Effects of dust 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 floating 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 floatability of dust on the liquid surface, leading to an increase in resistance. Simply reducing the contact size may cause the embedding of dust into wear track in low-normal-force applications