Electric contact performance: effects of contact surface morphology and the size of dust particles

Dust deposition is influenced by many factors such as orientation of the coupon, electric static field, and permittivity of the lubricant which covers the coupon surface. Morphology of the surface is found to be an important factor which effects the dust size and density distribution curve: the rougher the surface, the larger the particles that are deposited. This phenomena is explained theoretically by means of the balance among various forces, including electric attracting force and mass gravity force of the dust particle. Experimental results showed that electric contact failure is closely related to the particle size and the morphology of the contact surface. Theoretical analysis indicates that there is a hazardous size range of the dust particles, within which dust particles are difficult to be moved away from the contact and thus cause the contact failure