摘要:

The paper deals with various methods of applying electricity to space-heating, water-heating and sundry special applications, with special reference to large-scale space-heating and water-heating installations.Reference is made to the possible economic limits of using electricity for direct heating.Details are given of certain combinations of radiant and convection heating, which it is claimed achieve maximum comfort conditions at a lower cost to the consumer and the supplier than other methods at present in use.Examples are given of installations carried out on the above basis, using a combination of thermal storage, local thermal storage and direct heating. A method of applying water heating to large-scale installations is described which considerably improves the overall efficiency as compared with present methods, and details are given of installations carried out.A policy for domestic electrification is outlined, with special reference to space heating and water heating for working-class houses.Reference is made to factors to be considered in computing annual fuel costs for space heating and water heating.

DOI:10.1049/ji-2.1942.0064

出版商:IEE    

年代:1942

数据来源: IET

摘要:

A few years ago, the most economical form of distribution system for use in cities was considered to be obtained by the use of duplicate high-voltage transformer-feeders in combination with radial low-voltage distribution. Since that time the solid low-voltage network has been widely adopted in other countries, particularly in America. With this arrangement the supply route to any consumer is at least duplicated all the way, which results, it is claimed, in improved voltage regulation and reliability of service. On the other hand the parallel operation of the transformers introduces unfamiliar problems such as increased fault duty in the l.v. network and the reverse flow of power from the l.v. network into transformer or h.v. cable faults. This latter has hitherto been dealt with by sensitive reverse-power protection on the transformers, but it now appears that all the requirements can be met merely by fuse protection. With this modification the scheme is worthy of serious consideration for application in this country, and it is thought that with certain precautions as to fault duty in areas of dense loading many existing city distribution systems could advantageously be converted to solid working. The scheme is, however, most attractive where a rather light section of l.v. cable is laid and is proving inadequate with orthodox methods.

DOI:10.1049/ji-2.1942.0066

出版商:IEE    

年代:1942

数据来源: IET

摘要:

The need for a direct-current amplifier, suitable for industrial conditions, has been realized and a suitable design has been developed. It is entirely mains-operated and the accuracy is independent of mains fluctuations or change in valve characteristics. The amplifier is capable of an output of 3 watts and has a power gain of about 1010. It can be used either as a voltage amplifier or as a current amplifier and is extremely stable. It has been applied to high-speed temperature-recording for the measurement of liquid steel, and also to the metering of heat transport in large hot-water plants. It has also been applied to optical pyrometry, measurements of illumination by barrier-layer-type photocells, to the polarograph and to many other problems in which very small e.m.f.'s are available as a function of the quantity to be measured. The theory of the amplifier has been worked out in sufficient detail to meet practical design requirements. The departure from linearity of response is of the order of only a few parts in 10 000, and voltages of a few microvolts and currents as low as 0.01 micro-amp. can be amplified, and thus used to operate recorders and controllers.

DOI:10.1049/ji-2.1942.0072

出版商:IEE    

年代:1942

数据来源: IET

摘要:

A brief history is followed by a description of a typical mains-voltage fluorescent lamp and the principles of its operation. Its high electric power-to-light conversion efficiency and the outstanding colour quality of the light are examined, together with conventions whereby these are assessed.As an example the 200/250-volt 80-watt lamp and its auxiliaries, marketed in this country in March 1940 to improve factory lighting in blackout conditions, are described in detail, and the characteristics of the components and the complete unit explained.It is concluded that this lamp is satisfactorily fulfilling a present industrial need, and that its quality has been so greatly appreciated that it is undoubtedly the forerunner of a new series of lighting lamps.

DOI:10.1049/ji-2.1942.0074

出版商:IEE    

年代:1942

数据来源: IET

摘要:

This paper deals with the scope of reactor short-circuit testing, and the type testing of the various forms of reactor construction.The principles of current-limiting reactor operation are briefly described, and proposals for the short-circuit rating of reactors are given.The short-circuit testing of reactors is considered from the point of view of the manner of testing, suitable test plant, and the dynamic and thermal effects of the test current.A suitable test programme is described, and examples of test results obtained by the authors are included, with an analysis of the oscillograms and suggested criteria for the acceptance of reactor short-circuit tests.

DOI:10.1049/ji-2.1942.0076

出版商:IEE    

年代:1942

数据来源: IET

DOI:10.1049/ji-2.1942.0080

出版商:IEE    

年代:1942

数据来源: IET

摘要:

The security of the windings of an alternator generating at 22 kV or above and connected directly to a network depends mainly on the ability of the insulation to withstand surge voltages.The distribution of surge voltages in the various types of stator winding hitherto adopted in commercial practice is examined, together with the relation of this distribution to that of the effective insulation available.As alternators nearly always operate with the neutral point of the windings unearthed, the voltage stresses on the insulation near the neutral in these circumstances are determined and the danger of the use of graded insulation is discussed.In no case does there appear to be an inherent tendency for all transient voltages to be distributed over the length of the stator winding in the same proportion as the generated voltage of the machine.

DOI:10.1049/ji-2.1942.0081

出版商:IEE    

年代:1942

数据来源: IET