Showing papers in "Transactions of The American Institute of Electrical Engineers in 1908"
TL;DR: In the autumn of 1896, the writer of this paper undertook an investigation of the phenomena existing when transmission line conductors are subjected to high alternating voltages as discussed by the authors, and this work was carried on near Telluride, Colorado, and extended over a period of about a year.
Abstract: In the autumn of 1896, the writer of this paper undertook an investigation of the phenomena existing when transmission line conductors are subjected to high alternating voltages. The work was carried on near Telluride, Colorado, and extended over a period of about a year. The results of this work were embodied in a report made by the writer in 1897.
20 citations
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TL;DR: In this article, a portable wireless telegraph station for use with pack or wheeled transport is described, and the masts are of steel, 30 ft. in height, and a single horizontal aerial is used, the earth connection being made with strips of metal gauze placed on the ground.
Abstract: MARCONI'S Wireless Telegraph Co., Ltd., gave a very interesting demonstration of the latest developments of wireless telephony at its works at Chelmsford on May 28. Although there was nothing very new from the scientific point of view, yet the developments in engineering design were remarkable, especially in the receiving apparatus. Many of the devices proved of the utmost value to the Army during the war. We were impressed with the portable wireless telegraph station for use with pack or wheeled transport. Six men are required to work the set, and the whole station can be erected in ten minutes. The masts are of steel, 30 ft. in height, and a single horizontal aerial is used, the earth connection being made with strips of metal gauze placed on the ground. The generating set consists of a two-cylinder, 23/4-h.p. petrol engine, which drives a high-frequency 1/2-kw. alternator. The “instrument load” consists of transmitting-valves, high-frequency transmitting-circuits, microphone, etc., all contained in a teak travelling-case.
16 citations
TL;DR: The fundamental law of electromagnetic induction, which is the basis of all our present mechanical generators of electric currents, is, in general, stated in two different ways as mentioned in this paper : the first is to the effect that if a conductor cuts magnetic lines of force, an electromotive force is generated.
Abstract: The fundamental law of electromagnetic induction, which is the basis of all our present mechanical generators of electric currents, is, in general, stated in two different ways. Faraday's statement is to the effect that if a conductor cuts magnetic lines of force, an electromotive force is generated. This simple statement, however, has been changed by later authorities, who define the same law by saying in effect that when the amount of flux enclosed by an electric circuit is changed, an electromotive force is induced. This is the more usual form taught to-day and recopied in most text-books in preference to Faraday's statement of it.
12 citations
TL;DR: In this article, it was shown that the advantages of a regulating storage battery for alternating-current generation are even more pronounced than in direct-current service, for the following reasons: 1.
Abstract: The general function of a storage battery in connection with an alternating-current system is the same as in a direct-current system, namely, to relieve the power plant and in some cases the transmission lines of the fluctuations of load, permitting the generating machinery and conductors to be utilized to the greatest advantage and at maximum economy by subjecting them to a steady load equal to the average, instead of a load whose fluctuations in some instances, as in heavy interurban railway work and in many industrial plants, are exceedingly rapid and severe. In many cases where alternating currents are developed, the advantages of a regulating storage battery are even more pronounced than in direct-current service, for the following reasons: 1. Alternating-current generation is particularly applicable to long distance interurban railway work where steam railroad conditions prevail, involving heavy units operating at comparatively infrequent intervals, producing fluctuations of load abnormally high as compared with the average. These conditions are comparable, except on a largely magnified scale, with those obtaining on the four or five car electric roads so common in the early history of electric railways.
9 citations
TL;DR: In this paper, it was shown that the effective resistance of the conductor, and its attenuation constant, may increase more than a million fold within the range of frequencies which may be met in industrial circuits.
Abstract: In the usual theory of transients the assumption is made, that resistance, inductance, capacity and conductance are constant. This however, is not correct, and as the result thereof, it was not possible to theoretically investigate, and numerically calculate the dissipation of high-frequency disturbances, the flatening of the wave fronts of impulses, the rounding off of steep waves, etc., with the time and the distance of travel, and there-from to determine the distance, to which the danger from such disturbances extends, and to investigate the conditions of line construction, which limit the danger zone of such phenomena to the smallest local extent. In the following, two of the foremost causes of change of the line constants with the equivalent frequency are investigated, the unequal current distribution in the conductor, and the electric radiation from the conductor, and shown, that within the range of frequencies which may be met in industrial circuits, the effective resistance of the conductor, and its attenuation constant, may increase more than a million fold. Equations of the line constants as function of the equivalent frequency are derived, and applications thereof made to a few problems: (1) The laws of conduction of high-frequency currents, such as produced by lightning discharges and similar disturbances, and the conclusions resulting therefrom on the nature of the conductor. (2) The decay of high-frequency sine waves in transmission lines. (3) The attenuation of rectangular waves. (4) The flattening of the wave front of steep impulses.
7 citations
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TL;DR: Campbell as discussed by the authors states that the very simplicity of the facts and principles which Maxwell stated is, apparently, the reason for their being overlooked in the present discussion, and points requiring restatement seem to be the following:
Abstract: George A. Campbell (by letter): The very simplicity of the facts and principles which Maxwell stated is, apparently, the reason for their being overlooked in the present discussion. The points requiring restatement seem to be the following:
3 citations
TL;DR: Our time is the age of power as mentioned in this paper, and it is not too much to say that our progress is preeminently due to the use of power in the development and use of technology.
Abstract: Without disparaging other aspects of our progress, it is not too much to say that our time is preeminently the age of power. This applies to the world at large, but especially to the United States. Our population is increasing with unprecedented rapidity, but our mineral production is increasing so much more rapidly that some have called this the age of metal. Steel, copper, and wood are combined in mechanical devices at a rate increasing more rapidly than ore production, so that others have characterized this as the age of the machine; yet that aspect of modern life which most impresses the student of progress is the increasing use of mechanical power through the development of prime movers and the utilization of new power sources. Rapidly as our population advances, it is outrun by metal production, and that in turn by machine building; yet our most rapid progress — the feature in which our advancement exceeds all others — is in the development and use of power.
TL;DR: In this article, the authors describe the actual operation of the New Haven single-phase electrification as closely as possible to those who are truly interested in its merits and faults, and provide an overall commentary.
Abstract: The object of this paper is to bring the actual operation of the New Haven single-phase electrification as closely as possible to those who are truly interested in its merits and faults. The duty assigned to the engineers of the New Haven railroad was to provide for the electrical operation of their trains. At the early period of April 1, 1905, when we settled down to this responsible task, the data in the field, upon which to base real conclusions, were about 5%, in comparison with the experience now available. The author covers "Major Faults," i.e. 1. Power house; 2. Insulation; 3. Circuit-breakers; 4. Line; and 5. Locomotives; as well as "Minor Faults;" 1. Generator burn-outs; 2. Distribution; a. Multiple-track circuits; b. Independent track circuits; 3. Contact wire; 4. Hard spots; a. Hangers; b, section breaks; c, deflectors; 5. Signal wires; and 6. Locomotive current collectors. He then covers the log of operation: 1. Electric passenger service; 2. Electricity versus steam; 3. Train-minute delays; a, table; b, chart; 4. Serious failures - over 300 train-minutes; 5. Engine repairs - a. Table showing engines in shop; 6. Engine capacity - a. Table showing trailing loads in excess of guarantees. 7. Engine-mileage - electricity and steam compared. Finally he covers the Electrification in Relation to Matters Other Than Traction and provides an overall commentary.
TL;DR: The single-phase alternator has been in comrrtercial use now for twenty years and it may seem surprising that there should be new developments at this late date.
Abstract: The single-phase alternator has been in comrrtercial use now for twenty years and it may seem surprising that there should be new developments at this late date. However, single-phase alternators have been used in the past almost exclusively for lighting work, and in units of comparatively small output and low speed. Recently, on account of the adoption of single-phase current for traction work, an important demand has arisen for large high-speed, low-frequency, single-phase generators. It is in the design and manufacture of such units that the engineer has had to overcome new difficulties. In large, high-speed, single-phase generators for 15 and 25 cycles the difficulties met with are due almost entirely to the large pole-pitch and high armature reaction which it is necessary to adopt. A 500-kw., 60-cycle, 72-pole, single-phase generator would have a pole-pitch of about 7 in., while a 6000-kw., 15-cycle, 2-pole machine would have one machine of about 120 in. It is easily seen that the design of these will be radically different.
TL;DR: In this paper, the authors used the words "addition" and "subtraction" to mean geometrical addition and subtraction of vectors according to the well-known conventional method.
Abstract: The object of this paper is to evolve diagrams by means of which nearly all the phenomena of the rotating field may be easily studied, and the various factors necessary for the calculation of fluxes, exciting current, etc., exactly determined. In order to avoid too frequent repetition of certain expressions, the author has adopted the expedient of using the words “addition” and “subtraction” to mean geometrical addition and subtraction of vectors according to the well-known conventional method.
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TL;DR: In this article, the authors outline the ordinary mine development and some of the standard electrical mining equipment, and describe some typical coal mining plants, with their especial features, and outline the conventional mine development.
Abstract: Before describing some typical coal-mining plants, with their especial features, the author will outline the ordinary mine development and some of the standard electrical mining equipment.
TL;DR: In this paper, the authors discuss the enormous economic waste which the wire, cable, and conduit equipment of a telephone system involves and how this waste can and should be greatly reduced in systems employing automatic switchboards.
Abstract: This paper treats of three principal topics: 1. The enormous economic waste which the wire, cable, and conduit equipment of a telephone system involves. 2. A recapitulation and discussion of reasons which make this waste necessary or expedient in manually operated systems. 3. How this waste can and should be greatly reduced in systems employing automatic switchboards.
TL;DR: This series of tests was started with the hope of being able to deduce some mathematical expression which would represent these phenomena with reasonable accuracy, and believing that the results will prove of some interest and value, the results are given.
Abstract: It has long been known that when an arcing ground occurs in a system, abnormal voltages and consequent failure of apparatus often result. This series of tests was started with the hope of being able to deduce some mathematical expression which would represent these phenomena with reasonable accuracy. The mathematical expression did not materialize, but in view of the importance of the subject, and believing that the results will prove of some interest and value, I give them in the following paper. The theoretical explanation might form the subject of a future paper.
TL;DR: The most important changes have taken place in the boiler room, while in the rest of the plant very few changes have been inaugurated other than a general increase of compactness in the turbo-generating room as mentioned in this paper.
Abstract: In the rapid development attending the introduction of the steam turbine, there has been but comparatively little tendency to introduce radical departures from accepted engine practice. The most important changes have taken place in the boiler room, while in the rest of the plant very few changes have been inaugurated other than a general increase of compactness in the turbo-generating room. Outside of the tendency to structural foundations for generating units, there is little opportunity for originality in design without involving a radical change in the ensemble.
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TL;DR: In this paper, a purely theoretical analysis of the field distortion of a split-pole converter is presented, and it is shown that the distortion does not necessarily involve electromotive force distortion.
Abstract: Introduction. The interesting discussion on the split-pole converter at the February New York meeting of the Institute instigated the following paper, which consists of a purely theoretical analysis, the principal object of which is to show how the field distortion of a split-pole converter does not necessarily involve electromotive force distortion.
TL;DR: In this paper, the authors dealt briefly with the points leading to the use of a chorded winding for alternating-current generators from the standpoint of manufacture and design, and to indicate the influence this winding has on the performance of a machine.
Abstract: Fractional pitch windings have been treated by various authors in the past, especially with regard to the influence they have upon the self-induction of the armature winding. The object of this paper is to deal briefly with the points leading to the use of a chorded winding for alternating-current generators from the standpoint of manufacture and design, and to indicate the influence this winding has on the performance of a machine.
TL;DR: In this paper, the work of designing a tower or pole for a given transmission line can proceed, and a statement must be made setting forth the loads which the structure should be capable of withstanding.
Abstract: Before the work of designing a tower or pole for a given transmission line can proceed, a statement must be made setting forth the loads which the structure should be capable of withstanding. This statement is, in general, based on a forecast of the probable extreme weather conditions which may occur in the vicinity of the line, and also on a prediction as to what accidents will probably occur to the conductors of the line.
TL;DR: Based on the commonly accepted definition of power-factor, as “The ratio of true power to volt-amperes”, there can be no single factor that will exactly express such a physical relationship in a delta-connected, unsymmetrical, three-phase system as mentioned in this paper.
Abstract: Based on the commonly accepted definition of power-factor, as “The ratio of true power to volt-amperes”, there can be no single factor that will exactly express such a physical relationship in a delta-connected, unsymmetrical, three-phase system.
TL;DR: In the early days, when alternators were designed by rule-of-thumb methods, the relative proportion of copper to iron was high as discussed by the authors, and in many cases failed to give the voltage for which they were designed.
Abstract: Many radical changes have accompanied the rapid development of alternating-current generators. In the early days, when alternators were designed by rule-of-thumb methods, the relative proportion of copper to iron was high. These machines had very poor inherent regulation, and in many cases failed to give the voltage for which they were designed. These “copper machines” were relatively light, and were considerably cheaper than the “iron machines” which succeeded them. The iron machines, though much heavier and more expensive than their predecessors, had much better regulation. Following this, the characteristics of alternators were more carefully studied so that the designer was able to reduce the weight and again approach the copper machine. Competition between the various manufacturing companies made it necessary for their engineers to design cheaper machines, resulting in a compromise between the “copper” and “iron” machines. We are now at this period, and the designer is to-day confronted with the question: what shall be the relative proportions of copper and iron in this machine? Doubtless the answer is, so to proportion the iron and copper as to obtain the cheapest possible machine.