摘要:

The development of electrical machines was facilitated by the availability of high conductivity copper conductors, and the nonferrous manufacturers are still meeting the requirements of the electrical and electronics industry. Having shown that copper it still in plentiful supply, the review describes over 80 standardised wrought coppers and copper alloys and 37 casting materials. Compositions are given together with basic mechanical and physical properties in the annealed, worked or heat-treated conditions as appropriate. Machining and jointing techniques are described and the suitability of the materials for end use requirements is discussed. Sources of further information are given.

DOI:10.1049/ip-a-1.1986.0030

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The paper reviews the methods developed for predicting the reliability of systems, based upon design information, failure data on components, extrapolation from test data, and the use of mathematical models which relate predicted reliability to the various factors which can affect it, such as stress, application environments, quality and reliability programme activities. The fundamental limitations inherent in reliability prediction and modelling, related to logical, physical and human factors aspects, are described. The paper concludes with approaches that should be adopted to ensure that reliability predictions are realistic and credible, taking full account of physical and managerial factors involved in design, development and production.

DOI:10.1049/ip-a-1.1986.0031

出版商:IEE    

年代:1986

数据来源: IET

摘要:

In recent years there has been great interest in simulating theoretically the growth of an electrical discharge in a gaseous dielectric. The review is a general introduction to the subject of discharge simulation and summarises the advances that have been made in modern computational techniques which enable the growth of a discharge to be traced from its initiation until instantaneous currents of perhaps many amperes are attained. In the first place the general continuity equations which govern the growth of a discharge are set up together with the appropriate boundary conditions. The formal solutions to these equations are summarised for the case of uniform applied electric fields and low ionisation densities when the space-charge distortion of the fields is negligible. Simulation models are then developed which take into account space-charge distortion of the field and enable the axial and radial development of a discharge between plane parallel electrodes to be traced from its initiation until the transient glow regime in reached. A summary is also given of preliminary investigations into the modelling of discharge growth in nonuniform-field electrode geometries. Most of the simulation methods described assume that all charged particles come into instantaneous equilibrium with ionisation and transport coefficients determined by the local values of the ratio electric field/gas pressure. In the later stages of discharge growth and near electrode surfaces this assumption is no longer valid, and possible models for following ionisation growth in nonequilibrium regions such as the cathode-fall are discussed and compared with corresponding Monte-Carlo and Boltzmann methods.

DOI:10.1049/ip-a-1.1986.0032

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The rapid development of electronic technology in the last twenty years has now brought it to a point where it is practical to use electronic control systems, with suitable associated sensors and actuators, to directly replace a number of existing mechanical or electromechanical systems in the motor vehicle. This is being done where there is a need for the improved accuracy, speed and reliability available from electronics, and also to provide new functions and features where these are necessary either to meet legal requirements, to provide new competitive product features, or to improve the performance or operation of the vehicle. The review describes the applications of electronics which have already taken place and also looks at the automotive electronic systems which, it is expected, will be introduced over the next few years.

DOI:10.1049/ip-a-1.1986.0033

出版商:IEE    

年代:1986

数据来源: IET