• Torsion Industries

Washers, Copal Bimetal

Torsion Industries offers Copal Bimetal Washers which are bimetal washers that prevent bimetallic galvanic electro-corrosion at copper and aluminium joints. Copal consists of copper (sheet metal) cladded on pure aluminium (base metal), both metals being diffused together to form an inseparable whole by roll bonding process. Copal, is therefore not and alloy and copper layers are not electro plating but are rather mechanically welded aluminium sheets. It is known that when the aluminium terminals are directly connected to copper terminals to carry current at a high voltage, a bimetallic galvanic corrosion occurs, resulting in a high resistance at the joint. The heated joints are oxidised and loses contact resulting in sparks, voltage dropout power losses and failure, damage to machinery. When Copal bimetal is placed as a transition plate between aluminium terminal and copper terminal at the joint (with copper facing copper and aluminium facing aluminium), bimetallic galvanic corrosion is averted due to absence of air in Copal bimetal. Copal has been successfully evaluated and used by many of the world's leading electrical equipment manufacturers. Copal bimetal is used in substation and switchyard bimetallic clamp and connectors, cable lugs and cable end connectors, distribution, panel boards, bus ducts and bus bar chambers, isolators and switchgears, oil and vacuum circuit breakers, overhead connectors and flexible connectors.