Influence of imbalance force angular position to vertical and horizontal rotors rolling bearings defects diagnostics

Instead of using the traditional periodical diagnostics, modern technological machinery has increasingly been using monitoring systems based on acceleration transducers of mechanical vibrations. Although, oftentimes it is difficult to identify rolling bearing faults, even if constantly monitoring and analyzing the machinery vibration acceleration or vibration velocity FFT spectra or their cascades. We usually run into such problems when analyzing gravity based technological processes (separators, diffusion machinery) in vertical machinery observations. This is because the angular position of imbalance mass varies often in this type of machinery, which causes the inner ring race fault in the bearing. This article describes the comparative experimental research data between the vertical and horizontal axis rotors. The test rig consists of the disk fixed onto the end of the shaft; the deep groove rolling bearing 6004-2Z/C3 with inner ring race defect is mounted behind the support. Throughout the experiment tests, the angular position of imbalance mass and inner ring race local defect is switched from 00 to 3600, each 450 angular step value. The study is carried out both with rotor axis oriented vertically and horizontally. In order to simplify the data being analyzed and to quantifiably assess the diagnostic experiments of vertical and horizontal rotor defects, statistical processing parameter called "Defect Visibility Ratio" (DVR) is being designed. Through the use of this statistical parameter, the defect-detection capabilities of rotor with bearing inner ring race fault can be determined quantifiably.