摘要:

Nicholas Callan (1799–1864) was an Irish priest and scientist who, although his name has been largely forgotten by historians, was a pioneer of electrical science. He invented the induction coil some fifteen years before Ruhmkorff, to whom credit is usually given. He developed some very practical batteries and also experimented with crude forms of electric lighting. Callan was also a very saintly man, donating a large part of his professor's salary for the relief of the poor. In the words of his obituary: ‘His extraordinary piety, his perfect simplicity and unaffected candour endeared him to everyone who knew him’.

DOI:10.1049/ip-a-1.1985.0089

出版商:IEE    

年代:1985

数据来源: IET

摘要:

Every edition of the Wiring Regulations has attracted criticism and praise, but no one today questions the IEE's right to make the rules. It was not always so. For many years insurance companies produced their own rules, which had to be followed before they would insure buildings with electrical installations. Those responsible for designing and installing wiring and equipment found the multiplicity of rules very irksome, and they pressed for uniformity. The Institution's rules were only gradually accepted as the Institution itself gained acceptance as an authoritative body. By the First World War, however, virtually all insurers accepted the IEE Rules. Now in their fifteenth edition, the Rules have been changed as ideas and technology have developed. Many of the early rules sound distinctly strange today: one hundred years ago it was not permitted to have a potential difference of more than 200V between two points in the same room, but there was no suggestion that anything should be earthed. The language used has always brought complaints, for being too complex and poorly expressed. One early defender of the IEE remarked that the Rules were ‘originally drafted in good English but afterwards amended in committee’.

DOI:10.1049/ip-a-1.1985.0090

出版商:IEE    

年代:1985

数据来源: IET

摘要:

With the spread of alternating-current systems at the end of the nineteenth century, the need for a convenient and reliable method of displaying waveforms became more urgent. Certain methods were developed to a high degree of usefulness, notably the rotating contacts, the Blondel/Duddell mechanical oscillographs and eventually, of course, the cathode-ray tube. The paper recalls three other methods which seemed, for a short time, to hold out great promise but which were not successful and soon faded into obscurity.

DOI:10.1049/ip-a-1.1985.0091

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The paper begins by outlining the difficulties which faced the early electrical entrepreneurs when they tried to devise methods of charging for electricity supply which were fair, accurate and economic. It discusses the alternatives to fully metered supplies, and also the arguments about the relative merits of energy and quantity meters. The major part of the paper describes the most important types of electricity supply meter and how they developed over a period of about ten years from the opening in 1882 of Edison's Holborn Viaduct electricity supply system, where meters were first used. Detailed technical descriptions of the meters are not given, but references to this information are quoted where possible. An attempt is made to show how widely the different designs of meter were used and to give the opinions of contemporary engineers about them.

DOI:10.1049/ip-a-1.1985.0092

出版商:IEE    

年代:1985

数据来源: IET

摘要:

While working in Wilhelm Weber's laboratory in Gottingen, Arthur Schuster made a series of observations that appeared to throw doubt on the validity of Ohm's law. The British Association established an investigating committee under James Clerk Maxwell. A new series of experiments, conducted at the Cavendish Laboratory by George Chrystal, validated Ohm's law and showed that Schuster's original observations were dependent on the use of tangent galvanometers in conjunction with AC currents.

DOI:10.1049/ip-a-1.1985.0093

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The paper extends an earlier paper in giving details of operating experience of some of the early networks in the London area and draws attention to their limitations and advantages at the time. It mentions the strongly held views of certain engineers of the advantages of AC over DC and the later efforts of some undertakings to use established DC network cables to supply AC. The use of pilot cables and substation instrumentation is mentioned, as are some of the methods of fault-location on the networks. The interconnection of cables at street corners gave rise to the construction of large manholes, with the ever-present need to seal pipes against entry of gas and water. The end of central-station generation came with the development of power networks such as that of the London Power Company, and the replacement of steam and diesel generators with three- or two-phase bulk-supply transformers. Some undertakings used to make their own cable-joint boxes and distribution boards, but the many manufacturers competing for business could be relied upon to produce almost any item of switchgear or control equipment required to meet a specific need. The paper touches on sales promotions to increase load and units sold, and mentions metering and early wiring installations.

DOI:10.1049/ip-a-1.1985.0094

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The two principal systems of duplex telegraphy are described, as are the more significant proposals, beginning in 1853, for duplexing short land lines. J.B. Stearns's involvement with the British Post Office Telegraphs in 1870 and the introduction of duplex working on that system are described in detail. The introduction of gutta percha insulated cables in the late 1840s, the subsequent understanding of current flow in such cables as a result of W. Thomson's theoretical approach and the qualitative reasoning of Samuel Alfred Varley led to the first models of submarine cables. Successful duplexing of long land lines and submarine cables by Stearns, Muirhead and others from 1873 was only made possible by accurate modelling. It is suggested that the credit for the first artificial line belongs to Samuel Alfred Varley.

DOI:10.1049/ip-a-1.1985.0095

出版商:IEE    

年代:1985

数据来源: IET

摘要:

When J.L. Baird, in 1923, commenced his work on television, he had in mind the development of a system which would enable people to sit in a cinema and see on the screen the finish of the Derby, or some other topical event. Subsequently, he demonstrated a crude form of large-screen television in July 1930, and, on 1st June 1932, at a special demonstration given in the Metropole Cinema, London, he reproduced televised images of the Derby. The first large-screen reproduction of a 405-line BBC television programme was shown on 7th December 1937 at the Palais-de-Luxe cinema, Bromley and further demonstrations were given in 1938 and 1939. These demonstrations stimulated much public interest in cinema television and, by September 1939, five London theatres had been equipped with large-screen television equipment. Scophony Ltd. also developed cinema television apparatus, and elsewhere, particularly in the USA and Germany, similar work was undertaken. Although considerable technical advances were made prior to the commencement of the 1939–1945 World War, and immediately afterwards, the proposed introduction of television in cinemas led to much debate between the BBC and the various film trade associations. The subject was considered by the Broadcasting Committee, 1949, by the Daniel Committee, 1952, and by the Pilkington Committee, 1960; but eventually the latter committee recommended against the introduction of a service of television for public showing. The paper considers the various technical and political factors which led to this decision.

DOI:10.1049/ip-a-1.1985.0096

出版商:IEE    

年代:1985

数据来源: IET

摘要:

In 1861 the British Association set up a committee, led by Thomson (i.e. Kelvin) and Clerk Maxwell, which proposed the electrical units which are still in use, based on the metric system. Names were given to them to avoid ambiguities, and prefixes based on ratios of 1000 were introduced, both on the lines suggested by Bright and Latimer Clark. These units, specified by material standards, became the International Units of 1893, which were in use until the SI units superseded them in 1948. The BA owned standard resistors made in 1865 and standard capacitors made in 1889. The resistors, which still exist, were less stable than the BA had hoped, and the true value of the BA ohm was uncertain.

DOI:10.1049/ip-a-1.1985.0097

出版商:IEE    

年代:1985

数据来源: IET

摘要:

From the late 1870s two weekly periodicals,The ElectricianandThe Electrical Review, not only reported widely on all developments and matters of interest to electrical engineers, but also provided a forum for their distinguished editorial staff and others to comment on matters of concern to the newly emerging industry. Their correspondence columns provided a lively outlet for professionals and amateurs concerns alike, sometimes reaching an intensity of argument which would be quite unacceptable today. This paper looks at the contributions made by the two papers to the newly emerging profession during the decade 1880–1890.

DOI:10.1049/ip-a-1.1985.0098

出版商:IEE    

年代:1985

数据来源: IET