摘要:

Demands for greatly increased power transformer ratings within transport limits which change only slowly have compelled transformer designers to devise new forms of construction which make the best possible use of materials.The paper illustrates this by giving an account of some design problems and some particular solutions. Details are given of a boltless core construction and its effect on noise level. The influence on transformer size and losses of the use of transposed-strip conductor is discussed, and an account is given of a method of calculating disc-winding temperature rise with a digital computer. Stray load losses in the transformer structure can be of considerable magnitude, and methods of reducing them are considered. Some test results are given for core-clamp losses, and a simple method of predicting the effect of magnetic tank shields is described.Finally, a brief account is included of a construction which allows large power transformers to be dismantled for transport and reassembled in such a way that abnormal site testing and processing are avoided.It is concluded that by all such means transformer designers will be able to meet demands for still greater transformer ratings.

DOI:10.1049/piee.1964.0137

出版商:IEE    

年代:1964

数据来源: IET

摘要:

The paper refers briefly to the d.c. electrification and to some operating statistics on the Indian Railways and gives a few details of the electrification schemes undertaken in the Second and Third Five-Year Plans, using a 25 kV single-phase industrial-frequency system. Power supply arrangements, traction overhead equipment, ancillary civil, signalling and telecommunication engineering work and a.c. rolling stock are described. It outlines the technical improvements made in fixed installations and rolling stock in the light of experience gained so far, the organisation set up for the execution of electrification projects and the efforts made to develop the manufacture of rolling stock and other equipment in India.

DOI:10.1049/piee.1964.0138

出版商:IEE    

年代:1964

数据来源: IET

摘要:

It is shown how voltage multiplication can be obtained by the transient reversal of the voltages in alternate units of series-connected systems. This leads to three groups of high-voltage generators whose performances are discussed theoretically. The results of preliminary experiments are reported briefly: these are in agreement with the theoretical predictions and show that voltages of about 1 MV are readily obtained by these methods.

DOI:10.1049/piee.1964.0139

出版商:IEE    

年代:1964

数据来源: IET

DOI:10.1049/piee.1964.0140

出版商:IEE    

年代:1964

数据来源: IET

摘要:

Halfwave bridge-type magnetic servoamplifiers, which have been widely used for instrumentation and control problems, have been improved by adding biased rectifiers in the control circuit. It has been shown that such amplifiers give higher gain than the conventional type of halfwave amplifier and maintain the large input impedance required by the synchrocontrol transformer output.The paper gives a systematic mathematical analysis of d.c. and fundamental-frequency gain of halfwave magnetic servoamplifiers with biased-rectifier control, considering resistive and capacitive loads. Graphical illustrations have been added to mathematical analysis wherever necessary. The result of the analysis shows good correspondence with experimental values.

DOI:10.1049/piee.1964.0141

出版商:IEE    

年代:1964

数据来源: IET