Electrical Machines

Höfundur S. K. Sahdev

Útgefandi Cambridge University Press

Snið Page Fidelity

Print ISBN 9781108431064

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Description

Efnisyfirlit

  • Electrical Machines
  • Title
  • Copyright
  • Dedication
  • Contents
  • Preface
  • Acknowledgements
  • CHAPTER 1: Electro Magnetic Circuits
  • Chapter Objectives
  • Introduction
  • 1.1 Magnetic Field and its Significance
  • 1.2 Magnetic Circuit and its Analysis
  • 1.3 Important Terms
  • 1.4 Comparison between Magnetic and Electric Circuits
  • 1.5 Ampere-turns Calculations
  • 1.6 Series Magnetic Circuits
  • 1.7 Parallel Magnetic Circuits
  • 1.8 Leakage Flux
  • 1.9 Magnetisation or B-H Curve
  • 1.10 Magnetic Hysteresis
  • 1.11 Hysteresis Loss
  • 1.12 Importance of Hysteresis Loop
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 1.13 Electro Magnetic Induction
  • 1.14 Faraday’s Laws of Electromagnetic Induction
  • 1.15 Direction of Induced emf
  • 1.16 Induced emf
  • 1.17 Dynamically Induced emf
  • 1.18 Statically Induced emf
  • 1.19 Self Inductance
  • 1.20 Mutual Inductance
  • 1.21 Co-efficient of Coupling
  • 1.22 Inductances in Series and Parallel
  • 1.23 Energy Stored in a Magnetic Field
  • 1.24 AC Excitation in Magnetic Circuits
  • 1.25 Eddy Current Loss
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 1.26 Electro-mechanical Energy Conversion Devices
  • 1.27 Torque Development by the Alignment of Two Fields
  • 1.27.1 Soft Iron Piece Placed in the Magnetic Field
  • 1.27.2 Permanent Magnet Placed in the Magnetic Field
  • 1.27.3 Electromagnet Placed in the Magnetic Field
  • 1.28 Production of Torque
  • 1.28.1 In Case of Permanent Magnet
  • 1.28.2 In Case of Electromagnet
  • 1.29 Production of Unidirectional Torque
  • 1.29.1 By Rotating the Main Magnets
  • 1.29.2 By Changing the Direction of Flow of Current in the Conductors of Electromagnet
  • 1.30 emf Induced in a Rotating Coil Placed in a Magnetic Field
  • 1.31 Elementary Concept of Electrical Machines
  • 1.31.1 Operation of Machine as a Generator (Conversion of Mechanical Energy into Electric Energy)
  • 1.31.2 Operation of Machine as a Motor
  • Conclusion
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 2: Single-Phase Transformers
  • Chapter Objectives
  • Introduction
  • 2.1 Transformer
  • 2.2 Working Principle of a Transformer
  • 2.3 Construction of Transformer
  • 2.3.1 Core Material
  • 2.3.2 Core Construction
  • 2.3.3 Transformer Winding
  • 2.3.4 Insulation
  • 2.3.5 Bushings
  • 2.3.6 Transformer Tank
  • 2.4 Simple Construction of Single-phase Small Rating (SAY 2 kVA) TRANSFORMERS
  • 2.5 An Ideal Transformer
  • 2.6 Transformer on DC
  • 2.7 emf Equation
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.8 Transformer on No-load
  • 2.9 Effect of Magnetisation on No-load (Exciting) Current
  • 2.10 Inrush of Magnetising Current
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.11 Transformer on Load
  • 2.12 Phasor Diagram of a Loaded Transformer
  • 2.13 Transformer with Winding Resistance
  • 2.14 Mutual and Leakage Fluxes
  • 2.15 Equivalent Reactance
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.16 Actual Transformer
  • 2.17 Simplified Equivalent Circuit
  • 2.18 Short Circuited Secondary of Transformer
  • 2.19 Expression for No-load Secondary Voltage
  • 2.20 Voltage Regulation
  • 2.21 Approximate Expression for Voltage Regulation
  • 2.22 Kapp Regulation Diagram
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.23 Losses in a Transformer
  • 2.24 Effects of Voltage and Frequency Variations on Iron Losses
  • 2.25 Efficiency of a Transformer
  • 2.26 Condition for Maximum Efficiency
  • 2.27 Efficiency vs Load
  • 2.28 Efficiency vs Power Factor
  • 2.29 All-day Efficiency
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.30 Transformer Tests
  • 2.31 Polarity Test
  • 2.32 Voltage Ratio Test
  • 2.33 Open-circuit or No-load Test
  • 2.34 Separation of Hysteresis and Eddy Current Losses
  • 2.35 Short Circuit Test
  • 2.36 Back-to-back Test
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.37 Classification of Transformers
  • 2.38 Parallel Operation of Transformers
  • 2.39 Necessity of Parallel Operation
  • 2.40 Conditions for Parallel Operation of One-phase Transformers
  • 2.41 Load Sharing between Two Transformers Connected in Parallel
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 2.42 Auto-transformer
  • 2.43 Auto-transformer vs Potential Divider
  • 2.44 Saving of Copper in an Auto-transformer
  • 2.45 Advantages of Auto-transformer over Two-winding Transformer
  • 2.46 Disadvantages of Auto-transformers
  • 2.47 Phasor Diagram of an Auto-transformer
  • 2.48 Equivalent Circuit of an Auto-transformer
  • 2.49 Simplified Equivalent Circuit of an Auto-transformer
  • 2.50 Conversion of a Two-winding Transformer to an Auto-transformer
  • 2.51 Comparison of Characteristics of Auto-transformers and Two-winding Transformers
  • 2.52 Applications of Auto-transformers
  • Section Practice Problems
  • Numerical Problems
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 3: Three-Phase Transformers
  • Chapter Objectives
  • Introduction
  • 3.1 Merits of Three-phase Transformer over Bank of Three Singlephase Transformers
  • 3.2 Construction of Three-phase Transformers
  • 3.3 Determination of Relative Primary and Secondary Windings in Case of Three-phase Transformer
  • 3.4 Polarity of Transformer Windings
  • 3.5 Phasor Representation of Alternating Quantities in Three-phase Transformer Connections
  • 3.6 Three-phase Transformer Connections
  • 3.7 Selection of Transformer Connections
  • 3.7.1 Star-Star (Yy0 or Yy6) Connections
  • 3.7.2 Delta-Delta (Dd0 or Dd6) Connections
  • 3.7.3 Star-Delta (Yd1 or Yd11) Connections
  • 3.7.4 Delta-Star (Dy1 or Dy11) Connections
  • 3.7.5 Delta-Zigzag Connections
  • 3.7.6 Star-Zigzag Connection
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 3.8 Parallel Operation of Three-phase Transformers
  • 3.9 Necessity of Parallel Operation of Three-phase Transformers
  • 3.10 Conditions for Parallel Operation of Three-phase Transformers
  • 3.11 Load Sharing between Three-phase Transformers Connected in Parallel
  • 3.12 Three Winding Transformers (Tertiary Winding)
  • 3.12.1 Stabilisation Provided by Tertiary Winding in Star-Star Transformer
  • 3.13 Tap-changers on Transformers
  • 3.14 Types of Tap-changers
  • 3.14.1 No-load (or Off-load) Tap-changer
  • 3.14.2 On-load Tap-changer
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 3.15 Transformation of Three-phase Power with Two Single-phase Transformers
  • 3.16 Open-Delta or V-V Connections
  • 3.17 Comparison of Delta and Open Delta Connections
  • 3.18 T-T Connections or Scott Connections
  • 3.19 Conversion of Three-phase to Two-phase and vice-versa
  • 3.20 Difference between Power and Distribution Transformers
  • 3.21 Cooling of Transformers
  • 3.22 Methods of Transformer Cooling
  • 3.23 Power Transformer and its Auxiliaries
  • 3.24 Maintenance Schedule of a Transformer
  • 3.25 Trouble Shooting of a Transformer
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 4: DC Generator
  • Chapter Objectives
  • Introduction
  • 4.1 DC Generator
  • 4.2 Main Constructional Features
  • 1. Magnetic Frame or Yoke
  • 2. Pole Core and Pole Shoes
  • 3. Field or Exciting Coils
  • 4. Armature Core
  • 5. Armature Winding
  • 6. Commutator
  • 7. Brushes
  • 8. Brush Rocker
  • 9. End Housings
  • 10. Bearings
  • 11. Shaft
  • 4.3 Simple Loop Generator and Function of Commutator
  • 4.4 Connections of Armature Coils with Commutator Segments and Location of Brushes
  • 4.5 Armature Winding
  • 4.6 Types of Armature Winding
  • 4.7 Drum Winding
  • 4.8 Lap Winding
  • 4.9 Numbering of Coils and Commutator Segments in Developed Winding Diagram
  • 4.10 Characteristics of a Simplex Lap Winding
  • 4.11 Characteristics of a Multiplex Lap Winding
  • 4.12 Equalising Connections and their Necessity
  • 4.13 Simplex Wave Winding
  • 4.14 Dummy Coils
  • 4.15 Applications of Lap and Wave Windings
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 4.16 emf Equation
  • 4.17 Torque Equation
  • 4.18 Armature Reaction
  • 4.19 Calculations for Armature Ampere-turns
  • 4.20 Commutation
  • 4.21 Cause of Delay in the Reversal of Current in the Coil going through Commutation and its Effect
  • 4.22 Magnitude of Reactance Voltage
  • 4.23 Good Commutation and Poor Commutation
  • 4.24 Interpoles and their Necessity
  • 4.25 Compensating Winding and its Necessity
  • 4.26 Methods of Improving Commutation
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 4.27 Types of DC Generators
  • 4.28 Separately-excited DC Generators
  • 4.29 Self-excited DC Generators
  • (i) Shunt Wound Generators
  • (ii) Series Wound Generators
  • (iii) Compound Wound Generators
  • 4.30 Voltage Regulation of a DC Shunt Generator
  • 4.31 Characteristics of DC Generators
  • 4.32 No-load Characteristics of DC Generators or Magnetisation Curve of DC Generator
  • 4.33 Voltage Build-up in Shunt Generators
  • 4.34 Critical Field Resistance of a DC Shunt Generator
  • 4.35 Load Characteristics of Shunt Generator
  • 4.36 Load Characteristics of Series Generators
  • 4.37 Load Characteristics of Compound Generator
  • 4.38 Causes of Failure to Build-up Voltage in a Generator
  • 4.39 Applications of DC Generators
  • 4.40 Losses in a DC Generator
  • 4.41 Constant and Variable Losses
  • 4.42 Stray Losses
  • 4.43 Power Flow Diagram
  • 4.44 Efficiency of a DC Generator
  • 4.45 Condition for Maximum Efficiency
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 5: DC Motors
  • Introduction
  • 5.1 DC Motor
  • 5.2 Working Principle of DC Motors
  • 5.3 Back emf
  • 5.4 Electro-magnetic Torque Developed in DC Motor
  • 5.5 Shaft Torque
  • 5.6 Comparison of Generator and Motor Action
  • 5.7 Types of DC Motors
  • 5.8 Characteristics of DC Motors
  • 5.9 Characteristics of Shunt Motors
  • 5.10 Characteristics of Series Motors
  • 5.11 Characteristics of Compound Motors
  • 5.12 Applications and Selection of DC Motors
  • 5.12.1 Applications of DC Motors
  • 5.12.2 Selection of DC Motors
  • 5.13 Starting of DC Motors
  • 5.14 Necessity of Starter for a DC Motor
  • 5.15 Starters for DC Shunt and Compound Wound Motors
  • 5.16 Three-point Shunt Motor Starter
  • 5.17 Four-point Starter
  • 5.18 Calculation of Step Resistances Used in Shunt Motor Starter
  • 5.19 Series Motor Starter
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 5.20 Speed Control of DC Motors
  • 5.21 Speed Control of Shunt Motors
  • 5.21.1 Field Control Method
  • 5.21.2 Armature Control Method
  • 5.22 Speed Control of Separately Excited Motors
  • 5.23 Speed Regulation
  • 5.24 Speed Control of DC Series Motors
  • 5.24.1 Armature Control Method
  • 5.24.2 Field Control Method
  • 5.24.3 Voltage Control Method
  • 5.25 Electric Braking
  • 5.26 Types of Electric Braking
  • 5.26.1 Plugging
  • 5.26.2 Rheostatic Braking
  • 5.26.3 Regenerative Braking
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 5.27 Losses in a DC Machine
  • 5.28 Constant and Variable Losses
  • 5.29 Stray Losses
  • 5.30 Power Flow Diagram
  • 5.31 Efficiency of a DC Machine
  • 5.32 Condition for Maximum Efficiency
  • 5.33 Test Performed to Determine Efficiency of DC Machines
  • 5.34 Brake Test
  • 5.35 Swinburne’s Test
  • 5.36 Hopkinson’s Test
  • 5.37 Testing of DC Series Machines
  • 5.38 Inspection/maintenance of DC Machines
  • 5.39 Faults in DC Machines
  • 5.40 Trouble Shooting in a DC Motor
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 6: Synchronous Generators or Alternators
  • Chapter Objectives
  • Introduction
  • 6.1 General Aspects of Synchronous Machines
  • 6.2 Basic Principles
  • 6.3 Generator and Motor Action
  • 6.4 Production of Sinusoidal Alternating emf
  • 6.5 Relation between Frequency, Speed and Number of Poles
  • 6.6 Advantages of Rotating Field System over Stationary Field System
  • 6.7 Constructional Features of Synchronous Machines
  • 6.8 Excitation Systems
  • 6.8.1 DC Exciters
  • 6.8.2 Static Excitation System
  • 6.8.3 Brushless Excitation System
  • Section Practice Problems
  • Short Answer Type Questions
  • 6.9 Armature Winding
  • 6.10 Types of Armature Winding
  • 6.11 Important Terms Used in Armature Winding
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 6.12 Coil Span Factor
  • 6.13 Distribution Factor
  • 6.14 Winding Factor
  • 6.15 Generation of Three-phase emf
  • 6.16 emf Equation
  • 6.17 Wave Shape
  • 6.18 Harmonics in Voltage Wave Form
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 6.19 Production of Revolving Field
  • 6.20 Ferrari’s Principle (Vector Representation of Alternating Field)
  • 6.21 Production of Two-phase Rotating Magnetic Field
  • 6.22 Production of Three-phase Rotating Magnetic Field
  • 6.23 Rating of Alternators
  • 6.24 Armature Resistance
  • 6.25 Armature Leakage Reactance
  • 6.26 Armature Reaction
  • 6.27 Effect of Armature Reaction on emf of Alternator
  • 6.28 Synchronous Reactance and Synchronous Impedance
  • 6.29 Equivalent Circuit of an Alternator and Phasor Diagram
  • 6.30 Expression for No-load Terminal Voltage
  • 6.31 Voltage Regulation
  • 6.32 Determination of Voltage Regulation
  • 6.33 Synchronous Impedance Method or emf Method
  • 6.33.1 Determination of Synchronous Impedance
  • 6.33.2 Determination of Synchronous Reactance
  • 6.34 Modern Alternators
  • 6.35 Short-Circuit Ratio (SCR)
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 6.36 Assumptions Made in Synchronous Impedance Method
  • 6.37 Ampere-turn (or mmf) Method
  • 6.38 Zero Power Factor or Potier Method
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 6.39 Power Developed by Cylindrical Synchronous Generators
  • 6.39.1 Power Output of an AC Generator (in Complex Form)
  • 6.39.2 Real Power Output of an AC Generator
  • 6.39.3 Reactive Power Output of an AC Generator
  • 6.39.4 Power Input to an AC Generator (in Complex Form)
  • 6.39.5 Real Power Input to an AC Generator
  • 6.39.6 Reactive Power Input to an AC Generator
  • 6.39.7 Condition for Maximum Power Output
  • 6.39.8 Condition for Maximum Power Input
  • 6.39.9 Power Equations, when Armature Resistance is Neglected
  • 6.40 Two-Reactance Concept for Salient Pole Synchronous Machines
  • 6.40.1 Determination of Xd and Xq by Low Voltage Slip Test
  • 6.41 Construction of Phasor Diagram for Two-Reac tion Concept
  • 6.42 Power Developed by a Salient Pole Synchronous Generator
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 6.43 Transients in Alternators
  • 6.43.1 Sub-transient, Transient and Direct-Reactance
  • 6.44 Losses in a Synchronous Machine and Efficiency
  • 6.45 Power Flow Diagram
  • 6.46 Necessity of Cooling
  • 6.47 Methods of Cooling
  • 6.48 Preventive Maintenance
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 7: Parallel Operation of Alternators
  • Chapter Objectives
  • Introduction
  • 7.1 Necessity of Parallel Operation of Alternators
  • 7.2 Requirements for Parallel Operation of Alternators
  • 7.3 Synchronising Alternators
  • 7.4 Conditions for Proper Synchronising
  • 7.5 Synchronising Single-phase Alternators
  • 7.5.1 Dark Lamp Method
  • 7.5.2 Bright Lamp Method
  • 7.6 Synchronising Three-phase Alternators
  • 7.6.1 Three Dark Lamps Method
  • 7.6.2 Two Bright and One Dark Lamp Method
  • 7.7 Synchronising Three-phase Alternators using Synchroscope
  • 7.8 Shifting of Load
  • 7.9 Load Sharing between Two Alternators
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 7.10 Two Alternators Operating in Parallel
  • 7.11 Synchronising Current, Power and Torque
  • 7.12 Effect of Change in Input Power of One of the Alternators
  • 7.13 Effect of Change in Excitation of One of the Alternators
  • 7.14 Effect of Reactance
  • 7.15 Effect of Governors’ Characteristics on Load Sharing
  • 7.16 Hunting
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 8: Synchronous Motors
  • Chapter Objectives
  • Introduction
  • 8.1 Working Principle of a Three-phase Synchronous Motor
  • 8.2 Effect of Load on Synchronous Motor
  • 8.3 Equivalent Circuit of a Synchronous Motor
  • 8.4 Phasor Diagram of a Synchronous Motor (Cylindrical Rotor)
  • (i) Phasor Diagram for Lagging Power Factor
  • (ii) Phasor Diagram at Unity Power Factor
  • (iii) Phasor Diagram for Leading Power Factor
  • 8.5 Relation between Supply Voltage V and Excitation Voltage E
  • 8.6 Different Torques in a Synchronous Motor
  • 8.7 Power Developed in a Synchronous Motor (Cylindrical Rotor)
  • 8.8 Phasor Diagrams of a Salient-pole Synchronous Motor
  • (a) For Lagging Power Factor cos ϕ
  • (b) For Leading Power Factor cos ϕ
  • (c) Unity Power Factor
  • 8.9 Power Developed in a Salient-pole Synchronous Motor
  • 8.10 Power Flow in a Synchronous Motor
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 8.11 Effect of Change in Excitation
  • 8.12 V-Curves and Inverted V-Curves
  • 8.13 Effect of Change in Load on a Synchronous Motor
  • 8.14 Methods of Starting of Synchronous Motors
  • 8.15 Synchronous Condenser
  • 8.16 Characteristics of Synchronous Motor
  • 8.17 Hunting
  • 8.18 Applications of Synchronous Motors
  • 8.19 Comparison between Three-phase Synchronous and Induction Motors
  • 8.20 Merits and Demerits of Synchronous Motor
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 9: Three-Phase Induction Motors
  • Chapter Objectives
  • Introduction
  • 9.1 Constructional Features of a Three-phase Induction Motor
  • 9.2 Production of Revolving Field
  • 9.3 Principle of Operation
  • 9.4 Reversal of Direction of Rotation of Three-phase Induction Motors
  • 9.5 Slip
  • 9.6 Frequency of Rotor Currents
  • 9.7 Speed of Rotor Field or mmf
  • 9.8 Rotor emf
  • 9.9 Rotor Resistance
  • 9.10 Rotor Reactance
  • 9.11 Rotor Impedance
  • 9.12 Rotor Current and Power Factor
  • 9.13 Simplified Equivalent Circuit of Rotor
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 9.14 Stator Parameters
  • 9.15 Induction Motor on No-load
  • 9.16 Induction Motor on Load
  • 9.17 Induction Motor vs Transformer
  • 9.18 Reasons of Low Power Factor of Induction Motors
  • 9.19 Main Losses in an Induction Motor
  • 9.20 Power Flow Diagram
  • 9.21 Relation between Rotor Copper Loss, Slip and Rotor Input
  • 9.22 Rotor Efficiency
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 9.23 Torque Developed by an Induction Motor
  • 9.24 Condition for Maximum Torque and Equation for Maximum Torque
  • 9.25 Starting Torque
  • 9.26 Ratio of Starting to Maximum Torque
  • 9.27 Ratio of Full Load Torque to Maximum Torque
  • 9.28 Effect of Change in Supply Voltage on Torque
  • 9.29 Torque-slip Curve
  • 9.30 Torque-speed Curve and Operating Region
  • 9.31 Effect of Rotor Resistance on Torque-slip Curve
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 9.32 Constant and Variable Losses in an Induction Motor
  • 9.33 Main Tests Performed on an Induction Motor
  • 9.33.1 Stator Resistance Test
  • 9.33.2 Voltage-ratio Test
  • 9.33.3 No-load Test
  • 9.33.4 Blocked Rotor Test
  • 9.33.5 Heat Run Test
  • 9.34 Equivalent Circuit of an Induction Motor
  • 9.35 Simplified Equivalent Circuit of an Induction Motor
  • 9.36 Maximum Power Output
  • 9.37 Circle Diagram
  • 9.38 Circle Diagram for the Approximate Equivalent Circuit of an Induction Motor
  • 9.39 Construction of a Circle Diagram for an Induction Motor
  • 9.40 Results Obtainable from Circle Diagram
  • 9.41 Maximum Quantities
  • 9.42 Significance of Some Lines in the Circle Diagram
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 9.43 Effect of Space Harmonies
  • 9.43.1 Cogging in Three-phase Induction Motors
  • 9.43.2 Crawling in Three-phase Induction Motors
  • 9.44 Performance Curves of Induction Motors
  • 9.45 Factors Governing Performance of Induction Motors
  • 9.46 High Starting Torque Cage Motors
  • 9.46.1 Deep Bar Cage Rotor Motors
  • 9.46.2 Double Cage Induction Motor
  • 9.47 Motor Enclosures
  • 1. Open Drip Proof (ODP) Enclosure
  • 2. Totally Enclosed Fan Cooled (TEFC) Enclosure
  • 3. Totally Enclosed Non-Ventilated (TENV) Enclosure
  • 4. Totally Enclosed Air Over (TEAO) Enclosure
  • 5. Totally Enclosed Wash Down (TEWD) Enclosure
  • 6. Explosion-proof Enclosures (EXPL)
  • 7. Hazardous Location (HAZ) Enclosures
  • 9.48 Standard Types of Squirrel Cage Motor
  • 9.48.1 Class A Motors
  • 9.48.2 Class B Motors
  • 9.48.3 Class C Motors
  • 9.48.4 Class D Motors
  • 9.48.5 Class E Motors
  • 9.48.6 Class F Motors
  • 9.49 Advantages and Disadvantages of Induction Motors
  • 9.49.1 Squirrel Cage Induction Motors
  • 9.49.2 Slip-ring Induction Motors
  • 9.50 Applications of Three-phase Induction Motors
  • 9.51 Comparison of Squirrel Cage and Phase Wound Induction Motors
  • 9.52 Comparison between Induction Motor and Synchronous Motor
  • 9.53 Installation of Induction Motors
  • 1. Inspection of the Motor on its Arrival and its Storage
  • 2. Selection of Location for the Installation of Motor and Control Gear
  • 3. Preparation of Foundation and Arrangement of Leveling
  • 4. Checking for Proper Alignment
  • 5. Fitting of Loading System
  • 6. Earthing
  • 9.54 Preventive Maintenance of Three-phase Induction Motors
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 10: Starting Methods and Speed Control of Three-Phase Induction Motors
  • Chapter Objectives
  • Introduction
  • 10.1 Necessity of a Starter
  • 10.2 Starting Methods of Squirrel Cage Induction Motors
  • 10.2.1 Direct on Line (D.O.L.) Starter
  • 10.2.2 Stator Resistance (or Reactance) Starter
  • 10.2.3 Star-Delta Starter
  • 10.2.4 Auto-transformer Starter
  • 10.3 Rotor Resistance Starter for Slip Ring Induction Motors
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 10.4 Speed Control of Induction Motors
  • 10.5 Speed Control by Changing the Slip
  • 10.5.1 Speed Control by Changing the Rotor Circuit Resistance
  • 10.5.2 Speed Control by Controlling the Supply Voltage
  • 10.5.3 Speed Control by Injecting Voltage in the Rotor Circuit
  • 10.6 Speed Control by Changing the Supply Frequency
  • 10.7 Speed Control by Changing the Poles
  • 10.8 Speed Control by Cascade Method
  • 10.9. Speed Control by Injecting an emf in the Rotor Circuit
  • 10.9.1 Kramer System of Speed Control
  • 10.9.2 Scherbius System of Speed Control
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 11: Single-Phase Motors
  • Chapter Objectives
  • Introduction
  • 11.1 Classification of Single-phase Motors
  • 11.2 Single-phase Induction Motors
  • 11.3 Nature of Field Produced in Single Phase Induction Motors
  • 11.4 Torque Produced by Single-phase Induction Motor
  • 11.5 Equivalent Circuit of Single-phase Induction Motor
  • 11.6 Rotating Magnetic Field from Two-phase Supply
  • 11.7 Methods to make Single-phase Induction Motor Self-starting
  • 11.8 Split Phase Motors
  • 11.9 Capacitor Motors
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 11.10 Shaded Pole Motor
  • 11.11 Reluctance Start Motor
  • 11.12 Single-phase Synchronous Motors
  • 11.13 Reluctance Motors
  • 11.14 Hysteresis Motors
  • 11.15 AC Series Motor or Commutator Motor
  • 11.16 Universal Motor
  • 11.17 Comparison of Single-phase Motors
  • 11.18 Trouble Shooting in Motors
  • Section Practice Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • CHAPTER 12: Special Purpose Machines
  • Chapter Objectives
  • Introduction
  • 12.1 Feedback Control System
  • 12.2 Servomechanism
  • 12.3 Servomotors
  • 12.4 DC Servomotors
  • 12.4.1 Field-controlled DC Servomotors
  • 12.4.2 Armature-controlled DC Servomotors
  • 12.4.3 Series Split-field DC Servomotors
  • 12.4.4 Permanent-magnet Armature-controlled DC Servomotor
  • 12.5 AC Servomotors
  • 12.6 Schrage motor
  • Section Practice Problems
  • Short Answer Type Questions
  • 12.7 Brushless Synchronous Generator
  • 12.7.1 Brushless DC Generator
  • 12.8 Brushless Synchronous Motor
  • 12.9 Three-brush (or Third-brush) Generator
  • 12.10 Brushless DC Motors
  • 12.11 Stepper Motors
  • 12.11.1 Permanent-magnet (PM) Stepper Motor
  • 12.11.2 Variable-reluctance (VR) Stepper Motor
  • Section Practice Problems
  • Numerical Problems
  • Short Answer Type Questions
  • 12.12 Switched Reluctance Motor (SRM)
  • 12.13 Linear Induction Motor (LIM)
  • 12.14 Permanent Magnet DC Motors
  • 12.15 Induction Generator
  • 12.16 Submersible Pumps and Motors
  • 12.17 Energy Efficient Motors
  • Section Practice Problems
  • Short Answer Type Questions
  • Review Questions
  • Multiple Choice Questions
  • Open Book Questions
  • Index

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