Pub Date : 1930-11-01DOI: 10.1109/JAIEE.1930.6537002
E. Hansson
This paper relates how one operating company has endeavored to protect its lines and transformers from lightning by means of additional insulation, ground wires, and various types of lightning arresters, and reports the results obtained. While some improvement was apparent from each scheme, the most effective protection seems to be derived from ample insulation.
{"title":"Lightning protection from the operating company's point of view","authors":"E. Hansson","doi":"10.1109/JAIEE.1930.6537002","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537002","url":null,"abstract":"This paper relates how one operating company has endeavored to protect its lines and transformers from lightning by means of additional insulation, ground wires, and various types of lightning arresters, and reports the results obtained. While some improvement was apparent from each scheme, the most effective protection seems to be derived from ample insulation.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124848704","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537000
W. F. Sims, C. Axell
This paper describes the switching equipment and its arrangement in an outdoor switching center at 132, 66, and 12 kv., in connection with an installation of three-winding transformers, This installation is a junction point on an interconnected system, from which energy is distributed at the lower voltage. The development of the original 12-kv. installation with indoor type of equipment enclosed in metal housings and concrete cells is described and the reasons leading to its extension with metal-clad oil filled gear are discussed. A feature of this metal-clad oil filled installation is that it is laid out on an isolated phase basis with wide separation between phases, which is the first time that this arrangement has been attempted with this type of equipment. Included in the design are complete facilities for grounding and testing of the equipment, which to insure maximum safety in their use are fully interlocked. A brief discussion of costs as compared with indoor installations is also given.
{"title":"Abridgment of outdoor switching equipment at Northwest station Commonwealth Edison company, Chicago, Illinois","authors":"W. F. Sims, C. Axell","doi":"10.1109/JAIEE.1930.6537000","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537000","url":null,"abstract":"This paper describes the switching equipment and its arrangement in an outdoor switching center at 132, 66, and 12 kv., in connection with an installation of three-winding transformers, This installation is a junction point on an interconnected system, from which energy is distributed at the lower voltage. The development of the original 12-kv. installation with indoor type of equipment enclosed in metal housings and concrete cells is described and the reasons leading to its extension with metal-clad oil filled gear are discussed. A feature of this metal-clad oil filled installation is that it is laid out on an isolated phase basis with wide separation between phases, which is the first time that this arrangement has been attempted with this type of equipment. Included in the design are complete facilities for grounding and testing of the equipment, which to insure maximum safety in their use are fully interlocked. A brief discussion of costs as compared with indoor installations is also given.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127720359","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537005
R. Wilbraham
This paper describes the problems attending the laying of eight 75-kv. submarine cables across the Delaware River in the vicinity of Wilmington. To insure against injury, the cables were laid in a backfilled trench the depth of which was determined by experiments. By terminating the cable on platforms just inside the pierhead lines it was possible to use a cable of 4050 ft. (maximum length possible for one of the accepted manufacturers to make) as compared with a river width of 5100 ft. To avoid the excessive healing of that portion of the cable out of water at the cable platforms, the steel armor was replaced by one of nonmagnetic material so designed as to avoid corrosion and electrolysis. The problem of laying the limited lengths of cable in the trench with minimum deviation was satisfactorily met with specially developed methods. The construction work was completed in five months, under winter conditions and with river traffic heavy.
{"title":"Abridgment of 75-kv. submarine cable for deep water station","authors":"R. Wilbraham","doi":"10.1109/JAIEE.1930.6537005","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537005","url":null,"abstract":"This paper describes the problems attending the laying of eight 75-kv. submarine cables across the Delaware River in the vicinity of Wilmington. To insure against injury, the cables were laid in a backfilled trench the depth of which was determined by experiments. By terminating the cable on platforms just inside the pierhead lines it was possible to use a cable of 4050 ft. (maximum length possible for one of the accepted manufacturers to make) as compared with a river width of 5100 ft. To avoid the excessive healing of that portion of the cable out of water at the cable platforms, the steel armor was replaced by one of nonmagnetic material so designed as to avoid corrosion and electrolysis. The problem of laying the limited lengths of cable in the trench with minimum deviation was satisfactorily met with specially developed methods. The construction work was completed in five months, under winter conditions and with river traffic heavy.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123268523","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537006
T. Rosebrugh
This paper deals mainly with a more general and systematic method than has hitherto been used in handling certain classes of problems involving steady-state transmission calculations in terms of real quantities.
{"title":"Abstract of the analytics of transmission calculations","authors":"T. Rosebrugh","doi":"10.1109/JAIEE.1930.6537006","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537006","url":null,"abstract":"This paper deals mainly with a more general and systematic method than has hitherto been used in handling certain classes of problems involving steady-state transmission calculations in terms of real quantities.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130253313","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537014
W. Kouwenhoven, C. L. Lemmon
This investigation was undertaken in order to determine the conditions of atmosphere under which the air capacitor may be regarded as having zero loss. A special guarded and shielded test capacitor was constructed having quartz insulation between the high-voltage and guard plates and low-loss molded Bakelite insulators between the measuring and guard plates. This capacitor was enclosed in a metal box and subjected to various conditions of temperature and humidity. Readings were made of continuous conduction current and a-c. phase defect angle. The measuring instruments used were the most sensitive available. A D'Arsonval galvanometer having a sensitivity of 1.5 × 10−12 amperes was used in the continuous current work and a Wien bridge sensitive to three seconds in the a-c. measurements. A gradient of approximately 4000 volts per cm. was used in all tests. Measurements were made of the effect of humidity at temperatures from 60 deg. fahr. to 100 deg. fahr. and in each run the humidity was varied from approximately 40 to 95 per cent. Readings were made of continuous conduction current and the phase angle of the test capacitor was compared with that of a standard air capacitor in which the humidity was maintained at a low value. It was found that the conduction was zero and the phase defect angle of an air capacitor was less than three seconds for values of humidity below 90 per cent. Observations were made also of the effect of the introduction of ions and dust particles into the condenser chamber.
{"title":"Abridgment of phase defect angle of an air capacitor","authors":"W. Kouwenhoven, C. L. Lemmon","doi":"10.1109/JAIEE.1930.6537014","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537014","url":null,"abstract":"This investigation was undertaken in order to determine the conditions of atmosphere under which the air capacitor may be regarded as having zero loss. A special guarded and shielded test capacitor was constructed having quartz insulation between the high-voltage and guard plates and low-loss molded Bakelite insulators between the measuring and guard plates. This capacitor was enclosed in a metal box and subjected to various conditions of temperature and humidity. Readings were made of continuous conduction current and a-c. phase defect angle. The measuring instruments used were the most sensitive available. A D'Arsonval galvanometer having a sensitivity of 1.5 × 10−12 amperes was used in the continuous current work and a Wien bridge sensitive to three seconds in the a-c. measurements. A gradient of approximately 4000 volts per cm. was used in all tests. Measurements were made of the effect of humidity at temperatures from 60 deg. fahr. to 100 deg. fahr. and in each run the humidity was varied from approximately 40 to 95 per cent. Readings were made of continuous conduction current and the phase angle of the test capacitor was compared with that of a standard air capacitor in which the humidity was maintained at a low value. It was found that the conduction was zero and the phase defect angle of an air capacitor was less than three seconds for values of humidity below 90 per cent. Observations were made also of the effect of the introduction of ions and dust particles into the condenser chamber.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121561586","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537012
E. E. Dreese
Many induction motors do not have the smooth speed — torque curves which are to be expected from elementary theory. Many motors at no-load show a tendency to run at some speed far below that normally to be expected. This is sometimes called “sub-synchronous” speed; or the motor is said to be “crawling.” In the present paper, one cause of this phenomenon is explained. It is found that certain combination of phases, rotor slots, and poles cause the motor to run as a synchronous motor at some intermediate speed between zero and normal no-load induction-motor speed. This effect has been christened the “synchronous-motor effect” in induction machines and is shown to be due to the locking of harmonic fields generated by the stator winding with similar harmonic fields generated by the rotor windings. A method is given for avoiding this trouble by the proper selection of the number of rotor slots.
{"title":"Abridgment of synchronous motor effects in induction machines","authors":"E. E. Dreese","doi":"10.1109/JAIEE.1930.6537012","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537012","url":null,"abstract":"Many induction motors do not have the smooth speed — torque curves which are to be expected from elementary theory. Many motors at no-load show a tendency to run at some speed far below that normally to be expected. This is sometimes called “sub-synchronous” speed; or the motor is said to be “crawling.” In the present paper, one cause of this phenomenon is explained. It is found that certain combination of phases, rotor slots, and poles cause the motor to run as a synchronous motor at some intermediate speed between zero and normal no-load induction-motor speed. This effect has been christened the “synchronous-motor effect” in induction machines and is shown to be due to the locking of harmonic fields generated by the stator winding with similar harmonic fields generated by the rotor windings. A method is given for avoiding this trouble by the proper selection of the number of rotor slots.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123466838","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537003
Roy B. Ashbrook, F. B. Doolittle
This paper gives a general description of the Southern California Edison Company's communication system which not only meets the requirements of load dispatching but also serves to bring about close cooperation between the outlying district forces and their directing heads at division headquarters and in the general office. The detail of development and construction by the company of the “serjdetour” arrester is made public for the first time. This piece of equipment has made possible a protective system which not only prevents damage to valuable communication equipment in stations for the extreme case of actual contact between telephone lines and power lines but also preserves continuity of communication service after power system disturbances which create surges of considerable magnitude on inductively exposed telephone lines have taken place. A brief outline is presented of the standardized assemblies of telephone equipment into units which are adaptable to wide variations in requirements by the use of different combinations and quantities of standard units. The communication building, the center of a telephone system, is described, as is also the method of handling traffic through this point. A brief description of the equipment for making initial tests on new lines and maintenance of existing facilities is given.
{"title":"Abridgment of the communication system of the Southern California Edison Company, Ltd.","authors":"Roy B. Ashbrook, F. B. Doolittle","doi":"10.1109/JAIEE.1930.6537003","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537003","url":null,"abstract":"This paper gives a general description of the Southern California Edison Company's communication system which not only meets the requirements of load dispatching but also serves to bring about close cooperation between the outlying district forces and their directing heads at division headquarters and in the general office. The detail of development and construction by the company of the “serjdetour” arrester is made public for the first time. This piece of equipment has made possible a protective system which not only prevents damage to valuable communication equipment in stations for the extreme case of actual contact between telephone lines and power lines but also preserves continuity of communication service after power system disturbances which create surges of considerable magnitude on inductively exposed telephone lines have taken place. A brief outline is presented of the standardized assemblies of telephone equipment into units which are adaptable to wide variations in requirements by the use of different combinations and quantities of standard units. The communication building, the center of a telephone system, is described, as is also the method of handling traffic through this point. A brief description of the equipment for making initial tests on new lines and maintenance of existing facilities is given.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132015535","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537010
A. Rossman
The drive unit of this system consists of a constant-speed a-c. motor supplemented by an adjustable-speed d-c. machine of much smaller size. Both rotor and frame of the a-c. motor are mounted on bearings. The d-c. machine is mechanically connected to the frame of the a-c. motor so that the d-c. machine may drive or be driven by the frame. The d-c. machine is electrically connected through a motor-generator set of equivalent rating, to the source of a-c. energy. The shaft speed of the a-c. motor is increased above the fixed speed by rotating the frame of the a-c. motor in the same direction as the rotor, and it is decreased by rotating the frame in the opposite direction. The direction of rotation and speed are governed by adjusting the voltage impressed on the armature of the d-c. drive machine by the generator of the motor-generator set. When the unit is used to drive fans, the speed range is obtained by a combination of armature voltage control and field control of the d-c. drive machine. This permits a still further reduction in the rating of the d-c. drive machine so that for comparatively wide ranges of speed, it forms but a small percentage of the total drive unit rating. Twenty-four units of this type, aggregating 7020 hp., are now being built for Powerton Power Station for driving forced and induced draft fans. This system of fan drive is being installed in preference to the two-speed squirrel-cage type induction motor system previously used, because it shows large savings in energy, costs little more, and provides a simple method of fan control which permits the adoption of a simplified system of automatic combustion control. The versatility of the system is further illustrated by a description of a 2500-hp. unit of this type designed to drive a high-pressure reciprocating boiler feed pump. During the first seven months of 1930, orders were placed for 35 of these units ranging in size from 166-hp. to 2500-hp., aggregating 16,000 hp. for installation in four different power stations.
{"title":"Abridgment of a new system of speed control for A-C. motors","authors":"A. Rossman","doi":"10.1109/JAIEE.1930.6537010","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537010","url":null,"abstract":"The drive unit of this system consists of a constant-speed a-c. motor supplemented by an adjustable-speed d-c. machine of much smaller size. Both rotor and frame of the a-c. motor are mounted on bearings. The d-c. machine is mechanically connected to the frame of the a-c. motor so that the d-c. machine may drive or be driven by the frame. The d-c. machine is electrically connected through a motor-generator set of equivalent rating, to the source of a-c. energy. The shaft speed of the a-c. motor is increased above the fixed speed by rotating the frame of the a-c. motor in the same direction as the rotor, and it is decreased by rotating the frame in the opposite direction. The direction of rotation and speed are governed by adjusting the voltage impressed on the armature of the d-c. drive machine by the generator of the motor-generator set. When the unit is used to drive fans, the speed range is obtained by a combination of armature voltage control and field control of the d-c. drive machine. This permits a still further reduction in the rating of the d-c. drive machine so that for comparatively wide ranges of speed, it forms but a small percentage of the total drive unit rating. Twenty-four units of this type, aggregating 7020 hp., are now being built for Powerton Power Station for driving forced and induced draft fans. This system of fan drive is being installed in preference to the two-speed squirrel-cage type induction motor system previously used, because it shows large savings in energy, costs little more, and provides a simple method of fan control which permits the adoption of a simplified system of automatic combustion control. The versatility of the system is further illustrated by a description of a 2500-hp. unit of this type designed to drive a high-pressure reciprocating boiler feed pump. During the first seven months of 1930, orders were placed for 35 of these units ranging in size from 166-hp. to 2500-hp., aggregating 16,000 hp. for installation in four different power stations.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133131171","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537017
W. T. Dempsey
At the National Conference on Street and Highway Safety, in the report for 1929, statement is made that 33,600 people were killed and 1,200,000 were injured on the streets and highways of the country for that year. It was also found that more than 50 per cent of these accidents occurred at street or highway intersections, which are accordingly rated as the most hazardous part of the roadway. To reduce these figures, ever mounting year by year, the intersection should be attacked vigorously by all those interested in an effort to reduce the number of accidents occurring here. The respective number of accidents occurring in daylight and those occurring at night is unknown, but experience has shown that brightly lighted intersections will in a great measure reduce the hazard at night.
{"title":"Illumination items: Street lighting at intersections","authors":"W. T. Dempsey","doi":"10.1109/JAIEE.1930.6537017","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537017","url":null,"abstract":"At the National Conference on Street and Highway Safety, in the report for 1929, statement is made that 33,600 people were killed and 1,200,000 were injured on the streets and highways of the country for that year. It was also found that more than 50 per cent of these accidents occurred at street or highway intersections, which are accordingly rated as the most hazardous part of the roadway. To reduce these figures, ever mounting year by year, the intersection should be attacked vigorously by all those interested in an effort to reduce the number of accidents occurring here. The respective number of accidents occurring in daylight and those occurring at night is unknown, but experience has shown that brightly lighted intersections will in a great measure reduce the hazard at night.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115617914","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 : 1930-11-01DOI: 10.1109/JAIEE.1930.6537004
E. Boehne
Experience has shown that rotating machinery connected directly to overhead lines is more vulnerable to surges than many other types of apparatus. This fact, together with a desire on the part of some to connect important units to the line in this manner, has necessitated a study of the protection problem. Such a study is here described, showing oscillograms taken when steep voltage surges were applied to machine windings measuring internal voltages to ground which are 200 per cent of the voltage allowed by the terminal lightning arrester. A simple traveling wave analysis of these oscillations is developed, which has successfully explained the pecularities of over 400 oscillograms taken under various terminal conditions. Practical methods of eliminating the oscillations with neutral impedance are outlined in the light of the theory developed, and oscillographic evidence supporting their reliability is given. A generalized theory of neutral protection is proposed. The importance of wave-front, surge impedance of incoming line, arrester resistance, and other factors is discussed. Methods for protection of the turn insulation and the insulation to ground of such machines are suggested, showing that the lightning arrester limits only the potential of waves entering the machine and cannot control oscillations which may take place within the machine. The advantages of thyrite as a neutral resistor are pointed out in connection with the short-circuit protection, telephone interference, and lightning protection problems of such machines. In Appendix A, the test circuits and methods used in the laboratory are discussed in relation to actual field conditions.
{"title":"Abridgment of voltage oscillations in armature windings under lightning impulses — I","authors":"E. Boehne","doi":"10.1109/JAIEE.1930.6537004","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6537004","url":null,"abstract":"Experience has shown that rotating machinery connected directly to overhead lines is more vulnerable to surges than many other types of apparatus. This fact, together with a desire on the part of some to connect important units to the line in this manner, has necessitated a study of the protection problem. Such a study is here described, showing oscillograms taken when steep voltage surges were applied to machine windings measuring internal voltages to ground which are 200 per cent of the voltage allowed by the terminal lightning arrester. A simple traveling wave analysis of these oscillations is developed, which has successfully explained the pecularities of over 400 oscillograms taken under various terminal conditions. Practical methods of eliminating the oscillations with neutral impedance are outlined in the light of the theory developed, and oscillographic evidence supporting their reliability is given. A generalized theory of neutral protection is proposed. The importance of wave-front, surge impedance of incoming line, arrester resistance, and other factors is discussed. Methods for protection of the turn insulation and the insulation to ground of such machines are suggested, showing that the lightning arrester limits only the potential of waves entering the machine and cannot control oscillations which may take place within the machine. The advantages of thyrite as a neutral resistor are pointed out in connection with the short-circuit protection, telephone interference, and lightning protection problems of such machines. In Appendix A, the test circuits and methods used in the laboratory are discussed in relation to actual field conditions.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130287581","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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