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1-10 results of 1943

care and repair of dynamos and motors

CONTENTS. The Operation and Care of Small EIectricaI Machinery, by HENRY B. BIXLER - - - 3 Dynamo and Motor Troubles - - 9 Repairs to the Commutator, by NORMAN G . MEADE - 16 Repairs to the Armature Winding, by NORMAN G. MEADE - - - - 22 Repairs to Armature and FieId Coils, by NORMAN G MEADE - , - - - - 31 Winding of Direct-Current Armature - . - -, p , v - . - 39 Copmi ht. 1910. The Induetdal Press. Publishers of WCI INERY. 49-65 Lafryette Straet, New York City CHAPTER I. THE OPERATION AND CARE OF SULL ELECTRICAL MACHINERY As the majority of uscrs of small electrical machinery are not familiar with the best methods employed to keep the machines in good running order and repair, the author alms to present a few practical suggestions, to be of some help in the making of necessary repairs, locating troubles, and removing the causes. The dynamo or motor should be instaIled in a dry place, and under no circumstances should water be allowed to come in contact with the machine. Excessive dampness always causes trouble, and this point should be guarded against. The machine ahonld be well ventilated, and kept free from dust as much as possible. Before starting a new machine, see that the bearings are well filled with good oil, and that the shaft turns freely i n the bearings. The oil-rings should turn with the shaft, and not stick, as the lubrication of the bearings depends upon the rings working right. This is important and should be care fully matched. If the machine is belt driven, the belt should not be too tight, as this mill cause undue wear on the bearing and may cause heating also. Always provide solid foundations or supports for the machine to rest on. Keep the machine cool, dry and clean, and very little trouble will result in its operation in general. When a new machine is installed and wired up, the connections should be carefully checked over to see whether they correspond with the diagram of connections sent with the machine. If this is found to be correct, and the machine refuses to act properly, the cause of the trouble should at once be located and the diaculty removed before going further. Troubles In the Field Coils First we mill consider the troubles that may exist in the field coils. and horn to proceed to correct them. If, on running a machine for some time, the field coils all become hot, the voltage may be too high and should be reduced to normal. If only a part of the coils becomes hot, it will usually be found that a connection exists between the coils and the frame of the machine called ground, which when found should be InsuIated with mlca or paper. Sometimes it will be found that some of the coils are cold while the remainder are excessively hot, and the cause of this is a short circuit in the cold coils, which means that the current i s not passing through the cofls. Test out the coils separately with a magneto or battery, and when the defective coil is found, it should be repaired by reinsulating it. A partial short circuit will cause the coils to heat, and should be fncn mrt n l , a rch, 1910. 4 No. 34-DYNAhi AND MOTOR REPAIRS treated as rrtaZcd abwk. in R . compo wd-woundm achine, i. e., one hav ing a shunt and series windlng on the field coils, an over-load will cause an excessive current to flow through the series coils, causing the heat to rise above normal. The load should be reduced or a shunt should be connected as shown in Fig. 1. This wiIl cause the current to divide, part of it flowing through the shunt, thereby reducing the heating of the series coils...

modern theory of physical phenomena radio activity ions electrons

conduction of electricity through gases and radio activity a text book with exp

steam engine principles and practice

Steam Engine Principle and Practice is a very profound and detailed book which was published by Terrel Croft. The author analyzes the types of steam engine describing the main American manufacturers and most common prices. Moreover, the unique role of steam engines in industry in the 1920th is described. A separate section is devoted to the construction and maintenance of steam engines. A number of illustrations of steam engines are included.

the electric light in its practical application

PREFACE. THE following pages are intended to give the reader an account of what has been effected in the numerous endeavours to obtain a practicable system of electric lighting. But the details have been confined to those necessary to form judgment of the advantages of each system. Abstruse discussion has been carefully avoided, and questions have not been raised to which answer could not be found in previous practice. The labours of Du Moncel and Fontaine, the reports of Tyndall, Houston, Thomson, Deacon, Haywood, and others, have been freely utilized, the object having been to give both pro and contra. Much descriptive matter and numerous illustrations have been taken from my translation of Fontaines Eclairage Electrique, now out of print and considerable indebtedness must be acknowledged to other sources, named in the text. Where my own experience has led me to a conclusion, I have ventured to express it, but I have always also stated the reason for the deduction. There must necessarily be, in a technical work of this character, many imperfections. Kecent and untried inven- tions, promising much, cannot be omitted from notice nor, from want of knowledge of detail, can a probably correct opinion be held. Electric lighting is, indeed, so far within its period of infancy that, in many cases, suspense of judgment is compulsory. Nearly every week marks an important advance, proving the present incomplete state of this branch of engineering. With regard to the future of electric lighting, little has been said in this book. Public opinion, if not always strictly to the correct idea of the accurate, generally approximates commercial value of a newly introduced method, and its perception of the advantages of the electric light, either future or immediate, has not been greatly misled, however exag- gerated may have been the statements of interested speculators. It is beyond doubt that in the present we may look for practical, if not great, improvements, that will cause in no distant future the adoption of electric lighting for very many important, as well as ultimately for general, purposes. Logical sequence has been followed as far as possible, so as to afford aid to the general reader. The first chapter deals with the principles of the voltaic arc, and distinguishes the method of lighting by incandescence. The various forms of lamps employing the voltaic arc are next described, with socalled candles and candle-lamps, followed by discussion of most of the proposed systems of lighting by the incandescence of carbon or platinum. The principal magneto- and dynamo- electric machines are then described, with the new multiplecircuit machines, followed by a full consideration of the mechanical efficiency of these machines, and sufficient simple mathematical data to enable the reader to form his own conclusion of the merits of a fresh project. Next the question of cost is entered into. The various well-defined schemes for division of the electric light are commented upon. The book is concluded with chapters on the maritime and military and various applications of the electric light, and descriptions of the several methods of preparing the carbons consumed in the lamps. There is also a chapter on apparatus for main- taining electric currents at constant strength, although this kind of apparatus has not met with practical application...

el dorado a tragedy

Originally published in 1903. This volume from the Cornell University Library's print collections was scanned on an APT BookScan and converted to JPG 2000 format by Kirtas Technologies. All titles scanned cover to cover and pages may include marks notations and other marginalia present in the original volume.

a course in vertebrate zology a guide to the dissection and comparative study

mond gas

discussion of the precision of measurements with examples taken mainly from phy

hydro electrolytic treatment of copper ores

1914 - THE HYDRO-ELECTROLYTIC TREATMENT OF COPPER ORES - It is the intention of this paper to give a brief summary o f the practised and suggested hydrometallurgical processes for the extraction of copper from its ores. The review of the literature. as given contains the salient points of what has been done in the history of the subject. The problems of economically treating low-grade copper ores have turned the attention of metallurgists toward such hydrometallurgical problems as are encountered with low-grade siliceous, oxidized and sulphide ores, and concentrates, especiallywhere water-power is cheap and fuel is expensive. The treat--ment of tailings from concentrates is another promising field for leaching methods, there being no other known possible method for economically extracting their copper contents. The same is also true 0. f complex refractory ores which are not amenable to smelting for the recovery of their several metals. And, lastly, there are metallurgists who entertain hopes of discovering a leaching method which will radically change all methods of copper extraction to something quicker and cheaper than the present smelting methods. I. PURELYC HE IICA M L E THOD S l . Alkali processes. 2. Sulphite 3. Sulphate 4. Chloride Copper is dissolved and precipitated by chemical reagents. 11. ELECTR LY M T ET IC HO D S l. Sulphate processes. 2. Chloride 66 208 ROBERT RHEA GOODRICH. Copper is dissolved chemically and is precipitated electrolytically. The deposition is usually accompanied by regeneration of the solvent. All acids react more or less with the constituents of the ore, causing a. Consumption of acid. b. The bringing in of elements detrimental to the process. Iron, arsenic, antimony and bismuth, while detrimental, are not necessarily fatal to an acid process. If lime, magnesia, zinc or manganese occur in large quantities in the ore, acid processes are not applicable-the limit can o, nly be determined by experiment. While calcium carbonate is detrimental, calcium sulphate is not. Alumina is undesirable, but not riecessarily very injurious. Many oxidized ores are iniproved by roasting. All sulphide ores require roasting for most of the leaching processes, the exception being chalcocite ores, which may be leached direct. Greenawalt, Hydrometallurgy of Copper, 1912 Ed., Chap. IX. 1. Alkali Processes. The alkali processes have not met with much encouragement in the hydrometallurgical extraction of copper from its ores, due largely to the low and slow solubility of copper minerals in solutions of the alkalies. Ammonia and ammonium compounds are the only alkaline solvents tried for the leaching of copper oxide ores on a commercial scale. Greenawalt, p. 172. The Mosher-Ludlow Ammonia-cyanide Process. This process is applicable to ores containing oxide and carbonate of copper. At the ordinary temperature, ammonia NH, forms a stable compound Cu NH, , I which readily dissolves in water containing slight excess of ammonia...

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