Electrical machines / Smarajit Ghosh.

Format:

Book

Author/Creator:

Ghosh, Smarajit.

Series:

Always learning.

Always Learning

Language:

English

Subjects (All):

Electrical engineering--India.

Electrical engineering.

Electric machinery--India.

Electric machinery.

Physical Description:

1 online resource (1 v.) : ill.

Edition:

2nd ed.

Place of Publication:

New Delhi, India : Pearson, 2012.

System Details:

text file

Summary:

This fully revised edition of the book is systematically organized as per the logical flow of the topics included in electrical machines courses in universities across India. It is written as a text-cum-guide so that the underlying principles can be readily understood, and is useful to both the novice as well as advanced readers. Emphasis has been laid on physical understanding and pedagogical aspects of the subject. In addition to conventional machines, the book's extensive coverage also includes rigorous treatment of transformers (current, potential and welding transformers), special machines, AC/DC servomotors, linear induction motors, permanent magnet DC motors and application of thyristors in rotating machines.

Contents:

Cover

Contents

Preface

Introduction

Electromagnetism

Direction of Current in a Conductor

Direction of Magnetic Flux in a Conductor

Flux Distribution of an Isolated Current-carrying Conductor

Force Between Two Current-carrying Conductors

Force on a Conductor in a Magnetic Field

Generation of Induced enf and Current

Faraday's Laws

Lenz's Law

Induced emf

Dynamically Induced emf

Statically Induced emf

Magnetic Circuits

Magnetomotive Force

Magnetic Field Intensity

Magnetic Flux

Single-phase Circuits

Series R-L Circuit

Series R-C Circuit

Series L-C-R Circuit

Power Triangle

Complex Power

Three-phase Circuits

Advantages of Three-phase System

Phase Sequence

Interconnection of Three Phases

Star and Delta Connections

Voltages, Currents and Power in Star Connections

Voltages, Currents and Power in Delta Connections

For Star Connections

Measurement of Three-phase Power

Principle of Energy Conversion

Energy in the Coupling Field

Energy in the Field

Co-energy

Electrical Energy Input to the system

Estimation of Mechanical Forces in an Electromagnetic System

Case 1: Motion of the Moving Part is Very Slow

Case 2: Motion of the Moving Part Instantaneously

Estimation of Magnetic Force in Linear Systems

Doubly Excited Systems

Cylindrical Rotating Machine

Case 1: Synchronous Motor/Machine

Case 2: ωm = ωs − ωr

Chapter 1: Transformers

1.1 Definition

1.2 Basic Principle

1.3 Types of Transformers

1.4 Construction of Single-phase Transformer

1.4.1 Core Type

1.4.2 Shell Type

1.4.3 Spiral Core Type

1.5 Transformer Windings

1.5.1 Concentric Windings

1.5.2 Sandwich Windings

1.6 Terminals and Leads

1.7 Bushings

1.8 Tapping

1.9 Cooling of Transformer

1.10 Transformer Oil.

1.11 Conservator and Breather

1.12 Buchholz Relay

1.13 Transformer Tank

1.14 Theory of Transformer

1.15 EMF Equation of a Transformer

1.16 Step-up and Step-down Transformer

1.17 Transformer on no Load

1.18 Transformer on Load

1.19 Equivalent Resistance

1.20 Magnetic Leakage

1.21 Equivalent Reactance

1.22 Transformer with Resistance and Leakage Reactance

1.23 Equivalent Circuit

1.24 Open Circuit Test or No-load Test

1.25 Short Circuit or Impedance Test

1.26 Separation of Core (or Iron) Losses in a Transformer

1.27 Total Approximate Voltage Drop of a Transformer

1.28 Exact Voltage Drop

1.29 Per Unit Resistance, Leakage Reactance and Impedance Voltage Drop

1.30 Voltage Regulation of Transformer

1.30.1 Inherent Voltage Regulation

1.30.2 Voltage Regulation Down

1.30.3 Voltage Regulation Up

1.31 Calculation for Voltage Regulation

1.31.1 Zero Voltage Regulation

1.31.2 Condition for Maximum Voltage Regulation

1.31.3 Kapp's Regulation

1.32 Losses in a Transformer

1.32.1 Core or Iron Loss

1.32.2 Copper Loss

1.33 Efficiency of a Transformer

1.34 Condition for Maximum Efficiency

1.34.1 Load Current at Maximum Efficiency

1.34.2 kVA Supplied at Maximum Efficiency

1.35 All-day Efficiency

1.36 Polarity Test of a Single-phase Transformer

1.37 Sumpner's Test

1.38 Parallel Operation of Single-phase Transformer

1.39 Load Sharing by Two Transformers

1.39.1 Equal Voltage Ratios

1.39.2 Unequal Voltage Ratios

1.40 Autotransformers

1.40.1 Construction

1.40.2 Copper Saving in Autotransformer

1.40.3 Conversion of Two-winding Transformer into Single-phase Transformer

1.40.4 Advantages of Autotransformers

1.40.5 Disadvantages of Autotransformers

1.40.6 Applications of Autotransformers

1.41 Pulse Transformer.

1.41.1 Pulse Response Characteristics

1.41.2 Usage of Pulse Transformer

1.42 Welding Transformers

1.42.1 Reactors Used with Welding Transformers

1.43 Current Transformer

1.44 Potential Transformer

1.45 TAP Changing Transformers

1.46 Off-load TAP-changing Transformers

1.47 On-load TAP-changing Transformers

1.48 On-load TAP Changer with Single Primary Winding

1.49 Preventive Autotransformer

1.50 Booster Transformer

1.51 Inrush Phenomenon

Additional Solved Problems

Significant Points

Short Questions and Answers

Supplementary Problems

Multiple-choice Questions and Answers

Chapter 2: Three-phase Transformers

2.1 Advantages of Three-phase Transformers

2.2 Principle of Operation

2.3 Construction of Three-phase Transformers

2.3.1 Core-type Construction

2.3.2 Shell-type Construction

2.4 Three-phase Transformer Connection

2.4.1 Star-Star (γ/γ) Connection

2.4.2 Delta-Delta (Δ/Δ) Connection

2.4.3 Star-Delta (γ/Δ) Connection

2.4.4 Delta-Star (Δ/γ) Connection

2.4.5 Delta-Zig-zag Star Connection

2.5 Open-delta or V-V Connection

2.6 Scott Connection or T-T Connection

2.7 Three-phase to Two-phase Conversion

2.8 Parallel Operations of Transformers

2.9 Three-phase to Six-phase Conversion

2.9.1 Double-star Connection

2.9.2 Double-delta Connection

2.9.3 Six-phase Star Connection

2.9.4 Diametrical Connection

2.10 Three-winding Transformer

2.11 Three-phase Transformer Connections

2.12 Rating of Transformers

Chapter 3: Basic Concepts of Rotating Machines

3.1 Electromagnetic Torque

3.2 Reluctance Torque

3.3 Constructional Features of Rotating Electrical Machines.

3.4 Construction of DC Machines

3.4.1 Magnetic Frame or Yoke

3.4.2 Pole Cores and Pole Shoes

3.4.3 Pole Coils

3.4.4 Armature Core

3.4.5 Armature Windings

3.4.6 Commutator

3.4.7 Brushes and Bearings

3.5 Ring Windings

3.6 Drum Windings

3.6.1 Number of Coil Sides Per Layer

3.6.2 Coil Span

3.6.3 Winding Pitch

3.6.4 Commutator Pitch

3.6.5 Numbering of Armature Conductors

3.6.6 Difference between Coil Span and Winding Pitch

3.7 Types of DC Windings

3.7.1 Simple Lap Winding

3.7.2 Wave Winding

3.8 Equalizing Connections for LAP Winding

3.9 Uses of Lap and Wave Windings

3.10 Dummy Coils

3.11 Principle of DC Generator

3.12 Operation of a Simple DC Generator with a Two-segment Commutator

3.13 Principle of DC Motor

3.14 Construction of Synchronous Machines

3.14.1 Stator

3.14.2 Rotor

3.14.3 Classifi cation of Synchronous Machines Based on the Prime Mover

3.14.4 Excitation System

3.14.5 Damper Windings

3.14.6 Frequency and Synchronous Speed

3.14.7 Armature Windings

3.15 Polyphase Induction Machines

3.15.1 Squirrel-cage Rotor

3.15.2 Wound Rotor

3.16 Air Gap

3.17 Principle of Operation of Three-phase Induction Motor

3.18 Synchronous Speed and Slip in Induction Motor

3.18.1 Synchronous Speed

3.18.2 Slip in Induction Motor

3.19 Frequency of Rotor Currents

3.20 Speed of the Rotor MMF

3.21 Electrical and Mechanical Degrees

3.22 Pitch Factor

3.23 Distribution Factor

3.24 Winding Factor

3.25 Flux Per Pole

3.26 Generated EMF in Full-pitched Coil

3.27 EMF Generated in AC Machines

3.27.1 Synchronous Machines

3.27.2 Induction Machines

3.27.3 A General Expression for the EMF of Synchronous Generator

3.28 EMF Generated in DC Generator

3.29 Concept of Rotating Magnetic Field

3.29.1 Case 1: ωt = θ = 0°.

3.29.2 Case 2: ωt = θ = 60°

3.29.3 Case 3: ωt = θ = 120°

3.29.4 Case 4: ωt = θ = 180°

Chapter 4: DC Generators

4.1 Types of DC Machines

4.2 DC Generator

4.3 Brush Drop

4.4 EMF Equation

4.4.1 Shunt Generator

4.4.2 Series Generator

4.4.3 Long-shunt Compound Generator

4.4.4 Short-shunt Compound Generator

4.5 Derivation for Eg

4.6 Losses in DC Generator

4.7 Stray Losses

4.8 Constant or Standing Losses

4.9 Power Stages

4.10 Efficiency

4.11 Condition for Maximum Efficiency

4.12 Armature Reaction in DC Machines

4.13 Demagnetizing and Cross-magnetizing Conductors

4.14 Demagnetizing Ampere-turns Per Pole

4.15 Cross-magnetizing Ampere-turns Per Pole

4.16 Compensating Windings

4.17 Number of Compensating Windings

4.18 Commutation

4.18.1 Linear Commutation

4.18.2 Retarded Commutation

4.18.3 Accelerated Commutation

4.18.4 Sinusoidal Commutation

4.19 Value of Reactance Voltage

4.20 Methods of Improving Commutation

4.20.1 Resistance Commutation

4.20.2 EMF Commutation

4.21 Equalizer Rings

4.22 Characteristics of DC Generators

4.23 Separately Excited Generators

4.23.1 No-load Saturation Characteristic

4.23.2 Internal and External Characteristic (or Load Characteristic)

4.24 No-load Curve for Self-excited Generators

4.25 Advantages and Disadvantages of Separately Excited Generators

4.26 Voltage Build-up of Shunt Generator

4.27 Conditions for Build-up of Shunt Generator

4.28 Reasons for Failure to Build-up of Shunt Generators

4.29 External Characteristic of Shunt Generator

4.30 Voltage Regulation

4.31 Internal or Total Characteristic.

4.32 External Characteristic and Internal Characteristic from OCC.

Notes:

Includes bibliographical references and index.

Description based on online resource; title from PDF title page (Safari, viewed Aug. 28, 2012).

ISBN:

9789332503229

9332503222

9788131776025

8131776026

OCLC:

810454463