Abstract
The starting of large thrust bearings in turbines is one of the most critical points in their operation as a pressure carrying oil film must be generated from initial conditions of load and zero relative velocity between the two surfaces. A force equal and opposite to the applied load must be produced before the surfaces separate. It is the purpose of this paper to discuss the origin and formation of this force. The results show that lapped and ground surfaces have inefficient lifting characteristics as compared with surfaces having irregularities on the surface of 1/20 mil and greater. In general, surface oil pockets have an important influence on the starting behavior of tilting pad bearings; without these oil pockets it is doubtful if the two bearing surfaces would part.
