Pub Date : 1922-07-01DOI: 10.1109/JOAIEE.1922.6592079
P. D. Lowell
Electron tube amplifiers now form an important part of practically all radio receiving sets except the most simple types. Storage cells, which have heretofore usually been required for operating amplifiers, require constant attention, are bulky and heavy, and have other serious disadvantages. The dry cells, which are often used as a source of plate voltage, have a comparatively short life and are expensive and inconvenient. It would be much more convenient to use an amplifier which could be supplied with power from 100-volt, 60-cycle mains. This paper describes a five-stage amplifier which operates satisfactorily on 60-cycle supply for both filaments and plates. This amplifier has three radio-frequency stages and two audio-frequency stages, and uses a crystal detector. A special transformer with five windings is used, the primary being supplied with 110-volts a-c. The 60-cycle current when used in an ordinary amplifier circuit introduces a strong 60-cycle note which offers serious interference. This has been practically eliminated by balancing resistances, grid condensers and special grid leaks of comparatively low resistance, telephone transformer in the output circuit, and crystal detector instead of electron tube detector. In the final form of the amplifier, there is only a slight residual hum which is not objectionable. The amplification obtained with a-c. supply was as good as that obtained with the same amplifier used with d-c. supply. The complete unit is light, compact, and portable. For the reception of damped waves, the amplifier as constructed operated most satisfactorily for wave lengths from 200 to 750 meters. This range was determined by the working range of the radio-frequency transformers used. By using suitable radio-frequency transformers, it is expected that the amplifier will be effective for the reception of damped waves and undamped waves as long as 10,000 meters. For the reception of undamped waves, a separate heterodyne should be employed. The paper gives circuit diagrams, and states the values of the condensers, resistors and inductors used.
{"title":"Note on the development of an electron tube amplifier: Which uses 60-cycle alternating current to supply power for the filaments and plates","authors":"P. D. Lowell","doi":"10.1109/JOAIEE.1922.6592079","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6592079","url":null,"abstract":"Electron tube amplifiers now form an important part of practically all radio receiving sets except the most simple types. Storage cells, which have heretofore usually been required for operating amplifiers, require constant attention, are bulky and heavy, and have other serious disadvantages. The dry cells, which are often used as a source of plate voltage, have a comparatively short life and are expensive and inconvenient. It would be much more convenient to use an amplifier which could be supplied with power from 100-volt, 60-cycle mains. This paper describes a five-stage amplifier which operates satisfactorily on 60-cycle supply for both filaments and plates. This amplifier has three radio-frequency stages and two audio-frequency stages, and uses a crystal detector. A special transformer with five windings is used, the primary being supplied with 110-volts a-c. The 60-cycle current when used in an ordinary amplifier circuit introduces a strong 60-cycle note which offers serious interference. This has been practically eliminated by balancing resistances, grid condensers and special grid leaks of comparatively low resistance, telephone transformer in the output circuit, and crystal detector instead of electron tube detector. In the final form of the amplifier, there is only a slight residual hum which is not objectionable. The amplification obtained with a-c. supply was as good as that obtained with the same amplifier used with d-c. supply. The complete unit is light, compact, and portable. For the reception of damped waves, the amplifier as constructed operated most satisfactorily for wave lengths from 200 to 750 meters. This range was determined by the working range of the radio-frequency transformers used. By using suitable radio-frequency transformers, it is expected that the amplifier will be effective for the reception of damped waves and undamped waves as long as 10,000 meters. For the reception of undamped waves, a separate heterodyne should be employed. The paper gives circuit diagrams, and states the values of the condensers, resistors and inductors used.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134361131","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}
Pub Date : 1922-05-01DOI: 10.1109/JoAIEE.1922.6590922
A. Field
To the Editor: An article under this heading appears in the January issue of the Journal, attributed to myself. In spite of the title the Article itself deals with only one type of frequency changer, and even for that machine only discusses some of the I2R losses, but the broad titles which appears above the article has no doubt arisen by reason of the inclusion, through some inadvertence, of the matter contained in a hastily compiled memorandum dealing with another subject, and not intended for publication; this composes the first five paragraphs and the first (unnumbered) figure of the article in question.
{"title":"Correspondence: Polyphase commutator machines","authors":"A. Field","doi":"10.1109/JoAIEE.1922.6590922","DOIUrl":"https://doi.org/10.1109/JoAIEE.1922.6590922","url":null,"abstract":"To the Editor: An article under this heading appears in the January issue of the Journal, attributed to myself. In spite of the title the Article itself deals with only one type of frequency changer, and even for that machine only discusses some of the I2R losses, but the broad titles which appears above the article has no doubt arisen by reason of the inclusion, through some inadvertence, of the matter contained in a hastily compiled memorandum dealing with another subject, and not intended for publication; this composes the first five paragraphs and the first (unnumbered) figure of the article in question.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115655468","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590921
S. Hibben
Several hundred prominent manufacturers of interior lighting devices exhibited in February 1922, in Milwaukee, the newest things in electric fixtures and glassware. Thousands of units were on display, presumably representing the best average home, store, and office lighting equipment that has been developed during the past year.
{"title":"Styles and tendencies in luminaire design: Impression from the annual lighting fixture market, Milwaukee","authors":"S. Hibben","doi":"10.1109/JOAIEE.1922.6590921","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590921","url":null,"abstract":"Several hundred prominent manufacturers of interior lighting devices exhibited in February 1922, in Milwaukee, the newest things in electric fixtures and glassware. Thousands of units were on display, presumably representing the best average home, store, and office lighting equipment that has been developed during the past year.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125061864","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590915
G. Faccioli
Although the prolbem of higher harmonics in the electrical circuits of transformers is a generation old and the solution has been given by a number of eminent engineers, still hardly a week passes in a department specializing on the manufacture of transformers that an instance does not appear of the lack of comprehension of the relations involved. If the problem were entirely confined to the realms of the manufacturing specialists, it might well be passed over and taken care of by local educational work. But the troubles which arise from time to time in the practise of transmission and distribution of electrical energy on polyphase circuits due entirely to the method of connection of the three phases of polyphase apparatus warrants a review of the subject in a simple form. What are the troubles which may arise in trails mission practise? The harmonics may, first set up potential strains in the transformer coils; second, raise the voltage of the line; third, burn out incandescent lamps; fourth, change the ratio of transformation of voltage under low-load conditions from its proper value as determined by the ratio of the number of turns on the primary coil to the number of turns on the secondary coil; fifth, produce a triple harmonic current in the neutral connection to ground; sixth, induce a distracting hum in telephone receivers connected to parallel telephone circuits; seventh, produce abnormally high voltages and large currents in odd places on the circuits due to a resonance with a natural frequency of the circuit; and so on. To get at the basic effect which causes these triple-harmonic troubles the magnetization current of a single-phase transformer may be considered. If the applied potential at the terminals of the transformer is the familiar smooth sine wave it is well-known that the magnetizing current is not a sine wave but is a smooth distorted wave. On the other hand, if a pure sine wave of current is forced through the primary there appears on both the primary and the secondary a smooth but distorted wave of potential. It must be one or the other. It often helps the understanding and avoids possible confusion to point out a resemblance which is actually a different phenomenon. Instead of finding by oscillographic tests that a current wave is smooth, it may be somewhat saw-toothed. This occurs when a generator supplies current to a condenser, such as an unloaded overhead line or electric cable. A generator usually has either twelve teeth on the armature per pair of poles (that is to say per cycle) or eighteen teeth. If there are twelve teeth, the nearest odd number for the necessarily odd harmonic is either eleven or thirteen. Likewise, if there are eighteen teeth there will be found either seventeen or nineteen saw-teeth or ripples on the main wave. These variations from a sine wave are known as teeth harmonics which entirely distinguish them from the distortions of the sine wave by the effect of variable permeability of the iron. The
{"title":"Triple harmonics in transformers","authors":"G. Faccioli","doi":"10.1109/JOAIEE.1922.6590915","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590915","url":null,"abstract":"Although the prolbem of higher harmonics in the electrical circuits of transformers is a generation old and the solution has been given by a number of eminent engineers, still hardly a week passes in a department specializing on the manufacture of transformers that an instance does not appear of the lack of comprehension of the relations involved. If the problem were entirely confined to the realms of the manufacturing specialists, it might well be passed over and taken care of by local educational work. But the troubles which arise from time to time in the practise of transmission and distribution of electrical energy on polyphase circuits due entirely to the method of connection of the three phases of polyphase apparatus warrants a review of the subject in a simple form. What are the troubles which may arise in trails mission practise? The harmonics may, first set up potential strains in the transformer coils; second, raise the voltage of the line; third, burn out incandescent lamps; fourth, change the ratio of transformation of voltage under low-load conditions from its proper value as determined by the ratio of the number of turns on the primary coil to the number of turns on the secondary coil; fifth, produce a triple harmonic current in the neutral connection to ground; sixth, induce a distracting hum in telephone receivers connected to parallel telephone circuits; seventh, produce abnormally high voltages and large currents in odd places on the circuits due to a resonance with a natural frequency of the circuit; and so on. To get at the basic effect which causes these triple-harmonic troubles the magnetization current of a single-phase transformer may be considered. If the applied potential at the terminals of the transformer is the familiar smooth sine wave it is well-known that the magnetizing current is not a sine wave but is a smooth distorted wave. On the other hand, if a pure sine wave of current is forced through the primary there appears on both the primary and the secondary a smooth but distorted wave of potential. It must be one or the other. It often helps the understanding and avoids possible confusion to point out a resemblance which is actually a different phenomenon. Instead of finding by oscillographic tests that a current wave is smooth, it may be somewhat saw-toothed. This occurs when a generator supplies current to a condenser, such as an unloaded overhead line or electric cable. A generator usually has either twelve teeth on the armature per pair of poles (that is to say per cycle) or eighteen teeth. If there are twelve teeth, the nearest odd number for the necessarily odd harmonic is either eleven or thirteen. Likewise, if there are eighteen teeth there will be found either seventeen or nineteen saw-teeth or ripples on the main wave. These variations from a sine wave are known as teeth harmonics which entirely distinguish them from the distortions of the sine wave by the effect of variable permeability of the iron. The","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"223 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123029899","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590913
E. Thomson
BEFORE the days of the discovery of the voltaic battery or the generation of electricity by contact of two different metals, the only source of electricity and the only knowledge which we had or which the world possessed depended on the development of electrical charges on the surfaces of non-conductors by friction. At least, the charges were the accompaniment of friction, the earliest manifestation of which was the ancient observation of Thales that amber (electron) when rubbed would attract light bodies. In the early part of the eighteenth century, experimentation in this field of the generation of electricity by friction really led to the discovery of some of the most fundamental principles of the science, such as the division of substances into conductors and non-conductors, electrics and dielectrics, positive and negative charges, and discharges uniting the two. Von Guericke constructed an electrical generator and frictional machine consisting of a revolving globe of sulphur, rubbed generally by the hand, while Franklin carried on many of his original experiments by the rubbing of glass rods or tubes, using fibrous material or fur as a rubber, and Franklin's famous machine for the generation of electricity was the well-known form consisting of a revolving glass sphere provided with a rubber on the one end of the diameter, and a collector at the other end communicating a charge from the rubbing surface of the globe to what was known as the “prime conductor.” This machine was soon succeeded by the revolving glass cylinder of the cylinder machine, which, in the hands of Ramsden, Von Marum, and others, became modified into the plate machine, where a circular glass plate instead of a cylinder was mounted so as to be rubbed on both sides, while the collector was a set of points on both sides connected with a prime conductor. The glass plate was found to be superior to the cylinder. I have not, however, noticed any reason having been given for this in the literature with which I am acquainted, other than that the plate gave the possibility of a greater velocity of travel, and with it gave greater length of rubbing surfaces in moderate space, since both sides were rubbed. It had been noticed that if the revolving plate was too thick it was not as effective as when it was of moderate thickness. We can now readily ascribe the true cause for the superiority of the plate machine in that when both sides were subjected to the action of the rubber, and if the sides were not too far apart, as would be the case in too thick a plate, the electrification would inductively act through the plate, or more properly, the capacity of the plate after it left the rubber would be less than in the case of the cylinder where only one side of the glass was charged by the friction, which charge would tend to bind to itself through the glass an opposite charge on the other side. There could not, therefore, be, when the glass left the rubber, anything like the elevation of p
{"title":"The nature of tribo-electricity or electricity of friction and other kindred matters","authors":"E. Thomson","doi":"10.1109/JOAIEE.1922.6590913","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590913","url":null,"abstract":"BEFORE the days of the discovery of the voltaic battery or the generation of electricity by contact of two different metals, the only source of electricity and the only knowledge which we had or which the world possessed depended on the development of electrical charges on the surfaces of non-conductors by friction. At least, the charges were the accompaniment of friction, the earliest manifestation of which was the ancient observation of Thales that amber (electron) when rubbed would attract light bodies. In the early part of the eighteenth century, experimentation in this field of the generation of electricity by friction really led to the discovery of some of the most fundamental principles of the science, such as the division of substances into conductors and non-conductors, electrics and dielectrics, positive and negative charges, and discharges uniting the two. Von Guericke constructed an electrical generator and frictional machine consisting of a revolving globe of sulphur, rubbed generally by the hand, while Franklin carried on many of his original experiments by the rubbing of glass rods or tubes, using fibrous material or fur as a rubber, and Franklin's famous machine for the generation of electricity was the well-known form consisting of a revolving glass sphere provided with a rubber on the one end of the diameter, and a collector at the other end communicating a charge from the rubbing surface of the globe to what was known as the “prime conductor.” This machine was soon succeeded by the revolving glass cylinder of the cylinder machine, which, in the hands of Ramsden, Von Marum, and others, became modified into the plate machine, where a circular glass plate instead of a cylinder was mounted so as to be rubbed on both sides, while the collector was a set of points on both sides connected with a prime conductor. The glass plate was found to be superior to the cylinder. I have not, however, noticed any reason having been given for this in the literature with which I am acquainted, other than that the plate gave the possibility of a greater velocity of travel, and with it gave greater length of rubbing surfaces in moderate space, since both sides were rubbed. It had been noticed that if the revolving plate was too thick it was not as effective as when it was of moderate thickness. We can now readily ascribe the true cause for the superiority of the plate machine in that when both sides were subjected to the action of the rubber, and if the sides were not too far apart, as would be the case in too thick a plate, the electrification would inductively act through the plate, or more properly, the capacity of the plate after it left the rubber would be less than in the case of the cylinder where only one side of the glass was charged by the friction, which charge would tend to bind to itself through the glass an opposite charge on the other side. There could not, therefore, be, when the glass left the rubber, anything like the elevation of p","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131049385","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590917
W. Costello
IN the early days of the cement industry, when grinding units were of relatively small capacity, motors of 75 h. p. were sufficiently large for power purposes. With the introduction of ball and compeb mills carrying heavy charges of metallic grinding medium, and the building of larger units, motors of much larger capacity were required. The modern tube mill uses a motor within the range of 200 to 600 h. p.
{"title":"Magnetic clutches in the cement industry","authors":"W. Costello","doi":"10.1109/JOAIEE.1922.6590917","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590917","url":null,"abstract":"IN the early days of the cement industry, when grinding units were of relatively small capacity, motors of 75 h. p. were sufficiently large for power purposes. With the introduction of ball and compeb mills carrying heavy charges of metallic grinding medium, and the building of larger units, motors of much larger capacity were required. The modern tube mill uses a motor within the range of 200 to 600 h. p.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"335 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115880313","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590916
H. W. Rogers
CEMENT mill machinery lends itself very readily to motor application, and while there are several direct-current motor installations, the majority of mills is driven by alternating-current induction motors.
水泥磨机很容易应用于电机，虽然有几个直流电机装置，但大多数磨机是由交流感应电机驱动的。
{"title":"The use of slip-ring induction motors and synchronous motors in cement mills","authors":"H. W. Rogers","doi":"10.1109/JOAIEE.1922.6590916","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590916","url":null,"abstract":"CEMENT mill machinery lends itself very readily to motor application, and while there are several direct-current motor installations, the majority of mills is driven by alternating-current induction motors.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122686281","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}
Pub Date : 1922-05-01DOI: 10.1109/JOAIEE.1922.6590919
W. Saunders
THE so-called St. Lawrence seaway is a proposition now seriously entertained, by which ocean ships may be provided with deep water navigation from the Atlantic Ocean through the great Lakes up to the head waters at Duluth. The depth proposed is from 25 to 30 feet. The cost, according to the figures given in a report of an international board of engineers, is in round numbers $270,000,000. These figures are based upon material and labor costs 80 per cent above pre-war prices and they include a hydroelectric power plant delivering about 1,700,000 horse power, this being a portion only of the potential power, which is estimated at between five and six million horse power.
{"title":"The St. Lawrence seaway","authors":"W. Saunders","doi":"10.1109/JOAIEE.1922.6590919","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6590919","url":null,"abstract":"THE so-called St. Lawrence seaway is a proposition now seriously entertained, by which ocean ships may be provided with deep water navigation from the Atlantic Ocean through the great Lakes up to the head waters at Duluth. The depth proposed is from 25 to 30 feet. The cost, according to the figures given in a report of an international board of engineers, is in round numbers $270,000,000. These figures are based upon material and labor costs 80 per cent above pre-war prices and they include a hydroelectric power plant delivering about 1,700,000 horse power, this being a portion only of the potential power, which is estimated at between five and six million horse power.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128574268","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}
Pub Date : 1922-04-01DOI: 10.1109/JOAIEE.1922.6591482
C. Hering
In liquid conductors, such as exist in some electric furnaces, and especially when high current densities are used, the writer has noticed that there are some new electromagnetic forces which do not appear to be accounted for by present mathematical treatments of the subject; as such very mobile conductors respond more readily to these forces than solid conductors do, they make the presence of such forces more evident; and as most of them presumably increase with the square of the current or the product of two currents, a force which under ordinary circumstances may be unnoticed may become quite formidable at such high current densities. Moreover, for a given current the flux encircling a conductor, which is what gives rise to these forces, becomes greater with diminishing cross sections.
{"title":"A new system of electromagnetic forces needed","authors":"C. Hering","doi":"10.1109/JOAIEE.1922.6591482","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6591482","url":null,"abstract":"In liquid conductors, such as exist in some electric furnaces, and especially when high current densities are used, the writer has noticed that there are some new electromagnetic forces which do not appear to be accounted for by present mathematical treatments of the subject; as such very mobile conductors respond more readily to these forces than solid conductors do, they make the presence of such forces more evident; and as most of them presumably increase with the square of the current or the product of two currents, a force which under ordinary circumstances may be unnoticed may become quite formidable at such high current densities. Moreover, for a given current the flux encircling a conductor, which is what gives rise to these forces, becomes greater with diminishing cross sections.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125430060","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}
Pub Date : 1922-04-01DOI: 10.1109/JOAIEE.1922.6591477
W. E. Forsythe
In a paper1 presented before the Illuminating Engineering Society in October 1921 at Rochester, the subject of color temperature and its relation to the quality of the emitted light for a number of different light sources was discussed. There it was shown that by the use of the color temperature of a light source a number is given which expresses the quality of the light of those sources to which the method applies.
{"title":"Color temperature and its relation to the quality of light","authors":"W. E. Forsythe","doi":"10.1109/JOAIEE.1922.6591477","DOIUrl":"https://doi.org/10.1109/JOAIEE.1922.6591477","url":null,"abstract":"In a paper1 presented before the Illuminating Engineering Society in October 1921 at Rochester, the subject of color temperature and its relation to the quality of the emitted light for a number of different light sources was discussed. There it was shown that by the use of the color temperature of a light source a number is given which expresses the quality of the light of those sources to which the method applies.","PeriodicalId":268640,"journal":{"name":"Journal of the American Institute of Electrical Engineers","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1922-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114855106","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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