Practical electricity (in hand book form) ...

Front matter

Class Book

Kii

Aa d.

Preface

After many months of preparation, the Electricians' Handy- Book is finished and given to the reader. The work of covering the whole immense field of electrical engineering from early days to the present time would certainly be an endless one; the work of writing the present book has been lightened by the fact that the progress of electrical science in its practical aspect has been in the direction of the survival of the fittest. This tendency has had the effect of removing from the field of engineering many most ingenious devices, whose consignment to oblivion might be a subject for regret. But this disappearance of the old makes the amount to be described and learned less, and thereby lightens the labor of author and student.

It is fair to say that the development of electrical engineering is largely in the direction of simplification. In early days results inferior to those attained in the present era were secured by the use of apparatus more elaborate than that which is now employed. The evils of complication have long been recognized, and the trend of invention has been to avoid it. One of the earliest objects of the inventor was the production of an arc lamp without mechanism; the results of these efforts have completely disappeared from view, and the greatly simplified arc lamps of the present day are their successors.

The same history can be traced for other branches of the science. Quantities of the most ingenious inventions are no longer in use, simpler machinery has taken their places. For electrical engineering is nothing if not practical, and sentiment has no part in dictating what shall survive and what shall be forgotten.

Something remains to be done in the elucidation of the theory. The very name of the science has never been adequately defined, although the working theory has been developed to a high degree of perfection. The greater general familiarity with the mere names of things electrical makes the subject seem less mysterious than formerly, when the words "ampere," "volt," and the like were rarely heard outside of a college. This should not induce the student to feel that his path is any shorter than was that of his predecessors. It is if anything a much longer one, made a little easier by the fact that it is now a better-marked one. But he has more to learn than had his predecessors, and it m.ust be more exactly learned. The modern science cannot be trifled with.

This book is sent on, its way with the fullest sense of the difficulties involved in its preparation. It is hoped 'that it will meet with a favorable reception. In its writing the literature of the science has been freely used, and such classics of engineering literature as Miller's "American Telephone Practice," Crocker's "Electric Lighting," Abbott's "Electrical Transmission of Energy," and other works have been consulted at length. The author's thanks are also due to the General Electric Company, the Leeds & Northrup Company, and to many others for assistance most kindly rendered. Any suggestions which would be available for future editions of the book will be gladly received from readers.

THE AUTHOR.

Chapter I. Mathematics

Electrical Calculations — Algebra — Direct and Inverse Proporticn— Percentage — Fractions — Compound Fractions — Inverted Addition and Subtraction — Multfplication and Division — Squares of Numbers — Cancelation — Powers of Ten or Exponential Notation — Logarithms — Angular Measurements — Radian System of Angular Measurement — Trigonometric Functions — Numerical Values of Circular Functions — Greek Letters — Useful Constants — Torque — The Dynamometer — The Prony Brake — Luminiferous Ether 17-40

Chapter II. Electric Quantity And Current

Electric Quantity — Storage of Electric Quantity — Condensers — Charging — Meaning of Quantity of Electricity — Earthing a Condenser — Capacity of Condensers — Single Surface Condensers — Unit of Quantity — The Storage of Quantity of Electricity — Capacity — Dielectrics — Specific Inductive Capacity or Inductivity — Examples of Capacity — Microfarad — Current and Rate Units — Conductors and Non-Conductors — Ether Waves Produced by Electricity — Action of a Conductor — Time Required to Produce a Current — Production of Current — Current, Amperes, and Coulombs — Current Strength or Intensity — Analogy for the Ampere — Speed of a Current — Arrival Curve — Direction of a Current — Memoria Technica — Field of F'orce and Lines of Force Due to Current — Electromotive Force — Production of Electromotive Force — Dynamic and Static Electricity — Electromotive Force and Energy — Conservation of Electricity — Electromotive F'orce and the Static Charge — Electromotive Force in Thunder Clouds — Electromotive Force the Cause of Current — Drop of Potential — Analogies of Drop of Potential — Electromotive Force and Difference of Potential — Voltage 41-62

Chapter III. The Electric Circuit

Ttie Electric Circuit — Constitution of a Circuit — Condensers in a Circuit — Open and Closed Circuits — Circuits Without Appliances — Appliances and Generators in Circuits — Electrolytic Conductors — Actions of a Circuit — Parallel and Shunt — Series — Series Multiple — Multiple Series — Series and Parallel — Outer Circuit — Short Circuit — Conductibility, Conductance, and Conductivity — Resistance — Resistance and Energy — The Ohm — Internal and External Resistance — Circuit Without Resistance — Electrolytic Conduction 63-73

Chapter IV

ohm's law.

Three Elements in a Circuit — Ohm's Law — Examples of Ohm's Law — Five Forms of Ohm's Law — Importance of Ohm's Law — Power — Examples — Constant Current Circuit — Constant Potential Circuit — Drop and Pall of Potential — R. 1. Drop and Counter E. M. F. — Examples of Power Calculations — Calculation of Resistance of Parallel Circuits — Examples of R. I. Drop Calculations — Example of Counter Electromotive Force Drop Calculations — Kirchhoff's Laws — Conductance and Cross-Sectional Area of Conductors — Circular Mil System — Application — Area of a Circular Mil — Examples — Wire Gauges — American Wire Gauge 74-87

Chapter V. Electro-chemistry

Water Decomposed by the Coulomb — Hydrogen Liberated by the Coulomb — Proportion of Hydrogen to Oxygen — Atomic Weights and Chemical Equivalents — Electro-Chemical Equivalents — Current Strength and Chemical Decomposition — Sammary — ^Example — Electromotive Force in Chemical Decomposition — Voltage Calculation 88-93

Chapter VI. Primary Batteries

The Primary Battery Cell — Three Constituent Parts — Simple Batteries ■ — 'ISomenclature — Negative and Positive Plates — Cell, Couple, and Pair — Exhaustion and Polarization — ^Local Action and Amalgamation — Volta's Battery — Volta's Pile or the Galvanic Pile — Wallaston's Battery — Hare's Calorimeter — Zamboni's Pile — Modern Batteries — Smee's Battery — Iron Negative Plates — Aluminium Negative Plates — Grove's Battery — Carbon Negative Plates — Moving Electrodes — Bunsen's Battery — Modifications of Bunsen's Battery — Gibbs' Battery — Poggendorff's Battery — Modifications of Poggendorff's Battery — Fuller's Mercury Bichromate Battery — Camacho Cascade Battery — ^Baudet Siphon Battery — Radiguet Battery — Grenet's Battery — Dip Batteries — Partz's' Battery— Depolarizing Mixtures and Exciting Solutions in Batteries of the Poggendorff Type — Mixtures of Sulphuric and Nitric Acids — Potassium Bichromate Solutions — The Daniell Battery — Modifications of Daniell's Battery — Sand Type of Daniell's Battery — Gravity Battery — Meidinger's Battery — Modification of the Gravity Cell — Caustic Alkali Batteries — Modifications of the Lalande and Chaperon Battery — Ammonium Chloride Batteries — Dry Batteries — Arrangement of Batteries 94-124

Chapter VII. Storage Batteries

The Primary Battery — Action of a Storage Battery — Regeneration — Grove's Gas Battery — Requirements of a Storage Battery — Function — Plante's Battery — F'orming — Storage Capacity — Faure's Battery — The Faure-Sellon-Volckmar Battery — Chemical Action — Resistance — Gould Storage Battery — Flelios-Upton Battery, Philadelphia — American Storage Battery — Crompton-Howell Battery — Pasted Plates — B. P. S. Battery — Chloride Battery — Tudor Battery — Suspended Plates — Other Types of Pasted Plates — Copper Storage Batteries — Zinc Acid Storage Batteries — ■ Waddell-Entz Battery — Edison's Storage Battery — The Discharge — Discharge on Open Circuit — Manufacturer's Data — Determination of Discharge — The Charge — ^Specific Gravity Variation of Electrolyte — Hydrometers — Gassing — Gas Evolution — The First Charge — Automatic Cut-off or Circuit Breaker — English Rule for Charging — Overcharge — Prevention of Sulphating — Short-Circuiting of Single Cells — Sediment — Buckling — •

CONTENTS.

Disintegration — Setting up a Battery — Preparing the Electrolyte — Impurities in the Electrolyte and Tests — Indications from Gassing — -Cadmium Plate — Connections for Charging from Lighting Circuits — The Polarity of the Circuit — Taking Out of Service — Cells — Insulation of Cells — Making Battery Connections — Practical Notes — End Cells — Counter Electromotive Force Cells — Floating Battery — Charging Plant Operation. 125-166

Chapter VIII. The Field Of Fokcb

The Field of Force — Ether and Current — Detection of the Field — Lines of Force Produced by a Curved Conductor — Motion of a Conductor in a Field of Force — Direction or Polarity of Lines of Force — Memoria Technica for Lines of F'orce — ^Utility of the Conception of Lines of Force — Density of a Field — The Magnetic Circuit — Energy and the Magnetic Circuit — Counter and Forward Electromotive Force — Building up the Field of Force — Potential Energy of the Field of Force — Energy and the Field of Force — Nature of the Magnetic Circuit — Permeability and Permeance — Iron and the Field of Force — Saturation — Three F'actors of the Magnetic Circuit — Magnetic Forc?s — Ampere Turns — Field Density — Permeability — Saturation of Iron — No Insulator of Magnetism — The Gauss — Reluctance and Reluctivity — Synonyms for B, H, and mii — B and H Curves — ^Interpretation — Practical Considerations — Permeability Curves — Soft Steel in Dynamos — Annealing — Determination of Curves — Relation Between Ampere Turns and Lines of Force — Leakage of Lines of Force — Stray Field — Permeance of a Magnetic Circuit — Hysteresis — Residual Magnetism — Hysteresis Curves — Loss of Energy Due to Hysteresis — Hysteretic Constant 167-187

Chapter IX. Magnets

The Electro-Magnet — Tractive Force of the Electro-Magnet — Spreading of Lines of Force — Illustrating Lines of Force About a. Magnet — Spiral Electro-Magnet — U-Shaped Electro-Magnets — Annular Chambered Magnet — Electro-Magnetic Tractive Power — Multipolar Magnets — Various Armatures — The Natural Magnet — The Permanent Magnet — Action of Magnet Poles on Each Other — Making Magnets by Single Touch — Making Magnets by Double Touch — Making U-Shaped Magnets — :\Iagnetizing by Coil and Electro-Magnet — Steel for Magnets — Preservation of ^Magnets — Examples of Permanent Magnets — Polarized and Magnetized — Constancy of Magnetism — Mutual Action of Currents — Ampere's Theory of Magnetism — ^Memoria Technica — Ampere's Theory of Terrestrial Magnetism — Attraction and Repulsion of Magnetic Poles — Action of a Current on the Magnet — Ampere's Rule — ^Right-Handed Screw Law 188-204

f

Chapter X. Induction

Electro-magnetic Induction — Threading, Interlinking, and Cuttting Lines of Force — Induction — Conditions for Inducing Electric Energy — Examples of Interlinking — Motionless Conductor in a Field of Force of Varying Density — Energy Relations — Fields of Force in Practice — Direction of Current Induced by Cutting Lines of Force — Two Systems of Induction ■ — Generator Without Motion — Examples of Induction — Telephone Receiver a Dynamo — Laws of Induction — Faraday's Law — Fleming's Rule — ^Ampere's Rule Adapted to Induction — Clerk-Maxwell's Rule— Lenz's Law — Example of the Application of Lenz's Law — Foucault or Eddy Currents — Variations in Impressed Electromotive Force — Direction of Currents Induced in Coils 205-217

8 ELECTRICIANS' BANDY BOOK.

Chapter XI. Direct-current Generators And Motors

Dynamo-Electric Generators — Interchangeability of Dynamo and Motor — Varieties of Dynamos — Elementary Idea of an Alternating Current Dynamo — Collecting or Slip Rings — Brvishes — Elementary Idea of a Direct-Current Dynamo — Increasing the Electromotive Force by Increasing the Turns — Increasing the Electromotive Force by Adding an Armature Core — Armature and Core — Field Poles — Open-Coil Armatures — Spindle or H Armature — Closed Coil Direct-Current Armature — ^Cutting Lines of Force Without Change in Number of Interlinking Lines 218-224

Chapter XII. Direct-current Armature Winding

Armatures — The Pacinotti Armature — The Gramme Ring — Modern Types of Closed-Coil Armatures — Commutator Connections of Ring Armature — Cores of Ring Armatures — Permeance of the Ring Core — Idle Wire — Circuit in a Ring Armature — Open-Wound F'our-Part Ring Armature — Mounting of a Ring Armature — Multipolar Ring Armature — The Drum Armature — Action of the Drum Armature — Drum Armature Winding — Simple System of Armature Winding — Eight Conductor Drum Armature — Twelve Conductor Bipolar Armature — Sixteen Conductor Bipolar Armature — Winding Tables — Windings for Multipolar Fields — Eighteen Conductor Four-Pole Armature — Circular Development — Commutator Connections — Wave and Lap Winding — Wave Winding — Lap Winding — Development of Commutator Connections — Development of Field Poles — Development of Current Induced — Straight Developments — Winding a Drum Armature — General Considerations in Laying Out Drum Armature Windings — Single Layer Winding for Bipolar Field — Double Layer Winding for Bipolar Field — Commutator Connections — Multipolar Windings — Multipolar Lap Windings — Nomenclature for Drum Armature Windings — General Formulas — Bipolar Winding by Formula — Multipolar Winding by Formula — Lap Winding 225-249

Chapter XIII. The Direct-current Generator

The Magneto Generator — The Modern Multipolar Dynamo — Field Winding of Dynamos — Series Winding — Action of Series Winding — Shunt Winding — Action of Shunt Winding — Compound Winding — Short Shunt Compound Winding — Long Shunt Compound Winding — Action of Short-Shunt and Long-Shunt M^inding — Self-Regulation of Compound Wound Dynamos ■ — Characteristic Cur/es — Over-Compounding — Example of Compound Winding Calculation — Excitation of Field Coils in Compound Dynamos — ■ Effect of Independent Excitation of Shunt Coil — Disconnecting or Opening the Shunt Coil — Separate Excitation of Shunt Coil — Exciting Series Coils from Main Circuit — Separately-Excited Generators — Action of the Separately-Excited Dynamo — Regulation of Separately-Excited Dynamos and Magnetos — The Separate Circuit Dynamo — Separately and Self-Excited Dynamo — Multipolar Dynamo Connections — ^Conventional Representation of Machines 250-264

Chapter XIV. Armature Reactions

Armature Polarity Due to its Windings — Action of Field Poles on Armature Core — Field Distortion — Armature Reaction Diagrams — Varying Densities of Field — Neutral Points — Brush Adjustment — Demagnetizing Turns — ^Reduction of Field Density — Action of the Demagnetizing Turns — Dead Turns — Spurious Resistance — Eddy or Foucault Currents — Eddy

CONTENTS. 9

Currents in Armature Cores — Eddy Currents in Core Disks — Eddy Currents in Pole Pieces — End Leakage of Lines of Force in Armature — Eddy Currents in Conductors 265-272

Chapter XV. Chaeacteeistic Cueves

Characteristic Curves — Horse-Power Lines — Types of Characteristic Curves — Drooping Characteristic — Interpretation of Characteristic Curves — Data for External Characteristic Curves — Data for Total Characteristic Curves — Drawing Characteristic Curves — Internal Characteristic — Terminology of Analytical Geometry — Line of Ohms — General Notes on Characteristic Curves — Critical Current — Shunt Wound Dynamo Characteristic — Critical Point of Shunt-Wound Dynamo — Total Current Characteristic in Shunt Dynamo — Total Characteristic of Shunt Dynamo — Ohm- Volt Curves 273-284

Chapter XVI

Direct-Current Electric Motor and Torque — Reversibility of Dynamo and Motor — Generator and Motor Connected — Counter Electromotive Force — Action of Counter Electromotive Force — Relations of Speed of Generator and Motor Connected — Counter Electromotive Force and the Armature 285-288

Chapter XVII. Open-coil Geneeatoes

Open Coil Armature Winding — The Brush Dynamo — Brush Dynamo Construction — The Thomson-Houston Armature — Homopolar, Acyclic or Unipolar Dynamo — Relation of Size and Output of Dynamos — Manufacturer's and Thompson's Rules — Deduction of Thompson's Factor — The Sixth Power Rule 289-296

Chapter XVIII

Disks for Smooth Surface Armature Cores — Disks for Grooved Armature Cores — Formed Coils — Wire Winding — Insulation of Conductors — Core Grooves and Wooden Wedges — Winding Armatures with Formed Coils — Pole Armatures — Disk Armature — Commutator Construction — Position of Commutator — Brushes and Brush Holders — Tangential Brushes — Trimming Metal Brushes — Radial Brushes — Position of Opposite Brushes — Brush Rigging — Relation of Depth of Air Gap to Sparking — Field Magnet for Multipolar Dynamos — Laminated Field Magnets — Sectional Laminated Field Magnets — Details of Multipolar Field Windings 297-315

CHAPLER XIX.

THE ALTEENATING CUEEENT.

Alternating Electromotive Force — Cycle, Wave and Frequency — Electromotive Force and Current Curve — Production of Alternating Electrom-otive Force and Current — Length of a Wave — Form of Alternating Electromotive Force and Current — Length of Wave and Frequency — ■ Cause of the Form of Alternating Electromotive Force and Curi-ent — Alternating Electromotive Force and Current Curves — Drawing the Electromotive Force and Current Curves — Degree System — The Sine Curve- Generating Circle — Interpretation of the Generating Circle — Rate of

Change — Graphic Representation of Rate of Change — Radius Vector and Resultant — Vector Diagram of a Sine Curve — Phase, Lag and Lead — ■ Angle of Lag and Lead — Quadrature and Opposition^Basis of Lag and Lead — Average Values — Effective Values — Calculation of Effective Values ■ — F'orm Factor — ^FormuIas for Effective Values — Power Factor — Qualities of a Circuit — Resistance — Reactance — Inductance — Inductance and the Henry — Electromotive Force in an Alternating Current Circuit — Counter Electromotive Force — Forward Electromotive Force — Counter and Forward Electromotive Force in an Alternating Current Circuit — Turns of a Circuit and Inductance — Reactance of Inductance — Ohmic Equivalent of Reactance of Inductance — Inductance Reactance in Subdivided Conductor — Capacity — Reactance of Capacity — Ohmic Equivalent of Reactance of Capacity — Impedance — Electric Resonance — Causes of Lag and Lead — Summation of Alternating Quantities — Composition of Resistance, Inductance and Capacity — Multiplication of Alternating Quantities — Power Curves — Two-Phase Current — Three-Phase Current 316-347

Chapter XX. Alternating Cuebent Geneeators

Generation of Alternating Current — Sjngle-Phase Armature — Multipolar Construction — Grouping of Windings — Principle of Alternating-Current Armature Winding — Drum-Armature Connections — Elementary Four-Pole Single-Phase Armature — Single-Phase Wave and Lap Winding — Ring Winding for Alternating Current — Conventional Representation of Collecting Rings — Pole Single-Phase Armature — Rotor and Stator — Inductor Alternator — Disk Windings — Two-Phase Winding — Three-Phase Winding — Six-Wire Connection of Three-Phase Alternator Winding — Y or Star Connections — Delta or Mesh Connection — Line Connections — Neutral Wire in the Y System 348-362

Chapter XXI. Alternating Current Motors

The Induction Motor — The Rotary Field — Magnetic Needle in a Rotary Field — Armature in a Rotary Field — ^Three-Phase Induction Motor — Induction Motors — Rotary and Revolving Field — Starting Torque — Squirrel Cage Armature — Starting Resistances — ^Starting Compensator — Lenz's Law and the Induction Motor — Construction of Induction Motors — The Synchronous Motor — Condition of Operation — Single-Phase Synchronous Motor — Synchronous Polyphase Motor — Self-Starting Synchronous Motor.

363-374

Chapter XXII. Transformers

Basis of Transformer Construction — Object of a Transformer — Choking ■ — Limitations of a Transformer — The Principle of a Transformer — Shell or Jacket Type of Transformer — Step-Up and Step-Down Transformers — Ratio of Transformation — Shell-Type Transformer — Core Transformers ■ — Disk-Wound Transformers — Pancake Coils — The Autotransformer — Action of the Transformer — Heat in Transformers — Oil Cooling — Water Cooling — Air Blast Cooling — Details of Transformer Construction — Shell- Type Transformers — Disk Winding — Constant Current Transformers — Oil for Transformers — Insulation in Transformers — Direct Current from Alternating Current — Rotary Converter — Use of the Rotary Converter — Principles of Construction — Relation of Voltage and Current — ^Rotary Converter in the Three-Wire System — Starting a Rotary Converter — ■ F'unctions of a Rotary Converter — The Rectifier — Operation of Transformers 375-396

CONTENTS. 11

Chapter XXIII. Management Of Motors And Dynamos

Starting Motors — The Starting Boxes — Magnetic Release Starting Box — Starting-Box Connection — Clianging Voltage — Motor Transformer — Action of tlie Motor Transformer — Step-Down and Step-Up Transformer — Motor Transformer I*ractice — Ttie Economy of Motor Transformers — Parallel Coupling of Dynamos — Parallel Coupling of Shunt Dynamos — Parallel Coupling of Compound Dynamos — Shunt-Wound Machines in Series — Reversal of Direction of Armature Rotation — Polarity Tests — Alternators in Step — Synchronizing — Regulators or Boosters — Booster Connections — Hand Regulation of Boosters — Automatic Regulation of Boosters — Booster Construction — Motor Dynamos as Boosters — Compensators — Floating Battery — ^Booster and Storage Battery Connections — ■ Crushers — The Crocker-Wheeler System of Speed Control — Accidents to Motors 397-415

Chapter XXIV. Care Of Dynamos And Motors

Reversing the Direction of Current — Stopping a Machine — Too High Speed — Loss of Magnetic Polarity — Wrong Polarity of Field — Refusal of Motor to Start — Slow Speed Without Load- — Idle Motors — Speed Regulation of Motor Without Load — Starting and Stopping Motors — Bad Contacts Between Winding and Commutator Bars — Temperature of Commutator — Collector Rings — Materials of Commaitator — Loose Commutator Bars — Oval Commutator — A Gummy or Sticky Commutator Surface — Lubricating the Commutator Surface — ^Erushes and Brush Holders — Brush Pressure—Replacing Brushes — Position of Brushes — Copper Brushes — Carbon Brushes — Setting Brushes — Hard Carbon Brushes — Lifting Brushes— End Motion in an Armature Shaft — Short Circuits in Armature — Sparking at the Commutator — Starting a Machine — Starting a Dynamo — Armature Running — Balancing of Armature — Centering of the Armature — Armature Out of Center — ^Foucault or Eddy Currents — Heating of Field Coils — Break in the Field Winding — Short Circuits in Field Winding — Earthing Dynarao Frames — Short Circuits in Outer Circuits — Wrong Connections in Compound Dynamos — Turning Down a Commutator — Sandpapering and Smoothing a Commutator — To Sandpaper a Commutator — Filing a Commutator — Short Circuits — Short Circuits Between Armature Windings and Frame — Alternator Brushes — Trouble in Rotors of Alternators — Self- Starting One-Phase Motor — Local Heating of the Windings of the Stator — Induction Motor Rotors — Svnchronous Motors — Polyphase Induction Motors — Field Ma.gnets of Alternators — Two-Phase Oper?tion — Breakdowns in Transformers — Care of Transformers — Oil for Filling Transformers — Moisture in Transformers — Inspection of Transformers — Short Circuits in Transformers 416-438

Chapter XXV. Station Notes

Temperature of Dynamo or Motor — Cleaning New Machine — Tnterchangeability of Parts — Cotton Waste — Access of Air — Oiling — Ring Oiling — Bearings — ^Safetv Fuses — Insulation of Windings — Broken Wires — Soldering — Nails, Tacks, and Iron Filings — Screws in Binding Posts — Covering Machines — Emera-encies and Danscer Sisnals — Forgetfuiness and Negligence — Keep One Hand in Your Pocket — Treatment of Electric Shock.

439-444

Chapter XXVI. Switchboards

Switchboards — Panels — Air Switches — Oil Switches — Overload and Ur'derload Cut-Outs — ^Safety Fuses — Overload Circuit Breakers — Underload Circuit Breakers — MagTietic Release Underload Circuit Breaker — • Mechanical Release Underload Circuit Breaker — Reverse Current Circuit Breaker — Combined Circuit Breaker — Circuit Breakers as Switches — • Alternating-Current Potential Regulator — Direct Current Ground Indicator — Ground Alarm 445-457

Chapter XXVII. Voltmeters And Ammeters

. The Voltmeter — Weston's Voltmeter — Damping Coil — Air Vane Damping — Empire Voltmeters — Graduation of Voltmeter Scales — General ISotes on Voltmeters — Cardew Voltmeter — Hot Wire Instruments — The Stanley Hot-Wire Instrument — .Ammeters — Total-Current Solenoid Ammeter — ■ Shunted Ammeter — Transformer Ammeter — Wattmeter — Pressure Lines or Pilot Wires — Compensated Voltmeters— Compensators — The Ohmic Compensator — The Inductance Compensator 458-471

Chapter XXVIII. Distribution

Two Distribution Systems — Arc and Incandescent Lamp Circuits — Constant-Current Systems — Constant-Potential Systems — Series Distribution — Limitations — Features of Series or Constant-Current System for Arc Lamps — Calculations — Advantage of High Potential — Standard Series Lighting Current — Series Incandescent Lighting — Film Cut Out — Relief Lamps — Multiple Series System — "Municipal" Series Incandescent Lighting — Series-Multiple System — Objections to Series Distribution — Parallel Distribution — Disadvantages of Parallel Distribution — Elementary Case of Parallel System — Potential Drop in Parallel System — Feeders, Mains and Leads — ^Classification — Loop System — Tree System — Closet System — Cylindrical and Conical Conductors — Calculation for Conical Conductor — Anti-Conical System — Anti-Parallel System — Individual Voltages of Lamps — Relations of Current to Drop — Uniform Potential Methods — Automatic Regulation of Voltage — -Independent Circuits — F'eeders — Auxiliary Feeder Connections — Transfer Bus-Bar — Example — Feeder Economy — Three Wire System — Saving in Copper — Two-Dynamo Three-Wire System — Single-Dynp.mo Three-Wire System — Three-Brush Dynamo — Storage Batteries in the Three-Wire System — Storage Battery Equalizer in Three- Wire System — Balancing Dynamo — Motor and Booster — Five and Seven- Wire System — High-Voltage Parallel Systems — Alternating-Current Distribution — Individual Transformers- -Choke Coils — Y Connection for Alternating Current — Delta Connection — Joints in Line Wire — Insulators.

472-512

Chapter XXIX. Electric Meters

Electric Meters — Wattmeter — Edison's Meter- — Forbes' Meter — Thomson's Meter — Shallenberger's Meter 513-517

Chapter XXX. Lightning Arresters

Lightning Arresters — Lightning Protectors — Comb or Saw-Tooth. Arrester — Magnetic Blow-Out Arrester — Non-Arcing Metal Arrester — Discriminating Arrester — Westinghouse Lightning Arrester — Low Equivalent Alternating Current Lightning Arrester — Double-Pole Lightning Arrester ■ — Tank Lightning Arrester c -- 518-522

CONTENTS. 13

Chapter XXXI. The Incandescent Lamp

Incandescent Lighting — The Incandescent Lamp — Tamidine Filaments - — Squirted Filaments — Carbonization — ^Calibration — Flashing — Occlusion of Gases by Filament — Lowering of Resistance by Flashing — Making Joints by Flashing — Pasted Joints — Electroplated and Other Joints — Leading-in Wires — Making the Lamps — Vacuum — Production of Vacuum — The Mercury Air Pump — Luminescence — Metallic Filaments — Oxide Filament — The' Nernst Lamp — The Glower — Glower Terminals — Heaters Ballast — The Cut Out — Direct Current Lamps — Vacuum Lamps — The Efficiency of the Nernst Lamp — Distribution of Light 523-534

Chapter XXXII. The Arc Lamp

The Voltaic Arc — Positive and Negative Carbons — Striking the Arc — Heat of the Arc— Voltage Drop — Counter Electromotive F'orce — The Resistance of the Arc Proper — 'Efficiency of the Arc Light — Quality of Carbons — Power Consamed in Arc — Effect of Air Blast — Effect of Magnet — Voltage Drop and Arc Length — Wearing of Carbons — Arc Light Carbons — The Direct Current Open Arc — Distribution of Light in Direct- Current Open Arc — Commercial Rating of Arc Light — Hissing Arc — Light Given by Arc Proper — Resistance of Short Arcs— The Resistance of Longer Arcs — Stationary State — Alternating-Current Arc — Power Factor in Alternating Current Arc — Influence of Wave Form — Distribution of Light of Alternating Current Arc Lamps — Reactance Coil or Economy Coil — Efficiency of Alternatrng Current Arc Lamps — Noise — Duration of Carbons — Length of Arc — Id closed-Arc Lamps — The Action of the Inclosed Arc — Globe and Carbon Holder — Inclosed Arc Lamp Carbons — The Clutch — Tripping Platform — Carbon Feed Lamps — Concentric Magnets — Dash Pots — Carbon Holders — Constant Current or Series Arc Lamp — Adjusting Weight — Action of an Arc Lamp on a Constant Potential Circuit — Action of the Resistance Coil in a Constant Potential Arc Lamp — The Parallel-Circuit System of Electric Supply — Constant- Potential Arc Lamps — Management of Inclosed-Arc Carbons — Adjusting Lamps — The Inclosing Globes — Negative and Positive Connections in Inclosed-Arc Lamps — Putting a Lamp Into Service — Oil — Clutcn Stop Adjustment — Cut-Out — Carbons for Inclosed Arc Lamp — To Carbon a Lamp — Lamps Without Mechanism — The Jablochkoff Candle — ^The Wallace Lamp — ^The Sun Lamp — Open-Air Incandescence 535-562

Chapter XXXIII. Photometry

Standards of Illuminating Power — Principle of the Photometer — Bar Photometer — Pnotometric Screens — The Bunsen Disk — The Leeson Disk — ■ Mounting the Disks — The Lummer-Brodhun Screen — The Standard English Candle — The Apparatus — Calculating the Scale of the Bar — The Observation — Other Standards — Table of Photometric Standards — ^Shadow Photometer — ^Bouguer's Photometer— Foucault's Photometer — Direct Photometry of an Arc Lamp — The Luminometer — Pupillary Photometer — Diffractive Photometer — Spherical Candle Power — Candle Power of Incandescent Lamps — The Photometry of the Arc Lamp — Mechanical Equivalent of Light — Watts per Candle Power in Arc Light — Watts per Candle Power in Incandescent Lamp — Quality of Arc Light — Distribution of Light from Arc Lamps in Service — Distribution of Light from Incandescent Lamps 563-588

Chapter XXXIV. Electric Railroads

The Electric-Car Motor — Standard Voltage and Allowable Temperature — Cause of Motor Heating — The Copper Loss — ^Determining the Heating of Motors — Conditions Causing Heating — Horse-Power of Car Motors — Traction Table — Construction of Electric-Car Motor — Switch Boxes and Circuit Breaker — Lightning Arresters — Controllers — Controller Points — ■ Driving Points: — Series-Parallel Controller — Hot Resistance — Blow-Out Magnet — Reverser — Board and Cut-Outs — Rheostat Controller — Motorman's Duties — Economical Running — Excessive Use of the Brake — Flat Wheels — Sliding Wheels — Skidding Wheels — Reversing — Leaving the Car — Bad Ground — Refusing to Start — Fuses — Examining Connections — ■ Controller Troubles — Broken-Down' Controller — Motor Troubles — Emergency Stop — Jerking Car — Car Heating — Electric Radiators — Power Circuit and Feeders — Insulators 584-608

Chapter XXXV. Electrical Measuring Instruments

The Galvanometer — Simple Galvanometer- Astatic Galvanometer — Fiber Suspension — Reflecting Galvanometer — Arrangement of Reflecting Galvanometer — Translucent Scale — Plane Mirror Reflecting Galvanometer — The Thomson or Kelvin Galvanometers — Regulation of Sensibility — • The Ballistic Galvanometer — The Deprez-D'Arsonval Galvanometer — Ballistic Measurement — Ballistic Calculation — The Tangent Galvanometer — The Sine Galvanometer — ^The Thomson or Kelvin Absolute Electrometer — Galvanometer Shunts — Compensating Resistance — Constant of a Galvanometer — Determination of the Constant- — Figure of Merit — Galvanometer Resistance — Siemens's Dynamometer — Rheostats — Resistance Coils — Resistance Boxes — Resistance Wire — The British Association Standard Ohm — Arranp-ement of Coils — Siemens's Plan — Modern Arrangements — The Decade Plan — Details in Coxistruction of Resistance Boxes — ^Metal Spools — Practical Notes — Wheatstone Bridge or Bridge Box — Operation of the Wheatstone Bridge — -Null Methods — The Meter Bridge — Bridge Key — Shunt to the Galvanoscope — Proportional Coils — Galvanoscope — Conditions of Sensitiveness — Direction of Deflection — The Potentiometer — Principle of the Potentiometer — High-Voltage Determinations with the Potentiometer — Current Measurement with the Potentiometer. . .604-641