Research of high reliability of noble metal slip-ring for supply of small electric power

摘要

Electrical sliding contact is a mechanism that transfers the current to a moving apparatus from a stationary power source. It is used for a lot of things to support our civilized society as a basic technology, such as commutator and brush of DC machine, slip ring and brush of AC machine, and trolley wire and pantograph sliding strip of electric railways. Therefore, long lifetime, maintenance free and high contact reliability are requested to sliding contacts. In large machines, carbon brushes are chiefly used as a brush material of electrical sliding contacts. However, a precious metal brush such as silver is sometimes used from viewpoint of high current density. On the other hand, for small current application gold plating is often used to realize high reliability and long life. In this paper, deterioration process is examined in a performance test where a lubricant is regularly applied. Consequently the wear process of gold plating layer is clearly observed.