This article helps mechanical engineers understand the selection of ball bearings depending upon the application and load conditions. Primarily the article helps you calculate the minimum and maximum load bearing capacity of bearing and most importantly... life of the bearing as an individual. Here the designation number of the ball bearing helps you know the design, working nature and the physical property of the bearings.

In this new edition, I have come up with accuracy, operating temperatures, re-lubrication features along with applications, utility and system of operations recommended by American Society of Mechanical Engineers (ASME). You can also observe reflections of rules abiding ANSI/API standards putting a significant relevance with bearing operations from maintenance point of view.

Introduction
For Pumps used in Petroleum Industries and Gas Industries, we have some standard statements meant to be followed:-

Each Shaft shall be supported by two radial bearings and one double acting Thrust Bearing which may or may not be combined with one of the radial bearings. This means, The thrust bearing may or may not be in the same axis as the rest of the two radial bearings. In other words, it can also said as, the thrust bearing can be arranged in such an order that, it may or may not be a part of the system bearing calculation although supporting the shaft.

Here, there can be only three possible system of arrangements,

1. Rolling Element radial and Thrust.
2. Hydrodynamic radial and rolling element thrust.
3. Hydrodynamic radial and thrust.

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