DOI:10.1049/jiee-1.1923.0092

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0093

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The object of this paper is to arouse discussion upon the relation between the architectural and electrical engineering professions, to explore the possibilities of closer joint working and means of keeping each profession advised of the needs and developments of the other in so far as they touch mutual and efficient working.The service rendered by the electrical industry to the public is the result of combined working between at least three sections of that industry.The rapid development of electricity in the field of heating and cooking is dealt with and also the factors determining the extent to which that medium can usefully be employed at different competing rates or prices for fuel, gas or electrical energy.The varying restrictions and conditions covering electricity supply in different districts are considered, and also the modern movement towards simplified tariffs and methods of charging.Suggestions are made as to the work of the architect in providing for the use of electricity in buildings and in allowing for extension, greater variety in use, and the arrangement of cables and ducts.The influence of electricity on the design and cost of buildings and probable developments in the near future are also discussed.The paper concludes with a suggestion that it should be possible, without interfering with the definite work of the architect, consulting engineer or contractor, to set up some joint body to act asliaisonin regard to policy and the distribution of information between the two professions.

DOI:10.1049/jiee-1.1923.0094

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The mathematical theory, of the magnetomotive force developed by armature windings is developed and presented in a new manner, and in such a form that it is at once directly applicable not only to, the more, common cases but also to abnormal cases, such as unbalanced windings, and to pole-changing windings, etc.An attempt has been made to present the subject matter in simple mathematical language and to give the various series concerned in as simple a form as possible. In general, the conclusions arrived at iiu the various sections of the paper have been succinctly stated.The method of treatment adopted is to start from the Fourier series representing the M.M.F. distribution due to a single coil, and to build up from this series the corresponding series for any complete winding. The effect of the value of the coil-span is discussed, it being shown that, in general, a single coil gives rise to an M.M.F. distribution corresponding to the joint effect of all numbers of poles from 2, 4, 6, etc., upwards. The effect of the spread of the coil-side is briefly discussed, and data relating to the various winding factors concerned are given in a simple graphical form applicable to harmonics of all orders, whether odd or even.The resulting M.M.F. due to a number of coils carrying the same current is then deduced from the effect of a single coil, heteropolar arrangements also being discussed.In the sections dealing with alternating-current windings, a similar method is employed. It is shown that all types of polyphase windings fall simply into one category, the treatment being perfectly general and directly applicable to all types of windings, whether normal polyphase, full-pitch or chorded, or a winding intended for pole-changing. The effects of higher harmonics in the current wave are discussed, and data relating to the harmonics present in the M.M.F. developed by polyphase windings are given.

DOI:10.1049/jiee-1.1923.0097

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0098

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The object of the paper is to determine the overload capacity of an induction motor when operated synchronously, and the pulling-in capacity at synchronism. Incidentally, in view of suggestions made in this connection in periodicals, experimental data have been obtained for (1) two methods of using a star-connected rotor for excitation, and (2) the resulting heating of rotor windings under the two methods of excitation. Further readings have been taken so as to enable curves of efficiency, power factor and stator current to be drawn.The conclusions are that the advantages of synchronous operation of induction motors are most pronounced when the method is utilized at times of light load and up to about 70 per cent of full load. At heavier loads there is a logs of efficiency and only a slight improvement in power factor. Owing to the necessity of adjusting the excitation to the load, synchronous operation is unsuitable in the case of fluctuating loads.

DOI:10.1049/jiee-1.1923.0099

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0100

出版商:IEE    

年代:1923

数据来源: IET

摘要:

The paper deals with the operation of directional wireless telegraphy in aircraft where the directional aerials are installed in the aircraft.The main difficulty in this work is to deal with the errors which arise. Curves are given showing the errors obtained, and formulae are developed showing the factors on which the errors depend. Methods of predicting and correcting the errors are given.Curves of variation in bearings of transmitting stations are given and discussed. A possible cause of these variations is given.

DOI:10.1049/jiee-1.1923.0101

出版商:IEE    

年代:1923

数据来源: IET

DOI:10.1049/jiee-1.1923.0102

出版商:IEE    

年代:1923

数据来源: IET

摘要:

A method is described of locating cable faults by means of a pair of towed electrodes, the cable section between fault and shore being energized by alternating or interrupted current. The limitations and difficulties of the method are discussed and remedies are indicated.Two practical trials of the gear are briefly described.Simple approximate formulae are derived for the range of the gear, and numerical values are calculated for three typical cables. It is shown that the device should be sufficiently sensitive to locate an earthed break in a modern cable up to 360 nauts from shore and an insulated break up to 100 nauts, though on account of the difficulty of handling the gear in deep water the useful ranges would often be much less.

DOI:10.1049/jiee-1.1923.0104

出版商:IEE    

年代:1923

数据来源: IET