• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.318-331
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• 2000

Electrical and tribological behaviours of a copper-graphite brush in a slipring-brush assembly were investigated to evaluate the characteristics of electric signal transmission between a slipring and a brush. Five brush materials containing different amounts of copper and graphite were studied. The result showed that a copper-graphite brush at a particular graphite content exhibited the most stable frictional and electrical behaviour suggesting an optimum amount of a solid lubricant in a metal-graphite brush system. Microscopic observation and the surface analysis showed good agreements with this phenomena. In addition, the deviation of the friction coefficient and electric signal distortion has a close relationship with a microscopic mechanical vibration and the change of a real contact area.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.187-193
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• 2000

Friction characteristics and electrical resistance of sliding contacts in slipring-brush assembly were investigated. Four brush materials containing relative amounts of copper and graphite were studied. The result showed that a copper-graphite brush at a particular graphite content exhibited the most stable frictional and electrical behaviour suggesting an optimum amount of solid lubricant in metal-graphite brush system. Microscopic observation and the surface analysis showed good agreement with this phenomena.

• KSTLE International Journal
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• v.2 no.1
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• pp.22-28
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• 2001

A resin bonded copper-graphite brush was investigated to evaluate the characteristics electrical signal transmission through a sliding contact as a function of the relative amount of graphite and copper in the brush. Particular attention was given to the correlation between electrical signal fluctuation and tribological properties in an electrical sliding contact system. A ring-on-block type tribotester was used for this experiment and the ring was made from pure copper. Results showed that a copper-graphite brush at a particular composition range exhibited the most stable frictional behavior with a minimum voltage drop. The amount of voltage drop at the friction interface was affected by the surface roughness, transfer film formation at the friction interface, and the real area of contact. Microscopic observations and the surface analysis showed a good agreement with the results from this experiment. The results also indicated that the electrical signal flunctuation was directly associated with the oscillation of the coefficient of friction during sliding by nanoscale variation of contacts at the friction interface.