δείτε την πρωτότυπη σελίδα τεκμηρίου στον ιστότοπο του αποθετηρίου του φορέα για περισσότερες πληροφορίες και για να δείτε όλα τα ψηφιακά αρχεία του τεκμηρίου*
No-load switching contacts may be operated when the associated electric circuit is power disconnected. Their practical characterization is mainly based on the resistance value between the contacting joints. Contact resistance evaluations are usually based on various parameters, such as geometry, pressure, effective contact area, heat dissipation, and foreign matter on contacting surfaces, i.e., dust particles, atmospheric contamination, and thin oxide layers. In this paper, data are presented which may aid physical interpretations concerning no-load switching contacts under high current density operation. Measurements were performed on industrial switches having the following nominal values: isolation switches 400 V/100 A, isolation switches 20 kV/200 A, and fuse isolators 20 kV/100 A. It is convincingly shown that beyond a threshold field intensity (corresponding to smaller currents than the nominal values) nonlinear I-V relationship may develop, leading to bistability and negative differential conductance phenomena. This has been attributed to the dominating tunnelling current component between oxidized (or nonideally contacted) metallic surfaces at high electric fields, resulting in an increased effective area of contact. The well established metal-insulator-metal (MIM) theory, as well as that concerning nonlinear current voltage phenomena developing in insulating solids at high electric fields, provide the required theoretical basis for the interpretation of the obtained curves.
(EN)
*Η εύρυθμη και αδιάλειπτη λειτουργία των διαδικτυακών διευθύνσεων των συλλογών (ψηφιακό αρχείο, καρτέλα τεκμηρίου στο αποθετήριο) είναι αποκλειστική ευθύνη των αντίστοιχων Φορέων περιεχομένου.
Βοηθείστε μας να κάνουμε καλύτερο το OpenArchives.gr.