Vibratory screens are used for grading i.e. separation of solid materials by grain size of materials. Other vibratory machineries like the road rollers and saw frames are also among the machines which are subjected to severe stress. High loads, high speed, acceleration, and centrifugal forces are strongly supported by the rolling bearings in the exciter units of these machines. These applications may also involve unpleasant ecological effects such as contamination and moisture.