Showing papers in "Transactions of The American Institute of Electrical Engineers in 1951"
257 citations
166 citations
TL;DR: In this paper, a modified slot discharge detection method, which permits tests without shutting down the machine or using auxilliary high-voltage test equipment, was investigated, which involves connection of frequency sensitive equipment across all or part of the ntral impedance.
Abstract: A modified slot discharge detection method, which permits tests without Shutting down the machine or using auxilliary high-voltage test equipment, was investigated. The method involves connection of frequency sensitive equipment across all or part of the ntral impedance. Tests on eight vertical water wheel generators in the range of 20,000- to 40,000-kva capacity indicate that the method is generally applicable when there is a current transformer or some other impedance in the generator neutral.
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TL;DR: In this paper, a method of analysis is outlined to solve steady-state problems arising in the operation of large interconnected transmission systems exchanging power between their own operating divisions and outside companies.
Abstract: A method of analysis is outlined to solve steady-state problems arising in the operation of large interconnected transmission systems exchanging power between their own operating divisions and outside companies Special attention is paid to the calculation of total and incremental losses for economic loading studies and to the allocation of incremental losses between the various subsidiary and outside companies This first part restricts itself to lay the necessary foundations for the numerical study made in a companion paper1 on the system of the American Gas and Electric Company
65 citations
TL;DR: In this article, the peak of the first cycle of magnetizing inrush current for a transformer was calculated using an approximate formula for determining the maximum values of successive cycles of current.
Abstract: THERE ARE formulas available by which it is possible to calculate the peak of the first cycle of magnetizing inrush current for a transformer. There have been no convenient formulas available for determining the maximum values of successive cycles of current. The usual approach has been to use a step-by-step process of mechanical integration that is quite time-consuming and usually is not worth the effort. Below are presented approximate formulas for determining the maximum values of the successive cycles of current that will be satisfactory for the majority of cases where this information is desired.
50 citations
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TL;DR: A null-balance type of transducer which is inherently capable of achieving an accuracy comparable to that of present-day transmission links is described.
Abstract: As the telemetering art progresses under the impetus of both aircraft and industrial needs, the requirement for accurate transducing becomes more and more important. This article describes a null-balance type of transducer which is inherently capable of achieving an accuracy comparable to that of present-day transmission links.
TL;DR: In this paper, a new synthetic resin bonded mica tape insulation for high-voltage stator windings is described, which is now being applied to turbine generators for central station service.
Abstract: This paper reports the development of a new synthetic resin bonded mica tape insulation for high-voltage stator windings. It reviews the problems associated with earlier forms of high-voltage machine insulation. The general construction and processing of the insulation are described briefly. Comprehensive test data are presented on the characteristics of the materials employed and the resultant physical and electrical properties obtained on the composite insulation. This new insulation is now being applied to turbine generators for central station service.
TL;DR: In this paper, the design of automatic control systems to give ''optimum'' response is discussed in terms of the area between a step disturbance and the control response, and also a ''weighted control area'' may be calculated directly from the system parameters without finding the roots of an algebraic equation.
Abstract: The design of automatic control systems to give ``optimum'' response is discussed in terms of the area between a step disturbance and the control response. It is shown that this ``control area'', and also a ``weighted control area'' may be calculated directly from the system parameters without finding the roots of an algebraic equation. Assumed optimum values of these areas permit direct synthesis of the necessary control sensitivities for an ``optimum'' control response. An example of an aircraft engine control is given and the connection with zero velocity error servos is shown.
TL;DR: In this paper, the emergency rating of a cable is evaluated based on the severity of the abnormal transmission of the cable's transceivers, a subject which is receiving increasing attention because of its economic as well as technical importance.
Abstract: THERMAL TRANSIENTS on cables have an important bearing on the emergency rating of a cable, a matter which is receiving increasing attention because of its economic as well as its technical importance
TL;DR: In this paper, the performance of circuit breakers in this service has been found by recent experiments to depend on the power supply system as well as on the size of the capacitor banks.
Abstract: The switching of capacitors differs from other switching by causing relatively large surge currents and possibly overvoltages. The performance of circuit breakers in this service has been found by recent experiments to depend on the power supply system as well as on the size of the capacitor banks. When circuit breakers open with no delayed restriking of the arc, they avoid the possibility of causing undesirably high current and voltage surges.
TL;DR: In this paper, the behavior of a-c rotating machines connected to stationary networks or transmission lines and other rotating machines under synchronous or asynchronous operation is analyzed, where the forward and backward components are correlated to the direct-axis and quadrature-axis components in a simple manner.
Abstract: This paper analyzes the behavior of a-c rotating machines connected to stationary networks or transmission lines and other rotating machines under synchronous or asynchronous operation. Rotating reference frames are introduced. The forward and backward components are correlated to the direct-axis and quadrature-axis components in a simple manner. Part I deals with the interconnection of a rotating machine and a terminal network or a transmission line with lumped or distributed constants. Part II deals with the interconnection of rotating machines. A general network of n machines is analyzed. Part III considers a general machine with n 1 stator phases and n 2 rotor phases under synchronous or asynchronous operation. Concatenation of induction machines and selsyns are studied by means of rotating reference frames.
TL;DR: The conclusions drawn from these elementary considerations will form a basis for predicting the performance of examples of certain novel circuits which shall have properties of an unusual nature.
Abstract: In this paper certain magnetic amplifier circuits will be illustrated and their circuit equations presented subject to certain assumptions. The equations will be interpreted in as clear a manner as the author thinks possible and some conclusions will be drawn. Since the mathematics of analysis of magnetic amplifiers is quite complex as viewed from continuous theory a clearer period by period interpretation will be pursued during which periods the equations may be considered as a continuous, elementary and reasonably accurate representation of the phenomena. The two periods which will be used are those during which the amplifier output current is large (conducting period); and during which the amplifier output current is of the order of the magnetizing current (nonconducting period). Equivalent circuits for each period will be set up. The final conditions of one period will represent the initial conditions of the following period. The two assumptions utilized in this analysis are ``ideal'' magnetization curves for the core materials, Figure 1, and ``ideal'' rectifiers. The best core materials and rectifiers manufactured today rather closely approximate these assumed conditions. A resistive load impedance will be used for simplification of the mathematics. The conclusions drawn from these elementary considerations will form a basis for predicting the performance of examples of certain novel circuits which shall have properties of an unusual nature. Practical discussion of these circuits is beyond the scope of this paper and will be presented elsewhere.
TL;DR: In this article, analog computing techniques may be useful in helping economists answer three questions: What are its topological features? What is its quantitative behavior for given parameters? What are good estimates of the parameters?
Abstract: A wide variety of models of interest to economists may be represented by electrical circuits. These models therefore lend themselves to investigation by use of an electrical analogue computer. The economist may study a model with any of three questions in mind: What are its topological features? What is its quantitative behavior for given parameters? What are good estimates of the parameters? This paper shows that analog computing techniques may be useful in helping economists answer all three of these questions.
TL;DR: In this article, the authors present a method for detecting and locating slot surface discharging on high-voltage machine stator windings, which may lead to a relatively high energy capacitive discharge which may seriously degrade basic insulation.
Abstract: Basic studies in connection with the nature and method of detection of slot discharge phenomena in high-voltage stator windings are presented. Discharging is seen to result from a loss of electrical contact between conducting coil surfaces in the slot portions and the core. This gives rise to a relatively high energy capacitive discharge which may seriously degrade basic insulation if it continues unchecked. The several possible methods for detection and location of discharge in stator windings were studied. The development of the slot discharge analyzer is described. This is useful as a maintenance tool for the detection and location of slot surface discharging on high-voltage machine stator windings.
TL;DR: In this article, a program studying voltage endurance of various mica insulations is reported, which includes dielectric breakdown data with both alternating and direct current on numerous similar samples.
Abstract: A program studying voltage endurance of various mica insulations is reported. This includes dielectric breakdown data with both alternating and direct current on numerous similar samples. Effects of repetitive testing, prolonged a-c (60-cycle) stress and mechanical damage to mica insulation are reported. Detection of insulation faults is described and conclusions are drawn that d-c overpotential maintenance tests can be equally searching but less damaging than a-c overpotential tests for large high-voltage rotating machinery.
TL;DR: In this paper, the Alnico family of permanent magnet alternators have been used for many years in small-sized units such as tachometer generators, governor frequency sources, and magnetos, but until recently have not been adopted widely as primary sources of power.
Abstract: PERMANENT-MAGNET alternators have been used for many years in small-sized units such as tachometer generators, governor frequency sources, and magnetos, but until recently have not been adopted widely as primary sources of power. With the development of dispersion-hardening alloys typified by the Alnico family and their application to rotating machinery, the permanent-magnet alternator has assumed a more important role for power applications. In some ratings these machines weigh less, consume less space, and cost less than d-c excited alternators. The saving in weight and space is accomplished chiefly by the elimination of the d-c exciter. When the exciter is absent, commutation problems are eliminated. Hence, these machines are assuming an important role for portable, aircraft, and other applications in which the saving of weight is an essential factor.