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Energy-saving Principles and Technologies for Induction Motors

Energy-saving Principles and Technologies for Induction Motors

Wenzhong Ma, Lianping Bai

ISBN: 978-1-118-98106-1

Nov 2017

224 pages

$108.99

Description

A unique guide to the integration of three-phase induction motors with the emphasis on conserving energy

• The energy-saving principle and technology for induction motor is a new topic, and there are few books currently available; this book provides a guide to the technology and aims to bringabout significant advancement in research, and play an important role in improving the level of motor energy saving
• Includes new and innovative topics such as a case study of energy saving in beam pumping system, and reactive compensation as a means of energy saving
• The authors have worked in this area for 20 years and this book is the result of their accumulated research and expertise. It is unique in its integration of three-phase induction motors with the emphasis on conserving energy
• Integrates the saving-energy principle, technology, and method of induction motors with on-site     experiences, showing readers how to meet the practical needs and to apply the theory into practice. It also provides case studies and analysis which can help solve problems on-site

About the Authors xiii

Preface xv

About the Book xvii

1 Introduction 1

1.1 The Energy]saving Status of an Electric Motor System 1

1.1.1 Basic Situation of an Electric Motor System in China 1

1.1.2 The Main Contents of Energy Saving for Electric Motors in China 2

1.1.3 Status of Energy Saving for Electric Motors in China and Abroad 2

1.2 Main Development Ways of Energy Saving for Electric Motor System 4

1.2.1 Efficiency Improvement of Y Series Asynchronous Motor 4

1.2.2 Promoting Frequency Speed Regulation Technology 5

1.2.3 Promoting High]Efficiency Motors and Permanent Magnet Motors 5

1.3 Energy Saving: The Basic National Policy of China 6

1.4 Main Contents of This Book 8

2 Overview of Three]Phase Asynchronous Motors 11

2.1 Basic Structure and Characteristics of Three]Phase Asynchronous Motors 11

2.1.1 Basic Characteristics of Three]Phase Asynchronous Motors 11

2.1.2 Basic Types of Three]Phase Asynchronous Motors 12

2.1.3 Basic Structure of Three]Phase Asynchronous Motors 12

2.1.4 Basic Parameters of Three]Phase Asynchronous Motors 16

2.2 The Principle of a Three]Phase Asynchronous Motor 17

2.3 Working Characteristic of Three]Phase Asynchronous Motors 21

2.3.1 Equivalent Circuit of Asynchronous Motors 22

2.3.2 Power Balance of Asynchronous Motors 23

2.3.3 Working Characteristics of Three]Phase Asynchronous Motors 25

2.4 Mechanical Characteristics of Three]Phase Asynchronous Motors 27

2.4.1 Three Types of Formulas of Mechanical Characteristics 27

2.4.2 Inherent Mechanical Characteristic of Asynchronous Motors 31

2.4.3 Man]Made Mechanical Characteristic of Asynchronous Motors 32

2.5 Start]up of Three]Phase Asynchronous Motors 35

2.5.1 Starting Requirements of Three]Phase Asynchronous Motors 35

2.5.2 Conditions for Squirrel Cage Asynchronous Motors Starting Directly 36

2.6 Energy Efficiency Standards of Three]Phase Asynchronous Motors 37

2.6.1 Energy Efficiency Standards of IEC Three]Phase Asynchronous Motors 38

2.6.2 Energy Efficiency Standards of Three]Phase Asynchronous Motors in the United States and EU 40

2.6.3 Energy Efficiency Standards of Three]Phase Asynchronous Motors in China 40

2.7 Mainstream Products of Three]Phase Asynchronous Motors 45

2.7.1 Brief Introduction of Existing Products of Three]Phase Asynchronous Motors 45

2.7.2 Characteristics of Main Series of Three Phase Asynchronous Motors 46

2.7.3 Main Technical Data of Y2 Series Three]Phase Asynchronous Motors 46

2.8 Main Subseries Three]Phase Asynchronous Motors in China 47

2.9 Discussion Topics in the Chapter 55

3 Economic Operation of the Three]Phase Induction Motor 57

3.1 Loss Analysis of the Three]Phase Induction Motor 57

3.1.1 The Analysis of Iron Loss 57

3.1.2 The Analysis of Mechanical Loss 58

3.1.3 Stator and Rotor Copper Loss Analysis 59

3.1.4 The Analysis of Stray Loss 59

3.1.5 The Power Grid Quality’s Impact on the Loss 60

3.2 Efficiency and Power Factor of the Three]Phase Asynchronous Motor 62

3.2.1 The Definition of Induction Motor’s Efficiency and Power Factor 62

3.2.2 The Calculation of Efficiency and Power Factor of Induction Motors 63

3.2.3 The Efficiency and Power Factor Curve of the Induct Motor 65

3.3 Economic Operation of the Three]Phase Induction Motor 67

3.3.1 The Terms and Definitions of Economic Operation for the Three]Phase Induction Motor 68

3.3.2 Basic Requirements for Economical Operation of the Three]Phase Induction Motor 69

3.3.3 Calculation of Three]Phase Induction Motor Comprehensive Efficiency 69

3.3.4 Judgment of Economic Operation 71

3.3.5 The Examples of Economic Operational Analysis 72

3.4 Calculation Methods for Energy Saving of the Three]Phase Induction Motor 75

3.4.1 Using Power to Calculate Energy]saving Amount 75

3.4.2 Comprehensive Efficiency Is Used to Calculate Power]Saving Rate 78

3.4.3 Using Accumulated Power to Calculate Power]Saving Rate 78

3.5 Comparison and Evaluation Method of Motor Energy]saving Effect 79

3.5.1 Unqualified Old Motor as Reference 79

3.5.2 Qualified Old Motor as Reference 79

3.5.3 In Accordance with the National Standard of Motor as Reference 79

3.6 Discussion Topics of the Chapter 80

4 The Energy]saving Principle and Method of the Motor Power and Load Match 81

4.1 Discussion on the “Lighter Load” 81

4.1.1 Boundary of the “Lighter Load” 81

4.1.2 Analysis of the Lighter Load Loss 83

4.2 Energy]saving Principle of Power Matching 84

4.2.1 The Power Matching Principle of Energy Conservation 84

4.2.2 Motor Selection Steps 87

4.2.3 The Selection of the Motor Rated Power 88

4.3 Double Power Induction Motors and Energy]saving Principle 92

4.3.1 Double]Power Induction Motors 92

4.3.2 Energy]saving Principle of the Double]Power Motors 93

4.3.3 Analysis of the Energy]saving Effect of Winding in Series 94

4.3.4 The Control Method of the Dual]Power Series Winding Motor 98

4.4 The Energy]saving Method of the Y]Δ Conversion 99

4.4.1 The Power Relations of Y]Δ 99

4.4.2 The Energy]saving Effect of Y]Δ Conversion 100

4.4.3 The Y]Δ Conversion Control Circuit 102

4.5 The Energy]saving Method of Extended Δ Winding Switching 104

4.5.1 The Design Principle of the Extended Δ Winding 104

4.5.2 The Switching Control Circuit for the Extended Δ 105

4.5.3 The Comparison of Dual]Power Motor 106

4.6 Discussion Topics in the Chapter 106

5 Energy]saving Principle and Methods of Speed Matching 109

5.1 Energy]saving Principle of Speed Matching 109

5.1.1 Basic Parameters of the Pump 109

5.1.2 Energy Analysis of Water Supply System 111

5.1.3 Efficiency Analysis of Speed Control Water Supply System 115

5.1.4 Comparison of Various Motor Speed Control Methods 116

5.2 Energy]saving Theoretical Analysis of Pump Speed Control 118

5.2.1 Characteristic Curve of Pipe Network 118

5.2.2 Pump Characteristic Curve 119

5.2.3 Theoretical Analysis of Pump Speed Control Energy Saving 121

5.2.4 Energy]saving Calculation of Variable Frequency Speed Controlling Water Supply System 123

5.3 Control Principle of Constant Pressure Water Supply System 124

5.3.1 Control Principle of Constant Pressure Water Supply 124

5.3.2 Constant Pressure Water Supply Control System 125

5.4 Application of Variable Frequency Speed Control Energy]saving Technology 127

5.4.1 Basic Principle of Motor Variable Frequency Speed Control 127

5.4.2 Selection of Frequency Converter 129

5.4.3 Instances of Converter Selection 131

5.4.4 Points Requiring Attention in the Operation of Converter 133

5.4.5 Application of VVVF Energy]saving Technology 134

5.5 Principles of Motor’s Pole Changing Speed Control 137

5.5.1 Pole Changing Working Principle of Motor 137

5.5.2 Common Pole Changing Methods of Motor 139

5.5.3 Common Connection Methods of Wiring Ends 142

5.6 Energy]saving Principles and Applications of Combined Pole Changing Speed Control 143

5.6.1 Examples of Multipump System 143

5.6.2 Energy]saving Principles of Combined Pole Changing Speed Control 145

5.6.3 Energy]saving Examples of Combined Pole Changing Speed Control 147

5.6.4 Comparison of Combined Pole Changing Speed Control and Variable Frequency Speed Control 148

5.7 Discussion Topics in the Chapter 149

6 Energy]saving Principle and Method of the Mechanical Properties Fit 151

6.1 Load Characteristics of A Beam]Pumping Unit 151

6.1.1 Working Principle of the Beam]Pumping Unit 152

6.1.2 Requirements of Beam Pumping Unit to Drive a Motor 154

6.2 Energy]saving Principle of Mechanical Properties Fit 154

6.2.1 Characteristics of an Ultra]High Slip Motor 154

6.2.2 Energy]saving Principle of the Adaptation of Mechanical Properties 157

6.2.3 Applications and Standards of Ultra]High Slip Motor 158

6.2.4 Applications of a Winding Motor 159

6.3 Energy]saving Instances of Mechanical Properties Fit 159

6.3.1 Power Factor and Comprehensive Efficiency of Motor Before Transformation 160

6.3.2 The Power Factor and Comprehensive Efficiency of Switching 22 kW Ultra]High Slip Motor 160

6.3.3 Energy]saving Effect of Motor 161

6.3.4 Overall Energy]saving Effect of the Pumping Unit System 161

6.4 Discussion Topics in the Chapter 162

7 The Energy]saving Principle of Induction Motor Reactive Power Compensation 163

7.1 Energy]saving Principle of Induction Motor Reactive Power Compensation 163

7.1.1 Reactive Power of Induction Motor 163

7.1.2 Energy]saving Principle of Induction Motor Reactive Power Compensation 164

7.1.3 Role of Induction Motor Reactive Power Compensation 167

7.1.4 Methods for Induction Motor Reactive Power Compensation 167

7.2 Capacity Selection for the Compensating Capacitor 168

7.2.1 The Calculation of Induction Motor’s Reactive Power 168

7.2.2 The Reactive Power Curve of Induction Motor 169

7.2.3 The Capacity Selection of the Induction Motor Compensation Capacitor 170

7.2.4 Low]Voltage Shunt Capacitor 172

7.2.5 Research of Reactive Power Compensation for Induction Motor 174

7.2.6 Experiential Formula for Compensation Capacitor of Induction Motor 176

7.3 Static Reactive Power Compensation of Induction Motor 177

7.3.1 Mode of Static Compensation 177

7.3.2 Caution for Static Compensation 180

7.3.3 Verification of the Static Compensation Capacitor 182

7.3.4 The Main Device Selection of the Compensation Device 184

7.4 Reactive Power Dynamic Compensation of the Induction Motor 185

7.4.1 Dynamic Compensation Based on TCR Phase Control 186

7.4.2 Dynamic Compensation]Based IGBT Control 189

7.5 Hybrid Compensation 192

7.5.1 Fluctuation Part of the Dynamic Compensation 192

7.5.2 Over Make Up Part of the Dynamic Compensation 195

7.6 The Discussion Topic of the Chapter 196

Further Reading 199

Index 201