Experimental Study of a Rotor Supported by Deep Groove Ball Bearing

Abstract

An experimental analysis has been done to analyze the effect of ball bearing support for a rigid, horizontal rotor. The effect of radial internal clearance of a ball bearing on its stiffness is studied by setting up a rigid, horizontal Jeffcott rotor supported by same type of ball bearings with known radial internal clearance. The nonlinear dynamic characteristics of the ball bearing are also studied by an experimental setup. The signal is acquired by displacement and acceleration transducers. Analysis of the acquired data with the help of Bode plots, cascade plots, time response plots, phase plane plots and frequency spectra brings out the non-linear nature of the ball bearing support. The effect of clearance on the varying compliance frequency, rotational frequency and the resultant sum-difference frequencies can be inferred from the various plots. The anisotropic nature of the ball bearing support shows up as the backward whirl components in full vibration spectra cascade plot. These experimental results validate theoretical results reported in literature.