Rotating machines with center-hung dynamic balancing rotors are widely used in several industries. During operation, the rotor may gain or lose material due to the wear and deposition of foreign materials in the rotors. As a result of this, the rotor becomes unbalanced. Unbalanced rotor usually causes excessive machine vibration that generates large forces on the bearing. It also results in enormous power loss and leads to potential damage to the system. So, the vibrations caused by the rotor have to be continuously monitored to prevent the potential damage to the rotating machinery. In this project, experimental studies are performed on a dynamic rotor test apparatus to obtain the vibration response of the rolling element bearings in the rotating system under several masses with different running speed conditions. The shaft is attached with four rotors, each having different mass and rotating in different planes. The rotor shaft vibration responses on the bearings are obtained using piezoelectric accelerometer. Dual-channel vibration analyzer (ADASH) is used to analyze the obtained vibration data. The identification of system characteristics is to be carried out. The results thus obtained can be used for condition monitoring of the unbalanced rotor system.