Horizontal)
          3. 11.1.3.3 X–Y Characteristic V (Vertical)
      2. 11.2 Recommended Contact Plating
        1. 11.2.1 Materials for Contact Plating
        2. 11.2.2 Ground Plating
        3. 11.2.3 Rhodium Plating
        4. 11.2.4 Ruthenium Plating
        5. 11.2.5 Other Platings
          1. 11.2.5.1 Copper Plating
          2. 11.2.5.2 Tungsten Plating
          3. 11.2.5.3 Rhenium Plating
          4. 11.2.5.4 Iridium Plating
          5. 11.2.5.5 Nitriding the Permalloy (Ni-Fe [48 wt%]) Blade Material
      3. 11.3 Contact Surface Degradation and Countermeasures
        1. 11.3.1 Surface Deactivation Treatment
          1. 11.3.1.1 Life Test of Samples Left for 24 Hours after Sealing
          2. 11.3.1.2 Life Test of Samples Left for One Week after Sealing
          3. 11.3.1.3 Life Test of Samples Left for One Month after Sealing
          4. 11.3.1.4 Life Test of Samples Left for Three Months, Six Months, and One Year after Sealing
        2. 11.3.2 Prevention of Contact Adhesion
      4. 11.4 Applications of Reed Switches
        1. 11.4.1 Reed Relays
        2. 11.4.2 Applications of Magnetic-Driven Reed Switches
      5. References
    4. 12. Low Current and High Frequency Miniature Switches: Microelectromechanical Systems (MEMS), Metal Contact Switches
      1. 12.1 Introduction
        1. 12.1.1 Common MEMS Actuation Methods
      2. 12.2 Micro-Contact Resistance Modeling
      3. 12.3 Contact Materials for Performance and Reliability
      4. 12.4 Failure Modes and Reliability
      5. 12.5 Conclusion
      6. References
    5. 13. Low Current Switching
      1. 13.1 Introduction and Device Classification
      2. 13.2 Device Types
        1. 13.2.1 Hand-Operated Switches
          1. 13.2.1.1 The Rocker Switch Mechanism
          2. 13.2.1.2 Lever Switches
          3. 13.2.1.3 Slide Switches
          4. 13.2.1.4 Rotary Switches
          5. 13.2.1.5 Push-Button Switches
          6. 13.2.1.6 Switching Devices Used below 0.5 A
        2. 13.2.2 Actuated Switches
          1. 13.2.2.1 Limit Switches
          2. 13.2.2.2 Thermostatic Controls
          3. 13.2.2.3 Electro-Mechanical Relay
      3. 13.3 Design Parameters for Static Switching Contacts
        1. 13.3.1 Small-Amplitude Sliding Motion
        2. 13.3.2 Contact Force and Contact Materials
          1. 13.3.2.1 Contacts at Current Levels below 1 A
          2. 13.3.2.2 Contacts at Current Levels between 1 and 30 A
          3. 13.3.2.3 Contact Force
      4. 13.4 Mechanical Design Parameters
        1. 13.4.1 Case Study (1): Hand-Operated Rocker-Switch Mechanism
          1. 13.4.1.1 Moving-Contact Dynamics of a Rocker-Switch Mechanism
          2. 13.4.1.2 Design Optimization of a Rocker-Switch Mechanism
        2. 13.4.2 The Opening Characteristics of Switching Devices
          1. 13.4.2.1 Moving Contact Dynamics at Opening
        3. 13.4.3 The Make Operation
          1. 13.4.3.1 Impact Mechanics
          2. 13.4.3.2 The Coefficient of Restitution
          3. 13.4.3.3 Impact Mechanics for a Pivoting Mechanism
          4. 13.4.3.4 The Velocity of Impact
          5. 13.4.3.5 Bounce Times
          6. 13.4.3.6 Total Bounce Times
          7. 13.4.3.7 Impact Times
          8. 13.4.3.8 Design Parameters for the Reduction of Contact Bounce
      5. 13.5 The Measurement of Contact Wear and Contact Dynamics
        1. 13.5.1 The Measurement of Contact Surfaces
        2. 13.5.2 Three Dimensional (3-D) Surface Measurement Systems
          1. 13.5.2.1 Contact Systems
          2. 13.5.2.2 Non-Contact Systems
        3. 13.5.3 Case Study (2): Example of Volumetric Erosion
        4. 13.5.4 The Measurement of Arc Motion and Contact Dynamics
      6. 13.6 Electrical Characteristics of Low-Current Switching Devices at Opening
        1. 13.6.1 Low-Current DC Arcs
          1. 13.6.1.1 Arc Voltage Characteristics
          2. 13.6.1.2 Voltage Steps below 7 A
          3. 13.6.1.3 Case Study (3): Arc Voltage, Current and Length under Quasi-Static Conditions for Ag/CdO Contacts
          4. 13.6.1.4 Opening Speed and Arc Length
          5. 13.6.1.5 Case Study (4): Automotive Systems
        2. 13.6.2 DC Erosion
          1. 13.6.2.1 Ag and Ag/MeO Contact Erosion/Deposition
        3. 13.6.3 Low-Current AC Arcs
          1. 13.6.3.1 Typical Waveforms and Arc Energy
        4. 13.6.4 AC Erosion
          1. 13.6.4.1 Point-on-Wave (POW) Studies Using Ag/CdO Contact Materials
      7. 13.7 Electrical Characteristics of Low Current Switching Devices at Closure
        1. 13.7.1 Contact Welding on Make
        2. 13.7.2 Reducing Contact Bounce
        3. 13.7.3 Pre-Impact Arcing
        4. 13.7.4 Influence of Velocity during the First Bounce
          1. 13.7.4.1 The First Bounce
        5. 13.7.5 Bounces after the First
        6. 13.7.6 Summary of Contact Bounce
      8. 13.8 Summary
        1. 13.8.1 Switch Design
        2. 13.8.2 Break Operation
          1. 13.8.2.1 DC Operation
          2. 13.8.2.2 AC Operation
        3. 13.8.3 Make Operation
          1. 13.8.3.1 Design Parameters
          2. 13.8.3.2 Reducing Contact Bounce
          3. 13.8.3.3 Arcing during the Bounce Process
      9. Acknowledgments
      10. References
    6. 14. Medium to High Current Switching: Low Voltage Contactors and Circuit Breakers, and Vacuum Interrupters
      1. 14.1 General Aspects of Switching in Air
        1. 14.1.1 Arc Chutes
        2. 14.1.2 Magnetic Blast Field
        3. 14.1.3 Arc Dwell Time on the Contacts
        4. 14.1.4 Sticking and Back-Commutation of the Arc
      2. 14.2 Contacts for Switching in Air
      3. 14.3 Low-Voltage Contactors
        1. 14.3.1 Principle/Requirements
        2. 14.3.2 Mechanical Arrangement
        3. 14.3.3 Quenching Principle and Contact and Arc Chute Design
        4. 14.3.4 Contact Materials
        5. 14.3.5 Trends
          1. 14.3.5.1 Contactors versus Electronics
          2. 14.3.5.2 Vacuum Contactors
          3. 14.3.5.3 Hybrid Contactors
          4. 14.3.5.4 Integration with Electronic Systems
      4. 14.4 Low-Voltage Circuit-Breakers and Miniature Circuit-Breakers
        1. 14.4.1 Principle/Requirements
        2. 14.4.2 General Arrangement
        3. 14.4.3 Quenching Principle and Design of Arc Chute and Contact System
          1. 14.4.3.1 Quenching Principles
          2. 14.4.3.2 Arc Chute and Contact Arrangement
        4. 14.4.4 Trip System
        5. 14.4.5 Examples of Miniature Circuit-Breakers
        6. 14.4.6 Contact Materials
        7. 14.4.7 Special Requirements for DC Switching
        8. 14.4.8 Current Limitation by Principles Other than Deion Arc Chutes
          1. 14.4.8.1 Arcs Squeezed in Narrow Insulating Slots
          2. 14.4.8.2 Reversible Phase Changes of Liquid or Low-Melting Metal
          3. 14.4.8.3 Temperature-Dependent Ceramics or Polymers
          4. 14.4.8.4 Contact Resistance between Powder Grains
          5. 14.4.8.5 Superconductors
      5. 14.5 Simulations of Low-Voltage Switching Devices
        1. 14.5.1 Simulation of Low-Voltage Arcs
          1. 14.5.1.1 General Principle of Simulation
          2. 14.5.1.2 Arc Roots on Cathode and Anode
          3. 14.5.1.3 Radiation
          4. 14.5.1.4 Interaction between Arc and Electrode or Wall Material (Ablation)
          5. 14.5.1.5 Plasma Properties
          6. 14.5.1.6 Simplification by Porous Media
        2. 14.5.2 Further Simulations of Contact and Switching Device Behavior
      6. 14.6 Vacuum Interrupters
        1. 14.6.1 Principle/Applications
        2. 14.6.2 Design
        3. 14.6.3 Recovery and the Influence of the Design
        4. 14.6.4 Contact Materials for Vacuum Interrupters and Their Influence on Switching
          1. 14.6.4.1 Requirements
          2. 14.6.4.2 Arc Interruption
          3. 14.6.4.3 Interruption of High Frequency Transients
          4. 14.6.4.4 Current Chopping
        5. 14.6.5 Simulation of Arcs in Vacuum Interrupters
      7. References
    7. 15. Arc Faults and Electrical Safety
      1. 15.1 Introduction
      2. 15.2 Arc Fault Circuit Interrupters (AFCIs)
      3. 15.3 Arcing Faults
        1. 15.3.1 Short-Circuit Arcing
        2. 15.3.2 Series Arcing
      4. 15.4 Glowing Connections
      5. 15.5 Arcing Fault Properties
        1. 15.5.1 Frequency
        2. 15.5.2 Electrode Materials
        3. 15.5.3 Arc Fault Current
        4. 15.5.4 Cable Impedance and Cable Length Effects
      6. 15.6 Other Types of Arcing Faults
      7. 15.7 Conclusions
      8. References
  14. Part IV Arcing Contact Materials
    1. 16. Arcing Contact Materials
      1. 16.1 Introduction
      2. 16.2 Silver Metal Oxides
      3. 16.2.1 Types
      4. 16.2.2 Manufacturing Technology
      5. 16.2.2.1 Internal Oxidation
      6. 16.2.2.2 Post-Oxidized Internally Oxidized Parts (Process B 1.0)
      7. 16.2.2.3 One-Sided Internally Oxidized Parts (Process B 2.01)
      8. 16.2.2.4 Preoxidized Internally Oxidized Parts (Process B.2.02)
      9. 16.2.2.5 Powder Metallurgical (PM) Silver Metal Oxides (Processes C and D)
      10. 16.2.3 Electrical Performance Factors
      11. 16.2.3.1 AC versus DC Testing
      12. 16.2.3.2 High Current Inrush DC Automotive and AC Loads
      13. 16.2.3.3 Inductive Loads
      14. 16.2.3.4 Silver–Tin Oxide Type Materials and Additives
      15. 16.2.3.5 Material Factor
      16. 16.2.3.6 Interpreting Material Research, Example from Old Silver Cadmium Oxide Research
      17. 16.2.4 Material Considerations Based on Electrical Switching Characteristics
      18. 16.2.4.1 Erosion/Materials Transfer/Welding
      19. 16.2.5 Transfer/Welding
      20. 16.2.6 Erosion/Mechanisms/Cracking
      21. 16.2.7 Erosion/Arc Mobility
      22. 16.2.8 Interruption Characteristics
      23. 16.2.9 Contact Resistance
      24. 16.2.9.1 Summary Metal Oxides
      25. 16.3 Silver Refractory Metals
      26. 16.3.1 Manufacturing Technology
      27. 16.3.1.1 Manufacturing Technology/Press Sinter Repress (Process D 1.0)
      28. 16.3.2 Material Technology/Extruded Material
      29. 16.3.2.1 Material Technology/Liquid Phase Sintering (Process D 2.0)
      30. 16.3.2.2 Material Technology/Press Sinter Infiltration (Process D 3.0)
      31. 16.3.3 Metallurgical/Metallographic Methods
      32. 16.3.3.1 Metallurgical/Metallographic Methods/Preparation
      33. 16.3.3.2 Metallurgical/Metallography/Quantitative Analysis
      34. 16.3.4 Metallurgical/Structure/Strength and Toughness
      35. 16.3.5 Electrical Properties (EP)
      36. 16.3.5.1 EP/Arc Erosion/Microstructure and Properties
      37. 16.3.5.2 EP/Arc Erosion/Silver Refractory
      38. 16.3.5.3 EP/Graphite Additions to Silver Tungsten and Silver Tungsten Carbide
      39. 16.3.5.4 EP/Copper Refractory Metals
      40. 16.3.5.5 EP/Erosion/Summary
      41. 16.3.5.6 EP/Composite Refractory Materials/Contact Resistance
      42. 16.4 Vacuum Interrupter Materials
      43. 16.5 Tungsten Contacts
      44. 16.6 Non-Noble Silver Alloys
      45. 16.6.1 Fine Silver
      46. 16.6.2 Hard Silver and Silver–Copper Alloys
      47. 16.7 Silver–Nickel Contact Materials
      48. 16.8 Silver Alloys and Noble Metals
      49. 16.8.1 Palladium and Silver–Palladium Alloys
      50. 16.8.2 Platinum
      51. 16.9 Silver–Graphite Contact Materials
      52. 16.10 Conclusion
      53. Acknowledgements
      54. References
    2. 17. Contact Design and Attachment
      1. 17.1 Introduction
      2. 17.1.1 Arc-Induced Contact Stresses and Interface Bond Quality
      3. 17.2 Staked Contact Assembly Designs
      4. 17.2.1 Contact Rivets
      5. 17.2.1.1 Solid Rivets
      6. 17.2.1.2 Machine-Made Composite Rivets
      7. 17.2.1.3 Brazed Composite Rivets
      8. 17.2.1.4 Rivet Staking
      9. 17.3 Welded Contact Assembly Designs
      10. 17.3.1 Resistance Welding
      11. 17.3.1.1 Button Welding
      12. 17.3.1.2 Wire-Welding
      13. 17.3.1.3 Contact Tape Welding
      14. 17.3.2 Special Welding Methods
      15. 17.3.2.1 Percussion Welding
      16. 17.3.2.2 Ultrasonic Welding of Contacts
      17. 17.3.2.3 Friction Welding of Contacts
      18. 17.4 Brazed Contact Assembly Designs
      19. 17.4.1 Methods for Brazing Individual Parts
      20. 17.4.1.1 Torch Brazing
      21. 17.4.1.2 Induction Brazing
      22. 17.4.1.3 Direct and Indirect Resistance Brazing
      23. 17.4.1.4 Furnace Brazing
      24. 17.4.1.5 Continuous Laminated Strip Brazing, “Toplay”
      25. 17.4.1.6 Brazed Assembly Quality Control Methods
      26. 17.5 Clad Metals, Inlay, and Edge Lay
      27. 17.6 Contact Alloys for Non-Arcing Separable Contacts
      28. 17.6.1 Gold and Gold Alloys
      29. 17.6.2 Manufacturing Technology
      30. 17.6.3 Physical and Chemical Properties
      31. 17.6.4 Metallurgical Properties
      32. 17.6.5 Contact Applications and Performance
      33. Acknowledgments
      34. References
    3. 18. Electrical Contact Material Testing Design and Measurement
      1. 18.1 Objectives
      2. 18.2 Device Testing and Model Switch Testing
      3. 18.2.1 Device Testing
      4. 18.2.2 Model Switch Testing
      5. 18.3 Electrical Contact Testing Variables
      6. 18.3.1 AC versus DC Testing
      7. 18.3.2 Switching Load Type
      8. 18.3.3 Opening and Closing Velocity Effects
      9. 18.3.4 Contact Bounce
      10. 18.3.5 Contact Carrier Mass and Conductivity
      11. 18.3.6 Contact Closing Force and Over Travel
      12. 18.3.7 Enclosed and Open Contact Devices
      13. 18.3.8 Testing at Different Ambient Temperatures
      14. 18.3.9 Erosion Measurement
      15. 18.3.10 Summary Electrical Contact Testing Variables
      16. 18.4 Electrical Testing Result Types and Measurement Methods
      17. 18.4.1 Contact Resistance
      18. 18.4.1.1 Model Testing
      19. 18.4.1.2 Evaluation and Presentation of Results
      20. 18.4.2 Contact Bounce Measurement
      21. 18.4.2.1 Model Testing
      22. 18.4.2.2 Evaluation
      23. 18.4.3 Contact Welding Measurement
      24. 18.4.3.1 Weld Strength Measured
      25. 18.4.4 Contact Erosion Measurements
      26. 18.4.4.1 Accelerated and Model Testing
      27. 18.4.4.2 Extrapolation at Rated Stress
      28. 18.4.4.3 Increase of the Switching Frequency
      29. 18.4.4.4 Testing at Increased Electrical Load
      30. 18.4.4.5 Fixed-Gap Models
      31. 18.4.4.6 Moving Contact Models
      32. 18.4.4.7 Evaluation and Presentation of Results
      33. 18.4.5 AC Arc Reignition Measurement
      34. 18.4.6 Arc Motion Measurements
      35. 18.4.6.1 Measurement
      36. 18.4.6.2 Electronic Optical
      37. 18.4.6.3 Model Switch Arc Motion Control
      38. 18.4.6.4 Evaluation and Presentation of Results
      39. 18.4.7 Arc-Wall Interaction Measurements
      40. References
    4. 19. Arc Interactions with Contaminants
      1. 19.1 Introduction
      2. 19.2 Organic Contamination and Activation
      3. 19.2.1 The Phenomena
      4. 19.2.2 Sources of Organic Vapors
      5. 19.2.3 Processes of Contact Activation
      6. 19.2.4 Activation Effects
      7. 19.2.5 Activation and Contact Resistance Problems
      8. 19.2.6 Methods for Detecting Carbon Contamination
      9. 19.3 Mineral Particulate Contamination of Arcing Contacts
      10. 19.4 Silicone Contamination of Arcing Contacts
      11. 19.4.1 Contamination from Silicone Vapors
      12. 19.4.2 Contamination from Silicone Migration
      13. 19.4.3 Summary of Silicone Contamination Mechanisms
      14. 19.5 Lubricants with Refractory Fillers
      15. 19.6 Oxidation of Contact Materials
      16. 19.7 Resistance Effects from Long Arcs
      17. Acknowledgments
      18. References
  15. Part V Sliding Electrical Contacts
    1. 20. Sliding Electrical Contacts (Graphitic Type Lubrication)
      1. 20.1 Introduction
      2. 20.2 Mechanical Aspects
      3. 20.2.1 Hardness
      4. 20.2.2 Friction and Wear
      5. 20.2.3 Tunnel Resistance and Vibration
      6. 20.3 Chemical Aspects
      7. 20.3.1 Oxidation
      8. 20.3.2 Moisture Film
      9. 20.4 Electrical Effects
      10. 20.4.1 Constriction Resistance
      11. 20.4.2 Film Resistance
      12. 20.4.3 Fundamental Aspects of Commutation
      13. 20.4.4 Equivalent Commutation Circuit and DC Motor Driving Automotive Fuel Pump
      14. 20.4.5 Arc Duration and Residual Current
      15. 20.5 Thermal Effects
      16. 20.5.1 Steady State
      17. 20.5.2 Actual Temperature
      18. 20.5.3 Thermal Mound
      19. 20.6 Brush Wear
      20. 20.6.1 Holm’s Wear Equation
      21. 20.6.2 Flashes and Smutting
      22. 20.6.3 Polarities and Other Aspects
      23. 20.7 Brush Materials and Abrasion
      24. 20.7.1 Electro- and Natural Graphite Brushes
      25. 20.7.2 Metal Graphite Brush and Others
      26. 20.8 Summary
      27. References
    2. 21. Illustrative Modern Brush Applications
      1. 21.1 Introduction
      2. 21.2 Brush Materials
      3. 21.2.1 Electrographite
      4. 21.2.2 Carbon-Graphite
      5. 21.2.3 Graphite
      6. 21.2.4 Resin-Bonded
      7. 21.2.5 Metal-Graphite
      8. 21.2.6 Altitude-Treated Brushes
      9. 21.3 Brush Applications
      10. 21.3.1 Minature Motors
      11. 21.3.2 Fractional Horsepower Motors
      12. 21.3.2.1 Wound Field/Permanent Magnet-Motor Characteristics
      13. 21.3.3 Automotive Brush Applications
      14. 21.3.3.1 Auxiliary Motors
      15. 21.3.3.2 Alternators
      16. 21.3.3.3 Starter Motors
      17. 21.3.4 Industrial Brushes
      18. 21.3.5 Diesel Electric Locomotive Brushes
      19. 21.3.6 Aircraft and Space Brushes
      20. 21.3.7 Brush Design
    3. 22. Sliding Contacts for Instrumentation and Control
      1. 22.1 Introduction
      2. 22.2 Sliding Contact—The Micro Perspective
      3. 22.2.1 Mechanical Aspects
      4. 22.2.2 Motion Initiation (Pre-Sliding)
      5. 22.2.3 Friction Forces
      6. 22.2.4 Motion Continuation
      7. 22.2.5 Adhesion
      8. 22.2.6 Adhesive Transfer
      9. 22.2.7 Plowing, or “Two-Body,” Abrasion
      10. 22.2.8 Hard Particle, or “Three-Body,” Abrasion
      11. 22.2.9 Motion Over Time
      12. 22.3 Electrical Performance
      13. 22.3.1 Contact Resistance Variation (Noise)
      14. 22.3.2 Non-Ohmic Noise
      15. 22.3.3 Non-Linear Noise (Frequency Dependent)
      16. 22.3.4 Contact Impedance
      17. 22.3.5 Data Integrity
      18. 22.4 Micro-Environment of Contact Region
      19. 22.4.1 Film Forming on the a-Spots
      20. 22.4.2 Unintentional Contamination
      21. 22.4.2.1 Particulates
      22. 22.4.2.2 Contamination or “Air Pollution”
      23. 22.4.2.3 Organic Off-Gasses
      24. 22.4.2.4 Friction Polymers
      25. 22.4.3 Lubrication (Intentional Contamination)
      26. 22.4.4 Lubrication Modes (Anaerobic and Aerobic)
      27. 22.4.4.1 Anaerobically Lubricated Contacts
      28. 22.4.4.2 Aerobically Lubricated Contacts
      29. 22.4.4.3 Temperature Extremes
      30. 22.4.4.4 Submerged in Flammable Fuels
      31. 22.4.4.5 Low-Pressure/Vacuum Operation
      32. 22.4.4.6 Vapor and Gas Lubrication
      33. 22.5 Macro Sliding Contact
      34. 22.5.1 Counterface Configuration
      35. 22.5.1.1 Flat Surfaces
      36. 22.5.1.2 Cylindrical Surfaces
      37. 22.5.1.3 Counterface Contact Shapes
      38. 22.5.2 Real versus Apparent Area of Contact
      39. 22.5.3 Brush Configurations
      40. 22.5.3.1 Cartridge Brush
      41. 22.5.3.2 Cantilever Composite Brush
      42. 22.5.3.3 Cantilever Metallic Finger
      43. 22.5.3.4 Cantilever Wire Brush
      44. 22.5.3.5 Multifilament or Fiber Brush
      45. 22.5.3.6 Benefits of Multiple Brushes
      46. 22.5.4 Forces on the Brush
      47. 22.6 Materials for Sliding Contacts
      48. 22.6.1 Materials for Counterfaces
      49. 22.6.2 Solid Lubricated Composite Materials for Brushes
      50. 22.6.3 Wire Brush Materials Criteria
      51. 22.7 Friction and Wear Characteristics
      52. 22.7.1 Friction
      53. 22.7.2 Wear
      54. 22.8 Contact Parameters and Sliding-Contact Assemblies
      55. 22.8.1 Contact Noise
      56. 22.8.2 Slip Rings as Transmission Lines
      57. 22.8.3 Results of Normal Operation
      58. 22.9 Future
      59. 22.10 Summary
      60. Acknowledgments
      61. References
    4. 23. Metal Fiber Brushes
      1. 23.1 Introduction
      2. 23.1.1 Fiber Brushes for Power
      3. 23.1.2 Diversification of Applications
      4. 23.1.3 Outline of Chapter
      5. 23.2 Sliding Wear of Multi-Fiber Brushes
      6. 23.2.1 Adhesive Wear
      7. 23.2.2 Holm-Archard Wear Equation
      8. 23.2.3 Low Wear Equilibrium
      9. 23.2.4 High Wear Regime
      10. 23.2.5 Plastic and Elastic Contact
      11. 23.2.6 Critical or Transition Brush Pressure
      12. 23.2.7 Wear of Fiber Brushes
      13. 23.2.8 Effects of Sliding Speed
      14. 23.2.9 Effect of Arcing and Bridge Transfer
      15. 23.3 Surface Films, Friction, and Materials Properties
      16. 23.3.1 Thin Film Behavior
      17. 23.3.2 Water Molecules
      18. 23.3.3 Film Disruption
      19. 23.3.3 Lubrication
      20. 23.4 Electrical Contact
      21. 23.4.1 Dependence of Electrical Resistance on Fiber Brush Construction
      22. 23.5 Brush Dynamics
      23. 23.5.1 Speed Effect
      24. 23.6 Future
      25. 23.7 Summary
      26. Acknowledgments
      27. References
  16. Part VI Contact Data
    1. 24. Useful Electric Contact Information
      1. 24.1 Introduction
      2. 24.2 Notes to the Tables
      3. References
  17. Author Index
  18. Subject Index