Unbalance is one of the faults in rotating machinery, which generates high vibrations. The presence of unbalance can be confirmed by vibration analysis: the FFT spectrum analysis and phase analysis. In spectrum analysis, if radial vibration at the rotational frequency of the machine, i.e., 1X, dominates the spectrum, and in phase analysis, if the phase shift between horizontal radial and vertical radial measurements is 90° or between radially opposite measurements is 180°, unbalance is present. An additional vibration analysis in the axial direction must also be carried out for overhung rotor. In this paper, an experiment is performed on a rotor to predict unbalance. Vibration is measured in terms of displacement. By vibration analysis, unbalance is indicated. Also, for this experiment, an attempt is made to relate it to the “Balancing of Rotating Masses” theory.