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Quick and practical skills of low-voltage electrician skills

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Electrician practical series of low-voltage electrical skills skills and practical skillsPublished time: 2016
Series items: Introduction to the practical series of electricians This book briefly introduces the basic structure and working principle of various low-voltage electrical equipment, focusing on the selection, installation, use, maintenance, common faults and troubleshooting methods of common low-voltage electrical equipment. The installation and maintenance of low-voltage overhead lines, indoor power distribution lines, and electrical lighting are introduced. The specific contents include the basic skills of low-voltage electricians, common low-voltage electrical appliances, common transformers, common motors, common control circuits for electric motors, low-voltage overhead lines, indoor power distribution lines, electrical lighting, and safe power consumption. This book is suitable for self-study of electricians with education level above junior high school. It can also be used as a reference for electrical technicians and electrical management personnel.
Chapter 1 Basic Skills of Low Voltage Electricians
1.1 The use of common electrical instruments 1
1.1.1 Use of ammeter 1
1.1.2 Use of voltmeter 2
1.1.3 Use of Analog Multimeter 4
1.1.4 Use of Digital Multimeter 6
1.1.5 Use of Clamp Ammeter 10
1.1.6 Use of Insulation Resistance Meters 13
1.2 Use of Common Electrician Tools 15
1.2.1 Use of Electrician Knife 15
1.2.2 Use of a screwdriver 17
1.2.3 Use of Wire Pliers 18
1.2.4 Use of Wire Strippers 18
1.2.5 Use of adjustable wrenches 19
1.2.6 Use of Electroscope
1.2.7 How to Use an Electric Soldering Iron 21
1.2.8 How to use crimping pliers 23
1.2.9 How to use the tensioner 24
1.2.10 How to use the pipe bender 25
Chapter 2 Common Low-Voltage Electrical Apparatus
2.1 Overview of low-voltage appliances 27
2.1.1 Characteristics and uses of low-voltage electrical appliances 27
2.1.2 Types of low-voltage electrical appliances 27
2.2 Selection and Maintenance of Common Low Voltage Electrical Appliances 28
2.2.1 Knife Switch 28
2.2.2 Open Load Switch 30
2.2.3 Enclosed Load Switch 32
2.2.4 Fuse
2.2.5 Circuit Breaker 37
2.2.6 AC contactor 41
2.2.7 Intermediate Relays 45
2.2.8 Time Relay 46
2.2.9 Thermal Relay 49
2.2.10 Control Buttons 51
2.2.11 Position switch 53
2.2.12 Combination switch 55
2.2.13 Earth leakage protection device 56
Chapter 3 Common Transformers and Transformers
3.1 Transformer Overview 61
3.1.1 Purpose of the Transformer
3.1.2 Working Principle of Transformer 61
3.1.3 The main types of transformers
3.1.4 Ratings of the Transformer 63
3.2 Oil-immersed power transformers 64
3.2.1 Structure of Oil-immersed Transformer 64
3.2.2 The role of the tap changer 64
3.2.3 The role of transformer oil 65
3.2.4 Selection of Transformer Capacity
3.2.5 Inspections before transformer operation 66
3.2.6 Inspection during transformer operation
3.2.7 Common faults of transformers and their troubleshooting methods 67
3.3 Dry-type power transformer 68
3.3.1 Main characteristics of dry-type transformers 68
3.3.2 Structure of Dry-type Transformer 69
3.3.3 Inspections before dry-type transformer operation 69
3.3.4 Inspection inspection during dry-type transformer operation
3.3.5 Common faults of dry-type transformers and their elimination methods
3.4 Voltage Transformer 71
3.4.1 Overview of voltage transformers 71
3.4.2 The main technical parameters of voltage transformers 72
3.4.3 Use and Maintenance of Voltage Transformers 73
3.5 Current Transformer 73
3.5.1 Overview of Current Transformers 73
3.5.2 Main technical parameters of current transformers 74
3.5.3 Use and Maintenance of Current Transformers 75
3.6 Arc Welding Transformer 75
3.6.1 Overview of Arc Welding Transformers 75
3.6.2 Main technical performance and parameters of arc welding transformers 77
3.6.3 Use and maintenance of arc welding transformers 77
3.6.4 Common faults of arc welding transformers and their troubleshooting methods
Chapter 4 Common Motors
4.1 Three-phase asynchronous motors 81
4.1.1 Uses and characteristics of three-phase asynchronous motors 81
4.1.2 Basic structure of three-phase asynchronous motors
4.1.3 Working principle of three-phase asynchronous motors 83
4.1.4 Method of changing the rotation direction of a three-phase asynchronous motor
4.1.5 Models of three-phase asynchronous motors 84
4.1.6 Three-phase asynchronous motor nameplate 85
4.1.7 Common wiring methods for three-phase asynchronous motors
4.1.8 Selection of Three-Phase Asynchronous Motors
4.1.9 Selection of the melt of a three-phase asynchronous motor
4.1.10 Use and maintenance of three-phase asynchronous motors
4.1.11 Common faults of three-phase asynchronous motors and their removal methods 93
4.2 Single-phase asynchronous motors 95
4.2.1 Uses of single-phase asynchronous motors 95
4.2.2 Basic structure of single-phase asynchronous motor
4.2.3 Working principle of single-phase asynchronous motors 96
4.2.4 Use and maintenance of single-phase asynchronous motors
4.2.5 Common faults of single-phase asynchronous motors and their removal methods
4.3 DC Motor 100
4.3.1 Use of DC Motors
4.3.2 Basic Structure of DC Motors
4.3.3 Working Principle of DC Motors
4.3.4 Excitation Methods of DC Motors
4.3.5 Use and Maintenance of DC Motors
4.3.6 Common faults of DC motors and their troubleshooting methods
Chapter 5 Motor Control Circuits
5.1 Overview
5.1.1 Classification of Electrical Control Circuits
5.1.2 Principles to be followed when drawing schematics 108
5.1.3 Principles to be followed when drawing wiring diagrams 109
5.1.4 Relevant regulations for drawing electrical schematics 109
5.1.5 Method steps for reading electrical schematics 110
5.1.6 General design methods of electrical control circuits
5.2 Basic Motor Control Circuits
5.2.1 One-way start and stop control circuit of three-phase asynchronous motor 113
5.2.2 Electric Interlocking Control Circuit of Motor 113
5.2.3 Interlock control circuit of two three-phase asynchronous motors 115
5.2.4 Forward and Reverse Control Circuit of Three-phase Asynchronous Motor with Button and Contactor Interlock 115
5.2.5 Motor jog and continuous operation control circuit using intermediate relay interlock 116
5.2.6 Multi-site Operation Control Circuit for Motors
5.2.7 Sequence Control Circuit for Multiple Motors
5.2.8 Stroke Control Circuit
5.2.9 Automatic Reciprocating Cycle Control Circuit 118
5.2.10 Automatic cycle control circuit without feed cutting
5.2.11 Control circuit for reversible operation of parallel-excitation DC motor 120
5.2.12 Reversible operation control circuit of series excited DC motor 121
5.3 Control Circuits of Common Electrical Equipment
5.3.1 Brake Control Circuit for Electromagnetic Brake of Hoisting Machinery 122
5.3.2 Construction site winch control circuit 122
5.3.3 Belt Conveyor Control Circuit 123
5.3.4 Concrete mixer control circuit 124
5.3.5 Automatic Water Supply Control Circuit 125
5.3.6 Oil pump motor control circuit for hydraulic press 127
5.3.7 Drain Pump Control Circuit 128
5.3.8 Towerless Booster Water Supply Circuit 130
5.3.9 Electric Hoist Control Circuit 131
Chapter 6 Low-voltage overhead lines
6.1 Overview of low-voltage overhead lines
6.1.1 Composition of low-voltage overhead lines
6.1.2 The role of various parts of low-voltage overhead lines
6.1.3 Basic requirements for low-voltage overhead lines 134
6.2 Pole 134
6.2.1 Types and Features of Pole 134
6.2.2 Buried Depth of Pole 136
6.3 Crossarms 136
6.3.1 Types and Characteristics of Cross Arms
6.3.2 Selection of Cross Arms
6.4 Insulators
6.4.1 Types of Insulators
6.4.2 Visual inspection of insulators
6.5 pull line 138
6.5.1 Types and Applications of Cable 138
6.5.2 The composition of the cable 139
6.5.3 Precautions for installing cable
6.6 Gold 140
6.7 Common overhead wires 141
6.7.1 Types of Common Overhead Wires
6.7.2 Selection of Common Overhead Wires
6.8 Construction of low-voltage overhead lines
6.8.1 Pole Positioning
6.8.2 Digging a Pit
6.8.3 Reinforcement of Pole Foundations
6.8.4 Assembling Electric Poles
6.8.5 Pole 145
6.8.6 Fabrication and Installation of Pull Lines 148
6.8.7 Pay-off, hanging and tight-line 149
6.8.8 Wire Connections
6.8.9 Method of Binding Wires to Insulators
6.8.10 Selection of Overhead Line Spacing and Wire Sag 154
6.8.11 Minimum distance requirements for overhead lines to ground and spans 155
6.9 Inspection and Maintenance of Overhead Lines
6.9.1 Inspection of overhead lines 156
6.9.2 Maintenance of Overhead Lines
6.10 Low-voltage household line and entry line 157
6.10.1 Low-voltage line entry method 157
6.10.2 Laying of low-voltage household line 157
6.10.3 Laying of Low-voltage Household Lines 159
Chapter 7 Indoor Power Distribution Lines
7.1 Overview of Indoor Power Distribution Lines
7.1.1 Types of Indoor Distribution Lines
7.1.2 Application of common indoor power distribution lines 161
7.1.3 Technical requirements for indoor power distribution lines 161
7.1.4 Construction steps for indoor wiring 162
7.2 Selection of Indoor Wires
7.2.1 Selection of Conductor Types
7.2.2 Selection of Conductor Cross-Section Area
7.3 Wire Connections
7.3.1 Basic requirements for wire joints 166
7.3.2 Connection method for single-core copper wire
7.3.3 Connection Methods for Multicore Copper Wires
7.3.4 Connection of single-core insulated conductors in the junction box
7.3.5 Connection of Multicore Insulated Conductor in Junction Box
7.3.6 Crimping of Aluminum Conductor 170
7.3.7 Connection of Multiple Stranded Aluminum Core Wires and Terminal Blocks
7.3.8 Wire and Terminal Connections
7.3.9 Wrapping of insulation tape after wire connection 172
7.4 Porcelain splint wiring 173
7.4.1 Types of Porcelain Splints
7.4.2 Methods and Precautions for Porcelain Plywood Wiring 173
7.5 Insulator Wiring
7.5.1 Types of Insulators
7.5.2 Insulator Fixing
7.5.3 Bundling of Conductors on Insulators
7.5.4 Insulator Wiring Methods and Precautions
7.6 Slot Board Wiring
7.6.1 Types of slot plates
7.6.2 Method of Slot Board Wiring
7.6.3 Specific requirements for slot board wiring 178
7.7 Plastic Sheathed Wire Wiring 179
7.7.1 Characteristics and Types of Plastic Sheathed Wire 179
7.7.2 Positioning and fixing of plastic sheathed wires 179
7.7.3 Laying of plastic sheathed wires 181
7.7.4 Methods and precautions for wiring of plastic sheathed wires 181
7.8 Conduit Wiring 182
7.8.1 Features and Types of Conduit Wiring
7.8.2 Conduit Selection
7.8.3 Method Steps for Wire Tube Processing 183
7.8.4 Conduit fixing
7.8.5 Threading the Cable 188
7.8.6 Cautions for Wiring Wiring
7.9 Wire Rope 189
7.9.1 General Requirements for Wire Rope 189
7.9.2 Installation of Steel Cable Hanger Wiring
7.9.3 Installation of Steel Sheath Plastic Sheath Wire Wiring
7.10 Common Faults in Lighting Circuits and Their Elimination Methods 192
Chapter 8 Electrical Lighting
8.1 Overview of Electrical Lighting
8.1.1 Classification of Electrical Lighting
8.1.2 Requirements for the quality of electrical lighting 195
8.1.3 Types of Common Electric Light Sources
8.2 Incandescent 196
8.2.1 Characteristics of incandescent lamps
8.2.2 Types of Common Lamp Holders for Incandescent Lamps
8.2.3 Installation and Use of Incandescent Lamps
8.3 Fluorescent Light 200
8.3.1 Features of Fluorescent Lights
8.3.2 Schematic diagram of the wiring of fluorescent lamps 201
8.3.3 Installation and use of fluorescent lamps 201
8.4 High-pressure mercury lamp 204
8.4.1 Characteristics of High Pressure Mercury Lamps
8.4.2 Installation and use of high-pressure mercury lamps 204
8.5 High pressure sodium lamp 205
8.5.1 Features of High Pressure Sodium Lamps 205
8.5.2 Installation and Use of High Pressure Sodium Lamps 206
8.6 Metal halide lamps 206
8.6.1 Characteristics of metal halide lamps 206
8.6.2 Installation and Use of Metal Halide Lamps
8.7 Tungsten Halogen Lamps 207
8.7.1 Characteristics of Tungsten Halogen Lamps
8.7.2 Installation and Use of Tungsten Halogen Lamps
8.8 LED lights 209
8.8.1 Understanding LED Lights 209
8.8.2 Installation and Use of LED Lights 210
8.8.3 Electrical Connections for LED Lights
8.9 Lighting 212
8.9.1 Classification of Common Lighting Fixtures
8.9.2 Basic requirements to be met for installing lighting fixtures 213
8.9.3 Arrangement of Lighting Fixtures
8.9.4 Installation of chandelier
8.9.5 Ceiling Light Installation 216
8.9.6 Installation of Wall Lights
8.9.7 Installation of Building Lanterns
8.9.8 Installation of Small Courtyard Poles
8.9.9 Precautions for conducting trial operation of building lighting 218
8.9.10 Installation of temporary lighting devices at the construction site 218
8.10 Switch Installation
8.10.1 Installation of Pull Switch 219
8.10.2 Installation of Dark Switch
8.11 Socket Installation 220
8.11.1 Technical requirements to be met by the installation socket 220
8.11.2 Socket Installation and Wiring
Chapter 9 Safe Electricity
9.1 Harm to the Human Body by Current 222
9.1.1 Forms of Current Harm to the Human Body 222
9.1.2 Hazard Analysis When Humans Get Shocked 223
9.2 Safe Current and Safe Voltage
9.2.1 Safe Current
9.2.2 Characteristics of Human Resistance 224
9.2.3 Safe Voltage 225
9.2.4 Precautions for Using Safe Voltage 225
9.3 Safe Power Consumption 226
9.3.1 Electricity Precautions
9.3.2 Hazards of Short Circuits
9.3.3 Measures to Prevent Damage to Insulating Materials
9.4 Types of Electric Shock and Measures to Prevent Electric Shock
9.4.1 Single-phase electric shock
9.4.2 Two-phase electric shock
9.4.3 Step Voltage Shock 228
9.4.4 Contact voltage and electric shock
9.4.5 Measures to Prevent Electric Shock
9.5 Electric shock first aid 229
9.5.1 Methods of Quickly Disconnecting Electric Shockers 229
9.5.2 Rescue for severe electric shock 230
9.6 Causes of Electrical Fires and Explosions
9.6.1 Characteristics of Fires and Explosions
9.6.2 Causes of Electrical Fires and Explosions 232
9.7 Measures to Prevent Electrical Fires
9.7.1 Electrical lines that should not use aluminum wires 232
9.7.2 Measures to Prevent Fires Caused by Short Circuits and Overloads
9.7.3 Measures to Prevent Fires Caused by Low-voltage Switches
9.7.4 Measures to Prevent Fire Caused by Power Switch and Socket 233
9.7.5 Measures to Prevent Fires Caused by Electric Motors
9.7.6 Measures to Prevent Fires Caused by Transformers
9.7.7 Measures to Prevent Electrical Fires During Thunderstorm Seasons
9.8 Treatment Methods and Fire Precautions in the event of an Electrical Fire 237
9.8.1 What to do if an electrical fire occurs 237
9.8.2 Fire fighting methods and precautions 238
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低压电工技能速成与实战技巧 Quick and practical skills of low voltage electrician skills

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