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Telecommunications Energy Conference, 1989. INTELEC '89. Conference Proceedings., Eleventh International

Date 15-18 Oct. 1989

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Displaying Results 1 - 25 of 129
  • The effects of grid design variables in valve regulated standby batteries

    Publication Year: 1989, Page(s):6.2/1 - 6.2/5 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (311 KB)

    Positive grid corrosion is one of the major causes of lead-acid battery performance failures. This phenomenon occurs slowly under normal conditions, so that any modifications of the grid design should be undertaken only after an extended testing period. It is very desirable to accelerate simulated battery life in order to obtain data on the status of corrosion, to correct problems, and ultimately ... View full abstract»

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  • INTELEC 89. Eleventh International Telecommunications Energy Conference. Conference Proceedings (Cat. No.89CH2849-8)

    Publication Year: 1989
    Request permission for commercial reuse | PDF file iconPDF (11 KB)
    Freely Available from IEEE
  • Modelling and analysis of lead acid battery operation

    Publication Year: 1989, Page(s):23.3/1 - 23.3/6 vol.2
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    A model of the lead-acid battery is presented based on a simple description of electrochemical reactions. Models of the electromotive force, the internal resistance, and the gassing phenomenon are detailed. Good agreement between simulation and measurement has led to the validation of a model for discharge and for the charge preceding gassing at constant temperature. As regards the calculation of ... View full abstract»

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  • Modern digital exchanges in old telecom power environment

    Publication Year: 1989, Page(s):21.2/1 - 21.2/3 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    When new digital telephone exchanges are installed in old telecommunications buildings, many different problems arise regarding the DC power supply of the new exchanges. The authors describe technical and economic considerations necessary to achieve optimal solutions. Based on a comparison between the use of adaptation systems and a modern power supply system, it is concluded that there are consid... View full abstract»

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  • Linear variable inductor in DC current sensors utilized in telecom solar battery chargers

    Publication Year: 1989, Page(s):23.2/1 - 23.2/3 vol.2
    Cited by:  Papers (8)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    The author describes an LVI (linear variable inductor) current sensor proposed for high-reliability solar-powered telecommunication battery chargers. Its design principle and implementation are discussed. In the proposed LVI sensor, high sensitivity at low current has been achieved by applying a prepolarization field to the sensor core structure. This sensor is shown to be superior to the other po... View full abstract»

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  • Trial results, performance and economic benefits of lowered cell float potential in a working central office environment

    Publication Year: 1989, Page(s):12.1/1 - 12.1/6 vol.1
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    The authors discuss results of room-temperature tests at lowered float potentials on cell and battery float characteristics. Also, they describe performance results and quantify improvements achieved in actual battery reserve time, resulting from the introduction of an additional cell into an existing -48 V DC telecommunication battery plant in a working telephone central office. Finally, they dis... View full abstract»

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  • Effective diagnosis methods for air-conditioning equipment in telecommunications buildings

    Publication Year: 1989, Page(s):21.1/1 - 21.1/7 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    Effective diagnosis methods to improve the efficiency and accuracy of air-conditioning equipment maintenance work developed at NTT are described. These methods consist of the refrigerant cycle diagnosis of air-conditioners and the deterioration diagnosis of pumps and ventilators. These technologies reduce manpower requirements and improve the accuracy of maintenance work on air-conditioning system... View full abstract»

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  • Plastic bonded electrodes in nickel cadmium batteries

    Publication Year: 1989, Page(s):23.1/1 - 23.1/3 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    The characteristics of nickel-cadmium batteries with plastic bonded electrodes are presented. The active materials, nickel hydroxide and cadmium oxide, are mixed with plastic powder and a solvent to form a thick paste. The paste is extruded or rolled into a strip, which is then laminated to current collectors of pure nickel or nickel-plated steel. The manufacturing process allows more efficient us... View full abstract»

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  • Integrated power station [power supply]

    Publication Year: 1989, Page(s):11.8/1 - 11.8/7 vol.1
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    The authors describes an integrated power station which supplies both uninterrupted DC power and AC power at a regulated voltage by UPS (uninterruptible power supply) or line conditioner, depending on which is more appropriate for the site requirements. The station is contained in a single mechanical structure, a standard 19 in. rack. The station is very versatile from both the power and the insta... View full abstract»

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  • ZVS PWM converter-utilizing partial resonance

    Publication Year: 1989, Page(s):20.9/1 - 20.9/6 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    Fixed-frequency PWM (pulse-width modulation) zero-voltage switching (ZVS) conversion was realized by applying partial resonance to the forward converter. The advantages of this technique are less EMI (electromagnetic interference) and power dissipation in the switching transistor, the ability to utilize a conventional PWM control method, ease of suppression of the EMI influence due to fixed-freque... View full abstract»

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  • Sealed lead-acid batteries gas-recombination mechanisms

    Publication Year: 1989, Page(s):17.4/1 - 17.4/5 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The oxygen recombination mechanism which allows lead batteries to be sealed, and causes of water loss, have been closely studied in order to make the large-scale manufacture of this battery possible and to ensure that it develops into a safe mass-consumer product. A detailed theoretical description of the recombination mechanisms is presented View full abstract»

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  • Two techniques in comparison for UPS's low generation of harmonic currents in the network

    Publication Year: 1989, Page(s):14.7/1 - 14.7/6 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    The solutions to the problem of sinusoidal wave distortion caused by voltage and current harmonics are described for two families of currently mass-produced uninterruptible power supply (UPS) systems. The first UPS range is three-phase from 10 to 300 kVA, realized by a fully controlled thyristor bridge where the generated harmonics distortion reduction is obtained by means of standard filters. The... View full abstract»

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  • High crest factor loads on UPS systems

    Publication Year: 1989, Page(s):19.8/1 - 19.8/4 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    Some of the problems that can be caused by high crest factor (HCF) in UPSs (uninterruptible power supply systems) are outlined. It is noted that the effect of a high crest factor load on a UPS will depend on the technique used to generate the UPS output voltage. Ways to avoid problems with HCF are discussed, including load balancing, the use of a fully rated neutral conductor, the measurement of v... View full abstract»

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  • A new dual reserve power system for small telephone exchanges

    Publication Year: 1989, Page(s):10.2/1 - 10.2/4 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    The author describes a new small DC power system that employs an aluminum air battery as an emergency standby reserve, in a dual reserve configuration. The background to the development is presented along with a simplified description of the system operation. Also considered are the influence of the aluminum air battery on the converter and the system efficiency and reliability View full abstract»

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  • Multiprocessor control of a renewable energy micro-power station

    Publication Year: 1989, Page(s):15.9/1 - 15.9/6 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    The authors describe the real-time energy management of a multigenerator micro-power station which is intended to supply an isolated village in Senegal using wind and solar power. Laboratory studies have led to a complete understanding of the windmill potential in Dakar, of the functioning and optimization of each generator, and of the transfer of available energy to the receptors. The preliminary... View full abstract»

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  • Photovoltaic generator for telephone boxes

    Publication Year: 1989, Page(s):22.5/1 - 22.5/2 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    The authors describe a nonconventional power supply for the illumination of call-boxes. The system uses a photovoltaic module to supply the energy required. Electronic control monitors give the status of different components of the system. Economic comparison with grid connection indicates a considerable saving in installation and running costs View full abstract»

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  • A new 48 V 30 A SMR with direct 380 V AC 3 ph input

    Publication Year: 1989, Page(s):11.7/1 - 11.7/8 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    The development approach and design solutions employed for the 380 V AC direct-input 48 V 30 A switch-mode rectifier are described. The unit achieved all design goals set out prior to development. The net result is a unit which incorporates the following characteristics: direct 380 V AC three-phase input, compact size, high efficiency and power factor, front to back cooling, stackable without baff... View full abstract»

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  • Al/O2 high power/high energy cells

    Publication Year: 1989, Page(s):18.4/1 - 18.4/5 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    The Al/O2 system is a primary, mechanically rechargeable power source delivering high power at a cell voltage of 1 V. It is suited best for applications at constant load or with low load variations where it is easy to control the efficiency. A major advantage is that it can be used at this high rate over a long to very long time. Using oxygen as the comburent makes it possible to mainta... View full abstract»

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  • Selection of the most suitable low voltage power system for a telecommunication station based on availability analyses

    Publication Year: 1989, Page(s):10.6/1 - 10.6/7 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The electrical system for the new RAI telecommunication station in Grottarossa (Rome) is a complex system that has to meet very high standards of performance. An approach to the design of such a system is proposed, based on reliability analysis applied to different scheme choices. Analysis results are compared with cost and other parameters of each solution, such as ease of maintenance and operati... View full abstract»

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  • Constant-frequency, zero-voltage-switched, clamped-mode parallel-resonant converter

    Publication Year: 1989, Page(s):16.4/1 - 16.4/7 vol.2
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    The DC behavior of a constant-frequency, clamped-mode parallel-resonant converter operating above resonant frequency is characterized. The converter is shown to be able to operate with zero-voltage turn-on for all the switches from no load to full load over a wide input range. Various circuit operating modes are identified and their corresponding operating regions defined. DC characteristics for t... View full abstract»

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  • 200 kVA continuous three-phase supply system

    Publication Year: 1989, Page(s):19.3/1 - 19.3/6 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    The authors describe a continuous supply unit using 40 kVA PWM (pulse-width modulation) inverters, which has been designed to provide variable output power, up to 200 kVA, for the processing systems in telecommunication networks. The system configuration includes at least one and up to 5+1 parallel rectifiers, at least one and up to 5+1 parallel inverters, battery, DC power switchboard system, and... View full abstract»

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  • Water-cooled switching power supply

    Publication Year: 1989, Page(s):20.8/1 - 20.8/7 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    The authors describe a novel water-cooled switching power supply that is one-third of the size of the conventional air-cooled 2.2 kW power supply. A size reduction of one-third makes it possible to locate the supply nearer the logic circuits. To achieve this size reduction: (1) the size of the output filter was reduced and a forward two-phase switching PWM (pulse width modulation) topology with a ... View full abstract»

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  • What is to do with used batteries within telecommunications services?

    Publication Year: 1989, Page(s):17.3/1 - 17.3/6 vol.2
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The authors consider what is to be done with used batteries that contain hazardous substances. It is emphasized that an international standard on types of cells and batteries that have to be returned to the manufacturer is necessary for batteries that are used by the common public. The International Recycling Symbol ISO 7000-1135 has been proposed for the marking; a coming EEC directive will speci... View full abstract»

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  • Effect of metal wave function on the IV characteristics of MOS solar cell

    Publication Year: 1989, Page(s):25.3/1 - 25.3/3 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    Results are presented which indicate that the metal wave function penetration effect cannot be neglected in calculating accurate I-V characteristics. The authors show a comparison between the variations of potential with x/d for different values of oxide layer thickness with and without considering the effect of metal wave penetration. On calculating the change ... View full abstract»

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  • Reducing the effects of high-frequency surges on central office grounding networks

    Publication Year: 1989, Page(s):13.2/1 - 13.2/9 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    The author discusses different ways in which the high-frequency components of ground faults or disturbances affect the performance of the grounding network, with emphasis of the roles of inductance and reflected waves. Due to the high-frequency nature of ground faults, a grounding network must provide electrical paths that exhibit not only a low DC resistance, but also, and more importantly, a low... View full abstract»

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