Effect of Atmospheric Temperature on Contact Resistance of Sliding Contacts Using a Ag-Coated Slip Ring and a Ag–Graphite Brush

Conference: ICEC 2014 - The 27th International Conference on Electrical Contacts
06/22/2014 - 06/26/2014 at Dresden, Deutschland

Proceedings: ICEC 2014

Pages: 6Language: englishTyp: PDF

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Authors:
Fuchimoto, Mifuyu; Sawa, Koichiro; Ueno, Takahiro (Nippon Institute of Technology, 4-1 Gakuendai, Minamisaitama-gun, Saitama 345-8501, Japan)

Abstract:
Sliding contact is the process of transferring the electrical current between a stationary and moving object. In DC motors, the static part is the brush and the moving object is the commutator. DC machines are used in many fields, such as metal rolling iron processing, electric railways, and paper mills. The brush–slip ring system of generators used in wind turbines requires a long lifespan. Thus, improved reliability and an extended lifespan are desirable qualities for sliding contact systems. Recently, it has become desirable to use new materials for the slip ring and brush to improve the contact reliability while also increasing the current capacity. Silver has been used for the slip ring and brush instead of conventionally used copper to achieve these effects. In this study, we focused on the contact voltage drop, coefficient of friction, and brush wear at atmospheric temperatures of -15, 0, and 20 °C using silver materials. When the silver content of the brush is low, the contact resistance tends to be high. In addition, when the silver content is less than 80%, brush wear is hardly affected by a change in atmosphere temperature.