Arc Duration and Rotational Frequency of Break Arcs Driven by Radial Magnet Field in a DC42 V Resistive Circuit

Naoya TAKESHITA  Junya SEKIKAWA  Takayoshi KUBONO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E94-C   No.9   pp.1388-1394
Publication Date: 2011/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.1388
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 –)
Category: 
Keyword: 
electrical contacts,  relay,  contact erosion,  permanent magnet,  high-speed camera,  

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Summary: 
Break arcs are rotated with the radial magnetic field formed by a magnet embedded in the fixed contact. They are generated in a DC42 V resistive circuit. The circuit current when the contacts are closed varies from 5 A to 21 A. The strength of a radial magnetic field for rotating break arcs changes. Arc duration is investigated. Then rotational frequency, arc length and Lorentz force when the periodic rotation of break arcs starts are analyzed to investigate the conditions required to rotate break arcs. The following results are obtained. The arc length L when the rotational motion of the break arc starts is almost constant at a constant magnetic flux density with an increase in circuit current. The arc length L decreases with an increase in the magnetic flux density of the radial magnetic field. The rotational motion of break arcs starts when the arc length L reaches a certain value determined by magnetic flux density. Rotational frequency and Lorentz force increase linearly with an increase in circuit current.