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Report on measurements made on signal strength at great distances during 1922 and 1923 by an expedition sent to Australia |
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Journal of the Institution of Electrical Engineers,
Volume 63,
Issue 346,
1925,
Page 933-1001
H.J.Round,
T.L.Eckersley,
K.Tremellen,
F.C.Lunnon,
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PDF (6636KB)
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DOI:10.1049/jiee-1.1925.0116
出版商:IEE
年代:1925
数据来源: IET
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| 2. |
The reversed-rotation short-circuit temperature-rise of induction motors |
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Journal of the Institution of Electrical Engineers,
Volume 63,
Issue 346,
1925,
Page 1012-1017
J.H.R.Nixon,
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PDF (609KB)
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摘要:
The paper analyses a method of testing induction motors for temperature-rise, used mainly when means of loading are not available.It is shown that the results of such tests are of the greatest value when studied in conjunction with certain design features of the machines, and simple expressions are developed which enable the test-measurements of heating to be converted to probable values of full-load temperature-rise.The conclusions reached are compared with the results of actual tests.
DOI:10.1049/jiee-1.1925.0118
出版商:IEE
年代:1925
数据来源: IET
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| 3. |
The regulation of the earth potentials of alternating current systems |
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Journal of the Institution of Electrical Engineers,
Volume 63,
Issue 346,
1925,
Page 1018-1022
T.R.Warren,
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PDF (575KB)
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摘要:
The determination of the change in the value of the earth potential of any part of an alternating-current system, when that part is earthed through an impedance of known value, is one of the primary aims of this paper. The author has already investigated the problem for systems in which the earth capacity currents can be safely neglected,† but, since this condition does not always hold even approximately in practice, it is hoped that the complete solution of the problem will prove more useful.The first part of the paper is devoted to the derivation of a simple equivalent network which represents the various leakage paths of the system, the method of solution being based on Kirchhoff's Law. The completeness of the theory in regard to its application under normal conditions of working is then demonstrated, and the effects due both to the presence of harmonics in the E.M.F. waves and to the voltage-drop, along the mains are fully considered.Following this there is a short description of methods to determine the values ofFandKwithout interrupting the supply to the consumers. Formulæ are given which enable the separate values off1f2andf3to be obtained in the case of three-wire three-phase systems:The last section contains a discussion of the Petersen coil method of earthing; special reference being made to transient current phenomena. The dangers attending the use of the coil are explained, and it is pointed out that this method of earthing would be expected to fulfil the same duties on any type of alternating-current system, irrespective of the form of its voltage diagram.
DOI:10.1049/jiee-1.1925.0119
出版商:IEE
年代:1925
数据来源: IET
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