Journal Archive

Platinum Metals Rev., 1962, 6, (1), 10

Erosion and Transfer in Electrical Contacts

Further Work on Transfer-Inductance Characteristics

The phenomena of transfer in electrical contacts are very complex and are not yet fully understood, although the influence of circuit inductance has long been recognised. Work carried out in this field by the Electrical Research Association is reviewed by W. Nethercot in the Association’s journal Co-operative Electrical Research. By using a new ultra-high-speed oscillograph it has been possible to study extremely short duration arcs in circuits with an inductance as low as about 0.1 microhenry, and the transfer-inductance characteristics of various contact materials normally used for relay contacts rated at up to 24 volts and ro amperes have been observed with inductance values from 0.1 microhenry upwards. It is suggested that the relay designer might deliberately relate inductance to the transfer characteristics of his contact materials: the data obtained show that with platinum and palladium this value can be as low as 0.25 to 1.0 microhenry.

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