2017 IEEE Holm Conference on Electrical Contacts

In many industrial applications like automotive, aeronautics, train but also nuclear energy connectors need to maintain low stable electrical contact resistance. However, they are subject to vibrations that cause severe fretting wear damage which increases the electrical contact resistance and degrades information transmission. Fretting wear damages can induce dramatic increase of the direct curre... View full abstract»

This paper presents a method to simulate the current and voltage of an electric arc initiated at the contact's opening in a contactor. Based on a simplified model of the electric arc and also on the dynamics of the contacts during the opening, this method allows to simulate the arc ignition as well as the arc extinction. This study is based on the hypothesis that the arc dynamic is much faster tha... View full abstract»

High technology domains such as aerospace, aviation and defense require a reliable transmission of RF signals. In these applications, RF connectors are exposed to severe environmental vibrations and are subjected to fretting wear damages. Former investigations on real connectors have shown that fretting wear leads to a dramatic increase of the DC electrical contact resistance (ECR), degrades RF mi... View full abstract»

ITER is a large scale fusion experimental device under construction in Cadarache (France) intended to prove the viability of fusion as an energy source. Ion Cyclotron Resonance Heating (ICRH) system is one of the three heating systems which will supply total heating power of 20 MW (40-55 MHz) up to one hour of operation. Radio-Frequency (RF) contacts are integrated within the antennas for assembly... View full abstract»

Hybrid DC circuit breaker (HDCCB), which combines a mechanical switch and a semiconductor, has become a research focus due to a rapid development of DC power system and its low on-state loss and short break time. However, there is still serious arc erosion for a conventional HDCCB because the current commutation is driven by the arc. A novel topology of HDCCB was proposed in former research. It is... View full abstract»

Electrical equipment has to carry the rated normal current and short time withstand current. As shown in previous publications, the voltage-temperature relation allows calculating the temperature of contact elements and connectors for steady- state operating points. In the case of transient electric-thermal load, a finite-element analysis (FEA) is required to calculate the time-dependent distribut... View full abstract»

Two mathematical models, spherical and axisymmetric, describing the temperature field in closed electrical contacts are compared and the rightness of their application is discussed. The ranges of the contact radius, time and current are determined for which one or another model could be applied with the required accuracy. The temperature field in the axisymmetric model is found in the form of alte... View full abstract»

As the first power transmission part of synchronous generator output, the thermal stability of the enclosed isolated phase bus-bar (EIPB) is important for the working safety of the power system. The thermal stability of large synchronous generator-side EIPB is hard to be analyzed or calculated because of the complex structure and the large size of EIPB in the power system. In this paper, a new co-... View full abstract»

The present work addresses the effects that occur from adjacent bridge structures that are believed to exist in real contacts. While in the present work these structures are idealized using hyperbolic surfaces, it is believed they provide reasonable estimates of what can happen in real situations. Using this approach, it is shown that the current density distribution across the contact remains fin... View full abstract»

Electrical lifetime and relative dynamic welding failure mechanisms of electromechanical relay for capacitive load are hot topics in the area of switching devices and electrical contact materials. In this work, the silver tin oxide contact material has been tested with a capacitive load by using our designed novel model switch. The typical waveforms of contact current and contact voltage at making... View full abstract»

The Laser Arc Image System (LAIS) provides unprecedented real-time, frame by frame visualization into the micro-second dynamic arc processes consisting of the heat and mass transfer between the electric contacts. These resulting high-speed images and data from the LAIS experiments serve as the empirical analytical tools for understanding the instantaneous arcing behavior, a phenomenon that have on... View full abstract»

A methodology to modify the behavior of the electrical arc in the extinguish process has been a topic of study by several researchers. The use of Deion plates to extinguish the electrical arc is very well studied in literature. This work proposes the use of permanent magnets inside of the arc chamber to improve the performance of the arc extinction. The permanent magnets generate a magnetic field ... View full abstract»

Temperature distribution and its time evolution are fundamental physics of arcs occurring during breaking process in electro-mechanic devices, which largely determine contact erosion. Aimed to the highly fluctuating switching arc, we implemented an optical system based on relatively strength of two individual spectrum emitted by the same excited atoms inside the plasma. Light emitted from arc is f... View full abstract»

Fretting corrosion is considered to be one of the most common failure mechanisms in electrical contacts for many applications. Micro-scale motion at the contact surface is the major driver of fretting degradation and produces material displacement and transfer. As a result, the buildup of an insulating oxide layer at the contact interface leads to a rapid substantial increase in contact resistance... View full abstract»