Cover image for Electrical fires and failures : a prevention and troubleshooting guide
Title:
Electrical fires and failures : a prevention and troubleshooting guide
Author:
Hattangadi, A. A.
Personal Author:
Publication Information:
New York McGraw-Hill, [2000]

©2000
Physical Description:
xviii, 281 pages : illustrations ; 24 cm
General Note:
Includes index.
Language:
English
ISBN:
9780071356510
Format :
Book

Available:*

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Call Number
Material Type
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Status
Central Library TH9445.E43 H38 2000 Adult Non-Fiction Non-Fiction Area
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Summary

Summary

Electrical Fires and Failures: A Prevention and Troubleshooting Guide is must reading for electrical supervisors, engineers and managers. Author A.A. Hattangadi shows you how improvements in specification and design...manufacture and installation...and operation and maintenance of minor components, can prevent failures and fires, while reducing capital and maintenance costs. He introduces the concept of "seed-defect, " basic flaws that can be identified and eliminated to achieve zero-failureperformance. You'll explore...*Failures of transformers, connectors and terminals*Fractures and overheating/burning of crimped sockets*Failures of wire strands, terminal boards, connector cable insulation and welded brazed and soldered joints*Metal fatigue and creep*Electrical contact resistance and shrinkage of non-metallic materials*Thermal degradation of insulating materials*Electrical tracking*And more.


Table of Contents

Forewordp. xiii
Prefacep. xv
1. Introductionp. 1
1.1 The Crying Need for a Book on Electrical Firesp. 2
1.2 Cure, Not Prevention, Gets Priority Todayp. 3
1.3 The Approach and the Direction of This Bookp. 5
1.4 Recurring Themes in This Bookp. 8
1.5 Significance of Connector and Terminal Failuresp. 10
1.6 Reasons for Failures of Electrical Equipmentp. 11
1.7 Methods for Preventing Failuresp. 13
1.8 Investigation of Electrical Fires and Failuresp. 13
1.9 Management Has a Vital Role to Playp. 14
1.10 The Plan of This Bookp. 16
1.11 Aspects Not Covered in This Bookp. 16
1.12 Summary of the Main Points in This Chapterp. 17
2. Terminologyp. 19
2.1 Introductionp. 19
2.2 Electrical Firep. 21
2.3 Failurep. 21
2.4 Defectp. 22
2.5 Seed-Defectsp. 23
2.6 Difference Between Defects and Seed-Defectsp. 24
2.7 Modes and Mechanisms of Failurep. 25
2.8 Failure Ratesp. 27
2.9 Inter-Relationships Between Termsp. 29
2.10 Metal Fatiguep. 29
2.11 Elasticity of Metalsp. 30
2.12 Metal Creepp. 30
2.13 Stress and Strainp. 31
2.14 Elastic Limitp. 33
2.15 Endurance Limitp. 33
2.16 Insulation Resistance and Dielectric Strengthp. 34
3. Electrical Firesp. 35
3.1 Introductionp. 35
3.2 Scope of This Chapterp. 38
3.3 Causes of Electrical Firesp. 41
3.4 Fires Due to Failure of Insulationp. 45
3.5 Types and Causes of Insulation Failuresp. 46
3.6 The Indian Electricity Act and Rulesp. 48
3.7 Importance of Protective Systemsp. 49
3.8 Protective Systems--Fusesp. 53
3.9 Protective Systems--Circuit Breakersp. 54
3.10 Prevention of Failures of Protective Systemsp. 54
3.11 Fires Due to Failures of Pressure Contacts and Fractures of Conductorsp. 55
3.12 Fire Prevention Measuresp. 57
3.13 Conclusionp. 58
3.14 Do's And Don'ts for Preventing Electrical Firesp. 59
4. Transformer Failuresp. 61
4.1 Introductionp. 61
4.2 Are Transformer Failures Due to Overloading?p. 64
4.3 Failure Modes of Power Transformersp. 66
4.4 Failures Due to Defects in Internal Connections and Terminalsp. 68
4.5 Failures Due to Interturn Shorts in Windingsp. 70
4.6 Failure of the Insulation Between Winding and the Tankp. 77
4.7 Other Failure Modesp. 78
4.8 Investigation of Transformer Failuresp. 82
4.9 Procurement of New Transformersp. 82
4.10 Do's and Don'ts for Investigating Transformer Failuresp. 83
4.11 Do's and Don'ts for Preventing Transformer Failuresp. 83
5. Failures of Electrical Connectors and Terminalsp. 85
5.1 Introductionp. 85
5.2 Typical Electrical Connectorsp. 86
5.3 Apparent Triviality of Connectors and Their Defectsp. 89
5.4 Effects of Failures of Electrical Connectorsp. 92
5.5 Criticality of Failures of Electrical Connectorsp. 93
5.6 Preventive Measuresp. 93
5.7 True or Root Causes of Connector Failuresp. 94
5.8 The Importance of Contact Forcep. 95
5.9 Contact Force Developed By Screws or Nuts/Boltsp. 95
5.10 Contact Force Developed by Springsp. 96
5.11 Modes and Mechanisms of Electrical Connector Failuresp. 96
5.12 Failures Due to Major Design Defectsp. 98
5.13 Failures Due to Overheatingp. 99
5.14 Do's and Don'ts for Preventing Failures of Electrical Connectors and Terminal Boardsp. 102
5.15 Conclusionp. 102
6. Overheating/Burning of Crimped Socketsp. 104
6.1 Introductionp. 104
6.2 The Socket System of Terminating Cablesp. 106
6.3 Tin Soldered Sockets or Lugsp. 106
6.4 Modes and Mechanisms of Socket Failuresp. 111
6.5 Measures for Preventing Overheating/Burning of Socketsp. 115
6.6 Overheating Due to Terminal Board Failuresp. 119
6.7 Wire Working Out of Socketp. 119
6.8 Do's and Don'ts for Preventing Overheating and Burning of Socketsp. 120
6.9 Conclusionp. 121
7. Failures of Plug/Socket Connectorsp. 122
7.1 Introductionp. 122
7.2 Specification for Plugs/Socketsp. 125
7.3 Importance of the Contact Forcep. 127
7.4 Three-pin Plugs/Sockets in Domestic and General Usep. 128
7.5 Industrial Multicore Couplersp. 131
7.6 Failure Modesp. 132
7.7 Overheating of Pin/Socketp. 133
7.8 Insulation Failures Between Adjacent Pins/Socketsp. 135
7.9 Open Circuitsp. 135
7.10 Multicore Connectors in Electronic Devicesp. 136
7.11 Open Circuits Due to External Forcesp. 136
7.12 Precautions During Installation of Multicore Cablesp. 137
7.13 Summaryp. 137
7.14 Do's and Don'ts for Preventing Failures of Multicore Couplersp. 138
8. Fractures of Crimped Socketsp. 139
8.1 Introductionp. 139
8.2 Fractures of Crimped Sockets Due to Material Defectsp. 140
8.3 Fractures Due to Sharp Bends and Stress Raisersp. 142
8.4 Fractures Due to Cracks Formed by Defective Crimpp. 144
8.5 Fractures Due to Excessive Vibrationp. 144
8.6 Fractures of Sockets Due to Thermal Stressesp. 146
8.7 Investigation of Fractures of Crimped Socketsp. 147
8.8 Do's and Don'ts for Preventing Fractures of Socketsp. 148
8.9 Conclusionp. 149
9. Failures of Wire Strandsp. 150
9.1 Introductionp. 149
9.2 Causes Common to Socket Fractures and Wire Strand Fracturesp. 151
9.3 Heat Shrinkable Sleevesp. 152
9.4 Strand Fractures Due to Sharp Edges on Socket Barrelp. 154
9.5 Strand Fractures Inside Insulating Sleevesp. 156
9.6 Do's and Don'ts for Preventing Strand Fracturesp. 157
9.7 Conclusionp. 157
10. Failure of Insulation on Connector Cablesp. 159
10.1 Introductionp. 159
10.2 Insulation Failures Due to Mechanical Damagep. 161
10.3 Insulation Failures Due to Thermal Damagep. 165
10.4 Insulation Failures Due to Chemical Damagep. 167
10.5 Insulation Failures Due to Electrical Damagep. 167
10.6 Remedial Measures Against Damage to Insulationp. 168
10.7 Do's and Don'ts for Preventing Cable Insulation Failuresp. 168
10.8 Conclusionp. 169
11. Failures of Terminal Boardsp. 170
11.1 Introductionp. 170
11.2 Failure Due to Inadequate Size of Terminalsp. 172
11.3 Failure Due to Inadequate Tightening of Threaded Fastenersp. 172
11.4 Failures Due to Shrinkage of Terminal Boardsp. 175
11.5 Design for Reliabilityp. 178
11.6 Importance of Contact Forcep. 180
11.7 Spring Washersp. 182
11.8 Terminal Board Failures Due to Trackingp. 183
11.9 Failures of Terminal Boards Due to Metal Creepp. 183
11.10 Do's and Don'ts for Preventing Terminal Board Failuresp. 184
11.11 Conclusionp. 185
12. Failures of Welded, Brazed and Soldered Jointsp. 186
12.1 Introductionp. 186
12.2 Butt Welded Jointsp. 188
12.3 Tig Welded Jointsp. 190
12.4 Brazed Jointsp. 191
12.5 Soldered Jointsp. 194
12.6 Do's and Don'ts for Welding, Brazing and Solderingp. 195
12.7 Conclusionp. 196
13. Metal Fatiguep. 198
13.1 Introductionp. 198
13.2 Tensile Stressp. 199
13.3 Stress Concentration Factor (SCF)p. 201
13.4 Fractures Due to Metal Fatiguep. 204
13.5 Alternating and Fluctuating Stressesp. 206
13.6 The Nature of Metal Fatiguep. 207
13.7 Causes of Fatigue Failuresp. 208
13.8 Appearance of Fatigue Fracturesp. 209
13.9 Do's and Don'ts for Preventing Fatigue Fracturesp. 210
13.10 Conclusionp. 210
14. Metal Creepp. 212
14.1 Introductionp. 212
14.2 Effects of Metal Creep on Electrical Contactsp. 214
14.3 Failures of Electrical Connections Due to Creepp. 217
14.4 Prevention of Failures Due to Metal Creepp. 220
14.5 Failures of Parallel Clampsp. 221
14.6 Do's and Don'ts for Preventing Failures Due to Metal Creepp. 222
14.7 Conclusionp. 223
15. Electrical Contact Resistancep. 224
15.1 Introductionp. 224
15.2 Importance of Electrical Contact Resistancep. 225
15.3 Factors Which Influence Electrical Contact Resistancep. 225
15.4 Contact Theory in Briefp. 229
15.5 Do's and Don'ts for Preventing Contact Failuresp. 231
15.6 Conclusionp. 232
16. Shrinkage of Non-Metallic Materialsp. 233
16.1 Introductionp. 233
16.2 Defective Design of Terminalsp. 234
16.3 Correct Design of Terminalsp. 236
16.4 Shrinkage of Insulation in Transformer Coilsp. 238
16.5 Slackening of Insulated Boltsp. 239
16.6 Field Coil Failures Due to Shrinkage of Insulationp. 240
16.7 Do's and Don'ts for Preventing Failures Due to Shrinkage of Insulating Materialsp. 240
16.8 Conclusionp. 241
17. Thermal Degradation of Insulating Materialsp. 242
17.1 Introductionp. 242
17.2 Characteristics of Thermal Degradationp. 243
17.3 Insulation Failures in Electrical Connectorsp. 245
17.4 Do's and Don'ts for Preventing Thermal Degradation of Insulationp. 245
17.5 Conclusionp. 246
18. Electrical Trackingp. 247
18.1 Introductionp. 247
18.2 Tracking Failures on Terminal Boardsp. 249
18.3 Testing of Materials for Tracking Propertiesp. 249
18.4 Prevention of Tracking Failuresp. 250
18.5 Do's and Don'ts for Preventing Failures Due to Trackingp. 251
18.6 Conclusionp. 252
19. Investigation of Failures and Firesp. 253
19.1 Introductionp. 253
19.2 Fixing Priorities for Investigationp. 254
19.3 Process of Investigationp. 256
19.4 Failure Investigation: Step-by-step Approachp. 256
19.5 Review of Failure Statisticsp. 259
19.6 Investigation of Electrical Firesp. 259
19.7 Action Planp. 261
19.8 Conclusionp. 262
Appendix 1p. 263
Fires Involving Electrical Equipment But not Classified as Electrical Firesp. 263
Appendix 2p. 265
Technical Measures for Preventing Electrical Fires and Minimizing the Damagesp. 265
Selected Readings and Termsp. 268
Indexp. 271

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