Carbon brush wear caused by silane additives

The influence of some silane and nonsilane additives used in the moisture cure technology on the excessive wear of the carbon brushes of DC motors was investigated. Silane vapours were shown to contaminate the brush-commutator contact increasing the brush wear. The rate of carbon brush wear was related to the amount of silane vapour reaching the brush commutator contact area. Higher molecular weight and lower volatility of the silane additives lead to reduced carbon brush wear. Good ventilation around the motor will potentially eliminate the need for research on special additives other than silanes for this application. The current findings are in agreement with the published literature on silicone contamination of electrical contacts. As even a very small quantity of the additive can substantially reduce the life of carbon brushes from years to few weeks, it is important to make a survey of the additives used in any industrial process to increase motor reliability.