Copper Tungsten

The copper tungsten grades for contact metals are Vaculoy CT60, CT70, CT75, CT78 and CT80. This range of compositions will cover most applications for arcing contacts in air blast, oil immersed and SF6 gas circuit breakers. The higher conductivity grade Vaculoy CT60 is also used for on-load tapchanger contacts operating in oil.

(See Copper Tungsten Table)

Silver Tungsten

The three grades of silver tungsten will cover most applications for arcing contacts in switchgear, control gear and circuit breakers operating in air or cell switches operating in chemical atmospheres. The higher conductivity grades ST50 and ST65 can also be used as main contacts and combined main/arcing contacts in medium duty switching operations or where an unacceptable temperature rise is experienced with higher tungsten grades.

Silver Tungsten Carbide

Vaculoy STC60 & STC72 are tungsten carbide silver composites with a higher hardness but lower electrical conductivity than the silver tungsten grades. They are suitable for air switching operations where a high arc and mechanical wear resistance are required. They are used in d.c. switchgear, miniature circuit breakers and heavy duty relays.

(See Silver Table)