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Showing papers in "Journal of the Institution of Electrical Engineers in 1912"




Journal ArticleDOI
TL;DR: In this article, the authors describe the nature of losses due to rotor eccentricity and the value of rotor currents set up by eccentricity, as well as oscillograph records of rotor voltage.
Abstract: General-Nature of losses due to rotor eccentricity-Outline of experiments- Description of motor employed-Flux distribution with rotor winding open-Flux distribution with rotor winding closed-Iron losses-Total no-load losses of motor-Variation of stator magnetising current with eccentricity-Magnetic pull on eccentric rotor-Value of rotor currents set up by eccentricity-Oscillograph records of rotor voltage-Conclusions.

6 citations


Journal ArticleDOI
TL;DR: In this paper, the authors deal with methods of predetermining the temperature rise in electric machinery and present experiments made to determine the amount of heat absorbed by air under various conditions as to temperature and velocity in passing over coils and through ventilating ducts.
Abstract: The paper deals with methods of predetermining the temperature rise in electric machinery. Data are given of the heat conductivity of insulating materials. The methods of carrying away heat by the circulation of air are discussed, and there is given an account of experiments made to determine the amount of heat absorbed by air under various conditions as to temperature and velocity in passing over coils and through ventilating ducts. The heat conductivity of punchings in actual machines is also considered.

5 citations



Journal ArticleDOI
TL;DR: In this article, a general equation of equilibrium for constant-current automatic starting was proposed for induction motors with self-contained resistance, and the graphical solution of proper working was provided.
Abstract: Induction motors with self-contained resistance - Hand and automatic control-Advantages of the latter-Value of the resistance in function of the speed to maintain a constant-current input-General equation of equilibrium for constant-current automatic starting-Necessity of ah independent variable-Variable ratio gear as given by a differential equation-The graphical solution-Condition of proper working-Sensitiveness and the influence of dynamic friction-The fluctuation of current in ordinary multi studs starter-The best theoretical conditions- Time necessary for starting-Energy loss at starting-Comparison with the automatic starting-Mechanical details.

2 citations





Journal ArticleDOI
TL;DR: In this paper, a short account of the uses and advantages of battery-booster plant, and the savings likely to be effected by its employment is given, followed by a short discussion of the effect of main generator compounding, the action of line diverters, and some causes of inaccurate working of diverter boosters in general.
Abstract: A brief mention is made of the object and scope of the paper, and this is followed by a short account of the uses and advantages of battery-booster plant, and the savings likely to be effected by its employment. Boosters are classified in three leading divisions, (A), (B), and (C). Under Class (A) are described the plain differential, Pirani, Cromptonand Lancashire systems, with a discussion of their prominent features. Those described under Class (B) are the Highfield and E.C.C. systems. A short discussion follows of the effect of main generator compounding, the action of line diverters, and of some causes of inaccurate working of diverter boosters in general. The advantages of boosters controlled by external regulators over those of the diverter type, and the leading principle of their operation, are briefly mentioned. Such boosters belong to the next class (C), and those described are Entz, B.T.H., Taylor-Scotson, Tilney, Thury, and Brown-Boveri, while the systems of Lincoln and Bijur are also referred to. Rate of rise of field flux is dealt with, and the practical necessity of the provision of a checking control on quick-acting booster regulators. Some methods of using battery-booster plant are then considered more fully, and several methods of adapting such plant to the control of winding gear are described. The question of the employment of batteries on alternating-current systems is next treated, and some of the necessary plant described including regulator solenoids, the split-pole converter, and a special form of automatic exciter responsive to variations in alternating-current generator load. Some figures are given relating to the plant at the Gary Steel Works, Indiana, U.S.A., and a short description is given of the Hucknall Colliery plant. Practical results obtained by different boosters are given, and a short summary of conclusions finishes the paper.

1 citations



Journal ArticleDOI
TL;DR: In this article, the author explains a way in which the oscillograph can be applied to show the internal currents in an armature without cutting one of the main coils, and also urges the insertion of the indicating coil during construction as a matter of course in all large machines, or others working near the limits of good commutation.
Abstract: After describing the methods already in use, the author explains a way in which the oscillograph can be applied to show the internal currents in an armature without cutting one of the main coils. Records are given illustrating various points about commutation to illustrate hismethod, and improvements in details are discussed. He also urges the insertion of the indicating coil during construction as a matter of course in all large machines, or others working near the limits of good commutation.