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Showing papers in "IEEE Transactions on Industry Applications in 1973"


Journal ArticleDOI
TL;DR: In this article, the theoretical problem of eliminating harmonics in inverter-output waveforms was considered, and numerical techniques were applied to solve the nonlinear equations of the problem on the computer.
Abstract: This paper considers the theoretical problem of eliminating harmonics in inverter-output waveforms. Generalized methods are developed for eliminating a fixed number of harmonics in the half-bridge and full-bridge inverter-output waveforms, and solutions are presented for eliminating up to five harmonics. Numerical techniques are applied to solve the nonlinear equations of the problem on the computer. The uneliminated higher order harmonics can be easily attenuated by using filter circuits in the output stage of the inverter. The results show the feasibility of obtaining practically sinusoidal output waveforms, which are highly desirable in most inverter applications.

1,159 citations


Journal ArticleDOI
TL;DR: Both in its initial concept and in its present form, the induction range has many desirable features when compared to conventional ranges as discussed by the authors, which are readily demonstrable by its superior thermal response, its convenience, and safety.
Abstract: Both in its initial concept and in its present form, the induction range has many desirable features when compared to conventional ranges. These are readily demonstrable by its superior thermal response, its convenience, and safety. All these attributes are possible because the use of electromagnetic induction permits the pan to be heated directly without heating the range surface first.

80 citations


Journal ArticleDOI
TL;DR: In this article, the authors compared the energy consumption and efficiency of electric and heat engine cars on an equal basis, by considering a reference electric car of 3150-lb weight similar in body construction, aerodynamics and rolling resistance to a conventional heat engine car of equal weight.
Abstract: Assuming the availability of a high energy and power density battery of 100 Wh/lb and 100 W/lb by the 1980' s, the energy consumption and efficiency of electric and heat engine cars are compared on an equal basis. This is achieved by considering a reference electric car of 3150-lb weight similar in body construction, aerodynamics, and rolling resistance to a conventional heat engine car of equal weight, and comparing the performance of the two cars over the same driving modes. The reference electric car is then used as a baseline to evaluate the possible improvements in future electric cars. The energy consumption for an optimized 2000-lb electric car of driving range, comfort, and performance comparable to a conventional car is estimated. Assuming a gradual growth in electric car population leading to their widespread use by the 1990's, the impact on electric power generation and distribution systems is estimated. Though the analysis is based on a high energy and power density battery the results may be extrapolated to electric cars using lower performance batteries. It is noted that batteries with lower energy density can provide sufficient driving range to fulfill a significant portion of our transportation needs and their continued development and improvement will accelerate the achievement of the high energy-density goal [1].

62 citations


Journal ArticleDOI
Louie J. Powell1
TL;DR: In this article, the causes of third harmonic currents and their effects on the power system are reviewed, and the common methods of neutral grounding with regard to circulating harmonic currents are discussed with respect to harmonic currents.
Abstract: It has long been recognized that third harmonic currents can and often do appear in the neutral of industrial generators. This paper will review the causes of such currents and the effects these currents have in the power system. The common methods of neutral grounding will be discussed with regard to circulating harmonic currents.

36 citations


Journal ArticleDOI
TL;DR: In this article, a method of analysis of induction motor performance with nonsinusoidal supply is presented based on the Fourier analysis of the impressed voltage waveform, and the resultant harmonic currents are calculated.
Abstract: A method of analysis of induction motor performance with nonsinusoidal supply is presented. It is based on the Fourier analysis of the impressed voltage waveform. Equivalent circuits for the various harmonics are derived, and the resultant harmonic currents are calculated. Experimental verification of the method is obtained by calculating the current waveform from the Fourier components and comparing it with oscillograms. Experimental data obtained from a cycloconverter and different types of inverters are used and show good agreement with calculated results. Evaluation of different schemes of power control and effects of a rapid variation of slip frequency are examined.

34 citations


Journal ArticleDOI
John C. Price.1
TL;DR: In this article, the static and dynamic characteristics of electric hot strip mill looper systems are reviewed. And the flexibility of control which is inherent in adjustable-voltage looper system permits the incorporation of a number of features which contribute to the effectiveness of the drive.
Abstract: In the modern hot strip mill, the loopers establish a low and relatively constant level of tension between stands. This aids in minimizing width deviation, and provides an isolated environment for the operation of automatic gage control equipment at each stand. The looper also serves to keep all stands of a mill in synchronism during speedup and slowdown when metal is in the mill. The flexibility of control which is inherent in adjustable-voltage looper systems permits the incorporation of a number of features which contribute to the effectiveness of the drive. Static and dynamic characteristics of electric hot strip mill looper systems are reviewed.

30 citations


Journal ArticleDOI
TL;DR: In this paper, the main components of the system, such as the alternator, converter, traction motors, and the whole control system are described in detail, considering the interaction between the different components.
Abstract: After a short explanation of the need to develop a new power transmission system, listing the general demands on the performance of a locomotive, the arrangement of an existing diesel electric locomotive, the DE 2500, is presented. The main components of the system, such as the alternator, converter, traction motors, and the whole control system are described in detail. Consideration is given to the interaction between the different components which had to be taken care of in the design. Good operating experience has shown that the system was well chosen. For the future a uniform drive scheme for different power supplies appears realizable.

24 citations


Journal ArticleDOI
TL;DR: In this article, the most practical approach to locating cable faults consists of a three-step procedure known as the System Approach, in which various test instruments are employed to first characterize a fault according to its electrical parameters, next localize the fault to an approximate location by measurements from a terminal, and finally locate the fault within that locality by physically tracing for its effect along the cable route.
Abstract: Results have shown that the most practical approach to locating cable faults consists of a three-step procedure known as the System Approach. By this process various test instruments are employed to first characterize a fault according to its electrical parameters; to next localize the fault to an approximate location by measurements from a terminal; and then to finally locate the fault within that locality by physically tracing for its effect along the cable route. Success is measured in terms of the minimum of time to restore service which in turn is usually a function of the selection and performance of available instrumentation. All of the recognized methods and instruments that can be used in each step of the System Approach are described giving typical features along with the advantages and disadvantages of each method. This information should enable responsible engineers to evaluate the practicality of their own resources for the intended purpose.

24 citations


Journal ArticleDOI
TL;DR: In this paper, a new theory of the end-effect of a high-speed linear induction motor, an experimental proof of the theory, and several countermeasures to eliminate the end effect are presented.
Abstract: This paper presents a new theory of the end-effect of a high-speed linear induction motor, an experimental proof of the theory, and several countermeasures to eliminate the end-effect. The theory is developed on the basis of a two-dimensional solution of electrodynamic equations and compared with the experimental results. The experiment has been made by use of a rotary type test facility; the maximum test velocity is 450 km/h. It is found that the theory agrees well with the experiment and that the end-effect exercises a very adverse influence on motor performance. The end-effect is investigated as functions of design parameters by making use of the theory. Some measures to counter the end-effect are proposed and discussed. A parallel-connected linear induction motor is also proposed as a measure to compensate the end-effect, and its performance is studied.

22 citations


Journal ArticleDOI
George W. Walsh1
TL;DR: In this article, the traveling wave nature of lightning is discussed and guidance is presented to facilitate proper economic lightning protection of industrial power system component arrangements, and the grounding treatment is very brief, being limited to the most salient considerations of equipment grounding in relation to the overall lightning protective system and the ground fault protective system.
Abstract: Guides are presented to facilitate proper economic lightning protection of industrial power system component arrangements. Basic concepts of the traveling wave nature of lightning are included to enhance understanding of protective practices as they have developed and emphasize the need for careful adherence to approved practices in critical areas. The grounding treatment is very brief, being limited to the most salient considerations of equipment grounding in relation to the overall lightning protective system and the ground fault protective system. The paper is referenced throughout to current industry standards, application guides, and codes.

21 citations


Journal ArticleDOI
Richard L. Curran1
TL;DR: In this paper, a quantitative analysis of coupled electrical power dissipation, heat transfer, and natural convection in a hypothetical all-electric glass tank furnace was conducted using a two-dimensional computer model.
Abstract: A quantitative mathematical analysis of coupled electrical power dissipation, heat transfer, and natural convection in a hypothetical all-electric glass tank furnace was conducted using a two-dimensional computer model. The model simulated numerically the complex interactions which occur among charge, mass, energy, and momentum transport in a vertical plane section through the melter. Computer generated contour plots of the power density, isotherms, and stream-lines in the rectangular enclosure are presented for both a flint glass and an amber glass, each with and without the variation of electrical resistivity with temperature taken into account. The total electrical power consumption was held constant in all cases investigated in order to establish a common basis for comparison of the results. It is shown that although the variation in melt resistivity, associated with the range of temperatures encountered in the interior of the hypothetical glass furnace, approaches 10 percent of the mean isothermal value, it has subsequently very little effect on the calculated temperature and velocity distribution within the enclosure over a wide range of effective thermal conductivities. Hence the electrical resistivity can be assumed consistent for all practical purposes when these are the results of primary interest. It is also shown that the electric melting behavior of colored glasses may be quite different from that of a flint glass under the same basic furnace operating conditions.

Journal ArticleDOI
TL;DR: A variable speed drive, which includes a prime mover driven alternator, a 36-SCR cycloconverter, and an induction motor, is simulated on a digital computer to permit a general solution when any number of the stator currents is zero.
Abstract: A variable speed drive, which includes a prime mover driven alternator, a 36-SCR cycloconverter, and an induction motor, is simulated on a digital computer. The induction motor model is developed to permit a general solution when any number of the stator currents is zero. Using conduction criteria for individual SCRs, a new cycloconverter model is derived which results in an input/output transfer function.

Journal ArticleDOI
TL;DR: The conditions under which ferroresonant overvoltages can occur on rural distribution systems are reviewed in this paper, and a guide for the selection of corrective or preventive measures on rural systems is presented.
Abstract: The conditions under which ferroresonant overvoltages can occur on rural distribution systems are reviewed. A brief description of the phenomenon of ferroresonance is given, and the reasons for the increasingly frequent occurrence of ferroresonance on modern systems are enumerated. Preventive or corrective measures that have been proposed are reviewed and evaluated. A guide for the selection of corrective or preventive measures on rural systems is presented.

Journal ArticleDOI
TL;DR: In this article, a radiation cross-linked heater is described, which undergoes dramatic resistance changes with temperature. But the authors focus on self- limiting features and some applications are discussed with special emphasis given to the self-limiting feature as applied to electrical pipe line heating.
Abstract: Power output of a resistive electrical heater is a function of resistance value. The authors describe a radiation cross-linked heater which undergoes dramatic resistance changes with temperature. Self- limiting features and some applications are discussed with special emphasis given to the self-limiting feature as applied to electrical pipe line heating.

Journal ArticleDOI
Arie Verhoef1
TL;DR: In this article, an endeavor has been made to classify the impulse-commutated inverter circuits and compare their characteristic features with each other, and the basic commutation circuits were considered generally, but yet varied enough to make some conclusions.
Abstract: In connection with the ever increasing applications of static inverters in the area of uninterruptable power systems and variable frequency ac motor drives, and the many forced-commutated inverter circuits that are proposed for these applications, an endeavor has been made to classify the impulse-commutated inverter circuits and to compare their characteristic features with each other. To attain this, the basic commutation circuits were considered generally, but yet varied enough to make some conclusions. Although there are but a few basic ways to insert a commutation impulse source in the forced-commutated inverter, many variations are possible, which make the design of inverters a difficult matter and very dependent on the desired specifications and the available components.

Journal ArticleDOI
TL;DR: In this paper, a new pulsewidth modulator circuit is proposed to cope with the symmetry problem in a transformer-coupled push-pull type power converter, which can be used to monitor the two primary currents and provide proper feedback of the integrated difference between these two currents.
Abstract: A wide variety of power converters is of the transformer-coupled push-pull type and uses pulsewidth modulation for output regulation. In designing and operating such converters, serious complications usually arise as a result of unsymmetrical switching of the two power transistors. Caused by small parameter dissymmetries of these transistors, asymmetrical switching normally drives the transformer into saturation. Resulting excessive saturation currents reduce efficiency and put a severe strain on the power transistors, which can eventually cause circuit failure. This paper presents a new pulsewidth modulator circuit which can be advantageously utilized in the design of such converters, and which can effectively cope with the aforementioned symmetry problem. Symmetry correction is accomplished by monitoring the two primary currents and by providing proper feedback of the integrated difference between these two currents.

Journal ArticleDOI
TL;DR: A plating for electrical contact surfaces should be selected on the bases of acceptable electrical characteristics (in conjunction with common contact surfaces) and of adequate corrosion resistance in the anticipated environments as discussed by the authors. But the problem electrical interfaces which must be considered is between the selected plating and nonplated aluminum contact surfaces.
Abstract: A plating for electrical contact surfaces should be selected on the bases of acceptable electrical characteristics (in conjunction with common contact surfaces) and of adequate corrosion resistance in the anticipated environments. One of the problem electrical interfaces which must be considered is between the selected plating and nonplated aluminum contact surfaces.

Journal ArticleDOI
TL;DR: In this article, a new concept in power generation has been theoretically developed and experimentally tested at Oklahoma State University, where the generator design incorporates new techniques in field modulation and solid-state alternator output processing.
Abstract: A new concept in power generation has been theoretically developed and experimentally tested at Oklahoma State University. The generator design incorporates new techniques in field modulation and solid-state alternator output processing. The resulting generator is smaller and lighter than comparable commercial models presently available, and it will operate such that frequency output is independent of the shaft speed of a prime mover.

Journal ArticleDOI
TL;DR: The steady-state properties and control strategies for the controlled-angle synchronous motor inverter system are investigated and some experimental results are presented and compared with theoretical predictions.
Abstract: This paper describes a controlled-power-angle synchronous motor inverter system which provides drive characteristics similar to those of an induction motor inverter system. The system consists of a conventional synchronous motor with a shaft-position sensor which controls the firing of thyristors in an inverter. This paper investigates the steady-state properties and control strategies for the controlled-angle synchronous motor inverter system. Some experimental results are presented and compared with theoretical predictions.

Journal ArticleDOI
TL;DR: Based on tests in laboratories and on German Federal Railways (GFR) trial vehicles type ET 25 as well as on an industrial locomotive type 500 of the Rheinische Braunkohlen AG the subsequent development has been concentrated on the improvement of the power factor and the displacement factor as mentioned in this paper.
Abstract: Based on tests in laboratories and on German Federal Railways (GFR) trial vehicles type ET 25 as well as on an industrial locomotive type 500 of the Rheinische Braunkohlen AG the subsequent development has been concentrated on the improvement of the power factor ? and the displacement factor cos ? in four vital stages: 1) introduction of half-control, unsymmetrical half-controlled, fully-controlled single-phase bridge connection with specially designed control systems: 2) introduction of sequence connection of several half-controlled bridges; 3) optimization of the so far applied connections for major assemblies such as rectifier transformer, rectifier, and smoothing reactor for improving the power factor; 4) introduction of sector control with self-commutating unsymmetrical bridge for improving the power factor.

Journal ArticleDOI
TL;DR: The structures, features, electrical characteristics, and successful application results of two types of high-voltage high-power reverse-conducting thyristors are described in this paper.
Abstract: The structures, features, electrical characteristics, and successful application results of two types of high-voltage high-power reverse-conducting thyristors are described. The first has blocking voltage ratings of 1300 V and current ratings of 400 A in the forward direction and 150 A in the reverse direction, with a turn-off time of 30 ?s. The second has ratings of blocking voltage of 2500 V, current ratings of 400 A in the forward direction and 150 A in the reverse direction, with a turn-off time of 40?s.

Journal ArticleDOI
TL;DR: The load waveforms produced by asymmetrical triggering of an inverse parallel connected pair of thyristors are of two categories as discussed by the authors : 1) the load current consists of asymmetrical discontinuous nonsinusoidal pulses, and 2) complete half-sinusoids of load voltage appear.
Abstract: The load waveforms produced by asymmetrical triggering of an inverse parallel connected pair of thyristors are of two categories. If each of the two firing angles ?,? (3 are greater than load phase angle ?, the load current consists of asymmetrical discontinuous nonsinusoidal pulses. For the case when firing angle 3 is less than p and satisfies the relationship sx ? - ? (where x =? is the extinction angle corresponding to the other firing angle ?), complete half-sinusoids of load voltage appear. Both modes of triggering result in load waveforms with even harmonic content, which are not present with symmetrical triggering.

Journal ArticleDOI
Takashi Tsuboi1, Shoji Izawa1, Koichi Wajima1, Takuzo Ogawa1, Takehiko Katta 
TL;DR: In this paper, the authors developed a new high-frequency chopper with regenerative braking for the Chiyoda Line of Teito Rapid Transit Authority in Tokyo, and they have been operated satisfactorily in revenue service since March 1971.
Abstract: In the chopper control system for electric railcars, it is effective to adopt high operational frequency of the chopper for achievement of the following: 1) decrease of higher harmonic current induced in the trolley wire, 2) reduction of weight for reactors and capacitors in the traction circuit, and 3) improvement of control response. Through development of reverse-conducting thyristors with very short turn-off time and a repulsion type two-phase chopper, we finally realized production of a new standard high-frequency chopper equipment with regenerative braking for 1500-V dc railcars. Technical achievements mentioned previously were completely realized as a result of adoption of high frequency, 660 Hz, in the equipment. The newly developed standard high-frequency chopper equipment for 30 cars were delivered to the Chiyoda Line of Teito Rapid Transit Authority in Tokyo, and they have been operated satisfactorily in revenue service since March 1971. This paper also describes: 1) the chopper circuit using fast-switching reverse-conducting thyristors and series saturable reactors, 2) analysis of commutation circuit and methods of suppressing reapplied forward voltage increasing rate (dv/dt) and shortening commutation period, 3) the composition of the traction circuit including the protection system, such as protection for overvoltage at the regenerative braking, and 4) test results on the Chiyoda Line of Teito Rapid Transit Authority.

Journal ArticleDOI
TL;DR: In this paper, a review of present practices as well as suggested modifications with an actual design example is presented for equipment grounding in industrial power systems that obtains any energy from a utility with a high ground fault current capability.
Abstract: One of the prime functions of equipment grounding is for safety to life and property. In designing an industrial power system that obtains any energy from a utility with a high ground fault current capability, it may be advisable to isolate the industrial and utility ground grids for safety reasons. A review of present practices as well as suggested modifications with an actual design example is presented.

Journal ArticleDOI
TL;DR: In this article, the behavior of ten types of silicon rectifiers under transient voltages was studied experimentally, and it was shown that the transient-voltage withstand capability of a silicon rectifier does not have any correlation with its steady-state peak reverse voltage (PRV) rating.
Abstract: The behavior of ten types of silicon rectifiers under transient voltages was studied experimentally. The steady-state peak reverse voltage (PRV) ratings of these rectifiers were from 300-1200 V, and the half-cycle average current ratings were from 25-300 A. The study shows that, at least for the samples tested, the transient-voltage withstand capability of a silicon rectifier does not have any correlation with its PRV rating. A silicon rectifier may be damaged by a transient voltage lower than its PRV rating while it is carrying current in the forward direction. The transient-voltage withstand capability can also be widely divergent for different types of rectifiers of the same PRV rating. It is proposed that the transient-voltage withstand capability of each type of silicon rectifier should be specified along with its steady-state PRV rating.

Journal ArticleDOI
TL;DR: The authors describes the cause and evaluation of veiling reflections and shows how lighting equipment can be designed to overcome the deleterious effects of such reflections without sacrificing other requirements of the system.
Abstract: Design of luminaires and lighting systems traditionally has been made in accordance with the criterion of providing adequate levels of ilumination. The problem of overcoming ``veiling reflection'' effects, which cause great losses of visibility, largely has been overlooked. This has resulted in the ``visual performance'' of persons engaged in tasks such as reading and writing seriously being impaired. This paper describes the cause and evaluation of veiling reflections and shows how lighting equipment can be designed to overcome the deleterious effects, without sacrificing other requirements of the system.

Journal ArticleDOI
TL;DR: In this article, a method of riding through voltage dips with dc coil magnetic contactors is described, and application of this method will depend upon the individual characteristics of each electrical system and the process that it serves.
Abstract: Continuous process plants are being designed today with fewer and larger components arranged in ``single train'' configurations. Maintaining operating continuity with fewer components requires high equipment reliability. Motor controls for larger components are using magnetic contactors equipped with automatic undervoltage reclosing. A voltage dip where contactors drop open and reclose can be very serious because of the nature of motors and their driven loads during voltage transients. The reclosing of magnetic starters on motors with a decaying internal voltage is reviewed. A method of riding through voltage dips with dc coil magnetic contactors is described. Application of this method will depend upon the individual characteristics of each electrical system and the process that it serves.

Journal ArticleDOI
John E. Stevenson1
TL;DR: In this paper, the effects of temperature, humidity, grounding, bonding, and circuit conditions on the measured leakage current values are discussed, and information on the measurement instrument, its frequency response, input impedance, and sensing characteristics is given.
Abstract: Leakage current from portable appliances has been limited to 0.5 mA American National Standards Institute (ANSI), Committee C101.1. Typical leakage currents are presented, and the effects of temperature, humidity, grounding, bonding, and circuit conditions on the measured values are discussed. Information on the measurement instrument, its frequency response, input impedance, and sensing characteristics is given.

Journal ArticleDOI
TL;DR: In this paper, the authors compared constant-torque adjustable-speed phase-controlled SCR dc drives with inverter drives from the standpoint of technical similarities and differences, application limitations, and relative costs.
Abstract: Constant-torque adjustable-speed phase-controlled SCR dc drives are compared with inverter drives from the standpoint of technical similarities and differences, application limitations, and relative costs. Various inverter types are discussed and compared. Finally, guidelines as to the factors influencing the ac versus dc decision are summarized and tabulated.

Journal ArticleDOI
L. J. Boutin1
TL;DR: Power dips and interruptions occur frequently in textile plants and adversely affect textile plants with regard to lighting, computers, and process controls as mentioned in this paper, and this can adversely affect the textile plants' performance.
Abstract: Power dips and interruptions occur frequently. They adversely affect textile plants with regard to lighting, computers, and process controls.