Influence of design, manufacturing & installation practices on rotor vibrations of large induction motors used in Petrochemical industry

In induction motors several kinds of internal and external excitations exists, which can cause lateral vibrations of rotors. In addition to mechanical excitations such as mechanical unbalance, also electromagnetic forces exist between rotor and stator which influences the rotor vibrations. Besides design and manufacturing factors, coupling selection, motor base design and field installation practices can significantly influence the rotor vibration of the motor. In this paper we will present and discuss the effects of various design, manufacturing and other external factors on the vibration of induction motors including the effects of electromagnetic forces. Rotordynamics analysis along with the measurement data will be presented to explain the vibration in the induction motors used in Petrochemical Industry Applications.