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A fault tolerant multiple outlet converter system has been developed at British Telecom Research Laboratories (BTRL). High reliability is obtained by the provision of multiple independent power sources with associated isolation/control circuitry for each power outlet. To achieve adequate reliability it is necessary to test the fault isolation components periodically to verify their correct operation...
NTT has been developing various techniques to protect telecommunications power supply systems against natural disasters, such as earthquakes, heavy rains, and lightning, because Japan is hit every year by such natural disasters. As a result of examinations in this area, NTT has intensified certain of its protection techniques in the area of earthquake-proofing, flood protection, and lightning protection...
Although development of power supply of SCUs was not the main target of the BIGFON concept a number of important hints for further studies on subscriber connection systems is given. The solutions set up in the BIGFON trial show that it is possible to fulfill the requirements of integrated systems even at the present time. But it is also shown that in connection with the development of transmission...
In this paper some principles of power feeding are discussed. For power supply of digital telphone sets the use of a DC/DC converter is a reasonable solution. With the implementation of the DC/DC converter into the terminal some problems must be solved like noise problems, decoupling problems and stabilized operation. A realization of a DC/DC converter is shown which has a good efficiency with loads...
There are no generally accepted computer sizing programs for stand-alone photovoltaic power systems, including the array and the battery, which have been verified for an extended period of time. In order to test the performance and the reliability of stand-alone photovoltaic power systems a computer sizing program for the solar array and battery has been developed. The program covers both vented low...
This paper reviews recent trends in lead-acid battery design aimed at the long established applications, discusses their impact on the needs of the more recently emerged photovoltaic application, and describes a battery design specifically developed for photovoltaics.
Telephone booth needs electrical power for lighting, payment card system, radio telephone. Connecting to a traditional network can be too expensive or not performant. The photovoltaic telephone booth is efficient. The system set up for a new or existant call box is easy, quick and simple. ?? Setting up 2 hours, 2 persons, no lifting material = assembly of the polyester roof on the call box + cabling...
Control characteristics of the half-wave magnetic amplifier for the high frequency dc-to-dc converter are analyzed. A new control method which removes a dead angle of the PWM output caused by the core characteristics and the reverse recovery of the diode in the converter is proposed. As the results, the wide regulation range is obtained for the high frequency, and the ferrite core is made possible...
- The GAS 4 Group was reestablished in 1980 by the Seventh Plenary Assembly of CCITT to rewrite the handbook "Primary sources of energy" (Chapter 1). - This contribution explains and comments the photovoltaic chapter of the new handbook to be published in 1985. It justifies the very low unavailability of 1,5. 10-5 specified for the telecommunication power plartstations (Chapter 2). - It...
In magtronic regulated power conversion Systems a special transformer is used allowing current control of coupling between primary and secondary coil. This new regulator is competitive to SCR-regulation technique. Being comparable in size and control speed, magtrunic regulation features: Reliability, High Efficiency, Low EMF and Low cost. This paper describes the new control component and presents...
In this paper are considered parameters to be taken into account for a first approach design of a group thermal engine Diesel type coupled with an electrical generator. Some considerations are made about little electrogenerator groups due to the importance of their utilization in the photovoltaic and aeolian hybrid systems. So, tables are tentatively formulated with a practical character for a quick...
Satellite communication payloads such as IWT-transponders are highly sensitive against poor power source quality especially if they are operated on a common mainbus. Therefore the requirements on an electrical power system are stringent in terms of impedance, ripple and stability. General layout criteria are discussed for a regulated bus system (TV-SAT/TDF) and also for an unregulated bus system (DFS/KOPERNIKUS).
A summary of the work on diesel engine generating systems that was carried out by CCITT-GAS4 in compiling the handbook on Primary Sources of Energy. The paper outlines the reliability requirements of diesel engine generating systems at remote locations and the various means of achieving that reliability. Particular emphasis is placed on environmental conditions, loads, plant selection and performance,...
Renewable energy systems, especially stand-alone systems, have been studied, developed, and tested at Jutland Telephone since 1978. Computer-based supervision and control equipment for automatic or remote control of renewable energy plants as well as of conventional telecom power plants have also been developed and tested, and this paper will present a sum-up of the operational experience gained at...
There can't be just one power supply for every application. For a special application however you can certainly reach an optimum. This paper shows how the design of an optimum power supply for the Siemens Transdata?? communications processor also depends on the design of the entire computer.
Information is given of a proposal for technical requirements of electrical and functional safety of equipment connected to the mains supply as well as to an administrations network. Such requirements have to be agreed upon in order to reduce the risks for hazardous voltage, current or frequency being transferred to the telecom network, there being able to cause human injury and equipment or operational...
The paper presents advancements in thermal engineering and packaging for switchmode circuit design in a 30 Amp and 50 Amp 56 Volt DC (48 Volts Nominal) rectifier product group. The development has resulted in a design with excellent operating specifications and increased power density in a convection cooled communications rectifier. The design criteria are reviewed and details are presented for the...
An IEC working group has extended the conventional approach of specifying requirement for protection against electric shock to become better appliccable to electronic equipment. A draft revision of IEC Publication 536 displays requirements for a completed set of Classes. electric shock, protection, classification, IEC
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