摘要:

The paper describes the considered methods of meeting a particular case of, voltage-drop in a large direct-current lighting network and for bringing into use the maximum amount of its copper with a minimum of cost.A fully automatic station was chosen in this instance for the reasons stated, and the author in discussing the subject has not attempted to review the relative merits of different types of automatic stations; but rather the method of dealing with a particular problem, and with this end in view has described the station which has come under his immediate control.So far as the author is aware, the plant described is that of the first fully, automatic, station in this country, for any purpose, and of the first fully automatic station in existence operating a three-wire system.

DOI:10.1049/jiee-1.1923.0057

出版商:IEE    

年代:1923

数据来源: IET

摘要:

It is the author's purpose to present concisely some of the more interesting problems encountered, and the methods adopted to solve them. The problems, although encountered in high-speed alternators, will be found to be of interest to engineers engaged in other branches of the electrical engineering industry.The following subjects are considered:—(1) The history and failures of turbo-alternators.(2) Mechanical construction of rotors and caps supporting the coil ends.(3) Stator windings and insulation.(4) Stator slots.(5) Alternator ventilation, water cooling and the necessity for clean air supply.(6) Exciter instability.(7) Eddy currents in rotors.(8) Oscillograph tests, in explanation of exciter instability, showing the necessity for precautions when breaking the main field by means of a quick-break switch without any discharge resistance.

DOI:10.1049/jiee-1.1923.0063

出版商:IEE    

年代:1923

数据来源: IET

摘要:

It is frequently a matter of convenience to use single-core lead-covered cables for transmitting power by means of alternating current, and in such cases the magnitude of the loss arising from the eddy currents induced in the lead sheath becomes a matter of importance. Recently some power-supply authorities have refused to connect to their lines any distributing system depending upon the use of such cables.The eddy losses in the sheaths of these cables may be divided into two groups, called herein “sheath eddies,” and “sheath circuit eddies.” The latter occur only when one or more cables have their sheaths connected at more than one place.The losses are analysed for a single cable, a pair of single-phase cables, and a set of three-phase cables.It is shown that the sheath eddies are in all cases negligible, and that the sheath circuit eddies may be kept within reasonable limits by proper regulations regarding the spacing of the cables.It is suggested that the I.E.E. Wiring Rules should contain such regulations, and that so long as these are adhered to there is no justification for refusing to connect single-core lead-covered cables to any ordinary a.c. system. The necessary data are given for the framing of the regulations.Similar questions arise regarding armoured cables. The results in this case are awaiting the conclusion of the experiments now being carried on at the University of Birmingham.

DOI:10.1049/jiee-1.1923.0067

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0068

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The first part of the paper is devoted to a discussion, of some of the principles on which the measurement of received signals is based, and the practical application of these principles under working conditions is considered.The latter part describes a system recently developed at the National Physical Laboratory which differs in several details from previous systems. Its operation is described in detail, and some of the possible sources of error and inaccuracy are considered.

DOI:10.1049/jiee-1.1923.0070

出版商:IEE    

年代:1923

数据来源: IET