摘要:

The paper discusses the technique of porcelain insulator testing. The ground covered includes the usual electrical and mechanical tests called for in the various national specifications, and also special tests of more recent origin.

DOI:10.1049/jiee-1.1929.0136

出版商:IEE    

年代:1929

数据来源: IET

摘要:

As a result of the experimental work carried out in the Birmingham electric power station, it has been demonstrated that the use of pulverized fuel gives a higher combustion heat efficiency in the boilers than is obtained with mechanical stokers.Boilers having a capacity far greater than those equipped in the past with mechanical stokers can be used, with a consequent reduction in the capital cost of boilers and boiler house; this is a set-off against the higher capital cost of the pulverized-fuel equipment compared with mechanical stokers.The evolution of pulverized-fuel installations is tending towards reduced equipment and greater simplicity in operation; this is effected by eliminating the coal driers and the conveying and storage of the pulverized fuel.

DOI:10.1049/jiee-1.1929.0140

出版商:IEE    

年代:1929

数据来源: IET

摘要:

The paper draws attention to the desirability of clear definition of such terms as power factor, kVA, etc., with regard to tariffs. Ambiguities are possible, and Sections (1) to (6) deal with those relating to polyphase power factor. The “ vector sum ” and “ arithmetic sum ” definitions of 3-phase power factor are stated, and a hypothetical 3-phase case is considered in order to support the contention that the latter definition is more advantageous as a tariff basis than the former. A suggestion is made with regard to the basis of a tariff when there is diversity of incidence of demand on individual phases. Sections (7)et seq.deal with the use of sine and cosine meters and the possible ambiguities resulting from variable power factors. Two single-phase meters on 3-phase balanced loads give rise to the same ambiguities from the same cause. A table of figures and a set of curves are given exhibiting the range of errors which may result in estimating kVA-hours and average power factor from these combinations of meters. The conclusion is drawn that it is not advisable to use them in certain circumstances. Section (17) summarizes the author's opinions on current practice in kVA measurement. Appendix 1 contains observations relating to the ideal neutral point of a 3-phase system when no real neutral is accessible.

DOI:10.1049/jiee-1.1929.0142

出版商:IEE    

年代:1929

数据来源: IET

摘要:

Much difficulty has been experienced in the past in determining the properties of micanite, especially the percentage of adhesive, mica and reinforcement which it contained. Since in some classes of micanite the quantity of adhesive has to be quite small, slight differences in the method of test produce large percentage variations in the results, and this has been a source of friction between user and manufacturer. The methods of test given herein for the determination of these properties have been arrived at after much investigation, with the co-operation of manufacturers' and users' experts.In view of the widely differing characteristics of micanite products, some notes on their manufacture, use and characteristics are included for the guidance of those interested.The Director of the E.R.A. will value comments and criticism from those who have occasion to use any of the tests.

DOI:10.1049/jiee-1.1929.0144

出版商:IEE    

年代:1929

数据来源: IET

摘要:

This paper describes a perfection of the dynamometer method of harmonic analysis in which accuracy and speed of operation have been combined with portability. Although intended primarily for the analysis of voltage waves on power circuits, where it gives the harmonics correct to 1/29th of 1 per cent of the fundamental, the method can also be used for the analysis of current waves and for finding the phase angle between harmonics of the same frequency in two different waves. Each harmonic is found separately from steady readings on two instruments.In the dynamometer method of analysis, a current related in some known way to the voltage or current to be analysed is passed through one coil of a dynamometer instrument, while through the other is passed a sinusoidal “analysing current” of exactly the frequency of the harmonic required to be found. The special feature of the present method is the production of the “analysing current” by means of a synchronously-driven contact disc of special design and a valve circuit.The paper describes in detail the operation of the analyser and establishes its accuracy. A few examples of its use are also given.

DOI:10.1049/jiee-1.1929.0145

出版商:IEE    

年代:1929

数据来源: IET

DOI:10.1049/jiee-1.1929.0148

出版商:IEE    

年代:1929

数据来源: IET