Pub Date : 1988-10-30DOI: 10.1109/INTLEC.1988.22398
J. Higginbottom, H. H. lea
The authors address the increasing impact of electromagnetic compatibility (EMC) requirements on the design of modern telecommunications switching equipment. Following a review of the environmental factors which have given rise to the increase of work on EMC, the impending European EMC Directive is introduced and compared with the legislative requirements in the US. The specific problems associated with the EMC characterization and formal testing of large distributed telecommunications installations are discussed, drawing on examples of various system configurations to illustrate particular aspects. A proposed method of testing is presented which offers a controlled and repeatable approach to RF emission and immunity testing within a total quality environment, enabling system-level emission characteristics to be determined, and the effect of subsequent product updates and enhancements to be predicted over a normal installation life of 20 years.<>
{"title":"EMC considerations for telecommunications switching centres","authors":"J. Higginbottom, H. H. lea","doi":"10.1109/INTLEC.1988.22398","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22398","url":null,"abstract":"The authors address the increasing impact of electromagnetic compatibility (EMC) requirements on the design of modern telecommunications switching equipment. Following a review of the environmental factors which have given rise to the increase of work on EMC, the impending European EMC Directive is introduced and compared with the legislative requirements in the US. The specific problems associated with the EMC characterization and formal testing of large distributed telecommunications installations are discussed, drawing on examples of various system configurations to illustrate particular aspects. A proposed method of testing is presented which offers a controlled and repeatable approach to RF emission and immunity testing within a total quality environment, enabling system-level emission characteristics to be determined, and the effect of subsequent product updates and enhancements to be predicted over a normal installation life of 20 years.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116078085","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22330
D. Berndt
Hydrogen and oxygen evolution are unavoidable secondary reactions in lead-acid batteries and these reactions imply increased heat production in the cell. Gas evolution is discussed with respect to open-circuit situations, float charging, and cycling. Heat-production processes are then considered, in connection with the heat of reaction, the Joule effect, and heat production during floating. Heat dissipation is also considered, and implications for battery cycling are discussed.<>
{"title":"Valve regulated lead acid batteries-gas and heat management","authors":"D. Berndt","doi":"10.1109/INTLEC.1988.22330","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22330","url":null,"abstract":"Hydrogen and oxygen evolution are unavoidable secondary reactions in lead-acid batteries and these reactions imply increased heat production in the cell. Gas evolution is discussed with respect to open-circuit situations, float charging, and cycling. Heat-production processes are then considered, in connection with the heat of reaction, the Joule effect, and heat production during floating. Heat dissipation is also considered, and implications for battery cycling are discussed.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122863526","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22337
I.C. Baeringer, F. Tarantino, E. L. Daniels
The authors describe an ultrasonic grid growth measurement technique that significantly minimizes the number of test cells required for stationary lead-acid battery life testing and provides growth curves that are based on the same plates throughout the test. At four different temperatures, three stationary cells are maintained at each temperature at 80 mV above the PbO/sub 2//PbSO/sub 4/ equilibrium potential. Positive plate growth and cell capacities are plotted so that activation energies can be obtained to permit room-temperature life predictions. The actual variation between mechanical and ultrasonic measurements of positive plate growth up to date indicates the difference to be less than 1%. Along with the obvious advantage that a nondestructive plate growth measuring technique provides, the accuracy and other advantages and limitations of the ultrasonic technique are discussed.<>
{"title":"Lead-acid battery life testing and ultrasonics","authors":"I.C. Baeringer, F. Tarantino, E. L. Daniels","doi":"10.1109/INTLEC.1988.22337","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22337","url":null,"abstract":"The authors describe an ultrasonic grid growth measurement technique that significantly minimizes the number of test cells required for stationary lead-acid battery life testing and provides growth curves that are based on the same plates throughout the test. At four different temperatures, three stationary cells are maintained at each temperature at 80 mV above the PbO/sub 2//PbSO/sub 4/ equilibrium potential. Positive plate growth and cell capacities are plotted so that activation energies can be obtained to permit room-temperature life predictions. The actual variation between mechanical and ultrasonic measurements of positive plate growth up to date indicates the difference to be less than 1%. Along with the obvious advantage that a nondestructive plate growth measuring technique provides, the accuracy and other advantages and limitations of the ultrasonic technique are discussed.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134265723","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22366
J. Gropper
The author presents a tradeoff study between photovoltaic power systems and closed-cycle vapor turbogenerators for telecommunications applications in Nigeria. Issues discussed are system availability requirements, potential solar-cell problems, and economic factors. It is concluded that, due to its inherent high reliability and high-starting capability in cold standby configurations, the closed-cycle vapor turbogenerator, either in stand-alone or in a solar hybrid configuration, is frequently the system of choice because it is a more cost-effective alternative for telecommunications applications which require high availability and minimum maintenance.<>
{"title":"Technical and economic trade-off study between photovoltaic power systems and closed cycle vapor turbogenerators","authors":"J. Gropper","doi":"10.1109/INTLEC.1988.22366","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22366","url":null,"abstract":"The author presents a tradeoff study between photovoltaic power systems and closed-cycle vapor turbogenerators for telecommunications applications in Nigeria. Issues discussed are system availability requirements, potential solar-cell problems, and economic factors. It is concluded that, due to its inherent high reliability and high-starting capability in cold standby configurations, the closed-cycle vapor turbogenerator, either in stand-alone or in a solar hybrid configuration, is frequently the system of choice because it is a more cost-effective alternative for telecommunications applications which require high availability and minimum maintenance.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131619244","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22365
J. Henderson
The author describes the current developments in AC standby power systems in British Telecom to support its communications network in the 1990s. The design of standby systems and standby engine sets is discussed for systems ranging from 5 MW to 1.5 kW. It is concluded that system designs and specifications have been produced to define a modern, flexible, and highly reliable standby power system for the major switching centres. At the lower end of the scale interest is concentrated in small self-contained packaged engine sets which can be rapidly installed in a minimum of space.<>
{"title":"AC power systems in British Telecom for the 1990s","authors":"J. Henderson","doi":"10.1109/INTLEC.1988.22365","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22365","url":null,"abstract":"The author describes the current developments in AC standby power systems in British Telecom to support its communications network in the 1990s. The design of standby systems and standby engine sets is discussed for systems ranging from 5 MW to 1.5 kW. It is concluded that system designs and specifications have been produced to define a modern, flexible, and highly reliable standby power system for the major switching centres. At the lower end of the scale interest is concentrated in small self-contained packaged engine sets which can be rapidly installed in a minimum of space.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123588847","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22361
R. Prudhoe, D. Longland
The authors outline Telecom Australia's development work and achievements in the use of the relatively high latent heat of fusion and thermal storage of phase change chemicals (PCC). Novel PCC applications, which have been successfully implemented into the Australian telecommunications network, relate to the use of PCC encapsulated in 1 m long plastic tubes to provide room temperature control after failure of the normal cooling plant. Experience has shown that the use of PCC in suitable installations can provide a simple, low-cost, maintenance-free solution to protect temperature-sensitive electronic equipment from excessive temperature rise during times of loss of normal cooling. The authors introduce a novel type of energy-conserving cooling system currently under testing and evaluation. This system combines the use of a variable-volume fresh-air cycle for normal operation on cool days, with refrigeration-type cooling on hot days, coupled with a PCC thermal storage to provide reserve cooling, for enhanced reliability.<>
{"title":"The use of phase change chemicals for reserve cooling and energy conserving cooling systems in telecommunication equipment buildings","authors":"R. Prudhoe, D. Longland","doi":"10.1109/INTLEC.1988.22361","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22361","url":null,"abstract":"The authors outline Telecom Australia's development work and achievements in the use of the relatively high latent heat of fusion and thermal storage of phase change chemicals (PCC). Novel PCC applications, which have been successfully implemented into the Australian telecommunications network, relate to the use of PCC encapsulated in 1 m long plastic tubes to provide room temperature control after failure of the normal cooling plant. Experience has shown that the use of PCC in suitable installations can provide a simple, low-cost, maintenance-free solution to protect temperature-sensitive electronic equipment from excessive temperature rise during times of loss of normal cooling. The authors introduce a novel type of energy-conserving cooling system currently under testing and evaluation. This system combines the use of a variable-volume fresh-air cycle for normal operation on cool days, with refrigeration-type cooling on hot days, coupled with a PCC thermal storage to provide reserve cooling, for enhanced reliability.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123676341","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22391
C. Leleu, J. Gropper
Studies for amelioration of the telecommunication network in and between the islands of the Federal Islamic Republic of Comoros were performed in 1980. The economic comparison of various possible sources of energy included solar and wind, and the photovoltaic generator was chosen as the primary power source for remote stations. The approach for system sizing was based on utilizing a daily simulation procedure, starting from insolation data obtained from many meteorological stations. Simulation tests performed on a hybrid generator provided information which was later proved correct by field results during operation. It is concluded that the use of a fuel-operated generator, such as the CCVT (closed-cycle vapor turbogenerator) with power adapted to partial recharge of batteries, has proved an optimum solution in conditions of insufficient insolation of sites located above sea level.<>
{"title":"Design criteria and practical experience with hybrid systems using photovoltaic cells and closed cycle vapor turbogenerators","authors":"C. Leleu, J. Gropper","doi":"10.1109/INTLEC.1988.22391","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22391","url":null,"abstract":"Studies for amelioration of the telecommunication network in and between the islands of the Federal Islamic Republic of Comoros were performed in 1980. The economic comparison of various possible sources of energy included solar and wind, and the photovoltaic generator was chosen as the primary power source for remote stations. The approach for system sizing was based on utilizing a daily simulation procedure, starting from insolation data obtained from many meteorological stations. Simulation tests performed on a hybrid generator provided information which was later proved correct by field results during operation. It is concluded that the use of a fuel-operated generator, such as the CCVT (closed-cycle vapor turbogenerator) with power adapted to partial recharge of batteries, has proved an optimum solution in conditions of insufficient insolation of sites located above sea level.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125364826","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22371
J. McKay
It is shown that in large buildings used by the Bell Regional Companies, conventional and modular cooling systems can handle up to about 1500 W for 2100 mm-high, 660 mm-wide frames, 2200 W/m/sup 2/ of floor space. This is for occupied spaces in which indoor air temperature is to be kept below 38 degrees C long term and 40 degrees C short term. For unoccupied spaces somewhat higher heat loads could be handled with the use of high-velocity air in closed cabinets. Above 2200 W/m/sup 2/ and certainly above 5400 W/m/sup 2/ heat dissipation, it is argued that designers should consider the use of water or some other high-heat-capacity cooling fluid instead of air. Smaller buildings do not normally utilize ducting or ceiling plenums, and are thus limited to around 430 W/m/sup 2/ of floor space. If ducts or plenums to allow more air flow past or through the equipment frames were used, the same heat dissipation levels as are feasible in large buildings could be achieved. For outdoor cabinets, some increase in heat dissipation beyond existing AT&T designs could be accomplished through passive measures such as shading, use of fins, and improved reflecting paints.<>
{"title":"Coping with very high heat loads in electronic telephone systems of the future","authors":"J. McKay","doi":"10.1109/INTLEC.1988.22371","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22371","url":null,"abstract":"It is shown that in large buildings used by the Bell Regional Companies, conventional and modular cooling systems can handle up to about 1500 W for 2100 mm-high, 660 mm-wide frames, 2200 W/m/sup 2/ of floor space. This is for occupied spaces in which indoor air temperature is to be kept below 38 degrees C long term and 40 degrees C short term. For unoccupied spaces somewhat higher heat loads could be handled with the use of high-velocity air in closed cabinets. Above 2200 W/m/sup 2/ and certainly above 5400 W/m/sup 2/ heat dissipation, it is argued that designers should consider the use of water or some other high-heat-capacity cooling fluid instead of air. Smaller buildings do not normally utilize ducting or ceiling plenums, and are thus limited to around 430 W/m/sup 2/ of floor space. If ducts or plenums to allow more air flow past or through the equipment frames were used, the same heat dissipation levels as are feasible in large buildings could be achieved. For outdoor cabinets, some increase in heat dissipation beyond existing AT&T designs could be accomplished through passive measures such as shading, use of fins, and improved reflecting paints.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131075567","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22386
Y. Nagai, Y. Tomokuni, K. Hirachi
It is shown that the 48 V, 100 A switching power supply unit possesses excellent characteristics including compactness, light weight, high efficiency, and a high power factor. It is also shown that by combining the power supply with a CPU-controlled monitor, it is possible to configure an uninterruptible power supply system for communications which has extremely high operability and reliability. This monitor has various control and display functions such as control of the number of operating units in accordance with the load current, the calculation and indication of residual battery capacity, and charging control based on residual capacity.<>
{"title":"A 48 V 100 A switching power supply unit and its application","authors":"Y. Nagai, Y. Tomokuni, K. Hirachi","doi":"10.1109/INTLEC.1988.22386","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22386","url":null,"abstract":"It is shown that the 48 V, 100 A switching power supply unit possesses excellent characteristics including compactness, light weight, high efficiency, and a high power factor. It is also shown that by combining the power supply with a CPU-controlled monitor, it is possible to configure an uninterruptible power supply system for communications which has extremely high operability and reliability. This monitor has various control and display functions such as control of the number of operating units in accordance with the load current, the calculation and indication of residual battery capacity, and charging control based on residual capacity.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129577688","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 : 1988-10-30DOI: 10.1109/INTLEC.1988.22352
K. Kuwabara, E. Hiyachika
Novel switched-capacitor (SC) DC-DC converters are derived from three basic SC DC-DC converters. The converter outputs can be regulated by changing the duty ratio of the transistor switch. These converters have features not found in conventional switching regulators (buck, boost, and buck-boost converters). Of these converters, the voltage polarity inverting converter is expected to be widely used for small-size, small-power units because it has the following features: (1) nonpulsating input current; (2) overcurrent protection can be added; and (3) multistage connection of output circuits enables the converter to be used as a step-up, step-down converter.<>
{"title":"Switched-capacitor DC-DC converters","authors":"K. Kuwabara, E. Hiyachika","doi":"10.1109/INTLEC.1988.22352","DOIUrl":"https://doi.org/10.1109/INTLEC.1988.22352","url":null,"abstract":"Novel switched-capacitor (SC) DC-DC converters are derived from three basic SC DC-DC converters. The converter outputs can be regulated by changing the duty ratio of the transistor switch. These converters have features not found in conventional switching regulators (buck, boost, and buck-boost converters). Of these converters, the voltage polarity inverting converter is expected to be widely used for small-size, small-power units because it has the following features: (1) nonpulsating input current; (2) overcurrent protection can be added; and (3) multistage connection of output circuits enables the converter to be used as a step-up, step-down converter.<<ETX>>","PeriodicalId":169486,"journal":{"name":"10th International Telecommunications Energy Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122145939","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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