Electric Measurement of Melting Phenomena for Breaking Relay Contacts

Noboru WAKATSUKI  Nobuo TAKATSU  Masahiro OIKAWA  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.8   pp.998-1002
Publication Date: 2009/08/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.998
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electro-Mechanical Devices (IS-EMD2008))
Category: Arc Discharge & Contact Phenomena
transient current switch circuit,  melting voltage,  electromagnetic relay,  arc ignition,  

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Using the transient current switch circuit in parallel with the energizing switching contacts for timely control of breaking operation, the increase of contact voltage is suppressed at the last stage of the breaking of electric contacts. Breaking contact voltage Vc and current Ic of electromagnetic relays with Ag contacting electrodes were measured with 12.5-50 V and 0.1-20 A for two hinge springs (Spring constants; 2 N/mm and 0.2 N/mm). The current-decreasing process was clearly measured at the melting voltage Um. After Vc=Um, the breaking time of contact current did not depend on mechanical motion controlled by the two hinge springs and energizing power-supply voltage, but depended on the contact current. The residue of melt electrode was observed optically as a white fusion spot, with radius depending on the energizing current.