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The specification for large UPS systems is becoming more standard, and this presentation is an attempt to highlight some of the less obvious points. The subjects chosen for discussion are input requirements of voltage, isolation and harmonics, together with considerations of the battery and the output filter. Areas for potential savings in energy and cost are investigated.
A new British Post Office standard power plant has been designed to operate from a single-phase a.c. mains or standby generator input, and to provide secure d.c. power to 50 V telecommunications equipment. The plant features standby rectifier capacity, battery standby with a choice of duration, and a regulated output during battery discharge without the need for end-cell switching. A range of standard...
The Swedish Telecommunications Administration - known in Sweden as Televerket - has one of the oldest telephone networks in the world. Advanced product development has enabled very high reliability values to be attained. It has therefore been possible to maintain costs and rates' at a low level. Changeover to digital technique will take place at an accelerated pace by replacement of older equipment...
This paper compares the reliability of four uninterruptible power supply (UPS) configurations; single module, parallel redundant, static bypass, and static bypass redundant. Equations for calculating the MTBF's of these configurations are presented along with component reliability estimates. Effects of failure rates of associated circuitry are included. System MTBF's of 200,000 hours for redundant...
The Buck/Boost Power System is a new telephone power supply capable of providing a fully regulated output under either a.c. mains operation or battery operation. This article discusses design objectives, principles and operation, technical problems to be overcome and economic aspects of the Buck/Boost System. It also describes the first large installation based on the buck/boost system for powering...
Developments in the telecommunication equipment require new centralized power plant policy. The paper describes the new type of power plant chosen by SIP, Italian Telephone Company, to face the telecomuunication equipment present and future requirements. A description of the plant is given together with the results of the first years of operation.
The paper describes some devices specially developed for the new type of centralized power plants for telecommunication equipment used by SIP, Italian Telephone Company. The remote rectifier's output power limitation device is of great usefulness in the power rating of the primary power plant, in particular of emergency generating sets. The selective supervising devices are an integral part of the...
Technical progresses in the field of power transistor permit now a direct switching of AC mains voltage. It is the main object of this paper to present a modular rectifying set, including two to five switching rectifiers. The main technical points concerning this type of telecommunication power plant will be discussed, thas is the electromagnetic compatibility between these materials and the surrounding...
A total battery plant system consisting of rectifier/chargers and a voltage control and distribution bay is discussed. The rectifier/chargers each have built-in provisions for testing and adjusting their high and low voltage alarms and their high voltage shutdowns without removing them from service or affecting their outputs during the testing sequence. Likewise, the voltage control and distribution...
Booster DC to DC converters operating with 20 kHz conversion frequency perform rapid regulation that make them very well suited to use as active filters for attenuation of low frequency noise. Booster converters with such filtering qualities are beeing used in a new series of 48 V DC power plants. The noise on the output is kept well below the limits that are specified in the CCITT-recommendations.
This paper will describe a power system configuration that provides improved energy efficiency for telephone power plants. This is accomplished by supplying the plant load with a voltage lower than typically used. The approach will be explained using a standard configuration for a +24 volt (12 cells per string) battery plant. The following points will be emphasized: - Circuitry necessary to maintain...
A high efficiency and economical arrangement for providing power to computers with 400 Hz CPU requirements is introduced. The system utilizes a conventional 60 Hz static switching bypass type 60 Hz UPS connected to a common battery with a switching type redundant 400 Hz solid state UPS thus eliminating the double conversion losses and lower efficiency of an added rotary frequency converter. A method...
In this paper an attempt is made to derive some major future trends for telecommunication power plants out of technological progress and some of the worldwide political processes. The main stress is laid on trends of some degree of universal applicability and thus detailed analysis of e.g. circuit solutions is avoided. General trends, system trends and trends for system components like rectifiers,...
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