Audel Electrical Trades Pocket Manual

Answers at your fingertips

This hands-on guide will help you trouble-shoot and solve electrical problems in industrial and commercial settings. You'll find plain-English explanations for a wide range of electrical equipment and systems, from transformers and switchgears to alarm and wiring systems. Use this book to quickly access reliable information and improve your on-the-job skills.

• Get useful rules of thumb and quick tricks

• Discover formulas, charts, and tables essential for plant electrical work

• Locate technical data quickly and get up to speed on everyday electrical questions

• Packed with illustrations that help you grasp ideas quickly and easily

Introduction xiii

Disclaimer xv

Chapter 1 The Laws That Control and Explain Electricity 1

Power Factor 3

Three-Phase Power 6

Circuit Protective Devices 9

Chapter 2 Power Generation and Distribution Within Commercial and Industrial Facilities 11

Electrical Power Generators 17

Total Loads Served 17

Types of Onsite Power Generation 18

Chapter 3 Power, Control, and Lighting Transformer 21

Electrical Power 24

Insulation Material Temperature Rise 25

Grounding 26

Terminal Connection Markings 26

Three-Phase, Oil–Cooled Power Transformers 26

Three-Phase Dry-Type Transformers 28

Dry-Type Single-Phase Control Circuit Transformers 29

Chapter 4 Electrical Switchgear 31

Motor Control Center 31

Primary Functions of Switchgear 32

Low-Voltage Power Distribution 33

Bus Bar and Circuit Breaker Arrangements 34

Optional Protective Devices 37

Metal-Clad Switchgear 38

Continuous Current Ratings 38

Arc-Resistant Switchgear 39

Chapter 5 Electrical Circuit Protective Devices 41

Molded Case Circuit Breakers 43

Miniature Circuit Breakers 45

Vacuum Circuit Breakers 45

Insulated Case Circuit Breakers 47

Low-voltage Power Circuit Breakers 47

Supplemental Protectors 47

Motor Circuit Protectors 47

Oil Circuit Breakers 48

Gas Insulated Circuit Breakers 48

Fuses 48

Circuit Breaker Maintenance 50

Coordination Between

Protective Devices 51

Chapter 6 Personnel Protective Devices 53

Introduction 53

Ground Fault Protection of Equipment 56

History and Nomenclature of GFCIs in the United States 56

Troubleshooting GFCIs 57

Time and Current Levels Protected by Circuit Breakers 58

Arc Fault Circuit Interrupters 59

Chapter 7 Three-Phase Motors 61

Electric Motor Principles of Operation 62

Rated Full Load Speed 66

Service Factor 67

Rated Ambient Temperature 67

Stator Winding Insulation Classes 68

Types of Torque Produced by a Motor 68

Chapter 8 Controlling and Protecting Three-Phase Motors 71

Components of a Motor Starter 71

Motor Starter Sizes 72

Methods of Starting Three-Phase Induction Motors 73

Full Voltage, Across the Line Motor Starters 73

How a Motor Starter Operates 73

Three-Wire Control Circuit Controlling a Three-Phase Motor Starter 76

Sizing of Overload Heater Elements 77

Chapter 9 Variable Frequency Drives 79

Four-Quadrant Operation 80

Torque 80

Parts of a Drive 82

Pulse Width Modulation 84

Six-Step Method of Drive Control 84

Programming Drives 85

Chapter 10 Programmable Logic Controllers 89

Black Box Concept 89

PLC Sizes 92

PLC Construction 92

Types of Inputs and Outputs 92

Timers 95

Counters 96

Benefits of Using PLCs 96

I/Os and Memory Adresses 97

Chapter 11 Electrical Services 99

Metering Equipment 101

Grounding of Electrical Systems 101

Bonding versus Grounding 103

Fault Current Path, Conduits, and Locknuts 103

Low and High Impedance Grounded Systems 104

Ungrounded Electrical Systems 104

Second Ground Fault 106

Separation of the Grounded

System Conductor (Neutral) and the Equipment Grounding Conductor 106

What Conductors Must Be Grounded 107

Separately Derived Systems 108

Standard Voltages 108

Chapter 12 Electrical Light Fixtures 111

Aplications for Light Fixtures 112

Design of Lighting Systems 112

Major Types of Lamps Used in Commercial and Industrial Facilities 113

Light Fixture Performance 113

Pattern of Illuminance 114

Types of Glare 116

Illuminating Engineers Society 116

Lamp Selection Parameters 116

Light Fixture Operating Controls 117

Photocells 117

Incandescent Lamps 117

Gas Discharge Lamps 118

Fluorescent Lamps 119

Fluorescent Ballast 119

High-Intensity Discharge Lamps 120

Mercury Vapor Lamps 120

Metal Halide Lamps 120

High-Pressure Sodium Lamps 121

Types of HID Ballasts 121

What Ballasts Do 121

Ballast Voltage Ratings 122

Ballast Wiring Diagrams 122

Chapter 13 Electrical Timers 123

Sections of a Timer 123

Five Common Modes, or Functions,of Timers 125

Nine Types of Timer Operating Principles 126

Timing Chart Levels 129

Complete Timing Charts 133

Chapter 14 Electrical Diagrams 135

Electrical Ladder Diagrams 135

Elements in Electrical Circuits 135

One-Line Diagrams 142

Chapter 15 Electrical Test Instruments 145

Words Used with Meters 145

Multimeters 146

Auto Ranging Meters 147

Three-Step Method 148

Auto Function Features 148

Ohmmeters 149

Meg-Ohmmeter 151

Clamp-On Amp Meters 151

Chapter 16 Electrical Troubleshooting 153

Introduction to Troubleshooting 153

Not Where It Is, but Where It Was Lost 154

Safety First 155

What Tools Are Needed 156

Cause verses Efect 158

A Six-Step Method 158

Chapter 17 Acess, Fire, and Burglar Alarm Systems 163

Facilities Access Control 163

Fire Alarm Systems 164

Alarm Signals 165

System Monitoring 166

Human Machine Interfaces 167

Notification Circuit Voltage Drop 169

Mass Notification Systems 169

Conductors for Fire Alarm Systems 170

Chapter 18 Computer Voice and Data Wiring Systems 171

Introduction 171

Hot Swapping Computer Signal Cables 171

Connecting a Desktop Computer as an Island 172

Connecting a Desktop Computer to a Wired Network 183

Connecting a Desktop Computer to a Wireless Network 184

Types of Computer Networks 186

Telephone Voice Communications Systems Wiring 187

Chapter 19 Reference Material 189

Amperage-Current 189

Capacitance Formulas 192

Conductor Cross-Sectional Area in Circular Mils (CMIL) 193

Direct Current Formulas 193

Fuse Opening Time 196

Heat Produced in a Conductor per Watt 197

Impedance Formulas 197

Impedance of a Conductor in a Conduit 198

kW to Amps 199

kVA to Amps 199

Motor Formulas for Three-Phase AC Motors 199

Motor Formulas 201

Transformer Formulas 213

Requirements of the Driven Load 235

Three Phase Motor Reference Material 343

Index 353

L. W. BRITTIAN is a licensed electrician with extensive experience in heavy industry such as refineries, petrochemical plants, and oil and gas production. He has authored numerous training materials for the electrical trades, taught at Texas A&M University and Texas State Technical College, and presented electrical training classes in Africa, Canada, Malaysia, and the United States.