Everett S. Lee

The Measurement of Surge Voltages on Transmission Lines Due to Lightning

This paper, after referring to the work of previous investigators in the application of the photographic Lichtenberg figures to the measurement of surge voltages, describes results of additional work in this field by the authors. Laboratory calibrations of photographic Lichtenberg figures, using the cathode ray oscillograph and the lightning generator, are shown. Data are presented relative to the accuracy obtainable with these figures as a means of measuring surge voltages. An extension of instrument design is described in which two recording elements are used to give greater certainty of result. Means for connecting a surge voltage recorder instrument to a transmission line by an insulator-string potentiometer are described, and calibration of the instrument with potentiometer is given up to 1400 kv. Specimen field records of surge voltages up to 2000 kv. are shown.

Testing High-Tension Impregnated Paper-Insulated, Lead-Covered Cable

The increase in voltage of cables has necessitated that the tests to assure satisfactory cable be more adequate than as standardized at present. This has resulted in an intensive study of the tests previously standardized, development of new tests, and the design and manufacture of suitable testing equipment to meet the new testing requirements. Measurements are made upon cables to determine the following properties of the insulation: Insulation Resistance Dielectric Strength Dielectric Power Loss and Power Factor Capacitance Ability to Withstand Bending Insulation Resistance: This measurement is being made in the same way on cables of all voltage rating. The results of the test on high-tension cables are of doubtful value as a criterion of the suitability of cable for use. Continued study of this measurement should be made. Dielectric Strength: Suitable testing equipment for satisfying the requirements of the increased voltages in dielectric strength tests has been made available. This includes sine-wave generators, adequate testing transformers, appropriate cable testing terminals. Data is given from which conclusions are drawn as to the magnitude and duration of test voltages. The adequacy of these values will become known through experience. The need for field testing is shown. Dielectric Power Loss and Power Factor: The tendency is to extend the measurement of dielectric power factor to include each reel length to be shipped. The Schering Bridge for making such measurements is described. The need for standardizing the testing procedure for power factor measurements is shown. Testing Installed Cable: The study of so-called “current-time curves” for rating installed cable should be continued. Preliminary measurements made at high frequencies as a means of rating installed cable did not show the results to be immediately usable. Testing With Direct Current: Data is given to show the d-c. to a-c.-ratio of breakdown voltage of some samples of 12 kv.-3-conductor. cable. Tests indicate that the d-c.-to a-c.-ratio will depend upon many conditions such as nature and structure of the material, thickness of the material, temperature of the material, shape and size of electrodes, and rate of application of the applied potential.

The electrical engineer

The life of Thomas A. Edison, whose 100th anniversary is being observed this year, truly embodies the spirit of “The electrical engineer” for his contributions have stimulated almost every phase of electrical activity. To men such as Edison and his cofounders of the AIEE, to men whose accomplishments have been deemed worthy of recognition, and to every electrical engineer who simply serves faithfully, the world owes much of its comfort, its efficiency, and its well-being.

IV---The Use of the Dynamometer Wattmeter for Measuring the Dielectric Power Loss and Power Factor of the Insulation of High-Tension Lead-Covered Cables

The use of the dynamometer wattmeter for measuring the dielectric power loss and power factor of cable and capacitor insulation is not new, but dates from about 1890. Dynamometer wattmeters as available today are suitable for making these measurements. Care and attention must be given to their application. The usual methods of application are: 1. Compensated dynamometer wattmeter method, with air capacitor, 2. Inductance variation method (phase-defect compensation method), with air capacitor, 3. Series resistor and wattmeter method, 4. Resonance wattmeter method. Comparative measurements of dielectric power loss and power factor of cable samples indicate that results are being obttained with the dynamometer wattmeter wherein the probable departure from the true value is within from 10 to 20 per cent. There is need for an effective means of standardizing any measuring equipment. Study of the calorimeter method for this purpose seems desirable.

The practical application of research

This review of typical advances in various fields and industries made possible by the practical application of research demonstrates the vital role played by measurements

The Measurement of Electrical Output of Large A-C. Turbo Generators During Water-Rate Tests

The water-rate of large a-c. turbo-generators is determined in place with the generator supplying power to the existing commercial load. Such procedure requires that the electrical output be accurately measured under conditions where the load is practically always varying slightly, and where it may be varying considerably. Portable test meters are frequently used for such measurement. The use of portable indicating wattmeters is absolutely feasible for such measurement even where the load variations are extreme, with the resultant accruing advantage that the superior operating characteristics of the portable indicating wattmeters, particularly as regards their permanency, are utilized. Either the two-wattmeter or three-wattmeter method for-measuring the power of a three-phase circuit may be employed. Great care should be used in selecting instruments, particular reference being made to their past history. Comparisons against secondary standards should be made under conditions simulating those of the test. Observations are made at frequent intervals depending upon the accuracy desired in the final result. The accuracy of the final values of water-rate obtainable in practise is such that the per cent average deviation from the mean will be within ± 0.25 per cent. This means that practically all individual test results will fall in a belt 1 per cent wide, while the probably true value of water-rate will be located within a belt which will vary in width from 0.5 per cent to 0.25 per cent depending upon the conditions.

What the technical reader expects of the scientist and engineer who write

In an address presented primarily to technical writers and editors, the editor of a well-known technical publication stresses the importance of the effective dissemination of ideas in the fields of engineering and science.

The engineer and automation in the process industries

The word “automation” has become one of the most overused, and probably misused, words in our modern vocabulary. To the electrical engineer, however, it means the advancement of electrical living as we progress from manual methods to mechanization, and thence to automation. To America as a whole it means more goods for more people at less cost.

Light's Diamond Jubilee and the engineer

The story of progress in electrical engineering can be written in terms of the lives of Edison Medalists, who have contributed to its advancement. In this year of celebration of Lights Diamond Jubilee, one should note with pride and satisfaction their many discoveries.

Career of the medalist

ONE OF THE pleasures of life is to tell of outstanding engineering accomplishments; and as I describe the engineering achievements of Isaac Fern Kinnard, I will be talking about a friend whom I have known and have lived with in engineering association for 30 years.