DISRUPTIVE STRENGTH WITH TRANSIENT VOLTAGES Joseph L. R. Hayden and Charles P. Stienmetz Vol. xxix-1910, pp. 1125-1158 Account of experimental investigation of the effects of time and energy on the dielectric strength of air and oil. Full description of the method of testing and analysis of results. Characteristic curves of the dielectric strength of air and oil with different shaped electrodes, showing effect of duration of stress and of the energy behind the stress. Empirical equations. Discussion, incorporated with that of H. W. Tobey's paper on "Dielectric Strength of Oil." J. B. Whitehead THE ELECTRIC STRENGTH OF AIR Vol. xxix-1910, pp. 1159-1187 Description and discussion of an experimental investigation of the dielectric strength of air and the formation of corona around cylindrical conductors, showing effects of temperature, pressure, and dimensions and material of the wire in dielectric strength of air. Description of a new and very accurate method of testing dielectric strength of air about conductors. Bibliography. Discussion, incorporated with that of H. W. Tobey's paper on "Dielectric Strength of Oil." H. W. Tobey DIELECTRIC STRENGTH OF OIL Vol. xxix-1910, pp. 1189-1207 Description of the properties of insulating oils and methods of testing and handling such oils. Tests showing effects of form of electrode, temperature and moisture on dielectric strength of oils, with characteristic curves. Analytical and experimental study of methods of drying and filtering oil. Discussion (including that of paper by Messrs. Joseph L. R. Hayden and Charles P. Steinmetz on "Disruptive Strength with Transient Voltages," and Mr. J. B. Whitehead's paper on "The Electric Strength of Air"), pp. 1208-1232, by Messrs. D. B. Rushmore, V. Karapetoff, Percy H. Thomas, A. E. Kennelly, W. H. Pratt, E. E. F. Creighton, J. C. Lincoln, Charles F. Scott, Harris J. Ryan, R. D. Mershon, C. P. Steinmetz, John B. Whitehead and M. A. de Chatelain. General comments on the results of the tests, with various suggested explanations of the phenomena of corona, and relation of diameter of the conductor and other factors to the apparent dielectric strength of air. Harold S. Osborne POTENTIAL STRESSES IN DIELECTRICS Vol. xxix-1910, pp. 1553-1581 General résumé of work done in developing graded insulation for cables with derivation of formulas and construction of various sets of curves from which the best designs for graded cables can be read directly. Analytical discussion of phenomena immediately preceding dielectric breakdown-corona in solid dielectrics-giving opinions of many eminent authorities, followed by a suggested explanation which is checked by tests. Bibliography. Discussion, pp. 1582-1624, by Messrs. J. B. Whitehead, Milton Franklin, A. E. Kennelly, W. S. Franklin, W. I. Middleton, Henry A. Morss, R. W. Atkinson, H. W. Fisher, Percy Thomas, C. J. Fechheimer, G. I. Rhodes, Armin Henry Pikler, C. P. Steinmetz, C. O. Mailloux, Tracy D. Waring, William A. Del Mar and H. S. Osborne. General discussion of graded insulation as applied to cables, generators and transformers, and also of the phenomena that precede breakdown in solid dielectrics. Formulas and experimental results bearing on the design of insulation. Effect of grading on the maximum safe kilowatt capacity of cables. 5. ELECTRIC CONDUCTORS Henry G. Stott LOCATING FAULTS IN UNDERGROUND DISTRIBUTION SYSTEMS Vol. xviii-1901, pp. 829-833 Description of a compass method for quickly and accurately locating faults in power cables through which periodically reversed current is sent. Working drawings of the current reverser. Discussion, incorporated with that of paper by Philip Torchio on "250-Volt Three-Wire Distribution for Lighting and Power." SUBMARINE CABLE TESTING IN THE SIGNAL CORPS U. S. ARMY Vol. xix-1902, pp. 685-695 General description of the electrical and mechanical specifications for Signal Corps cable and the tests which it must undergo. Change of insulation resistance with temperature treated in detail, and a chart given for reducing resistances to standard temperatures. Discussion, incorporated with that of paper by Louis Bell on "Emergency Engineering for Harbor Defence." THE OPERATION AND Maintenance of high-tenSION UNDERGROUND SYSTEM Brief remarks on the general subject. The New York Edison Company lines. breaking down defective insulation. Discussion, incorporated with that of paper by H. G. Stott on "The Use of Automatic Means for Disconnecting Disabled Apparatus." THE ELECTRICAL CONDUCTIVITY OF COMMERCIAL COPPER Lawrence Addicks Vol. xxii-1903, pp. 695-702 Experimental study of the relation between chemical composition, mechanical strength, physical structure and conductivity of copper. Discussion, p. 703, by Messrs. B. J. Arnold and F. J. Newbury. Properties of standard copper conductors. SAFETY DEVICES IN CENTRAL STATIONS AND SUBSTATIONS Philip Torchio Discussion, incorporated with that of paper by Peter Junkersfeld on "Multiple Versus Independent Operation of Units and Central Stations." PROTECTION OF CABLES FROM ARCS DUE TO THE FAILURE OF ADJACENT CABLES holes. LIBRARY OF MILWAUKEE SCHOOL OF ENGINEERING 5. ELECTRIC CONDUCTORS 25 Discussion, pp. 475-479, by Messrs. Ralph D. Mershon, W. F. Wells, H. C. Wirt, W. G. Carlton, H. B. Alverson, E. M. Lake, A. M. Hunt and J. W. F. Blizard. General remarks on the protection of high-tension cables in manholes and in power houses. Formulas for fire-proof coverings. HIGH-POWER SURGES IN ELECTRIC DISTRIBUTION SYSTEMS Charles P. Steinmetz Vol. xxiv-1905, pp. 297-315 Theoretical and mathematical investigation of high-power surge in Manhattan Railway cable distribution system. Discussion, incorporated with paper by Percy H. Thomas on “An Experimental Study of the Rise of Potential on Commercial Transmission Lines Due to Static Disturbances caused by Switching, Grounding, Etc." H. W. Fisher DATA RELATING TO ELECTRIC CONDUCTORS AND CABLES Vol. xxiv-1905, pp. 397-414 Experimental study of the safe current-carrying capacity of insulated wires and cables. Effect of steel strands on cable impedance and method of overcoming it. Table of reactances for different sizes of wire and cables at different spacings. Tests of variation of insulation resistance and electrostatic capacity with temperature and of the heating of cables in ducts. Discussion, pp. 415-419, by Messrs. H. G. Stott, C. W. Rice, C. O. Mailloux, Charles P. Steinmetz and H. W. Fisher. Conditions under which high-reactance cable is desirable. John Langan STANDARDIZING RUBBER-COVERED WIRES AND CABLES Vol. xxv-1906, pp. 191-204 Protest against potential test as a criterion of insulation. Characteristics and properties of different grades of rubber, with instructions for easily determining the quality of rubber insulation. Suggested specifications for rubber-covered wires. Discussion, incorporated with paper by Wallace S. Clark on "Comments on Present Underground Cable Practice." COMMENTS ON PRESENT UNDERGROUND CABLE PRACTICE Wallace S. Clark Vol. xxv-1906, pp. 205-213 Notes on electrolysis troubles with the low-tension cables. Effect of grounding sheath. Properties of insulation, tests of durability and record of operation of 11,000-volt 25-cycle rubber-covered leaded cables. Specifications of Rubber Covered Wire Engineers' Association for 30 per cent. rubber compound. Discussion (included with paper by John Langan on "Standardizing Rubber Covered Wires and Cables"), pp. 214-239, by Messrs. H. W. Fisher, H. G. Stott, Wallace D. Clark, John Langan, Philip Torchio, A. E. Kennelly, E. W. Stevenson, Townsend Wolcott, Durand Woodman, William McClellan, J. B. Taylor, C. F. Scott, S. S. Wheeler, Dugald C. Jackson, F. R. Cutcheon, J. H. Schumacher, H. J. Gille, John Pearson and E. H. Scofield. General discussion of the requirements of rubber insulation and the methods of fixing and testing them. Results of tests on rubber insulated wires showing effect of percentage of Para on the performance characteristics under different conditions and indicating the method of determining the quality of insulation. UNDERGROUND TRANSMISSION AND DISTRIBUTION OF ELECTRICAL ENERGY Charles E. Phelps Vol. xxvi-1907, pp. 25-30 Classification of cable faults, followed by seven-year record of the performance of various kinds of power, telephone and telegraph cables. Brief analytical discussion of the causes and remedies for these various faults. No discussion. CONSTANTS OF CABLES AND MAGNETIC CONDUCTORS Vol. xxvi-1907, pp. 555-568 Ernst J. Berg Derivation of equations for inductance and capacity of parallel conductors, followed by an analysis of single-conductor cable performance under various conditions. Estimated effective resistance and reactance with grounded and ungrounded sheath and with iron armor; also estimated effective resistance of iron wire and cable. Discussion, p. 926, by Mr. W. A. Del Mar. Exact formula for inductance of parallel wires. THE HEATING OF COPPER WIRES BY ELECTRIC CURRENTS A. E. Kennelly and E. R. Shepard Vol. xxvi-1907, pp. 969-995 Experimental investigation of the heating of wires under various conditions of cooling by thermal conduction-through insulation, sand, water and molding. Much data on thermal resistivity of insulation materials, wood and various soils. Graphical diagrams of the current carrying capacity of different sized wires under the various conditions. No discussion. POWER-FACTOR, ALTERNATING-CURRENTt inductive cAPACITY, CHEMICAL, AND OTHER TESTS OF RUBBER-COVERED WIRES OF DIFFERENT MANUFACTURERS Henry W. Fisher Vol. xxvi-1907, pp. 997-1020 Experimental investigation tending to show the relations that exist between the chemical composition of the rubber compound and the electrical properties of the wire-breakdown e. m. f., insulation resistance, |