PRINCIPLES OF MEASUREMENT AND INSTRUMENTATION & INSTRUMENTS

Size: px

Start display at page:

Download "PRINCIPLES OF MEASUREMENT AND INSTRUMENTATION & INSTRUMENTS"

Gary Ramsey
5 years ago
Views:

1 Contents i SYLLABUS osmania university UNIT - I PRINCIPLES OF MEASUREMENT AND INSTRUMENTATION & INSTRUMENTS Principles of Measurement and Instrumentation and Instruments : Objectives of Measurements, Analog Versus Digital Measurements, Accuracy, Precision and Uncertainity, Sources of Measurement Error, Standard Cell and Standard Resistance, Basic Characteristics of Measuring Instruments with a Moving Element. Instruments : Ammeter, Voltmeter, Expression for Torque of Moving Coil, Moving Iron, Dynamometer, Induction and Electrostatic Instruments. Extension of Range of Instruments Wattmeter, Torque Expression for Dynamometer, Instruments, Reactive Power Measurement. UNIT - II MEASUREMENT OF ENERGY, POWER FACTOR AND FREQUENCY METER Energy Meters, Single Phase and Poly Phase, Driving Torque and Braking Torque Equations, Errors and Testing Compensation, Maximum Demand Indicator, Power Factor Meters, Frequency Meters, Electrical Resonance and Weston Type of Synchroscope. UNIT - III BRIDGE METHODS Measurement of Inductance, Capacitance and Resistance Using Bridge. Maxwell s Anderson, Wein, Heaviside Campbell s Desauty s, Schering s Bridges, Kelvin s Doublebridge, Price Guard Wire Bridge, Loss of Charge Method, Megger, Wagners Earthing Device.

2 ii Contents UNIT - IV MAGNETIC MEASUREMENTS Ballistic Galvanometer, Calibration by Hibbert Magnetic Standard, Flux Meter, Lloyd- Fischer Square for Measuring Iron Loss. Testing of Ring and Bar Specimens. Determination of B-H Curve and Hysteresis Loop using C.R.O., Determination of Leakage Factor. UNIT - V POTENTIOMETERS AND INSTRUMENT TRANSFORMERS Potentiometers : Crompton s D.C. and A.C. Polar and co-ordinate Types, Applications, Measurement of Impedance, Calibration of Ammeter, Voltmeter and Wattmeter, Use of Oscilloscope in Frequency, Phase and Amplitude Measurements. Instrument Transformers : Ratio and Phase Angle Errors and their Reduction.

3 Contents iii ELECTRICAL MEASUREMENTS AND INSTRUMENTS FOR b.e. (o.u) II year I semester (COMMON TO EEE AND EIE) CONTENTS UNIT - I [PRINCIPLES OF MEASUREMENT AND INSTRUMENTATION & INSTRUMENTS] INTRODUCTION TO O MEASUREMENT AND INSTRUMENTATION TION SIGNIFICANCE OF MEASUREMENTS OBJECTIVES OF MEASUREMENT STAND ANDARDS ARDS OF MEASUREMENTS Classification of Standards STAND ANDARD ARD CELL AND STAND ANDARD ARD RESISTANCE Standard Cell Standard Resistors MODES OF MEASUREMENTS METHODS OF MEASUREMENT GENERALIZED MEASUREMENT SYSTEM AND ITS FUNCTIONAL ELEMENT Primary Sensing Elements Variable Conversion Elements Manipulation Elements Data Transmission Elements Data Presentation Elements

4 iv Contents 1.9 ERRORS IN MEASUREMENT TYPES OF ERRORS Gross Errors Systematic Errors Random Errors (or) Residual Errors Sources of Measurement Errors APPLICATIONS OF MEASUREMENT SYSTEMS ANALOG VERSUS DIGITAL MEASUREMENT INSTRUMENTS Classification of Instruments Absolute and Secondary Instruments Analog and Digital Instrument Mechanical, Electrical and Electronic Instruments Manual and Automatic Instruments Self-Contained and Remote Indicating Instruments Self-Operated and Power ower-operated Instruments Deflection and Null Output Instruments Factor Relating to Selection of Instruments Functions of Instruments Characteristics of Instruments Static Characteristics Dynamic Characteristics AMMETERS AND VOLTMETERS TMETERS Types of Measuring Instruments Normally used as Ammeters and Voltmeters

5 Contents v 1.14 MOVING COIL (MC) INSTRUMENT Permanent Magnet Moving Coil (PMMC) Instrument (or) D Arsonval Instrument Construction and Working of PMMC Instruments Expression for Deflecting Torque (T d ) of PMMC Extension of Range of PMMC Instruments Extension of Range of Ammeters and Voltmeter Ammeters Shunt Voltmeter Multipliers Errors in PMMC Instrument Advantages of PMMC Instrument Disadvantages of PMMC Instrument Applications of PMMC Instruments Electrodynamometer (Electrodynamic) Type Instrument Construction of Electrodynamometer Type ype Operating Principle of Electrodynamometer Type Instrument Torque Equation of Electrodynamometer Instruments Electrodynamometer Ammeters Electrodynamometer Voltmeter oltmeter Errors in Electrodynamometer Instruments Shape of Scale Electrodynamometer Type Instruments Advantages of Electrodynamometer Instruments Disadvantages of Electrodynamometer Instruments Applications of Electrodynamometer Instruments Comparison between PMMC and Electrodynamometer

6 vi Contents 1.15 MOVING IRON (M.I.) INSTRUMENTS Classification of Moving Iron Instruments Repulsion (or) Double Iron Type Instruments Attraction Type M.I. Instruments Comparison between Attraction and Repulsion Type Instruments Expression for Deflecting Torque Extension of Range of M.I. Instruments Errors in MI Instruments Errors with both D.C..C. and A.C Errors with A.C Only Advantages of M.I. Instruments Disadvantages of M.I. Instruments Applications of M.I. Instruments COMPARISON BETWEEN MOVING COIL AND MOVING IRON INSTRUMENTS INDUCTION TYPE INSTRUMENTS Working Principle of Induction Type Instruments Classification of Induction Type Instruments Farrais Type Shaded Pole ole Type Induction Ammeters Induction Voltmeters oltmeters Errors in Induction Ammeters and Voltmeters Advantages of Induction Type Instruments Disadvantages of Induction Type Instruments Applications of Induction Type Instruments

7 Contents vii 1.18 ELECTROSTATIC TIC INSTRUMENT Working Principle of Electrostatic Instrument Force and Torque Equation of Electrostatic Instrument Types of Electrostatic Voltmeter Quadrant Type Electrostatic Voltmeter Kelvin Multicellular Voltmeter Attracted Disc Types Electrostatic Voltmeter oltmeter Extension of Range of Electrostatic Instruments Resistance Potential Divider Capacitance Potential Divider Advantages of Electrostatic Instruments Disadvantages of Electrostatic Instruments Applications of Electrostatic Instruments WATTMETER Wattmeter Connections Types of Wattmeters DYNAMOMETER TYPE OR ELECTRODYNAMOMETER WATTMETER Construction and Working of Dynamometer Wattmeter attmeter Types of Dynamometer Wattmeters Torque Equation of Dynamometer Wattmeter Error in Electrodynamometer Type Advantages of Electrodynamometer Type Wattmeter Disadvantages of Electrodynamometer Type Wattmeter INDUCTION WATTMETER Advantages of Induction Wattmeter Disadvantages of Induction Wattmeter Applications of Induction Wattmeter

8 viii Contents 1.22 COMPARISON BETWEEN DYNAMOMETER TYPE AND INDUCTION TYPE WATTMETERS TTMETERS ELECTROSTATIC TIC WATTMETER LOW POWER FACT CTOR (LPF) WATTMETER MEASUREMENT OF REACTIVE/REACTIVE POWER MEASUREMENT Use of Single Phase Varmeter armeter Use of Polyphase Varmeter Use of One Wattmeter Method (or) Reactive Power Measurement in Three Phase Circuit SOLVED PROBLEMS Short Questions and Answers UNIT - II [MEASUREMENT OF ENERGY,, POWER FACT CTOR AND FREQUENCY METER] ENERGY METERS SINGLE PHASE INDUCTION TYPE ENERGY Y (OR) WATT TT-HOUR METER Errors and Compensations in Single Phase Induction Type Energy Meter Testing of Energy Meters Testing of Energy Meter using Rotating Substandard (R.S.S.S.).) Meters (or) Testing Methods Meter Testing Circuit using Phase Shifting Device Advantages of Single Phase Induction Type Energy Meter Disadvantages of Single Phase Indiction Type Energy Meter POLYPHASE ENERGY METER Two Element Energy Meter

9 Contents ix 2.4 MAXIMUM DEMAND INDICATORS [M.D.I.].I.] Types of Demand Indicators Wright Maximum Demand Indicator Merz Price Maximum Demand Indicator TRIVECTOR METER POWER FACT CTOR METERS (P.F.F.M.).M.) Types of Power Factor Meters Electrodynamometer Power Factor Meter Moving Iron Power Factor Meter FREQUENCY METERS (F.M.) Types of Frequency Meters Mechanical Resonance Type or Vibrating Reed Frequency Meters Electrical Resonance Type Frequency Meter Weston Type Frequency Meter SYNCHROSCOPE Types of Synchroscope Electrodynamometer (or) Weston Type Synchroscope Moving Iron Synchroscope SOLVED PROBLEMS Short Questions and Answers UNIT - III [BRIDGE METHODS] INTRODUCTION TYPES OF BRIDGES D.C. Bridges A.C. Bridges Sources and Detectors General Equation for A.C. Bridge Balance Applications of A.C. Bridges

10 x Contents 3.3 MEASUREMENT OF RESISTANCES Classification of Resistances Measurement of Medium Resistance Ammeter-Voltmeter Method Substitution Method Wheatstone Bridge Method Ohmmeter Method Measurement of Low Resistances Ammeter-Voltmeter Method Kelvin elvin s s Double Bridge Method Potentiometer Method Ducter Ohmmeter Method Measurement of High Resistance Methods for Measurement of High Resistances Direct Deflection Methods Loss of Charge Method Megaohm Bridge Method Megger MEASUREMENT OF INDUCTANCE Measurement of Self-Inductances Maxwell s Inductance Bridge Maxwell s Inductance-Capacitance Bridge Hay s Bridge Anderson s Bridge Owen s Bridge

11 Contents xi Measurement of Mutual-Inductance Mutual-Inductance Measured as Self-Inductance Heaviside Mutual-Inductance Bridge Campbell s Modification of Heaviside Bridge Heaviside Campbell Equal Ratio Bridge Campbell s Bridge MEASUREMENT OF CAPACIT CITANCE De sauty s Bridge Modified De Sauty s Bridge Schering Bridge Low ow Voltage Schering Bridge High Voltage Schering Bridge MEASUREMENT OF FREQUENCY Wien ien s s Bridge SOURCES OF ERRORS IN BRIDGE CIRCUITS Precautions to Reduce Errors in Bridge Circuits WAGNER S EARTHING DEVICE SOLVED PROBLEMS Short Questions and Answers UNIT - IV [MAGNETIC MEASUREMENTS] INTRODUCTION BALLISTIC GALVANOMETER ANOMETER Construction of Ballistic Galvanometer Theory of Ballistic Galvanometer Calibration of a Ballistic Galvanometer Use of Shunt with Ballistic Galvanometer

12 xii Contents 4.3 FLUX METER Construction of Flux Meter Operation of Flux Meter Theory of Flux Meter Use of Shunt with Flux Meter Advantages and Disadvantages of Flux Meter COMPARISON BETWEEN BALLISTIC GALVANOMETER ANOMETER AND FLUX METERS APPLICATIONS OF BALLISTIC GALVANOMETER ANOMETER AND FLUX METER Measurement of Magnetic Flux Density (B) Measurement of Magnetizing Force (H) Determination of B-H Curve Determination of Hysteris Loop Determination of Leakage Factor TESTING OF RING SPECIMENS TESTING OF BAR SPECIMENS MAGNETIC TESTING UNDER A.C. CONDITION Iron Loss Curves Hysteresis Loss Eddy Current Loss Separation of Iron Losses METHODS OF MEASURING IRON LOSSES Wattmeter Method Epstein Square Lloyd Fisher Square Comparison between Epstein and Lloyd Fisher Square

13 Contents xiii A.C. Bridge Methods Maxwell s Bridge Campbell s Bridge Method A.C. Potentiometer Method Oscillographic Method SOLVED PROBLEMS Short Questions and Answers UNIT - V [POTENTIOMETERS AND INSTRUMENT TRANSFORMERS] POTENTIOMETERS TENTIOMETERS Basic Principle of Potentiometer otentiometer Types of Potentiometers otentiometers D.C..C. POTENTIOMETER TENTIOMETER Basic Slide Wire ire Potentiometer otentiometer Crompton s s Potentiometer (Laboratory Type) ype) Duo-R -Range (or) Multiple-R -Range Potentiometer otentiometer Applications of D.C..C. Potentiometer Measurement of Resistance Measurement of Current Measurement of Power Calibration of Ammeter Calibration of Voltmeter oltmeter Calibration of Wattmeter SELF-BALANCING POTENTIOMETER A.C. POTENTIOMETERS Drysdale-Tinsley Polar Type A.C. Potentiometer Gall-Tinsley Co-ordinate ordinate Type A.C. Potentiometer Errors in A.C. Potentiometers otentiometers

14 xiv Contents Advantages of A.C. Potentiometers otentiometers Disadvantages of A.C. Potentiometer Applications of A.C. Potentiometer Voltmeter Calibration Ammeter Calibration Wattmeter and Energy Meter Calibration Measurement of Self Reactance of a Coil COMPARISON BETWEEN D.C. AND A.C. POTENTIOMETER INSTRUMENT TRANSFORMERS (I.T.).) Use of Instrument Transformer TERMS RELATING TO O INSTRUMENT TRANSFORMER CURRENT TRANSFORMER (C.T.).) Relationships in a Current Transformer Errors in Current Transformer Characteristics of Current Transformer Reduction of Errors in Current Transformer Clamp on/clip on/tong ong Tester Type Current Transformers POTENTIAL TRANSFORMER (P.T.T.).) Relationships in A Potential Transformer Errors in Potential Transformer ransformer Characteristics of Potential Transformer Reduction of Errors in Potential Transformer ransformer COMPARISON BETWEEN CURRENT AND POTENTIAL TRANSFORMER

15 Contents xv 5.11 TESTING OF INSTRUMENT TRANSFORMER Testing of Current Transformers ransformers Absolute Null Method Comparison Method Testing of Potential Transformers Absolute Null Method Comparison Method ADVANT ANTAGES GES,, DISADVANT ANTAGES AND APPLICATIONS INSTRUMENT TRANSFORMER MEASUREMENT OF IMPEDANCE CATHODE RAY Y OSCILLOSCOPE OSCOPE (C.R.O) Block Diagram of C.R.O Working of C.R.O Cathode Ray ay Tube (C.R.T.).) Electron Gun Assembly Deflection Plates Assembly Fluorescent Screen Glass Tube (or) Envelope Base Deflection Methods in C.R.O Electrostatic Deflection Magnetic Deflection Applications of C.R.O.. (or) Use of Oscilloscope in Frequency Phase and Amplitude Measurement SOLVED PROBLEMS Short Questions and Answers

16 xvi Contents PREVIOUS UNIVERSITY QUESTION PAPERS [June ] [Supplementary]... QP.1 - QP.2 [Nov./Dec ] [Main]... QP.3 - QP.4 [July ] [Supplementary]... QP.5 - QP.6 [December ] [Main]... QP.7 - QP.8.8 [June/July ] [Supplementary]...QP QP.9 - QP.10

Bhoj Reddy Engineering College for Women, Hyderabad Department of Electronics and Communication Engineering Electrical and Electronics Instrumentation

Bhoj Reddy Engineering College for Women, Hyderabad Department of Electronics and Communication Engineering Electrical and Electronics Instrumentation Academic Year: 2016-17 III B Tech II Semester Branch: