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American Institute of Electrical Engineers, Transactions of the

Volume XXXVII: 1918

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Displaying Results 1 - 25 of 35
  • Synoptical and Topical Index of A.I.E.E. Transactions

    Publication Year: 1918 , Page(s): 1 - 57
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  • Index

    Publication Year: 1918 , Page(s): v - vii
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  • Report of the Board of Directors for Fiscal Year Ending April 30, 1918

    Publication Year: 1918 , Page(s): 1867 - 1888
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  • Standardization Rules of the American Institute of Electrical Engineers

    Publication Year: 1918 , Page(s): 1747 - 1866
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  • Research in America after the War

    Publication Year: 1918 , Page(s): 1723 - 1746
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  • American Engineering Research

    Publication Year: 1918 , Page(s): 1709 - 1721
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  • Drum Shapes as Affecting the Mine Hoist Duty Cycle and Motor Rating

    Publication Year: 1918 , Page(s): 1677 - 1708
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    The standardization of mine hoists, from an engineering standpoint is considered impossible on account of the wide variation in the conditions and methods under which anthracite coal is mined. The problem of drum shape consists in varying the diameter of different parts of the winding drum so that the load may be accelerated and retarded at the beginning and end of its travel with the minimum consumption of power. Numerical examples of the performance of various drum shapes under assumed conditions are given. View full abstract»

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  • The Use of Electric Power in the Mining of Anthracite Coal

    Publication Year: 1918 , Page(s): 1671 - 1676
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    This paper gives figures as to the power cost and current consumption of anthracite mines and the reasons for these being in excess of the requirements for bituminous mines. Estimates are also given as to the additional coal that will be released by the electrification of the anthracite mines. Illustrations are included showing representative installations of electric drive. View full abstract»

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  • 110,000-Volt Transmission Line over the St. Lawrence River

    Publication Year: 1918 , Page(s): 1653 - 1670
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    The paper deals with some remarkable construction recently completed by the Shawinigan Water & Power Company near Three Rivers, Quebec. The St. Lawrence river is crossed by transmission line wires on a span of 4800 feet, being the longest span in the world. Due to necessities of navigation clearance, the towers are 350 feet high. The preliminary investigation leading to the adoption of this construction is outlined, and a general description is given of the design and construction of the towers, insulators and cables. The provisions for protection from ice and the method of sag calculations are also given. View full abstract»

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  • Electrification of the Montreal Tunnel Zone

    Publication Year: 1918 , Page(s): 1637 - 1652
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    The author describes the electrification of the tunnel through Mt. Royal at Montreal which was built to give the Canadian Northern Railway entrance into the heart of the city. The tunnel emerges from the mountain several feet above the level of the city and it is proposed to extend an elevated line at the same uniform grade to connect with the proposed viaduct on the lines of the Harbor Commission. The tunnel is 3.1 miles long and the method of construction is described in detail. The power is purchased and delivered to a substation near the west portal of the tunnel. The equipment of the substation is described. At present there are six electric locomotives in operation having a one-hour rating of 1280 h.p., and it is proposed to add multiple unit motor cars for handling the local traffic. Details of the equipment and dimensions of both the locomotives and motor cars are given. The catenary system, which is described in detail, has a number of unusual features due to special local conditions and the extremely low temperatures which sometimes prevail in Montreal. View full abstract»

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  • Electric Power Generation in Ontario on Systems of Hydroelectric Power Commission

    Publication Year: 1918 , Page(s): 1607 - 1636
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  • Electric Motors in the Cement Industry

    Publication Year: 1918 , Page(s): 1531 - 1605
    Cited by:  Papers (1)
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    This paper has been compiled by the Committee on Industrial and Domestic Power to give general information regarding the different classes of machinery used in the cement industry and the sizes and types of motor best adapted for the work. The paper gives, first, a brief description of the process. This is followed by an outline of the various kinds of machinery used together with data as to power requirements. The types of motor best suited to each application together with starting characteristics, overload capacity, torque and other features are indicated. View full abstract»

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  • Electric Welding-A New Industry

    Publication Year: 1918 , Page(s): 1519 - 1529
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    This paper covers a brief review of the uses of electric spot and arc welding in this country prior to the formation of the Electric Welding Committee of the Emergency Fleet Corporation. It compares the status of the art at the present time and emphasizes the developments that have been made in apparatus in the last six months. It treats of the activities of the Welding Committee in applying electric welding processes to the shipbuilding industry and points the way to the general applicability of this method to other industries. It shows that the results obtained by investigation and physical tests prove that the applications of this process to heavy work are satisfactory. View full abstract»

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  • Application of Harmonic Analysis to the Theory of Synchronous Machines

    Publication Year: 1918 , Page(s): 1477 - 1517
    Cited by:  Papers (2)
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    It is shown that the flux distribution in the air gap of a synchronous machine consists of a series of component distributions that are simple harmonic wave trains, either stationary or moving at constant velocities. Methods are suggested for determining the effects of slots and the saturation of the magnetic circuit on the magnitudes of these component distributions. Expressions for the voltage generated and the power developed thereby are given. The theory is applied to the operation of a three-phase synchronous machine under different conditions of load, both qualitatively and quantitatively. A table of comparative calculated field currents is appended. View full abstract»

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  • Economic Proportion of Hydroelectric and Steam Power

    Publication Year: 1918 , Page(s): 1471 - 1475
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    This paper describes a new method of determining for any power system, what proportion of generation should be hydroelectric, and what steam, from the standpoint of economics. A method is outlined for obtaining a curve showing ``Total cost per kilowatt-year for hydroelectric and steam power'', for any percentage combination of generation. With system load curve, fixed charges on steam and hydroelectric plants, cost of fuel and other steam energy charges all known quantities, this curve can readily be calculated, and one can see at a glance the limiting economical percentage of steam power for the given conditions. View full abstract»

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  • Magnetic Pull in Electric Machines

    Publication Year: 1918 , Page(s): 1425 - 1469
    Cited by:  Papers (7)
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  • Critical Review of the Bibliography on Unbalanced Magnetic Pull in Dynamo-Electric Machines

    Publication Year: 1918 , Page(s): 1417 - 1424
    Cited by:  Papers (3)
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  • A Direct-Current Generator for Constant Potential at Variable Speed

    Publication Year: 1918 , Page(s): 1405 - 1415
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    The standing of this problem in the past is briefly reviewed. As far as is known to the author the type of machine described presents a new solution, the advantages of which are shown to be: 1. The machine is self-excited, i. e., regulates independent of any other source of potential. 2. The machine regulates independent of speed and load and may be compounded. 3. The regulation is inherent, i.e., no external regulating device is used. 4. The regulation is instantaneous. 5. The regulation is approximately independent of the heating. The theory of the machine is described and diagrams of connections given. Performance curves obtained from tests are shown. A method is described whereby instantaneous regulation of the voltage is obtained, which method also secures approximately a constant voltage independent of the heating. Finally there follows a discussion of the efficiency of the new machine as compared with a standard machine of the same speed and output. View full abstract»

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  • Skin Effect in Tubular and Flat Conductors

    Publication Year: 1918 , Page(s): 1379 - 1403
    Cited by:  Papers (42)  |  Patents (3)
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    A method is presented for calculating the skin effect resistance ratio of a tube, which is a form of conductor to be recommended for high-frequency work. A formula is also developed by means of which the asymptote to the curve of the ratio R??/R may be drawn, and thus the magnitude of the skin effect at extremely high frequencies may be obtained. The values of the ratio R??/R for tubes of various thicknesses, are plotted in a set of curves (Fig. 3) which may be used for the solution of practical problems. A similar method is described for the calculation of skin effect in a thin strap. Although the calculations cannot be carried out for as high frequencies as the calculation for tube, it indicates a method of coordinating the test results for straps, which have been published. A set of empirical curves for straps is given in Fig. 7, from which approximate values of R??/R for any case may be read. View full abstract»

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  • The Automatic Hydroelectric Plant

    Publication Year: 1918 , Page(s): 1367 - 1378
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    The automatic hydroelectric generating station of the Iowa Railway and Light Company at Cedar Rapids, Iowa, is a radical step in advance in the elimination of operator's wages in a station of appreciable size, without sacrificina complete control. This station consists of three 400-kw., 500-kv-a., 60-rev. per min., 2300-volt, vertical generating units, tied in to a system, of which the main generating station contains about 20,000 kv-a. in steam turbo-generators. One striking feature is the entire omission of the usual governors, the waterwheel gates being motor driven and controlled by contact-making ammeters. Each unit has its individual control panel, consisting of the necessary contactors and relays to connect it to the bus at the proper time. A motor-driven drum controller gives the proper time element between the different, step's in the operation of placing the generator on the line. Any generator can be started either by a float switch when the pond level reaches the proper height or by a remote control button in the steam station. The starting of the first generator throws on the line the motor of one of the two exciter sets, and the generator cannot be connected to the bus until the excitation voltage has reached the normal value. The waterwheel gates are then partly opened and the generator comes up to approximately normal speed. It is then connected to the bus without field through an iron-core reactance. Then a weak field is applied. View full abstract»

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  • Protection from Flashing for Direct-Current Apparatus

    Publication Year: 1918 , Page(s): 1341 - 1365
    Cited by:  Papers (4)
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    The equipment developed for the protection of direct-current apparatus as described in this paper is applicable to all direct-current apparatus and all methods of operation. Special means of protection for use only with particular apparatus or conditions of operation have not been mentioned. The principal steps in the experimental development of high-speed circuit breakers and flash barriers are briefly given. The protection afforded by the high-speed breaker or barriers is sufficient for most apparatus and service, but complete protection for any direct-current apparatus and service requires both the high-speed breaker and flash barriers. Attention is directed to the importance of arranging the connections to the brush rigging so that the magnetic action on the arc will be a minimum, and properly directed, so the flash will do the least damage. View full abstract»

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  • Reactance of Synchronous Machines and its Applications

    Publication Year: 1918 , Page(s): 1209 - 1340
    Cited by:  Papers (27)
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    Part I treats of the calculation and application of the armature self-inductive reactance of synchronous machines. A short, reliable method is given in the form of curves, Figs. 20A, B, C, making the calculation from design sheet data a matter of a few minutes. Table I shows a comparison of calculated and test values (obtained from saturation and synchronous impedance curves) for 138 machines, ranging from high-speed turbine generators to the low-speed engine type. Three points were brought out during the investigation: (1) That in polyphase machines, the armature self-inductive reactance, just as the armature reaction, is a polyphase, not a single-phase phenomenon, and therefore the mutual induction of phases in a three-phase machine increases the effective self-induction of each phase by approximately 50 per cent over the single phase value, while in two-phase machines, in which the mutual induction of phases is zero, the effective self-induction of the phase is the same for two-phase or single-phase operation. (2) That the variation of armature reactance during the cycle, due to salient-pole construction, is practically eliminated in Y-connected, three-phase machines for the reason that the variation, consisting almost entirely of a third harmonic, is cancelled in such machines. This leaves, in effect, a uniform reluctance for the leakage flux emanating from the tooth tips. (3) That in the familiar method of obtaining the armature self-induction from the saturation and synchronous impedance curves (i.e. View full abstract»

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  • Sustained Short-Circuit Phenomena and Flux Distribution of Salient-Pole Alternators

    Publication Year: 1918 , Page(s): 1141 - 1208
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    It is shown in Section IV that with the ordinary field forms met with in practise, the resultant flux wave under s. s. c. (sustained short circuits) will be extremely distorted, see Figs. 16, (4th wave) 23, 27, 27A, etc., for the simple reason that with the very low voltages obtained under such conditions, the fundamental of the B-curve of the field is reduced so much by the armature reaction that the higher harmonics assume a very predominant role and become several hundred per cent of the s.s.c. fundamental. See Fig 26 and Tables XI, XII, and XIII. As a corollary to the foregoing it is found that the B-curve under load will not differ radically from the no-load field form since the fundamental will remain large enough to hold its own. See Fig. 22 and also footnote (4). The cross magnetizing effect of the armature reaction is, of course, to make the B-curve unsymmetrical with respect to the mid-pole axis. Compare Figs. 7 and 22. The magnetic oscillations are studied not only by means of full-pitch stator coils but also by means of rotor coils No. 7 and 8, Fig. 3, and stator coils No. 9, 10, 11, 12, 15, and 16, Figs. 3 and 3A. Attention is called to the following facts for which explanations and theoretical proofs are offered. (1) The ripples at the crest of the e. m. f. View full abstract»

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  • Method of Symmetrical Co-Ordinates Applied to the Solution of Polyphase Networks

    Publication Year: 1918 , Page(s): 1027 - 1140
    Cited by:  Papers (193)
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    In the introduction a general discussion of unsymmetrical systems of co-planar vectors leads to the conclusion that they may be represented by symmetrical systems of the same number of vectors, the number of symmetrical systems required to define the given system being equal to its degrees of freedom. A few trigonometrical theorems which are to be used in the paper are called to mind. The paper is subdivided into three parts, an abstract of which follows. It is recommended that only that part of Part I up to formula (33) and the portion dealing with star-delta transformations be read before proceeding with Part II. Part I deals with the resolution of unsymmetrical groups of numbers into symmetrical groups. These numbers may represent rotating vectors of systems of operators. A new operator termed the sequence operator is introduced which simplifies the manipulation. Formulas are derived for three-phase circuits. Star-delta transformations for symmetrical co-ordinates are given and expressions for power deduced. A short discussion of harmonics in three-phase systems is given. Part II deals with the practical application of this method to symmetrical rotating machines operating on unsymmetrical circuits. General formulas are derived and such special cases, as the single-phase induction motor, synchronous motor-generator, phase converters of various types, are discussed. View full abstract»

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  • Pre-Charged Condensers in Series and in Parallel

    Publication Year: 1918 , Page(s): 1015 - 1025
    Cited by:  Papers (1)
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    A condenser is charged from a source of direct voltage, and then is used as a booster in series with this source to charge another condenser. By repeating this process a large number of times the second condenser is finally subjected to twice the voltage of the source. This is the principle of the Delon apparatus for testing cables, and is explained in a numerical example. Then the more general case of two or more ``pre-charged'' condensers in series is considered, when these condensers are connected to some source of direct voltage; it is shown how to determine the final distribution of voltages among them. A similar problem is solved for pre-charged condensers in parallel. Finally a general network of pre-charged condensers is considered, and equations are derived similar to Kirchoff's laws, from which the final distribution of voltages and charges may be computed knowing the initial distribution. View full abstract»

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