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1 – 10 of over 24000
Article
Publication date: 6 February 2007

Antonio Moreno‐Muñoz, Mª Dolores Redel, Daniel Oterino and Juan J.G. De la Rosa

The purpose of this paper is to address the issue of power quality through a case study in an IT‐intensive modern office building.

Abstract

Purpose

The purpose of this paper is to address the issue of power quality through a case study in an IT‐intensive modern office building.

Design/methodology/approach

This paper presents results from a power quality audit conducted last year. Firstly, the power site inspection included: (a) a walk‐down of the facility's electrical system to inspect the condition of equipment and becoming familiar with the electrical system; (b) interviewing facility electrical personnel and end‐users on failure of equipment; (c) identifying and collecting the electronic equipment that is most sensitive to power disturbances; (d) requesting and reviewing equipment literature and electromagnetic compatibility characteristics; (e) after that, in the power quality monitoring, voltage and current were measured at various floors.

Findings

It was found that the main problems for the equipment installed were harmonics and leakage currents. The paper examines the causes and effects of power disturbances that affect computer or any other microprocessor based equipment and analyses the disadvantages of modern power supplies.

Practical implications

This provides useful information for facilities managers on the current state of power disturbances. The convenience of “enhanced power supply” is also discussed. Finally, it is addressed the role of standards on the protection of IT and the implications for the final costumer.

Originality/value

This paper has provided empirical data from a power site survey developed in a high tech building. This case study demonstrates the impacts of generalized electronic devices on the power quality of the buildings and the implications on energy uses.

Details

Facilities, vol. 25 no. 1/2
Type: Research Article
ISSN: 0263-2772

Keywords

Article
Publication date: 6 November 2017

Jingsong Li, Lixiang Wang, Qingxin Yang, Shanming Wang, Yongjian Li, Changgeng Zhang and Baojun Qu

Due to existence of skin effect under rotational excitation, especially to high-frequency motors and power transformers run at the frequency of hundreds or even thousands…

Abstract

Purpose

Due to existence of skin effect under rotational excitation, especially to high-frequency motors and power transformers run at the frequency of hundreds or even thousands of hertz, core losses will increase significantly, which may cause local overheating damage, and the efficiency and longevity will be decreased. The purpose of this paper is to accurately calculate the rotational anomalous loss in electrical steel sheets.

Design/methodology/approach

The influence of skin effect to rotational anomalous loss coefficient is described in detail. Based on the rotational core losses calculation approach, the transformed coefficient and parameters of rotational anomalous loss are determined in accordance with experimental data obtained by using 3D magnetic properties testing system. Then, a variable loss coefficient calculation model of rotational anomalous loss is built. Meanwhile, a separation of the total 2D elliptical rotation experimental core losses is worked out.

Findings

The two methods are analysed and compared qualitatively. It should be noted that the novel calculation model can be more effectively presented anomalous loss features. Moreover, quantitative comparisons between 2D elliptical rotation and alternating core losses have achieved beneficial conclusions.

Originality/value

Transformed rotational anomalous loss coefficient and parameters of electrical steel sheets considering skin effect are determined. Based on that, a novel calculation model evaluating 2D elliptical rotation anomalous loss is presented and verified based on the experimental measurement and the separation of the total 2D elliptical rotation core losses. The 2D elliptical rotation core losses separation method and quantitative comparison with alternating excitation are helpful to engineering application.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 August 1962

IT was in 1954 that English Electric formed an Aircraft Equipment Division, from a section of the Company which had already been producing electrical equipment for…

Abstract

IT was in 1954 that English Electric formed an Aircraft Equipment Division, from a section of the Company which had already been producing electrical equipment for aeronautical applications, with the intention of becoming a major producer in the field of aircraft electrics. Progress since that time has continued unabated with considerable effort and capital being expended to establish the Division as a competitive technical unit.

Details

Aircraft Engineering and Aerospace Technology, vol. 34 no. 8
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 September 1970

Accles & Pollock Ltd. of Oldbury, Worcestershire, a TI Steel Tube Division company, will be exhibiting a comprehensive range of precision steel tube and tubular products…

Abstract

Accles & Pollock Ltd. of Oldbury, Worcestershire, a TI Steel Tube Division company, will be exhibiting a comprehensive range of precision steel tube and tubular products, including plain, annularly convoluted and thin wall tube, at Farnborough.

Details

Aircraft Engineering and Aerospace Technology, vol. 42 no. 9
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 November 1959

R.P. Northup

In chemical plants, corrosion is present to some extent in practically all electrical installations. Some of this corrosion is of a limited nature and relatively harmless…

Abstract

In chemical plants, corrosion is present to some extent in practically all electrical installations. Some of this corrosion is of a limited nature and relatively harmless. In other cases a more suitable material or a better appreciation of design factors would avoid severe cases which call for costly shutdowns. Numerous metals and alloys are available for electrical installations; all have advantages and disadvantages. This information, together with pertinent design factors, is the key to trouble‐free electrical units.

Details

Anti-Corrosion Methods and Materials, vol. 6 no. 11
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 30 September 2014

Michael J. Armstrong and Christine A.H. Ross

This article is aims to inform aircraft propulsion system designers of the implications which fundamental power distribution design assumptions have on the effectiveness…

Abstract

Purpose

This article is aims to inform aircraft propulsion system designers of the implications which fundamental power distribution design assumptions have on the effectiveness and viability of turboelectric distributed propulsion (TeDP) systems. Improvements and challenges associated with selecting alternating or direct current for normal- and superconducting distribution systems are presented. Additionally, for superconducting systems, the benefits of bi-polar DC distribution are discussed, as well as the implications of operating voltage on the mass and efficiency of TeDP grid components.

Design/methodology/approach

The approach to this paper selects several high-level fundamental configuration decisions, which must be made, and it qualitatively discusses potential implications of these decisions.

Findings

Near term TeDP architectures which employ conventionally conducting systems may benefit from alternating current (AC) distribution concepts to eliminate the mass and losses associated with power conversion. Farther term TeDP concepts which employ superconducting technologies may benefit from direct current (DC) distribution to reduce the cryocooling requirements stemming from AC conduction losses. Selecting the operating voltage for superconducting concepts requires a divergence from the present day criteria employed with terrestrial superconducting transmission systems.

Practical implications

The criteria presented in the paper will assist in the early conceptual architecting of TeDP systems.

Originality/value

The governing principles behind the configuration of multi-MW airborne electrical microgrid systems are presently immature. This paper represents a unique look and the motivating principles behind fundamental electrical configuration decisions in the context of TeDP.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 86 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 January 1996

Linda M. Aguilar and Michael A. Singer

United States history is steeped in trade and trade debate, from the pivotal role of the Boston Tea Party in shaping the United States as a nation to the recent debate…

231

Abstract

United States history is steeped in trade and trade debate, from the pivotal role of the Boston Tea Party in shaping the United States as a nation to the recent debate over the merits of U.S. ratification of the present version of the General Agreement on Tariffs and Trade (GATT) negotiations. It is no surprise, then, that the U.S. Department of Commerce is actively involved in promoting exports. In 1993, President Clinton announced a national export strategy for the United States, described as “a comprehensive plan [that] upgrades and coordinates the government's export promotion and export finance programs to help American firms compete in the global marketplace” (U.S. Department of Commerce, 1994). In particular, the strategy identifies past problems with U.S. trade promotion efforts and recommends improvements upon current ones. This includes enhancing existing trade finance programs such as the Exim Bank and the Overseas Private Investment Corporation, and creating the Tied Aid Fund to help U.S. firms compete on a level playing field. As an outcrop of this initiative, the Commerce Department identified 10 foreign nations as the big emerging markets (BEMs) of the upcoming century, markets where the potential for trade growth is the greatest.

Details

Competitiveness Review: An International Business Journal, vol. 6 no. 1
Type: Research Article
ISSN: 1059-5422

Article
Publication date: 22 February 2013

Amanze Rajesh Ejiogu

The purpose of this paper is to provide an overview on the e‐waste topic, highlight the economic arguments for dumping e‐waste in developing countries and examine the…

2801

Abstract

Purpose

The purpose of this paper is to provide an overview on the e‐waste topic, highlight the economic arguments for dumping e‐waste in developing countries and examine the issues around the e‐waste problems in Nigeria.

Design/methodology/approach

The methodology adopted is based on a review of existing literature, personal observation and interviews.

Findings

Electronic waste, or e‐waste, has emerged as a major problem in quite a number of developing countries, as well as an opportunity for development and economic growth. As a result of its high toxic content, it creates problems of environmental pollution and is a hazard to human health when not handled properly. However, there is a huge demand for good quality, second‐hand equipment in developing countries and there seem to be strong economic arguments for exporting scrap electronic and electrical equipment to those countries. The e‐waste trade has grown in Nigeria, causing several socio‐economic problems.

Originality/value

The paper contributes to the growing body of knowledge on e‐waste in developing countries, especially Nigeria. It provides insight into the economic arguments that encourage the continuance of the e‐waste problem.

Details

Management of Environmental Quality: An International Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1477-7835

Keywords

Book part
Publication date: 4 April 2016

Stefano Fenoaltea

This paper presents the second-generation estimates for the Italian engineering industry in 1911, a year documented both by the customary demographic census, and the first…

Abstract

This paper presents the second-generation estimates for the Italian engineering industry in 1911, a year documented both by the customary demographic census, and the first industrial census. The first part of this paper uses the census data to estimate the industry’s value added, sector by sector; the second further disaggregates each sector by activity, and estimates the value added, employment, physical product, and metal consumption of each one. A third, concluding section dwells on the dependence of cross-section estimates on time-series evidence. Three appendices detail the specific algorithms that generate the present estimates; a fourth, a useful sample of firm-specific data.

Details

Research in Economic History
Type: Book
ISBN: 978-1-78635-276-7

Keywords

Article
Publication date: 1 June 2004

Martin Goosey

Increasing awareness of man's impact on the environment and pressure to behave in a more sustainable manner are encouraging both the recycling and reuse of materials and…

1966

Abstract

Increasing awareness of man's impact on the environment and pressure to behave in a more sustainable manner are encouraging both the recycling and reuse of materials and the replacement of hazardous chemicals with more benign ones. The Waste Electrical and Electronic Equipment (WEEE) Directive and the Restriction on the use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS) Directive, have recently been adopted into law with the specific intention of further encouraging these activities through legislation. In addition to these directives, there is a growing need to adopt sound design principles so that new products are created in a more environmentally acceptable way and that their environmental impact throughout their lifecycles is minimised. This paper gives an overview of this new European legislation and discusses its impact on the electronics industry. The potential benefits of adopting such an approach are outlined.

Details

Circuit World, vol. 30 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

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