Variable Speed Pumping: A Guide to Successful Applications

Front Cover......Page 1
Variable Speed Pumping: A Guide to Successful Applications......Page 4
Copyright Page......Page 5
Table of Contents......Page 6
1.1 Objectives of the guide......Page 14
1.2 Acknowledgements......Page 16
2.1 System characteristics......Page 18
2.2 System curves......Page 19
2.4 Pump operating point......Page 21
3.2 Introduction to variable speed concept......Page 24
3.3 Process requirements......Page 25
4.2 Rotodynamic pumps......Page 28
4.3 Positive displacement pumps......Page 41
5.1 Flow duration diagrams......Page 52
5.2 Specific energy......Page 53
5.3 Flow regulation by varying speed......Page 56
5.4 Flow regulated by throttling......Page 57
5.6 System awareness – notes of caution......Page 58
5.7 Conclusions on a VSD within a system......Page 59
6.1 Types of electric motors......Page 60
6.2 Asynchronous induction motors......Page 62
6.3 Alternative electrical designs of motors......Page 66
6.4 Motor construction and cooling......Page 69
6.5 Motor starting......Page 70
7.2 Variable speed drives for induction motors......Page 72
7.3 Variable speed drives for other AC motors......Page 76
7.5 Drive controller algorithms......Page 77
7.7 Power drive systems......Page 78
7.8 Integrated motors and drives......Page 79
8.1 Methods of controlling a rotodynamic pump......Page 80
8.2 Control principles for rotodynamic pumps......Page 81
8.3 Speed variation for positive displacement pumps......Page 88
8.4 Control principles for PD pumps......Page 89
8.6 Soft starting and stopping......Page 90
9.2 Flow charts......Page 92
10.1 Justification......Page 96
10.3 Flow charts......Page 97
10.4 Retrofitting a motor mounted VFD......Page 99
11.1 Tangible benefits to the user......Page 102
11.3 Potential drawbacks of PWM VFDs......Page 103
11.4 Operational issues......Page 104
11.5 Power drive system integration......Page 108
11.7 Motor design......Page 111
12.1 Life cycle cost (LCC)......Page 114
12.2 Capital cost savings......Page 115
Introduction......Page 118
Case study 1......Page 119
Case study 2......Page 122
Case study 3......Page 124
Case study 4......Page 126
Case study 5......Page 127
Case study 6......Page 129
Case study 7......Page 131
Case study 8......Page 132
A1.1 Energy efficiency......Page 134
A1.2 Efficiency labelling......Page 135
A1.3 Motor sizing......Page 137
A2.1 Inverter designs......Page 140
A2.2 Rectifier design......Page 146
A2.3 Control strategies......Page 147
A2.4 Factors to be considered in sizing variable frequency drives......Page 150
A3.1 European Directives......Page 152
A3.2 United States regulations and standards......Page 155
A3.3 Harmonics......Page 156
A4.2 Speed......Page 164
A4.3 Insulation design......Page 165
A4.5 Sleeve (journal) bearings......Page 166
A4.6 Reliability......Page 167
A5.1 Changes of pump speed......Page 168
A5.2 Change of impeller diameter......Page 170
A6.1 Energy efficiency in the supply chain......Page 172
A6.3 Motor losses......Page 173
A6.4 Converter losses......Page 175
A6.5 Drive train efficiencies......Page 176
A6.6 Measuring efficiency......Page 177
A7.1 Summary......Page 178
A8.1 Abbreviations of terms......Page 182