Transformer Equipment Research Articles

Distinction between X-ray exposure technique factors for conventional high tension transformer and capacitor energy storage X-ray equipment

The use of capacitor energy storage X-ray equipment in medical radiography has increased in this country in the last few years. The high voltage waveform applied to the X-ray tube in this type of equipment is quite different from that in conventional units. Because of this, technique factors such as kVp and mA s have different effects on the X-ray beam quality and quantity than would be expected with conventional single- or three-phase equipment. Inappropriate setting of these technique factors by technologists who are unfamiliar with these differences may lead to increased patient exposure with no commensurate increase in radiographic quality. Dose measurements made with a masonite phantom plus comparison of radiographs made utilizing technique charts provided by manufacturers of capacitor energy storage X-ray systems were used to demonstrate this fact.

Analogue Computer Study of some Fundamental Control Relations Involving Alternators and Diesel Engines

The purpose of this investigation is to study the effect that the amortisseur winding has on the stability of an alternator when it is driven by an engine. The simulation of the system was done with the use of an analogue computer. The effect of each amorlisseur winding was studied separately and together. This type of information is not available and the control engineer needs these results when analysing certain complex systems. In order to arrive at system equations, the alternator is treated as a many-winding transformer, and the equations are obtained from the transformer equipment circuit. A transformation due to Blondel was applied to these system equations which in effect causes the demodulation of the frequency of the alternator. Then, on the analogue computer, only variations of amplitude and not the individual frequency had to be simulated. This study revealed that the amorlisseur windings could be treated as feedback compensation to the prime mover, and this paper presents the development of a transfer function that represents the effect of the amorlisseur windings. An analogue computer diagram is developed to represent the diesel engine. This particular alternator analogue diagram is different from those tried for other simulations ; the analogue computer is stable and yields accurate results when wired in the manner described in this report. A root locus analysis shows conditions where the amorlisseur windings can help stabilize a system. For the particular alternator parameters used in this study the amorlisseur winding is most effective if the system tends to have oscillations in the neighbourhood of two or three hertz.

The Green Tariff of the Electricite de France

Editor's Note. In submitting this article in its English translation the translators wrote: We have sought to adhere to the meaning of the original French but also have taken some editorial license in clarifying the meaning for the reader. The 'Tariff Vert' or Green tariff, instituted late in 1956 by Electricite de France, the nationalized electric utility system of France represents the most advanced and sophisticated application of marginal cost pricing yet attempted. Regardless of whether the principles are specifically applicable to American conditions, the work of Boiteux, Dessus and others associated together in the formulation and implementation of the tariff are worthy of study and have been receiving increasing attention from American economists. This article first describes the impact of inflation on the electric tariff set up in France in the 1935-38 period which was still in effect in 1956. As will become apparent, the original tariff became completely irrational as a result of inflation. The later part of the translation is given to the Green Tariff. It is noted that this tariff is applicable to wholesale service at voltages ranging upward to 220 kv, an extremely high service voltage. Customers apparently furnish their own transformation equipment. Any rates quoted in American currency are at the approximate exchange rates prevailing at the time and have been computed by the translators. Readers are referred to the paper by Professor James R. Nelson at the American Economic Association meetings of December 1962 in which the tariff was analyzed. It is understood that Professor Nelson will bring out a book which will contain translations of numerous French articles and papers on the subject.

The Zeta transformer and auxiliary circuit equipment

The paper outlines the design and construction of the Zeta high-power pulse transformer and its associated core-biasing circuit. Details are given of the pulse-shaping reactor and non-linear resistance unit with reference to the circuit calculations made on a high-speed digital computer, and also of the saturable reactor which assists in the switching operation and the current transformers and voltage dividers which were supplied. The design of the stabilizing axial-field winding is also discussed.

Electrostatic precipitator pulse power supply

IT IS NOT SURPRISING that the fundamentally important advances in the electrostatic method of separating suspended particles from gases have resulted primarily from improved methods of supplying high-voltage power. Much recent research in the electrostatic collection of particles has been directed toward improving and stabilizing electrical energization, both in connection with conventional rectifier equipment and in the development of entirely new methods of supplying electric energy. Conventional methods of supplying high-voltage power to precipitators stem directly from Cottrell's pioneer work, and essentially comprise transformer and rectifier equipment, usually with unfiltered output.

Use of Equivalent Annual Ambient Temperature in Overloading Transformers and Voltage Regulators

In the ``Interim Report on Guides for Overloading Transformers and Voltage Regulators,'' <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> reference is made to the use of equivalent annual ambient temperatures in determining the loading of transformer equipment. This paper is to show a method of calculating the equivalent annual ambient temperature from readily available climatological data to avoid difficulties in other methods that have been proposed. An outline is given also of conditions under which the equivalent annual ambient temperature may be applied in determining permissible overloads for transformers.

Electromagnetic phenomena in high-voltage testing equipment

The paper discusses a number of electromagnetic phenomena which may be encountered in the operation of high-voltage testing equipment. Although secondary in magnitude these effects are not secondary in importance, since they may vitiate the accuracy of important tests and lead to the loss of much time and money. Theoretical deductions are throughout supported by actual experimental results.Part 1 deals with wave-form distortion in the usual single-phase normal-frequency transformer equipment. The factors considered include core saturation, capacitance loading, and induction-regulator and alternator characteristics. Information is also given as to the effect of wave-form on breakdown voltage and dielectric losses.Part 2 deals with transient phenomena in testing-transformer circuits. The production of over-voltages by switching and by discharges in the load is discussed in detail. Oscillations in rectifier circuits are also considered.Part 3 deals with wave-form distortion in the impulse generator. Special attention is given to the superimposed oscillations introduced by load capacitance and by measuring circuits. The theory of the oscillation transformer is developed as a special case of the impulse generator, and test results are given for an actual equipment.

High Voltage X-ray Tube and Constant Potential Transformer Equipment

This is a preliminary report on the design, construction and operation of a porcelain insulated, grounded anode X-ray tube, to operate at 800,000 volts constant potential. This is a hot cathode tube with water-cooled anode.

Neon tube sign lighting

The high-voltage cold-cathode neon tube as developed for commercial sign lighting is one of the few types of gaseous-conduction lamps to gain prominence. Their operating characteristics and associated transformer equipment are described in this article, and their advantages pointed out.

A Compact X-ray Treatment Unit

This subject and the illustrations are presented because of the interest aroused in the installation of newer equipment for the administration of short wave-length therapy. The continued use of superficial and intermediate therapy is in no wise changed. The newer methods have not altogether displaced the older methods of treating pathological conditions. It is often necessary to combine, for practical purposes, the higher voltage equipment with the older machines. In many laboratories there is no need for this economy. The new short wave-length equipment can simply be added to the existing department. However, the unit here presented combines the two different types of treatment equipment in small and compact space. A great variety of cases can be seen in the practice of general roentgenology. The chief factors here shown are: 1. A central control station which is safe for the operator. 2. A central compartment for the transformer and such other equipment as is unsafe, unsightly, and makes a great noise. 3. So far as the short wave-length equipment is concerned, all danger of the patient or operator coming in contact with the high-tension current is removed. 4. The factors controlling dosage are more rigidly standardized. 5. The patient is removed as far as possible from all psychologic disturbances which might be caused by the fear of strange sights, unpleasant noise, and danger. 6. The flexibility of the equipment facilitates economy in space and in personnel, in handling a great variety of patients. The overhead in Room No. 2 might be connected with the larger transformer (it is here connected only with the 140 kilovolt transformer), thus increasing still further the flexibility of equipment and even allowing the treatment of two areas at one time.

Illumination items: By the lighting and illumination committee: New practises in street lighting

Two radical departures have been made in the installation of a new street-lighting system in Kansas City, Mo. These are the removal of all street-lighting equipment in each of seven substations, and the placing of a large part of the lamp circuits underground, a special cable buried in the earth without ducts save at street crossings being used. Ducts are used at street crossings to facilitate repairs in case of cable burnouts or other breakdowns. The removal of all of the usual series transformer and switching equipment from the substations means the saving of a great amount of valuable space and in some cases obviated the necessity of special substations for the street-lighting equipment. This in itself has meant a material saving in expense. The placing of the series circuits underground has enabled the use of a simple and attractive ornamental post on streets where there are no street-car lines. On the streets with street-car lines and steel trolley poles, the conductors being carried overhead. The plans which were followed made possible the avoidance of the unsightly wiring and lamp supports that overhead construction usually involves. These results have been attained because it was possible to start with a comparatively clean slate, much of the previous street lighting having been with gas.