Insulator (electricity)

About: Insulator (electricity) is a research topic. Over the lifetime, 15941 publications have been published within this topic receiving 108950 citations. The topic is also known as: electrical insulator.

Insulator contour optimization by a neural network

Abstract: Contour optimization of axi-symmetric insulators in multi-dielectric arrangements by a neural network (NN) has been carried out to obtain not only a uniform but also a complex electric stress distribution along the insulator surface. Three case studies have been reported In detail. Multilayer feed-forward networks with error backpropagation and also with resilient propagation learning algorithms have been employed. The training and test data have been prepared by means of electric field calculations. The results show that optimized insulator contours have been obtained with an acceptable degree of accuracy with the help of a trained NN.

Self-consistent theory of unipolar charge-carrier injection in metal/ insulator/metal systems

Abstract: A consistent device model to describe current-voltage characteristics of metal∕insulator∕metal systems is developed. In this model the insulator and the metal electrodes are described within the same theoretical framework using density of states distributions. This approach leads to differential equations for the electric field which have to be solved in a self-consistent manner by considering the continuity of the electric displacement and the electrochemical potential in the complete system. The model is capable of describing the current-voltage characteristics of the metal∕insulator∕metal system in forward and reverse biases for arbitrary values of the metal∕insulator injection barriers. In the case of high injection barriers, approximations are provided offering a tool for comparison with experiments. Numerical calculations are performed exemplarily using a simplified model of an organic semiconductor.

AC Flashover Voltages Along Epoxy Surfaces in Gaseous Helium Compared to Liquid Nitrogen and Transformer Oil

Abstract: Gaseous helium at high pressure is regarded as a potential coolant for superconducting cables. The dielectric aspects of cryogenic helium gas are both complex and demanding. In this experimental study, we looked at the interface between a smooth epoxy surface and high pressure helium gas in a homogeneous electric field. The ac flashover voltages of epoxy samples whose heights are 3 and 5 mm of diameters 9.5, 12.7, and 19 mm are presented. The results have been analyzed using Weibull statistics. In addition to the behavior of the epoxy in gaseous helium as a function of pressure and temperature, we also present data of the characteristics of the epoxy surface in transformer oil at 293 K and in liquid nitrogen (77 K). The breakdown characteristics of a uniform field gap in gaseous helium as a function of pressure and temperature under ac, dc, and lightning impulse voltages are also given. Field calculations have been made for one of the experimental geometries in an attempt to explain some of the anomalies in the experimental results. The results show that cold compressed helium gas is a viable dielectric but requires different insulator designs compared to insulators for liquid nitrogen.

Structurally strong heat insulator for high transient temperatures

Abstract: A structurally strong heat insulator is depicted in the backing plate and pressure plate regions of an aircraft multiple disc brake assembly. The insulator is constructed from a plurality of perforated metal sheets in order to withstand the large compressive forces experienced during a brake application. The sheets are compiled randomly into an insulating stack which thereby offsets the holes in adjacent sheets. The holes decrease the surface area and the offset increases the heat conduction path, both which reduce the amount of heat cnducted through the stack.

System and method to delay closure of a normally closed electrical circuit

Abstract: A system and method are provided to delay closure of an electrical circuit of a battery-powered electrical device, intended to operate remotely in an environment in which the pH value changes from one value to another. Two electrical contacts of an electrical circuit are separated by an insulator that holds the circuit open until the device is exposed to an environment having a predetermined pH value. Exposure of the insulator to an environment having that pH value causes the insulator to dissolve and the circuit to close, energizing the device. Alternatively, A Hall effect transistor or a reed switch may be used as the switch. It is held open by the presence of a magnetic field held in place by material that is dissolvable at a predetermined pH level. When a region having that pH level is reached, the material dissolves and the circuit closes.