DOI:10.1049/ji-2.1946.0092

出版商:IEE    

年代:1946

数据来源: IET

摘要:

This paper deals with the variations of capacitance and loss angle occurring in precision capacitors used for measurement purposes. The degree of accuracy required in current practice is discussed, and compared with the performance of available instruments. The causes of variation are discussed with relation to time, humidity, temperature, frequency, voltage and screening. The properties of materials used in capacitor construction are discussed in relation to the foregoing variables. Special attention is given to the less well-known causes of change in capacitance and loss angle, and also to experimental difficulties which lead to errors in the measurement of these quantities. In particular, attention is directed in an Appendix to an apparently unrealized source of error in loss-angle measurements on samples with a guard ring.

DOI:10.1049/ji-2.1946.0093

出版商:IEE    

年代:1946

数据来源: IET

摘要:

The general principles involved in the design of joints and sealing ends for pressure cable installations are discussed. Design standards based on experimental results are given, and practical methods of construction are described. An account is also given of the gas-control accessories of a pressure cable, including leak location methods. Special attention is given to the problem of voltage surges in relation to joints and scaling ends. It is shown that the voltage surges specified as representing service conditions are now a critical factor determining the amount of insulation. The relative economics of providing for the voltage surges by additional insulation or alternatively by surge diverters is examined.

DOI:10.1049/ji-2.1946.0096

出版商:IEE    

年代:1946

数据来源: IET

摘要:

In Part 1, the various ways in which vibration manifests itself, namely noise, vibration, stress and rotational oscillation, are considered. The available methods of measuring vibration are described and their relative merits and limitations discussed. Methods of calibrating measuring apparatus are given, with an indication of their limits. The suppression of vibration is considered from the points of view of what is desirable, how much can be obtained at the source and how much by resilient mountings, attention being given to the effect of ground and source impedance. Practical examples are given of the reductions in vibration which have been achieved in certain cases by improvements in the source and by resilient mountings.Part 2 concerns the determination of elastic design data on resilientmaterials and mountings for use as described in Part 1 for reducing vibration transmission. The limitations of a previous moving-iron-drive resonance-type method are discussed, and the advantages of a moving-coil-drive co-ordinate-potentiometer method pointed out. The apparatus is described in detail, and results of tests on typical materials and mountings are given and discussed.

DOI:10.1049/ji-2.1946.0099

出版商:IEE    

年代:1946

数据来源: IET

摘要:

Owing to the large number of items discussed, and for the purpose of convenient reference, the paper has been arranged in the following manner:—Introduction.Part1.Basic data.(1) physical constants, temperatures and other fundamental data.(2) The thermal efficiency of electric immersion heaters and other methods of water-heating.Part2.Apparatus details.(3) The mechanism of water-heating, immersion heaters, thermostats and electrical details.(4) Storage vessels, and methods of fixing immersion heaters and thermostats.(5) Pipes and pipe fittings.(6) Taps or cocks.Part3.The leakage of heat energy from hot-water storage vessels and pipes; thermal insulation, and thermo-syphon circulation.(7) The leakage or waste of heat energy from the surface of hotstorage vessels, pipes, towel-rails, and radiators, and in deadleg connections to taps.(8) Thermal insulation to hot-storage vessels and pipes.(9) Thermo-syphon or gravity circulation, intended and fortuitous.Part4.The general design and arrangement of the installation.(10) Position of the hot-storage vessel, and the lay-out of the interconnecting pipe-work.Conclusions.Appendix. Test report on a water-heating unit designed for installation in a single-floor dwelling.

DOI:10.1049/ji-2.1946.0102

出版商:IEE    

年代:1946

数据来源: IET