ABSTRACT
This chapter looks at several available contact materials and describes the advantages and disadvantage of each material for given applications. It explains the information about how to select the right material, the contact size, and the clamping force. The chapter discusses the ways these contact materials can be attached and tested. Movable contacts are switching contacts that are opened and closed occasionally or frequently. Although the contact force is lower, the basic theory of current flow applies equally for fixed and movable contacts. Careful consideration must be given to the contact forces for movable copper contacts. There are several copper-based alloys and mixtures that can be used in movable contacts. Copper-chromium is the strongest available substance that can be used as a backing material for silver contacts. Despite high cost, this alloy is used when high strength and good conductivity are needed for lightweight, movable copper contact arms.
