Counter-Measures for Relay Failures due to Dynamic Welding: A Robust Engineering Design

Thomas J. SCHOEPF  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.5   pp.728-735
Publication Date: 2009/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.728
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electromechanical Devices and Components
automotive relay,  silver contacts,  silver tin oxide,  inrush current,  dynamic welding,  robust engineering,  

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In prior work, contact welding phenomena were observed in automotive relays during break of motor inrush current. The switching performance of the type of relay investigated could be correlated with the parameters: over-travel, coil suppression, and the break current. In the present work the author further explores the impact of both the contact material (silver tin oxide versus fine grain silver) and the contact surface topography (brand new and pre-aged contacts). He further assesses the robustness of the system "relay" with those parameters using the Taguchi methods for robust design. Furthermore, the robustness of two alternative automotive relay types will be discussed.