Volume : III, Issue : V, May - 2013

Impact of Surface Film on Electrical Contact Resistance of Silver Impregnated Graphite Contacts

Hemant Kagra

Abstract :

Silver impregnated Graphite (SIG) contacts are used in Metal to Carbon Relays, which are used in railway signaling on Indian Railways for operating various signaling functions viz. signals / points / track circuits etc. During the course of operation, various films viz. carbide / impurities etc. get developed on these contacts, which influence its contact resistance. EDX analysis confirmed the existence of carbide film on SIG surface, which introduced a tunnel resistance during mating of contacts. Consequently, the electrical current stops flowing and the relays fail. This causes disruption to rail operations and adversely affects the train safety & punctuality. The philosophy of development of surface films on these contacts and their effect on the contact resistance, including the relationship of film resistance with various contact parameters, has been deliberated and suggestions to minimize their effect have been discussed.

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Article: Download PDF   DOI : 10.36106/ijar  

Cite This Article:

Hemant Kagra Impact of Surface Film on Electrical Contact Resistance of Silver Impregnated Graphite Contacts Indian Journal of Applied Research, Vol.III, Issue.V May 2013

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