Dust effects on various lubricated sliding contacts

Sliding electric contact experiments show that, in dusty environments, liquid lubricants appear to perform better than wax lubricants. Experimental and theoretical analysis indicates that high permittivity of the lubricants plays an important role in attracting dust. The mixture of dust particles and wax could be very harmful to the contact, especially under low normal force. Dust particles floated on the surface of liquid droplets appear to have high mobility, which reduces the dust problem. Electric current flowing through the contacts possibly melts the wax and decreases contact resistance. On the contrary, electric current weakens the mobility and floating ability of dust on the liquid surface, which leads to an increase in resistance. Simply reducing the contact size can cause the embedding of dust into wear tracks in low normal force applications