Random Occurrence of Contact Welding in Electrical Endurance Tests

Laijun ZHAO  Zhenbiao LI  Hansi ZHANG  Makoto HASEGAWA  

IEICE TRANSACTIONS on Electronics   Vol.E94-C   No.9   pp.1362-1368
Publication Date: 2011/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.1362
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electro-Mechanical Devices – Papers selected from International Session on Electro-Mechanical Devices (IS-EMD2010) and other research results –)
relay,  welding,  arc duration,  number of operations,  

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To clarify how the occurrence of contact welding is related to the series of arc duration characteristics in consecutive make and break operations, electrical endurance tests were conducted on commercially available automotive relays, and the voltage waveforms of make and break arcs between the electrodes were recorded with LabVIEW. Experimental results indicate that welding may occur suddenly or randomly with increasing number of operations. A single arc or a group of make or break arcs with a long arc duration does not necessarily result in contact welding, but a group of longer make or break arcs within a narrow range of operation numbers can cause imminent contact welding (such an effect can be called the “group of longer arcing duration effect”). It is confirmed that contact welding may occur in both make and break operations, but the welding probability during make operations is much higher than that during break operations.