摘要:

This paper discusses the application of the following types of cables and methods of laying to the various parts of a three-wire d.c. network.Types of cables: Single-core, three-core, and triple-concentric.Methods of laying : Conduit, direct, and solid.It endeavours to show that, wherever it can be adopted, the most satisfactory network is that composed of single-core lead-covered cables, the feeders being drawn into conduits and the distributors and services laid direct.The paper also describes the “looped-neutral” service, the object of which is to facilitate the location of faults on the smaller sizes of triple-concentric vulcanized-bitumen distributors, and to improve the continuity of supply under fault conditions.

DOI:10.1049/jiee-1.1925.0034

出版商:IEE    

年代:1925

数据来源: IET

摘要:

The paper is intended to form a corollary to that of Professor Cramp and Miss Calderwood † and deals with the losses involved in the distribution of alternating currents in sheathed cables in which the sheath is of magnetic material.Single-core rubber-insulated cables, each enclosed in a separate iron tube, and also single-core cables armoured with one or two layers of galvanized iron or steel wires, are dealt with, and experimental data are given showing the measured losses in each case.It is shown that, while the losses due to induction in a tube are considerable, those in a wire-armoured cable are comparatively very small, and also that the distance separating the individual cables forming a circuit has very little effect in determining the losses involved. In the case of the wire-armoured cable, also, the connection of the sheaths of separate cables so as to form a closed sheath circuit has no appreciable effect upon the losses, and the current which will flow in such a circuit is so small as to produce no considerable heating.

DOI:10.1049/jiee-1.1925.0041

出版商:IEE    

年代:1925

数据来源: IET

摘要:

In a previous paper Miss Calderwood and the present author examined the losses in the lead sheath of a single-core cable when carrying an alternating current, and concluded that, provided the outgoing and return cables were laid within a certain limiting distance of one another, no difficulty would arise due to eddy currents in the sheaths at normal frequencies. In the present paper this work is extended to cover the case of single-core cables that are both lead-covered and armoured.A theoretical investigation of the reactances and losses is carried out and is checked against the actual test figures obtained by Harvey and Busby. It is shown :—1. That the flux in the armour, the reactance due to that flux, and the appropriate hysteresis and eddy losses can all be approximately predetermined.2. That for low-tension transmission, lead-covered and armoured cables are impracticable with armouring as at present constructed.3. That the use of such cables for e.h.t. transmission is not precluded by the magnetic conditions introduced by the armour, and consequently such cables are practicable. There would, however, be some difficulties to be overcome due to large capacity currents when the transmission distance is great.

DOI:10.1049/jiee-1.1925.0042

出版商:IEE    

年代:1925

数据来源: IET

摘要:

The paper deals with a new method of high-frequency resistance measurement involving the application of a circle diagram to a resonance curve. Various methods of measurement are evolved and experimental results are given. The application to the accurate determination of wave-length is suggested.

DOI:10.1049/jiee-1.1925.0048

出版商:IEE    

年代:1925

数据来源: IET

DOI:10.1049/jiee-1.1925.0050

出版商:IEE    

年代:1925

数据来源: IET