摘要:

The author describes current practice in street traffic signalling, dealing particularly with vehicle-actuated signals as adapted for use in Great Britain. Detailed descriptions are confined to the system with which the author is most familiar (the Autoflex vehicle-actuated system). Brief references are, however, made to other systems and to practice in other parts of the world. All parts of the equipment are treated, including signals, controllers, and detectors. The paper is divided into two main portions, the first dealing with generalities and isolated intersections and the second with interlinking of numbers of intersections. The subject is treated from the traffic aspect as well as from the electrical aspect, and details of the performance of certain of the schemes are given.

DOI:10.1049/jiee-1.1938.0022

出版商:IEE    

年代:1938

数据来源: IET

摘要:

An account is given of an experimental investigation made on a direct-current machine, concerning current displacement (or, as some would say, eddy currents) in the conductors of the armature winding. The investigation is a sequel to a theoretical investigation previously published in theJournal.The method adopted is that of making measurements of current density at several levels in the slot; the method is described with regard to oscillograms and also r.m.s. values. A series of results, obtained under shortcircuit conditions, is reproduced, and it is shown that the oscillograms obtained represent variations of current density substantially in accord with thos.e predicted from theory. The investigation was extended to cover open-circuit and full-load conditions, and results are reproduced. The necessity for further investigations is discussed, whilst tentative general conclusions are arrived at which should be of assistance to designers of direct-current machines.

DOI:10.1049/jiee-1.1938.0026

出版商:IEE    

年代:1938

数据来源: IET

摘要:

will be generally agreed that demand is just as important a factor as supply in the price-fixing of electricity. The consumer, like the producer, is a free agent, and just as the latter cannot be forced to sell at a loss so the former cannot be compelled to buy at a loss, i.e. to take more than it pays him to do. It is true that the price is actually fixed by the producer, but the consumer has the ultimate veto; and the amount he takes will be governed by the price just as certainly as that price is governed by the cost of production. That being so, it would be expected that all tariff discussions would envisage demand and utility just as much as they do supply and costs. A glance at any engineering index will dispel this idea, and will show at least a hundred entries under the heading of " Costs " for every one under the heading "Demand." Moreover, whilst the term " elasticity of demand " has been employed in tariff discussions, no precise definition appears to have been attempted, still less any appraisal of its value and consequence in electricity supply.The present paper is devoted almost entirely to the demand aspect and to the effect it has, or should have, upon tariff construction. Part I is a statement of the theory of supply and demand and the price reaction as generally accepted by economists, but interpreted with reference to, and illustrated by, electricity supply. The case of free competition is first dealt with, and then the case of monopoly. Elasticity of demand is explained and defined, and its probable values for various electrical loads are then surmised. This part of the work should not require to be done again.Part II is an attempt at quantitative application of the theory. Various electrical demand curves are examined and analysed into their component parts. Several methods are tried of plotting and biasing the figures in order to compensate for other variables. Probable elasticity values are estimated, and their bearing on tariff policy is outlined. This part of the paper is a commencement merely, and will be useful rather for its trigger action than for its actual content.The paper concludes with a short appendix dealing with terms and relationships.

DOI:10.1049/jiee-1.1938.0027

出版商:IEE    

年代:1938

数据来源: IET

摘要:

Curves are given from which, by two interpolations, the reflection coefficient of the ground can be determined for any angle of incidence or any value of dielectric constant and conductivity of that surface. Curves are given for the two cases in which the electric vector of the incident radiation is polarized in and perpendicular to the plane of incidence respectively, so that the reflection coefficient can also be determined for any state of polarization.

DOI:10.1049/jiee-1.1938.0031

出版商:IEE    

年代:1938

数据来源: IET