e. m. f. waves, and for measuring angular velocity variations in one revolution. Discussion, p. 1130, by F. A. C. Perrine and C. P. Steinmetz. THE CATHODE RAY ALTERNATING-CURRENT WAVE INDICATOR Harris J. Ryan Vol. xxii-1903, pp. 539-548 Description of the construction and mode of operation of the cathode tube wave tracer. Discussion, pp. 549-552, by Messrs. G. S. Dunn, P. H. Thomas, Harris J. Ryan, A. F. Ganz, William J. Hammer, C. H. Sharp, H. W. Fisher, A. S. Langsdorf and W. E. Goldsborough A GRAPHIC RECORDING AMMETER A. H. Armstrong Vol. xxii-1903, pp. 689-694 Description of the construction and operation of the Armstrong recording instruments for railway testing. No discussion. J. D. Nies SOME NOTES ON POLYPHASE METERING Vol. xxiv-1905, pp. 165-180 Brief outline of nature and magnitude of errors introduced by presence of shunt and series instrument transformers. Relative merits of singlemeter, two-meter and three-meter and polyphase meter methods for measuring energy in three-phase circuits. Discussion, incorporated with paper by W. J. Mowbray on "Maintenance of Meters." F. P. Cox NOTES ON THE USE OF INSTRUMENTS ON SWITCHBOARDS Vol. xxiv-1905, pp. 181-184 Brief mention of some of the factors which enter into the choice of watt-hour meter rating for a given service, and reference to some of the errors that can be avoided by proper selection and installation of watthour meters. Discussion, incorporated with paper by W. J. Mowbray on "Maintenance of Meters." THE OSCILLOGRAPH AND ITS USES Lewis T. Robinson measurement. Discussion, incorporated with paper by W. J. Mowbray on "Maintenance of Meters." MAINTENANCE OF METERS W. J. Mowbray Vol. xxiv--1905, pp. 215-218 General description of a rotating standard watt-hour meter with plurality of current coils. General remarks on methods of increasing permanence of calibration. Discussion (including that of paper by J. D. Nies on "Some Notes on Polyphase Metering"; paper by F. P. Cox on "Notes on the Use of Instruments on Switchboards," and paper by Lewis T. Robinson on "The Oscillograph and Its Uses"), pp. 219-245, by Messrs. J. W. Lieb, Jr., Caryl D. Haskins, Edward B. Rosa, Clayton H. Sharp, A. R. Everest, W. H. Pratt, G. C. Van Buren, A. H. Ackerman, J. F. Stevens, William McClellan, Charles Hewitt, William Bradshaw, Stephen Q. Hayes, C. W. Hutton, J. W. Swaren, R. F. Monges, C. L. Cory and F. E. Smith. General remarks on the choice, installation and maintenance of indicating and integrating switchboard instruments. Tests on permanence of calibration of very large number of watt-hour meters giving the limits of accuracy. METHODS OF MEASUREMENT OF HIGH ELECTRICAL PRESSURES S. M. Kintner Vol. xxiv-1905, pp. 421-444 Brief résumé of the various methods of measuring very high e. m. f's., pointing out the principal limitations of each. Experimental study of the spark gap for e. m. f. measurement, showing the effect of various current limiting devices, grounding and shielding. Description and discussion of the advantages of an oil-immersed electrostatic voltmeter for e. m. f's. up to 100,000 volts. Discussion, pp. 445-451, by Messrs. Charles P. Steinmetz, Samuel Sheldon, C. O. Mailloux, H. G. Stott, H. W. Fisher, E. F. Northrup, Charles A. Perkins and S. M. Kintner. Advantages of potential transformers in very high e. m. f. measurements. Accuracy of needle-gap measurements and effect of degree of sharpness thereon. A NEW INSTRUMENT FOR THE MEASUREMENT OF ALTERNATING CURRENTS E. F. Northrup Vol. xxiv-1905, pp. 741-757 Description of the construction and mode of operation of a hot-wire instrument devised for zero measurements of either alternating current or direct current, together with analytical discussion of the mode of adjustment for different kinds of work. Discussion, pp. 758-760, by Messrs. E. F. Northrup, H. G. Stott, F. N. Waterman and H. W. Fisher. General remarks concerning the probable limitations of the instruments. THREE-PHASE POWER FACTOR Austin Burt Vol. xxvii-1908, pp. 801-814 Derivation of formula for the mean power-factor of a three-phase system, together with a method of determining power-factor from wattmeter readings. Discussion, pp. 815-817, by Messrs. Comfort A. Adams, Frederick Bedell, H. L. Wallau and B. A. Behrend. Physical demonstration of the two-wattmeter method of determining three-phase power factor. METHOD OF TESTING TRANSFORMER CORE LOSSES GIVING SINE WAVE RESULTS ON COMMERCIAL CIRCUITS L. W. Chubb Vol. xxviii-1909, pp. 417-431 The use, construction and limits of accuracy of a special instrument— iron-loss voltmeter-consisting of a wattmeter connected in series with an exciting winding on a steel core and calibrated to read the impressed voltage of sine wave e. m. f. Also a description of a method of adjusting form factor in core-loss tests. Discussion, pp. 432-438, by Messrs. Frederick Bedell, Charles P. Steinmetz, M. G. Lloyd, L. T. Robinson, Charles F. Scott and L. W. Chubb. General discussion of the use and limitations of iron-loss voltmeter. Description of a method for obtaining sine wave from a commercial circuit. C. NON-ELECTRICAL MEASUREMENTS AND INSTRUMENTS P. O. Keilholtz ANGULAR VARIATIONS IN STEAM ENGINES Vol. xviii-1901, pp. 703-740 Mathematical investigation of the turning moments due to steam and to inertia of the reciprocating parts, developing method of determining the relation between balancing effect of fly-wheel and the deviation from the position of absolutely uniform speed. Description of method of measuring any velocity variations by means of electrically driven tuning fork with detailed results of tests on a tandem compound engine. Discussion, incorporated with that of paper by Walter I. Slichter on "Angular Velocity in Steam Engines in Relation to Paralleling of Alternators." AN INTEGRATING PHOTOMETER FOR GLOW LAMPS AND SOURCES OF LIGHT Chas. P. Matthews Vol. xx-1902, pp. 59-70 Theory, design, construction and operation of a special intensity photometer invented by the author for use in making photometric measurements of incandescent lamps and flames. Discussion, incorporated with that of paper by Clayton H. Sharp on "The Commercial Accuracy of Photometrical Measurements." SOME METHODS OF PHOTOMETRY AS APPLIED TO INCANDESCENT LAMPS J. T. Marshall Vol. xx-1902, pp. 77-85 A description of method of calibrating and using sliding scale photometer for commercial testing and inspection of incandescent lamps. Discussion, incorporated with that of paper by Clayton H. Sharp on "The Commercial Accuracy of Photometrical Measurements." THE COMMERCIAL ACCURACY OF PHOTOMETRICAL MEASUREMENTS Clayton H. Sharp Vol. xx--1902, pp. 87-93 Experimental investigation of the limits of accuracy in different classes of photometrical measurements. Discussion (including that of paper by Chas. P. Matthews on “Integrating Photometer for Glow Lamps and Sources of Light Intensity"; paper by Douglass Burnett on "Distributed Lighting"; and paper by J. T. Marshall on "Some Methods of Photometry as Applied to Incandescent Lamps"), pp. 94-110, by Messrs. Douglass Burnett, Edward L. Nichols, Francis R. Upton, L. B. Marks, W. S. Howell, F. S. Smith, Edward B. Rosa, Calvin W. Rice, William J. Hammer, W. S. Stratton, Clayton H. Sharp, J. T. Marshall, Chas. F. Scott, Chas. P. Matthews, Edward P. Thompson, Alex J. Wurts, R. H. Henderson, Max Von Reckinghausen, P. M. Lincoln, N. W. Storer and F. W. Jones. Merits of mean spherical candle-power method of rating illuminants. Methods of measuring illumination. Description of Cooper-Hewitt mercury vapor lamp. MEASUREMENT OF TEMPERATURE BY ELECTRICAL MEANS Edwin F. Northrup Vol. xxv-1906, pp. 473-504 Theory, construction and connections for resistance pyrometers, profusely illustrated with drawings and connection diagrams. Discussion, pp. 505-506, by Mr. E. F. Schuetz. C. O. Mailloux A NEW CO, RECORDER Vol. xxvi-1907, pp. 1771-1787 Description of Orsat apparatus followed by detailed description of the Westover recorder. Discussion, p. 1788, by A. A. Adler. THE MEASUREMENT OF ROTARY SPEEDS OF DYNAMO MACHINES BY THE A. E. Kennelly and S. E. Whiting Discussion, pp. 647-649, by Messrs. J. B. Taylor, C. A. Perkins, C. H. Sharp and A. E. Kennelly. Range of speed obtained with ordinary stroboscopic fork. NOTE ON A SIMPLE DEVICE FOR FINDING THE SLIP OF AN INDUCTION MOTOR Charles A. Perkins Vol. xxiv-1905, pp. 879-880 Description of device. Kenneth L. Curtis D. INSTRUMENT TRANSFORMERS THE CURRENT TRANSFORMER Vol. XXV-1906, pp. 715-726 Method of predetermining the performance of series transformer from tests of exciting current and internal losses. Method of measuring small inductances. Discussion, pp. 727-734, by Mr. L. T. Robinson. Testing of series transformer for ratio and phase angle. Oscillograms of exciting current of series transformers. ELECTRICAL MEASUREMENTS ON CIRCUITS REQUIRING CURRENT AND L. T. Robinson Vol. xxxviii-1909, pp. 1005-1039 Theoretical discussion of the effects of instrument transformers on the accuracy of ammeter and wattmeter measurements, together with tables of correction factors for phase angle error in power measurements. Theory of operation of series transformer showing effects of variation in frequency, secondary impedance, line current, power-factor and wave form. Description of methods of testing series and shunt instrument transformers with ratio and phase angle performance curves from actual test. Discussion, pp. 1040-1052, by Messrs. C. H. Sharp, M. G. Lloyd, L. W. Chubb, J. Dalemont, Albert F. Ganz and L. T. Robinson. Methods of measuring ratio and phase angle of current transformers and correction factor for instrument transformers in polyphase measure ments. SOME RECENT DEVELOPMENTS IN EXACT ALTERNATING-CURRENT Clayton H. Sharp and William W. Crawford Discussion, pp. 1542-1552, by Messrs. V. Karapetoff, L. T. Robinson, W. H. Pratt, C. P. Steinmetz, Clayton H. Sharp and William W. Crawford. General remarks on precision measurements of alternating-current quantities. Description of a water-cooled electrodynamometer, also of a method of measuring very high frequency alternating current. |