Selection of ball and roller bearings for electrical machines

The paper has been prepared to indicate the lines on which the selection of bearings should proceed in cases where it has been decided to employ ball or roller bearings for electrical machines. In order that due allowance may be made for bearings under different conditions of loading, it is suggested that some method should be adopted that would employ definite factors graded according to the service required, by means of which the capacity of bearings could be properly checked when necessary. It is not sufficient simply to use the makers´ tables of safe loads for all purposes, and certain ¿load factors¿ are put forward in order to furnish a rational basis of comparison. In conclusion, observations of a general character are made with regard to capacities, costs, types, etc. A list of previous papers on the subject is given for reference.