摘要:

When considering the requirements of insulation for high-voltage equipment there are a number of factors which must be taken into account; some of them affect the long-term life of the insulation, and others affect its performance only under abnormal stress of very short duration. As the result of the increasing knowledge of the behaviour of power systems, the characteristics of the various forms of insulation used in the construction of high-voltage equipment and improved techniques in testing, it is now possible to introduce into apparatus specifications clauses which deal much more specifically with insulation requirements than in the past. Many specifications which are being reviewed at present are incorporating new requirements for the performance of insulation. It is the object of the paper to consider in general terms the system characteristics which affect the choice of insulation, to assess the various over-voltages which may be imposed upon apparatus, to consider the different forms of overvoltage protection which are available, and to offer guidance on the selection of insulation for the usual applications covered by national and international specifications.

DOI:10.1049/pi-1.1954.0022

出版商:IEE    

年代:1954

数据来源: IET

摘要:

The arrangements for the sound and television broadcasts of the Coronation of Her Majesty Queen Elizabeth II are described in detail after a brief comparison has been drawn between the coverage provided for this event and that for the Coronation of King George VI in 1937.The television programme was broadcast simultaneously to the United Kingdom and to parts of Western Europe, much temporary equipment being installed to carry the vision signals and to convert from the 405-line British standard to the several standards (441, 625 and 819 lines) used on the Continent. The sound programme was broadcast, with commentaries in many languages, in most countries of the world.The problems of siting microphones and cameras in Westminster Abbey—where they had to be invisible—are enunciated, and the functions of the sound and vision control rooms at the Abbey and along the processional route are described.The nature of this largest outside broadcast ever undertaken by the BBC and the Post Office called for many special arrangements, and details are given of the signal circuits installed, the lip microphones which enabled commentaries to be heard above adjacent crowd noises, and the methods used for equalizing and synchronizing the signals from a total of 21 cameras. Finally, an account is given of the sound and television recording arrangements of the BBC andthe North American organizations, so that telerecordings could be screened in America within 11 hours of the event, and so that a permanent record of an historic occasion would be available for the future.

DOI:10.1049/pi-1.1954.0025

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-1.1954.0028

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-1.1954.0029

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-1.1954.0030

出版商:IEE    

年代:1954

数据来源: IET

DOI:10.1049/pi-1.1954.0031

出版商:IEE    

年代:1954

数据来源: IET