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Conference Proceedings., Eleventh International Telecommunications Energy Conference

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
  • A -50 V/100 Amp high frequency switch mode rectifier unit and its application to digital switching system

    Publication Year: 1989, Page(s):11.1/1 - 11.1/5 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The authors describe the development of a 20 kW off-line switch mode rectifier system to power a large-capacity digital switching system which is under development. The rectifier unit uses a double forward circuit topology composed of four power MOSFET modules that are controlled by pulse width modulation; this makes it possible to reduce the size and weight of magnetic components. The unit is con... View full abstract»

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  • Evolution of grounding systems in telecommunications

    Publication Year: 1989, Page(s):10.7/1 - 10.7/6 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    The authors report a method for planning, constructing, and running grounding installations. This method has been fully tested by SIP for exchanges and networks in areas characterized by a particularly high specific resistivity; and by ENEL for links in line-carried waves on HV overhead lines. The approach developed aims at making it reliable over a considerable length of time and optimizing the c... View full abstract»

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  • Inrush current control for equipment powered by UPSs

    Publication Year: 1989, Page(s):19.4/1 - 19.4/7 vol.2
    Cited by:  Papers (9)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    With the present-day widespread use of uninterruptible power supplies (UPS) in power equipment, inrush becomes a major concern since most UPSs have a limited ability to furnish high peak-current demands. The author discusses inrush current in general and presents, both conceptually and in block-diagram form, a proposal for circuitry that manages and eliminates the inductive inrush current concerns... 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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  • 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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  • SIP experiences in air conditioning of telephone exchanges

    Publication Year: 1989, Page(s):8.2/1 - 8.2/8 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    It is noted that a break in the air-conditioning system of an electronically equipped telephone exchange, if not immediately repaired, can cause heavy damage and, ultimately, breakdown. The authors describe the method used by SIP for the air-conditioning of electronic telephone exchanges, particularly the latest experience, using programmable logic controllers equipped with communication modules c... View full abstract»

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  • Boost/complementary buck DC/DC converter for space applications

    Publication Year: 1989, Page(s):16.6/1 - 16.6/6 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    A DC/DC converter for space applications is described whose switching cell can be varied by means of two jumpers on the printed board. When the minimization of the conducted emission is a primary requirements and the avionic bus (i.e. 28 V DC) is used, the boost plus push-pull configuration will be preferred; if the voltage source is much higher, for instance 150 V DC, and excellent audio suscepti... View full abstract»

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  • New power supply system for switching system

    Publication Year: 1989, Page(s):10.5/1 - 10.5/5 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    NEC has attempted to develop a well-balanced switching system, a total system including switching equipment, and a compact and lightweight power plant. A successful result of this effort allows the switching equipment and the power plant to be installed in the same room. The author introduces this new power supply system, which is a space and cost-saving power plant View full abstract»

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  • A new 40 kVA transistorized PWM inverter

    Publication Year: 1989, Page(s):19.2/1 - 19.2/6 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The authors describe a modular three-phase 40 kVA inverter developed as part of a 200 kVA UPS (uninterruptible power supply) unit for the processing system in telecommunications networks. The main characteristics of this inverter are: PWM (pulse-width modulation) conversion at high frequency; wide DC supply voltage range; 50 Hz or 60 Hz operation; parallel operation with equal sharing; good diagno... View full abstract»

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  • New technology for lead acid batteries

    Publication Year: 1989, Page(s):6.6/1 - 6.6/6 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    A recently developed technology allows the use of pure lead for positive spine grids and pure copper for negative grids, straps, and terminal posts. This technology totally avoids the use of antimony, while increasing life and improving performances in connection with high rate discharges. Other advantages are higher reliability; lower manpower cost, due to automation of the process; lower total c... View full abstract»

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  • Mechanical ventilation of digital equipment in exchange with high heatload

    Publication Year: 1989, Page(s):1.8/1 - 1.8/5 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The authors show how Copenhagen Telephone Company (KTAS) solves the problems of high heat load in rooms with digital equipment, using nothing but filtered air. Experience with four years of operation of these integrated ventilation systems is described and their economics are considered, with particular emphasis on the running costs. Fifty-two systems are in service with heat loads of up to 350 W/... View full abstract»

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  • A 100 kHz, 2.7 kW rectifier using a series-resonant converter bypassing discharge current

    Publication Year: 1989, Page(s):16.5/1 - 16.5/7 vol.2
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    The fundamental characteristics of a newly developed series-resonant converter bypassing discharge current (SRCBDC) and of a 2.7 kW rectifier using this converter are described. The SRCBDC has significant advantages over conventional series-resonant converters and is particularly useful for application to rectifiers. The advantages of the SRCBDC are as follows. It is possible to switch at zero cur... View full abstract»

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  • 50 W photovoltaic system electronic control unit

    Publication Year: 1989, Page(s):15.8/1 - 15.8/3 vol.2
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    The authors present an electronic regulator unit for small remote 50 W photovoltaic systems that can automatically and autonomously control energy and power for telecommunications systems of 12 V nominal DC voltage. The electronic control unit employs dual voltage operation, temperature compensation, and other circuits required for long-period work. The basic technical regulator data are maximal c... View full abstract»

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  • A new analytical model of the p-i-n structure for a-Si:H solar cell

    Publication Year: 1989, Page(s):25.1/1 - 25.1/5 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    A novel analytical method has been developed for studying the transport problem in a hydrogenated amorphous silicon (a-Si:H) p-i-n solar cell. The model relies on the widely used assumption of a variable minority carrier but, unlike other analytical models, it takes into account both the majority and the minority carriers in the whole structure. Thus, exact boundary conditions can be applied to ca... 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 (9)  |  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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  • Chaotic modes in electrotechnical system with transducers

    Publication Year: 1989, Page(s):10.4/1 - 10.4/5 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    Nonlinear electrotechnic systems with electric power inverters can be described by equations with constant or convertible commutation moments depending on the type of semiconductor element model used. To investigate such systems a qualitatively new theory is needed that is capable of a comparatively deep analysis of the characteristics of the objects studied. Recent studies of the incidental fluct... View full abstract»

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  • A control method for a high frequency link inverter using cycloconverter techniques

    Publication Year: 1989, Page(s):19.1/1 - 19.1/6 vol.2
    Cited by:  Papers (9)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    The authors describe a novel control method for a high-frequency link inverter using cycloconverter techniques and discuss its output voltage characteristics. In this method, the cycloconverter converts a high-frequency voltage to a low-frequency voltage by operating in three modes: positive rectifying mode, negative rectifying mode, and free-wheeling mode. Pulse-width-modulation control is perfor... View full abstract»

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  • The evolution and application of microprocessor control and monitor units in the central office power equipment

    Publication Year: 1989, Page(s):9.1/1 - 9.1/9 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    In July 1983, the first microprocessor-controlled power plant was installed in a Southern Bell central office to power a Northern Telecom DMS-100 switch. Since that time, the evolution of applications for that technology has continued to expand to meet desired or forecasted requirements. The initial technology is discussed, followed by a description of second-generation units. In order to achieve ... View full abstract»

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  • Ultrasonic carrier PWM converter employing IGBT in the near future

    Publication Year: 1989, Page(s):20.7/1 - 20.7/5 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    The authors describe an ultrasonic PWM (pulse-width modulated) carrier-frequency current sourced power converter employing IGBTs (insulated-gate bipolar transistors) with a self-aligned DMOS structure. The sinusoidal waveform (rather than the ultrasonic corrected triangular waveform) method is employed for the PWM pulse pattern to operate the converter. Because of the ultrasonic PWM carrier freque... View full abstract»

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  • Evaluation of the parameters influencing the behaviour of the gas recombining Pb-acid batteries

    Publication Year: 1989, Page(s):6.5/1 - 6.5/7 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    A method for evaluating the parameters controlling the behavior of gas-recombining lead-acid batteries has been proposed by M. Maja and N. Penazzi, (see J. Power Sources, vol.25, no.2, p.99-109 (1989) and J. Power Sources, vol.25, no.3, p.229-38 (1989)) and tests have shown the feasibility of the procedure. The method proposed is based on the measurement of the internal pressure of a cell filled w... View full abstract»

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  • Performance estimation of a token bus industrial local area network

    Publication Year: 1989, Page(s):7.4/1 - 7.4/5 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    A local area network (LAN) was developed to connect the distributed parts of power plant process control systems. The following requirements had to be met: fast transfer of short messages (alarms); transfer of long messages with high throughput; reliable transfer of data in harsh environments; and access to shared resources for all participants in process control. Performance measurements were car... 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 (16)
    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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  • Solar energy supply system for induction motors and various loads

    Publication Year: 1989, Page(s):15.7/1 - 15.7/7 vol.2
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    The authors consider end-user energy transformation in standby solar energy power plants and analyze various possible solutions for utilizing the energy stored in the battery to supply electrical motors, lights, etc. The conversion efficiency and the reliability of the whole system are among the parameters selected to define the optimum system design. Both solar and wind energy conversion technolo... View full abstract»

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