DOCSLIB.ORG

426444764 Att'ys

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
426444764 Att'ys No. 1,836. Reissued June 26, 1900. L. GAULARD, Dec'd. &. J. D. GIBBS. THE WESTINGHOUSEELECTRIC COMPANY, Assignee. SYSTEM OF ELECTRICAL DISTRIBUTION. Application fled Aug. 6, 1889.) 2. Sheets-Sheet . ii. Ow HE aS77MGHOASA Adeo/AP/O Co. ASS16AEA OA LUCIEN CALL ARD - OECD JOHNIXON-IBBS. 1N WEMJOS 426444764 Att'ys No. 1,836. Reissued June 26, 1900. L. GAULARD, Dec'd. &. J. D. GIBBS. THE WESTINGHOUSEELECTRIC COMPANY, Assignee. SYSTEM OF ELECTRICAL DISTRIBUTION. Application fled Aug. 6, 1889.) 2. Sheets-Sheet 2. II " " . I D R 1.9, MI H E seese 7A/AMA, SAA/GA/02/SAAZAC/APC Co, ASS/GN E E Of LUCIEN CALL ARD-DEC D. JOHN DIXN EBS. fAZ JORS. /62/6ela, 244 as UNITED STATES PATENT OFFICE. 1. --- THE WESTINGHOUSE ELECTRIC COMPANY, OF PITTSBURG, PENNSYLVANIA, AND JOHN DIXON GIBBS, OF LONDON, ENGLAND, FOR THE WESTING. HOUSE ELECTRIC COMPANY, ASSIGNEE, BY MESNE ASSIGNMENTS, OF IUCIEN GAULARD, DECEASED, AND JOHN DIXON GIBBS, ASSIGNOR TO THE WESTINGHOUSE ELECTRIC AND PITTSBURG, PENNSYLVANIA. MANUFACTURING COMPANY, OF systEM of ELECTRICAL DISTRIBUTION. SPECIFICATION forming part of Reissued Letters Patent No. 11,836, dated June 26, 1900. Original No. 351,589, dated October 26, 1886. Application for reissue filed August 6, 1889. Serial No. 319,955, To all w/von, it may concern: a transverse vertical section of one form of Be it known that LUCIEN GAULARD, de converter, and Fig. 3 is a diagram showing ceased,late a citizen of the Republic of France, one plan of arranging the apparatus when the and JoHNDIXONGIBBS, a subject of the Queen transference of energy is to be effected at more 5 of Great Britain, and a resident of London, in. than one point. 50 the county of Middlesex, England, were the In the drawings, D represents a dynamo original, first, and joint inventors of certain electric generator of suitable construction,or new and useful Improvements in Methods of ganized for the production in the main line and Apparatus for the Distribution and Con of alternating currents-that is to say, suc Io version of Electric Energy, of which the fol cessive electric currents or pulsations alter 55 lowing is a specification. nately of positive and negative polarity and The said invention relates to the distribu of equal potential and duration. It has been tion of electrical energy for industrial pur found by experiment that the dynamo-elec poses; and it consists in an improved art or tric machine of Alteneck, described in United f5 method and an organization of apparatus States Letters Patent No. 234,353, of Novem whereby the same is carried into effect, by ber 9, 1880, is well adapted for said purpose; means of which it is possible to transmit from but it is not desirable to be confined to any a central or supply station, through a main particular construction of generators for set conductor, a primary electric current of com ting up alternating currents in the line, as 2o paratively-small quantity, but of high poten there are many forms of these known and tial, and at a point or points more or less dis used which will serve sufficiently well. tant, where the said electric energy is to be In order to operate a dynamo-electric ma utilized to transfer the energy residing in such chine for the production of alternate cur primary current of high potential into one or rents, it is necessary to provide some means 25 more secondary currents of lower potential, for maintaining its magnetic field. This may o but of greater quantity. be accomplished by a separate current de To this end the invention comprises certain rived from an independent dynamo-machine, combinations of apparatus having an organi technically termed the 'exciter.' Such in zation and mode of operation particularly dependent exciter is shown in the drawings 3o adapted to effect such transference of electric at E. It may be an ordinary direct-current 75 energy. dynamo - machine of any suitable construc f means of the said improved method and tion. The current of the exciter E is con apparatus it becomes possible to conveya use ducted from its terminals n n by means of ful quantity of electric energy to a much wires 1 and 2 to and through the field-mag 35 greater distance than has heretofore been nethelices of the main dynamo or generator D. practicable, while the cost of the necessary In order to vary, when required, the elec plant for electric lighting and other analogous motive force of the generator D, it is conven purposes, especially that of the main elec ient to effect a corresponding variation in the trical conductors, is very materially dimin strength of the current in the field produced 4o ished. by the exciter E. This may be done in the The accompanying drawings represent an case of a shunt-Wound exciter by an adjust organization of apparatus which has been able resistance inserted in the field of the ex found to be well adapted for carrying out the citer. This plan is shown in the drawings. said invention. R is a rheostat composed of a series of grad go 45 Figure 1 is a theoretical plan showing the uated resistance-coils r r, &c. A movable general principle of the apparatus. Fig. 2 is contact-arin or other equivalent device S is 11,836 provided, by means of which the current for netic field. In the particular artingemefit maintaining the field produced by the exciter shown in Figs. 1 and 3 of the drawings each E may conveniently be regulated. The same convolution of the secondary conductor is in o result may be reached in other well-known terposed between two adjacent convolutions 5 ways. The power for operating the main dy of the primary conductor, so that the number namo D, as well as the exciter E, is furnished of convolutions, as well as their mean distance by a suitable steam-engine or other conven from the axis of the core, is the same. Experi ient motor M. ence indicates that the more nearly the last 75 At a point where the electric current is to mentioned relation is preserved the higher to be utilized for any suitable purpose-as, for will be the efficiency of the apparatus. The instance, in one or more incandescent elec relative disposition of the primary and second tric lamps-is placed one or more secondary ary helices may otherwise be greatly varied generators or converters, as shown at C in without materialehange in the result. For ex Fig. 1. The general principle of the said sec ample, one maybe superposed upon the other, t5 ondary generator is analogous to that of the as in Fig. 2, or the two may be placed upon well-known inductorium or induction - coil different parts of the same core or cores, ac with this exception, that while the induction cording to circumstances. coil has heretofore usually been employed to It is to be observed that the secondary con transfer electric energy from currents of low ductors shown in Fig. 1 of the drawings are 20 potential and great quantity into currents of not united in series like the primary conduc high potential and small quantity the fanc tors; but their ends are joined together, as tion of the secondary generator or converter shown at III and IV, in parallel or multiple as applied in the said invention is precisely are, and from the last-named junction-points : the reverse of this-namely, to transfer elec of the secondary the conductors W and WI are 25 tric energy from currents of high potential to led to an electric lamp or other translating currents of low potential and increased quan device L, by which the circuit is completed. tity. Converters have been constructed for The mode of operation of the apparatus will effecting this result in a variety of forms, all now be described. 95 of which involve the same principle. In or When the dynamo-electric generator D is 30 der that this principle may be better under set in operation, a rapid succession of alter stood, we will describe the construction and nating positive and negative currents or pull mode of operation of a simple form of the sations of equal potential and duration, tech converter, which is shown at C in Fig. 1. Two nically termed an 'alternating' current, are Od iron cores b b are preferably built up from set up in the main or primary conductor, the 35 a large number of small soft-iron wires, insu path of which may be traced in Fig. 1, as fol lated from each other and mechanically se lows: from one terminal of the generator D cured together in a solid bundle. by the line conductor 3 to the primary con It is usually preferable to unite the ends of ductors 4 and 5 of the secondary generator C, the cores so that they will become magnetic thence returning by the line conductor 6 to 40 ally continuous. In Fig. 3, for example, the the opposite terminal of the generator. The cores are shown in the form of a rectangle; alternate current proceeding from the pri but the core or cores may be straight cylin mary generator D by its inductive action in ders or closed figures of oval, annular, horse the secondary generator C creates a magnetic shoe, or other shape, this being merely a mat field of alternate polarity, and this alterna 45 ter of convenience in construction or econo tion of the magnetism of the field, in accord my in operation, but involving no change of ance with a well known law, generates by in principle.
Load more

Recommended publications
  • Transformers, the Unsung Technology
    NUMBERS DON’T LIE_BY VACLAV SMIL OPINION lem. It so puts to shame all mechanical attempts at regulation, it handles with such ease, certainty, and economy vast loads of energy that are instantly given to or taken from it. It is so reliable, strong, and certain. In this mingled steel and copper, extraordinary forces are so nicely balanced as to be almost unsuspected.” The biggest modern incarnations of this enduring design have made it pos- sible to deliver electricity across great distances. In 1890, de Ferranti stepped up from 2.5 kilovolts to 10 kV, enough to bridge 11 kilometers in London. Now ABB, based in Zurich, is working on stepping up to a record-breaking 1,100 kV, to span more than 3,000 km in China. The sheer number of transformers has risen above anything Stanley could have imagined, thanks to the explosion of por- table electronic devices that have to be charged. In 2016, the global output of smartphones alone was in excess of 1.8 bil- TRANSFORMERS, THE lion units, each one supported by a char- ger housing a tiny transformer. You don’t UNSUNG TECHNOLOGY have to take your mobile phone charger apart to see the heart of that small device: A complete iPhone charger teardown is I HAVE ALWAYS DISLIKED EXAGGERATED CLAIMS of imminent posted on the Net, with the transformer scientific and technical breakthroughs, like inexpensive fusion, cheap as its single largest component. supersonic travel, and the terraforming of other planets. But I am fond But many chargers contain even tinier of the simple devices that do so much of the fundamental work of mod- transformers.
    [Show full text]
  • Pedaling Energy Harvesting by Low Speed Gearless Generator 1Prof T
    International Journal for Research in Engineering Application & Management (IJREAM) ISSN : 2454-9150 Vol-03, Issue-11, Feb 2018 Pedaling Energy Harvesting by Low Speed Gearless Generator 1Prof T. T. Bellundagi, 2Prof A. S. Jaibhai, 3Prof A. E. Shivdas 1,2,3Assistant Professor, 1, 2, 3Electrical Dept TSSM’S BSCOER Narhe Pune, India. [email protected], [email protected], [email protected] Abstract - In rural areas of India today also we use bicycle as main medium of transportation. The pedaling energy generated is wasted. It can be used for a better purpose by converting pedaling power in to electrical energy. The same concept of the energy generated due to pedaling can be obtained by gym cycles in urban areas. The energy generated can be stored and can be used for running electrical appliances [1]. These types of systems are already available in markets but they are less efficient, needs more rpm to generate power. This paper presents design of gym cycle which produces same output with less rpm. In this paper low speed generator is designed and modified the position of generator which eliminates gears and belt arrangement. In Low speed generator high power magnets are implemented and number of poles are increased also gauge of winding used is 23.The main intention of this paper is to build straight forward human powered low speed generator. It is clean way of generating energy efficiently. Keywords – Pedaling Energy, Gearless Generator, harvesting, low speed generator, electrical appliances. I. INTRODUCTION II. HISTORY World is a storehouse of energy. We all know that energy can The generator evolved from work by Michael Faraday either be created or destroyed but can be transformed from one and Joseph Henry in the 1820s.
    [Show full text]
  • William Stanley Lighted a Town and Powered an Industry
    William Stanley Lighted a Town and Powered an Industry by Bernard A. Drew and Gerard Chapman preface by Samuel Sass Berkshire History Fall 1985 Vol. VI No. 1 Published by the Berkshire County Historical Society Pittsfield Massachusetts Preface: At a meeting of engineers in New York a half century ago, a paper was read which contained the following description of a historic event in the development of electrical technology: For the setting we have a small town among the snow-clad New England Hills. There a young man, in fragile health, is attacking single-handed the control of a mysterious form of energy, incalculable in its characteristics, and potentially so deadly that great experts among his contemporaries condemned attempts to use it. With rare courage he laid his plans, with little therapy or precedent to guide him; with persistent experimental skill he deduced the needed knowledge when mathematics failed; with resourcefulness that even lead him to local photographers to requisition their stock of tin-type plates (for the magnetic circuit of his transformer), successfully met the lack of suitable materials, and with intensive devotion and sustained effort, despite poor health, he brought his undertaking, in an almost unbelievably short time, to triumphant success. This triumphant success occurred in Great Barrington, Massachusetts, in 1886, and the young man in fragile health was William Stanley. A century ago he demonstrated the feasibility of transforming to a higher level the generated alternating current voltage, for transmission at a distance, and reducing it at the consumer end to a usable level. One hears or reads on occasion that Stanley “invented” the transformer.
    [Show full text]
  • Electrification and the Ideological Origins of Energy
    A Dissertation entitled “Keep Your Dirty Lights On:” Electrification and the Ideological Origins of Energy Exceptionalism in American Society by Daniel A. French Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in History _________________________________________ Dr. Diane F. Britton, Committee Chairperson _________________________________________ Dr. Peter Linebaugh, Committee Member _________________________________________ Dr. Daryl Moorhead, Committee Member _________________________________________ Dr. Kim E. Nielsen, Committee Member _________________________________________ Dr. Patricia Komuniecki Dean College of Graduate Studies The University of Toledo December 2014 Copyright 2014, Daniel A. French This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the express permission of the author. An Abstract of “Keep Your Dirty Lights On:” Electrification and the Ideological Origins of Energy Exceptionalism in American Society by Daniel A. French Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in History The University of Toledo December 2014 Electricity has been defined by American society as a modern and clean form of energy since it came into practical use at the end of the nineteenth century, yet no comprehensive study exists which examines the roots of these definitions. This dissertation considers the social meanings of electricity as an energy technology that became adopted between the mid- nineteenth and early decades of the twentieth centuries. Arguing that both technical and cultural factors played a role, this study shows how electricity became an abstracted form of energy in the minds of Americans. As technological advancements allowed for an increasing physical distance between power generation and power consumption, the commodity of electricity became consciously detached from the steam and coal that produced it.
    [Show full text]
  • The History of Transformers Began with That of Electricity Itself; As Voltages Became Ever Higher, Transformers Became Ever More Powerful
    HISTORY The history of transformers began with that of electricity itself; as voltages became ever higher, transformers became ever more powerful 126 TRANSFORMERS MAGAZINE | Volume 7, Issue 1 | 2020 François DEVAUX Though it was considered a DC device, the VSDUN LQGXFHU ˴ WKH IRUHUXQQHU RI WRGD\˹V WUDQVIRUPHU ˴ FRQWULEXWHG VLJQL̨FDQWO\ WR the development of transformer technology The transformation of transformers A short history of power transformers through the age 1. Introduction to the development of transformers as and Heinrich Ruhmkorff, among oth- a key segment of the electric power in- ers) took Faraday’s discovery further, Little did Michael Faraday know that dustry. inducing a high voltage using a spark his observation of electromagnetic in- inductor – the forerunner of today’s duction in 1831 would revolutionize A number of pioneers (Nicolas Cal- transformer. Though it was considered the application of electricity and lead len, Charles Page, Antoine Massen a DC device, the spark inducer contribut- )LJXUH$/67+20̵VWKUHHSKDVHWUDQVIRUPHUGHVWLQHGIRUFXVWRPHUQHUJLHOHFWULTXHGX5KLQDOVRPDQXIDFWXUHGLQ6DLQW2XHQ ABSTRACT major steps realized in the develop- them, played a pioneering role in that ment of transformers since the be- evolution. From Michael Faraday’s observation ginning. It also showcases how GE of electromagnetic induction in 1831 Renewable Energy’s Grid Solutions’ KEYWORDS through today’s largest standard, ancestor companies such as DELLE, converter and industrial power trans- British Electric, Thomson-Houston, history, power transformers, green trans- formers, this article summarizes the GEC Alsthom, AEG to name few of formers, HVDC converter transformers www.transformers-magazine.com 127 HISTORY 2. The transformer’s commercial era As production lines started up at the end of the 19th century, the transform- er became an essential device for the transmission and distribution of electric power.
    [Show full text]
  • The War of the Currents
    The War of the Currents Thomas Edison Nikola Tesla Courtesy U.S. Dept. of Interior, National Park Courtesy Nikola Tesla Museum Service, Edison Natl. Historic Site John Cowdrey ©2006 John Cowdrey ost of us don’t give a second thought to where our electricity comes from, how it gets to the DC vs. AC M outlet, or the fact that it arrives as alternating current (AC). In fact, it’s hard to believe that a battle was Direct current (DC) electricity comes from sources ever waged over whether to use AC or DC (direct current) such as batteries, photovoltaic (PV) modules, electricity—why not just choose the best form? However, at and DC generators. DC voltage doesn’t change the turn of the twentieth century, two powerful inventors polarity—the positive pole always has a positive battled over the future of electrical transmission. The voltage with respect to the negative pole. Since outcome led to the interconnected power system we rely charges flow from a higher potential (voltage) on today. to a lower potential, DC provides a constant, unidirectional flow. Early Electric Generation Alternating current (AC) electricity is produced First pioneered at the turn of the nineteenth century, from rotating generators and can now be the earliest sources of continuous electrical energy were synthesized by inverters and variable-speed batteries—DC devices. However, these batteries did not motor drives. The familiar AC voltage takes the produce enough energy to economically run bright lights or form of a sine wave, with the voltage’s magnitude powerful motors for any useful length of time.
    [Show full text]
  • Fort Heureusement, Tme Introduction Magistrale De Gerard Cholvy Pose
    COMPTES RENDUS - BOOK REVIEWS 473 Fort heureusement, tme introduction magistrale de Gerard Cholvy pose des jalons precieux, foumit une bibliographie critique et propose des avenues de recherche fecondes (origines, implantation, methodes, encadrement, relations avec les Eglises, dimensions internationales, spiritualite). Un indispensable index des noms propres, une utile chronologie, une liste des abreviations (en realite des sigles) qui permet de se retrouver dans ce rnonde quelque peu esoterique et des notes biographiques qui aident a situer le regard de chaque auteur d'article ( << ancien » du mouvement, universitaire en mal de these, etc.) completent cette somme indispensable de membra disjecta. On peut regretter que, comrne beaucoup d'ouvrages publies dans I'hexagone a l'enseigne de !'Europe, Ia part du pays de de Gaulle et de Petain occupe les deux tiers de I'espace. Si Ia Belgique, I'Espagne et Ia Pologne y figurent, I'ltalie en es~ tout a fait absente et Ia Grande-Bretagne n'y apparait qu'a travers des mou­ vements internationaux. Pierre SAVARD Universite d'Ottawa * * * PHIL GARDNER- The Lost Elementary Schools of Victorian England. Beckenham, Kent: Croom Helm, 1984. pp. viii, 296. What is a school? To the producers of the official statistics of educational organization in Victorian England the term clearly did not apply to the myriad small, local and often informal places of learning attended by many working-class children. Official statistics in consequence do not take account of the educational reality of the industrial and urban working class. In this very important contribution to the history of English education, Phil Gardner demonstrates that historians of education generally- even those on the left- have reproduced a part of the official view of working-class schooling.
    [Show full text]
  • George Westinghouse and the Business of Innovation During the Age of Edison
    Steven W. Usselman From Novelty to Utility: George Westinghouse and the Business of Innovation during the Age of Edison This article argues that Thomas Edison and George West- inghouse, despite some shared characteristics in their approach to technical problems and a common interest in electric power, pursued distinct markets for innovation. Edison sold novelties to upper-class urbanites, whereas Westinghouse provided equipment to railroads and other industrial customers. As a consequence, the two entrepre- neurs consistently exhibited different attitudes toward the process of innovation and different inclinations as business- men. Westinghouse, more than Edison, foreshadowed the coming of corporate research and development. ince the late 1970s, few areas of inquiry in business history Shave proved as fruitful as the study of corporate research and development. Moving beyond an older, simpler image of R&D as science applied by industry to produce novelty, historians now interpret R&D programs as components of corporate strategies designed to address specific business conditions.1 Corporations typically created laboratories in hopes of attaining order and con- trol over established lines of business.2 In joining programs of technological development to their production and marketing STEVEN W. USSELMAN is associate professor of history at the University of North Carolina at Charlotte. I wish to thank David Hounshell for his sustaining interest in this project and for his help in obtaining illustrations and Glenn Porter for his wise counsel after reading an earlier draft of this essay. 1 For a recent review of this literature, see John Kenly Smith, Jr., "The Scientific Tradition in American Industrial Research," Technology and Culture 31 (1990): 121-31.
    [Show full text]
  • An Electric Power System Is a Network of Electrical Components Used to Supply, Transmit and Use Electric Power
    An electric power system is a network of electrical components used to supply, transmit and use electric power. An example of an electric power system is the network that supplies a region's homes and industry with power—for sizable regions, this power system is known as the grid and can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centres to the load centres and the distribution system that feeds the power to nearby homes and industries. Smaller power systems are also found in industry, hospitals, commercial buildings and homes. The majority of these systems rely upon three-phase AC power—the standard for large-scale power transmission and distribution across the modern world. Specialised power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners and automobiles. In 1881 two electricians built the world's first power system at Godalming in England. It was powered by a power station consisting of two waterwheels that produced an alternating current that in turn supplied seven Siemens arc lamps at 250 volts and 34 incandescent lamps at 40 volts.[1] However supply to the lamps was intermittent and in 1882 Thomas Edison and his company, The Edison Electric Light Company, developed the first steam powered electric power station on Pearl Street in New York City. The Pearl Street Station initially powered around 3,000 lamps for 59 customers.[2][3] The power station used direct current and operated at a single voltage.
    [Show full text]
  • Electrical Engineering Is a Field of Engineering That Generally Deals with the Study and Application of Electricity, Electronics, and Electromagnetism
    Page 1 of 8 ELECTRICAL ENGINEERING 4.1 Electrical Engineering is: Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics, and electromagnetism. This field first became an identifiable occupation in the latter half of the 19th century after commercialization of the electric telegraph, the telephone, and electric power distribution and use. Subsequently, broadcasting and recording media made electronics part of daily life. The invention of the transistor and, subsequently, the integrated circuit brought down the cost of electronics to the point where they can be used in almost any household object. Electrical engineering has now subdivided into a wide range of subfields including electronics, digital computers, power engineering, telecommunications, control systems, RF engineering, signal processing, instrumentation, and microelectronics. The subject of electronic engineering is often treated as its own subfield but it intersects with all the other subfields, including the power electronics of power engineering. Electrical engineers typically hold a degree in electrical engineering or electronic engineering. Practicing engineers may have professional certification and be members of a professional body. Such bodies include the Institute of Electrical and Electronic Engineers (IEEE) and the Institution of Engineering and Technology (IET). Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from basic circuit theory to the management skills required of project manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to a top end analyzer to sophisticated design and manufacturing software. History Electricity has been a subject of scientific interest since at least the early 17th century.
    [Show full text]
  • DC Vs AC - War of Currents for Future Power Systems: a HVDC Technology Overview
    INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 5, ISSUE 05, MAY 2016 ISSN 2277-8616 DC Vs AC - War Of Currents For Future Power Systems: A HVDC Technology Overview Anil K. Rai, Chandra Shekhar Sharma Abstract: DC vs AC discussion began in 1880s with development of first commercial power transmission in Wall Street, New York. Later, when AC technology came into notice by efforts of inventor and researcher Sir Nicola Tesla, soon the advantages of AC transmission and AC devices overtook the DC technology. It was hoped that DC technology had lost battle of currents. Today, with researches going on FACTS devices and bulk power transmission, HVDC has again gained a reputation in power sector. Solution of this centuries old debate is to develop HVDC systems that assists HVAC systems for better performance, stability and control Index Terms: DC, AC, HVAC, HVDC, VSC-HVDC, CSC-HVDC, LCC-HVDC, war of currents, bulk power ———————————————————— 1 Introduction Soon, as the technology got matured, the invention of poly- Historical background of DC vs AC power transmission goes phase circuits and affordable induction motor, and other way back to 1880s, at that time power transmission was only machinery, gave rise to AC Power Systems overhauling the possible using Direct Current (DC) technology. First DC Power Systems, which in fact had an early invention commercial power transmission was in Wall Street, New York. advantage. Most of the remaining DC systems and Networks It was Sir Thomas Alva Edison, who pioneered DC technology, were of low power ratings. They were also localized to large and up until then availability of DC generators and cities and had limited use in electric traction (trolley buses, incandescent bulbs working on DC, made DC technology the elevators, railways and trains).
    [Show full text]
  • Alternating Current.Pdf
    ALTERNATING CURRENT An alternating current (AC) is an electrical current where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy. However in certain applications different waveforms are used, such as triangular or square waves. Used generically, AC refers to the form in which electricity is delivered to businesses and residences. However, audio and radio signals carried on electrical wire are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal. History William Stanley Jr designed one of the first practical coils to produce alternating currents. His design was an early precursor of the modern transformer, called an induction coil. From 1881 to 1889, the system used today was devised by Nikola Tesla, George Westinghouse, Lucien Gaulard, John Gibbs, and Oliver Shallenger. These systems overcame the limitations imposed by using direct current, as found in the system that Thomas Edison first used to distribute electricity commercially. The first long-distance transmission of alternating current took place in 1891 near Telluride, Colorado, followed a few months later in Germany. Thomas Edison strongly advocated the use of direct current (DC), having many patents in that technology, but eventually alternating current came into general use (see War of Currents). Charles Proteus Steinmetz of General Electric solved many of the problems associated with electricity generation and transmission using alternating current.
    [Show full text]