Audel Electrical Course for Apprentices and Journeymen

Paul Rosenberg is a master electrician with extensive experience in all aspects of the industry. An instructor at Iowa State University, he has written for all the major electrical industry publications. He is also the author of Audel Questions and Answers for Electrician's Examinations, 14th Edition.

Introduction xiii

Chapter 1 Electricity and Matter 1

Elements, Atoms, Molecules, and Compounds 1

Electron Theory 3

Electric Current 9

Insulators and Conductors 11

Questions 12

Chapter 2 Units and Definitions 13

Fundamental and Derived Units 13

Definitions 15

Magnetic Units 17

Temperature Units 18

Questions 18

Chapter 3 Electrical Symbols 21

Graphic Electrical Wiring Symbols 21

0.1 Drafting Practices Applicable to Graphic Electrical Wiring Symbols 21

0.2 Explanation Supplementing the Schedule of Symbols 23

List of Symbols 27

1.0 Lighting Outlets 27

2.0 Receptacle Outlets 28

3.0 Switch Outlets 31

4.0 Signaling System Outlets: Institutional, Commercial, and Industrial Occupancies 31

5.0 Signaling System Outlets: Residential Occupancies 36

6.0 Panelboards, Switchboards, and Related Equipment 37

7.0 Bus Ducts and Wireways 38

8.0 Remote Control Stations for Motors or Other Equipment* 39

9.0 Circuiting 39

10.0 Electric Distribution or Lighting System, Underground 40

11.0 Electric Distribution or Lighting System Aerial 41

Arrester, Lightning Arrester (Electric Surge, etc.) Gap 42

Battery 43

Circuit Breakers 43

Circuit Return 45

Coil, Magnetic Blowout* 45

Contact, Electrical 46

Contactor 48

Machine, Rotating 49

Meter Instrument 53

Path, Transmission, Conductor, Cable Wiring 55

Polarity Symbol 56

Switch 57

Transformer 58

Chapter 4 Magnets and Magnetic Fields 63

Magnetic Poles 63

Magnetic and Nonmagnetic Substances 64

The Earth as Magnet 64

Magnetic Lines of Force 65

Molecular Theory of Magnetism 66

Strength of a Magnet 68

Lifting Power of a Magnet 68

Questions 69

Chapter 5 Ohm’s Law 71

Statement of Ohm’s Law 71

Analogy of Ohm’s Law 71

Illustrations of Ohm’s Law 72

Ohm’s Law and Power 74

The Ohm’s Law Circle 74

Formulas 75

Ohm’s Law 75

Power in Watts 75

Questions 76

Chapter 6 Capacitors 77

Capacitance 83

Capacitance in Series and Parallel 84

Capacitance in Other Than Regular Capacitors 86

Formulas 87

Questions 87

Chapter 7 Resistance 89

Skin Effect 97

Conductivity 97

Voltage-Drop Calculation 99

Measuring Conductors 100

Questions 101

Chapter 8 Resistance in Series and Parallel 103

Resistances in Series 103

Resistances in Parallel 104

Series-Parallel Circuits 107

Questions 109

Chapter 9 Electrolysis 111

Terminology 111

Chemistry of Electrolysis 112

Electroplating 114

Corrosion 114

Questions 116

Chapter 10 Primary and Secondary Cells 117

The Voltaic Cell 117

Primary Cells 119

Secondary Cells 122

Questions 127

Chapter 11 Electromagnetism 129

Galvanoscope 134

Solenoids 135

Questions 136

Chapter 12 Laws Governing Magnetic Circuits 139

Strength of a Magnetic Pole 141

Intensity of Magnetizing Force 142

Magnetic Reluctance 142

Formulas 149

Questions 149

Chapter 13 Work, Power, Energy, Torque, and Efficiency 151

Torque 155

Prony Brake 156

Formulas 158

Questions 158

Chapter 14 Instruments and Measurements 161

Voltmeters and Ammeters 163

Edison Pendulum Ammeter 163

Battery Gauge 164

Indicating Wattmeter 165

Ohmmeters 168

Thermostats 169

Thermocouples 169

Questions 170

Chapter 15 Insulation Testing 171

Test Voltages vs. Equipment Ratings 172

Cables and Conductors 174

Conductors in Parallel 181

Effect of Temperature on Insulation Resistance* 185

Questions 185

Chapter 16 Electromagnetic Induction 187

Basic Principles 187

Lenz's Law 188

Fleming's Rule 192

Mutual Induction 192

Eddy Currents 194

Questions 195

Chapter 17 Alternating Currents 197

Advantages of AC 197

Generation of AC 197

AC Sine Wave 201

Paralleling Alternators 203

Formulas 204

Questions 204

Chapter 18 DC Generators 207

Generators vs. Alternators 207

Generation of EMF 207

Armatures 208

Brushes 211

Types of Generators 212

Generator Voltage Control 214

Questions 214

Chapter 19 DC Motors 215

Armature Movement 215

DC Motors vs. DC Generators 215

Regulation of DC Motors 216

Starting the DC Motor 220

Reversing Motor Direction 220

Questions 221

Chapter 20 Inductance and Reactance 223

Inductance 223

Inductive Reactance 223

Impedance 224

Effects of Circuit Inductance 225

Phase Angle 226

True Power and Power Factor 229

Worked Examples 230

Formulas 232

Questions 233

Chapter 21 Capacitance in AC Circuits 235

Analogy of Capacitor Action 235

Capacitor Action 236

Capacitance 236

Current and Voltage Relations 237

Capacitive Reactance 238

Inductive and Capacitive Circuits 238

Formulas 241

Questions 241

Chapter 22 Resistance, Capacitance, and Inductance in Series and Parallel 243

RC Circuit 243

RLC Circuit 244

Parallel LC Circuit 248

Resonance 249

System Power Factor 251

Formulas 253

Questions 253

Chapter 23 Polyphase Circuits 255

Multiphase Systems 255

Two-Phase Systems 255

Three-Phase Systems 257

Questions 261

Chapter 24 Power in Polyphase Circuits 263

Three-Phase Wye Connection 264

Three-Phase Delta Connection 266

Economy and Phases 268

Neutral Current in Three-Phase, Four-Wire Systems 269

Formulas 273

Questions 274

Chapter 25 Transformer Principles 277

Induction Coil 277

Transformer Types 279

Principles of Operation 280

Windings and Voltages 281

Formulas 284

Questions 284

Chapter 26 Transformer Facts 285

Transformer Impedance 287

Transformers in Parallel 289

Transformer Insulation 289

Types of Transformers 290

Effects of Altitudes 290

Ambient Temperature 290

Transformer Polarity 291

Termination Marking 292

Formulas 293

Questions 294

Chapter 27 Transforming Polyphase Power 295

Single-Phase for Three-Phase 295

Three-Phase Transformers 297

Two-Phase to Three-Phase Conversion 299

Delta- and Wye-Connection Voltages and Currents 301

Questions 302

Chapter 28 Autotransformers 303

Autotransformers and Conventional Transformers 303

Induction Voltage Regulator 304

Transformer Booster 305

Questions 306

Chapter 29 Instrument Transformers 307

Use of Instrument Transformers 307

Types of Instrument Transformers 307

Potential Transformers 308

Current Transformers 309

Ratings 309

Opening the Secondary Circuit 309

Symbols 310

Ground Fault Protection 310

Questions 312

Chapter 30 Polyphase Induction Motors 313

Rotating Magnetic Field 313

Squirrel Cage Rotor Winding 316

Wound Rotors 320

Dual Voltages 320

Induction Motors on Start 324

Altitude Correction 326

Power Factor 326

Questions 328

Chapter 31 Power-Factor Correction 329

Reactive Kilovolt-Amperes 329

Use of Correction Table 329

Correction with Capacitors 331

Use of Chart 331

Use of Mathematics 332

Overloads 335

Reasons for Corrections 335

Questions 336

Chapter 32 Synchronous Motors 337

Characteristics 337

Operation 337

Power Factor 339

Regulation 340

Questions 342

Chapter 33 Single-Phase Motors 343

Phase Splitting 343

Shading-Coil Motors 344

Universal Motors 345

Hysteresis Motors 345

Split-Phase Induction Motor 345

Capacitor-Start Motors 347

Capacitor-Start, Capacitor-Run Motor 347

Repulsion Motors 348

Repulsion-Induction Motors 350

Questions 351

Chapter 34 Grounding and Ground Testing 353

Grounding Requirements 353

Conduction in Soil 354

Grounding Electrode 356

Fall-of-Potential Method 356

System Grounding 362

Questions 366

Chapter 35 Rectifiers 367

Mercury-Arc Rectifier 367

Dry-Contact Rectifiers 368

Solid-State Rectifiers 370

Rectifier Connections 371

Questions 373

Chapter 36 Number of Bends in Conduit 375

Chapter 37 Torque Test for Bolts and Screws 381

Appendix 383

Index 391