The paper deals with two recent developments in the design of audio-frequency metal locators. The first is the introduction of discrimination against low-conductivity magnetic bodies for the purpose of suppressing unwanted signals. A solution is described which forms the basis of a number of these locators. The principle is to utilize the existence of a phase difference between desired and undesired signals. The need for a more radical departure from the established principles is then examined and the second development (locator No. 7) is discussed. In this locator an alternating magnetic field is set up over a large area, and local field distortions, due to metallic bodies, are observed directly by means of a balanced-coil system. In this way it is possible to attain high sensitivity and operating speed, to eliminate interference between operators, and, for war-time applications, to safeguard the user from booby-traps sensitive to an alternating field.
{"title":"Development of locators of small metallic bodies buried in the ground","authors":"B. Roston","doi":"10.1049/JI-2.1948.0179","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0179","url":null,"abstract":"The paper deals with two recent developments in the design of audio-frequency metal locators. The first is the introduction of discrimination against low-conductivity magnetic bodies for the purpose of suppressing unwanted signals. A solution is described which forms the basis of a number of these locators. The principle is to utilize the existence of a phase difference between desired and undesired signals. The need for a more radical departure from the established principles is then examined and the second development (locator No. 7) is discussed. In this locator an alternating magnetic field is set up over a large area, and local field distortions, due to metallic bodies, are observed directly by means of a balanced-coil system. In this way it is possible to attain high sensitivity and operating speed, to eliminate interference between operators, and, for war-time applications, to safeguard the user from booby-traps sensitive to an alternating field.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125339834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The authors' reply to the discussion on “The influence of inverse time-relay characteristics on discriminative time”","authors":"E. Connon, E. Smith","doi":"10.1049/ji-2.1948.0222","DOIUrl":"https://doi.org/10.1049/ji-2.1948.0222","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134270853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A flash tube is a gas-filled device designed to produce a brilliant flash of light when it is used to short-circuit a charged capacitor. The discharge is characterized by a high output of radiation in the infrared and ultra-violet as well as in the visible regions.A brief historical review is followed by an outline of the general construction of modern flash tubes. Their electrical characteristics are given together with curves showing current, voltage and power against time. The effect of the tube parameters on the complete circuit characteristics are examined.Some measurements of light intensity, luminous energy and efficiency are given, and the development of the typical high-current arc spectra of xenon under flash-tube conditions is illustrated by a series of spectrograms.Circuits for the control of these tubes are described, suitable for both isolated-flash and repetition-flash applications.The concluding Sections deal with a number of recent applications and with an examination of the possibilities of the flash tube as an aid to the examination of high-speed phenomena, both photographically and visually.
{"title":"The flash tube and its applications","authors":"J. N. Aldington, A. J. Meadowcroft","doi":"10.1049/JI-2.1948.0184","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0184","url":null,"abstract":"A flash tube is a gas-filled device designed to produce a brilliant flash of light when it is used to short-circuit a charged capacitor. The discharge is characterized by a high output of radiation in the infrared and ultra-violet as well as in the visible regions.A brief historical review is followed by an outline of the general construction of modern flash tubes. Their electrical characteristics are given together with curves showing current, voltage and power against time. The effect of the tube parameters on the complete circuit characteristics are examined.Some measurements of light intensity, luminous energy and efficiency are given, and the development of the typical high-current arc spectra of xenon under flash-tube conditions is illustrated by a series of spectrograms.Circuits for the control of these tubes are described, suitable for both isolated-flash and repetition-flash applications.The concluding Sections deal with a number of recent applications and with an examination of the possibilities of the flash tube as an aid to the examination of high-speed phenomena, both photographically and visually.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114451152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The authors' replies to the discussion on \"Development of locators of small metallic bodies buried in the ground\"","authors":"B. Roston","doi":"10.1049/JI-2.1948.0181","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0181","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122904904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper is concerned with transformer economics from the viewpoint of an electricity supply undertaking. It describes a new method of approach by the device of "yearly economic efficiency." This term is defined and its use illustrated by reference to a range of distribution transformers. A comparison formula is next deduced and applied to two transformers of the same size but having different characteristics. Finally, a supply undertaking is examined and operating conditions are tabulated. The constants necessary for the comparison or purchasing formula are obtained from the information available, and an actual purchasing formula is worked out. Economic efficiency curves for the undertaking's distribution transformers are given, and the lines on which improvements should be made are indicated.
{"title":"Transformer economic efficiency","authors":"B. Calvert","doi":"10.1049/JI-2.1948.0188","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0188","url":null,"abstract":"The paper is concerned with transformer economics from the viewpoint of an electricity supply undertaking. It describes a new method of approach by the device of \"yearly economic efficiency.\" This term is defined and its use illustrated by reference to a range of distribution transformers. A comparison formula is next deduced and applied to two transformers of the same size but having different characteristics. Finally, a supply undertaking is examined and operating conditions are tabulated. The constants necessary for the comparison or purchasing formula are obtained from the information available, and an actual purchasing formula is worked out. Economic efficiency curves for the undertaking's distribution transformers are given, and the lines on which improvements should be made are indicated.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125898349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Corrigendum: The predetermination of the magnetic properties of ferromagnetic laminae at power and audio frequencies","authors":"O. Butler, C. Mang","doi":"10.1049/JI-2.1948.0223","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0223","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122149439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The authors' reply to the discussion on \"The flash tube and its applications\"","authors":"J. N. Aldington, A. J. Meadowcroft","doi":"10.1049/JI-2.1948.0186","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0186","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128103236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The authors' replies to the discussion on “Tooth-ripple losses in unwound pole-shoes” and “Parasitic losses in synchronous-machine damper windings”","authors":"W. J. Gibbs, J. H. Walker","doi":"10.1049/JI-2.1948.0150","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0150","url":null,"abstract":"","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116324635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For electric cables, as used for indoor wiring, the only standard of reference now existing in this country is B.S.7, which covers only rubber insulants; for lack of any other specification, the dimensions therein specified for rubber compounds are being misapplied to other insulating materials, without taking into account the different properties of the latter.A new “basic specification” is proposed, composed of a series of electrical, physical, thermal, mechanical and chemical tests; and the author suggests the use of such an agreed basic specification for the determination of minimum dimensions of any approved materials of which the cable may be composed.Following out this suggestion, the author deals with such test requirements under the two headings: (a) electrical specification, which covers the primary purpose of the cable to transmit electrical power, and (b) mechanical specification, which covers the adequate protection of the cable in service.Under the electrical specification some calculations and graphs of interest are given as illustrations only of the more comprehensive survey that is necessary.The author further deals with practical and economic considerations, which may have some bearing on purely echnical conclusions, e.g.:(a) The lack of importance of eccentric insulation, provided the required minimum thickness is used.(b) The incorrectness of stipulating an average thickness with a plus and minus tolerance as against the correct method of specifying either a minimum thickness or a maximum, or both.(c) The increase of cable costs, basically as the square of the radial thicknesses imposed.In particular, the properties of pre-war rubber, reclaimed rubber, p.v.c. compounds and polythene are compared.
{"title":"Factors governing specifications for electric power cables","authors":"W. Bowen","doi":"10.1049/JI-2.1948.0152","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0152","url":null,"abstract":"For electric cables, as used for indoor wiring, the only standard of reference now existing in this country is B.S.7, which covers only rubber insulants; for lack of any other specification, the dimensions therein specified for rubber compounds are being misapplied to other insulating materials, without taking into account the different properties of the latter.A new “basic specification” is proposed, composed of a series of electrical, physical, thermal, mechanical and chemical tests; and the author suggests the use of such an agreed basic specification for the determination of minimum dimensions of any approved materials of which the cable may be composed.Following out this suggestion, the author deals with such test requirements under the two headings: (a) electrical specification, which covers the primary purpose of the cable to transmit electrical power, and (b) mechanical specification, which covers the adequate protection of the cable in service.Under the electrical specification some calculations and graphs of interest are given as illustrations only of the more comprehensive survey that is necessary.The author further deals with practical and economic considerations, which may have some bearing on purely echnical conclusions, e.g.:(a) The lack of importance of eccentric insulation, provided the required minimum thickness is used.(b) The incorrectness of stipulating an average thickness with a plus and minus tolerance as against the correct method of specifying either a minimum thickness or a maximum, or both.(c) The increase of cable costs, basically as the square of the radial thicknesses imposed.In particular, the properties of pre-war rubber, reclaimed rubber, p.v.c. compounds and polythene are compared.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127552368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper describes a method of localizing sustained earth-faults on systems protected by Petersen coils. The method is based on the measurement of variations of electrostatic field strength in the vicinity of the overhead line. A description is given of the apparatus used and of results of tests made. The practical applications of the method are explained. An additional use of the apparatus is indicated as a voltage detector on overhead high-voltage lines.
{"title":"A method for detection of sustained earth-faults in rural overhead lines protected by petersen coils","authors":"B. D. Zelikin","doi":"10.1049/JI-2.1948.0172","DOIUrl":"https://doi.org/10.1049/JI-2.1948.0172","url":null,"abstract":"The paper describes a method of localizing sustained earth-faults on systems protected by Petersen coils. The method is based on the measurement of variations of electrostatic field strength in the vicinity of the overhead line. A description is given of the apparatus used and of results of tests made. The practical applications of the method are explained. An additional use of the apparatus is indicated as a voltage detector on overhead high-voltage lines.","PeriodicalId":307627,"journal":{"name":"Journal of the Institution of Electrical Engineers - Part II: Power Engineering","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1948-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123263418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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