Characterization of tribological properties of greases for industrial circuit breakers

Proper grease selection is essential for the electrical industry to minimize friction and wear between the components of circuit breakers under mechanical contact. In this investigation, the tribological properties of commercially available greases for industrial circuit breakers were evaluated. Three tribological tests were performed: the ITeE-PIB Polish Method for testing lubricants under scuffing conditions (extreme pressure, EP), a four-ball test under ASTM D 2266 (anti-wear, AW), and a ball-on-disk test based on ASTM G-99. The worn materials were characterized with an optical 3D profilometer measurement system and a scanning electron microscope (SEM). Additionally, selected greases with the best tribological performance were tested on a testing bench intended for circuit breakers, according to electrical safety standards, which validated the results obtained in the laboratory.