ARC EROSION REDUCTION ON ELECTRICAL CONTACTS USING TRANSVERSE CURRENTINJECTION

Electrical contact lifetime is often directly determined by are erosio n, A method for reducing are erosion was developed consisting of injec ting from an external current source an additional electrical current flowing parallel to the contact surface, This method was examined in t hree are environments using the additional transverse electrical curre nt with a density less than 1 A/mm(2): 1) automobile ignition contacts ; 2) pulsed air are; and 3) low pressure (P = 100 mTorr) are in nitrog en. SEM and X-ray examination showed that application of a transverse current in a contact during arcing changed the phase composition and m icrostructure of the contact surface, Under optimal conditions, the mi crostructure which is formed is significantly more erosion resistant t han without the transverse current injection.