DESIGN OF ROTATING ELECTRICAL MACHINES

advertisement

DESIGN OF ROTATING ELECTRICAL MACHINES

Introduction

DESIGN OF ROTATING ELECTRICAL MACHINES

    Electrical machines are almost entirely used in producing electricity, and there are very few electricity-producing processes where rotating machines are not used. In such processes, at least auxiliary motors are usually needed. In distributed energy systems, new machine types play a considerable role: for instance, the era of permanent magnet machines has commenced.

advertisement

    About half of all electricity produced globally is used in electric motors, and the share of accurately controlled motor drives applications is increasing. Electrical drives provide probably the best control properties for a wide variety of processes. The torque of an electric motor may be controlled accurately, and the efficiencies of the power electronic and electromechanical conversion processes are high. What is most important is that a controlled electric motor drive may save considerable amounts of energy. In the future, electric drives will probably play an important role also in the traction of cars and working machines. Because of the large energy flows, electric drives have a significant impact on the environment. If drives are poorly designed or used inefficiently, we burden our environment in vain. Environmental threats give electrical engineers a good reason for designing new and efficient electric drives.

Electrical installation handbook

advertisement

Table of contents

1 Principal Laws and Methods in Electrical Machine Design

1.1 Electromagnetic Principles

1.2 Numerical Solution

1.3 The Most Common Principles Applied to Analytic Calculation

1.4 Application of the Principle of Virtual Work in the Determination of Force and Torque

1.5 Maxwell’s Stress Tensor; Radial and Tangential Stress 32

1.6 Self-Inductance and Mutual Inductance 36

1.7 Per Unit Values 42

1.8 Phasor Diagrams

2 Windings of Electrical Machines 48

2.1 Basic Principles

2.2 Phase Windings 54

2.3 Three-Phase Integral Slot Stator Winding 57

2.4 Voltage Phasor Diagram and Winding Factor 64

2.5 Winding Analysis 72

2.6 Short Pitching 74

2.7 Current Linkage of a Slot Winding 81

2.8 Poly-Phase Fractional Slot Windings 94

2.9 Phase Systems and Zones of Windings

2.10 Symmetry Conditions

2.11 Base Windings Fractional Slot Windings

2.13 Single- and Double-Phase Windings 124

2.14 Windings Permitting a Varying Number of Poles 127

2.15 Commutator Windings

2.16 Compensating Windings and Commutating Poles 146

2.17 Rotor Windings of Asynchronous Machines 149

2.18 Damper Windings

3 Design of Magnetic Circuits 155

3.1 Air Gap and its Magnetic Voltage

3.2 Equivalent Core Length 173

3.3 Magnetic Voltage of a Tooth and a Salient Pole

3.4 Magnetic Voltage of Stator and Rotor Yokes 180

3.5 No-Load Curve, Equivalent Air Gap and Magnetizing Current of the Machine 

3.6 Magnetic Materials of a Rotating Machine

3.7 Permanent Magnets in Rotating Machines

3.8 Assembly of Iron Stacks

4 Inductances 229

4.1 Magnetizing Inductance 230

4.2 Leakage Inductance

4.3 Calculation of Flux Leakage

5 Resistances 265

5.1 DC Resistance 265

5.2 Influence of Skin Effect on Resistance

6 Design Process of Rotating Electrical Machines 293

6.1 Eco-Design Principles of Rotating Electrical Machines 293

6.2 Design Process of a Rotating Electrical Machine

Download full PDF in Comment section

advertisement