ABSTRACT
Rotor unbalance is themost common malfunction in rotating machinery. It is so widespread that, if any lateral vibration occurs in the rotor, there exists a tendency to associate it with unbalances. ‘‘Balancing the machine!’’ is usually the indication for the cure, very often executed with no investigation of what kind of vibrations the machine exhibits and what might have caused the malfunction. Quite frequently, balancing procedures performed on the machine, which actually suffers from another type of malfunction, worsens the situation, sometimes dramatically, especially when the malfunction is due to a rotor crack, as pointed
Rotor vibrations due to unbalance have been recognized for over 100 years. Balancing procedures are equally old. However, during the last 25 years they have experienced substantial improvements due to implementation of vibration measuring electronic instruments and application of computers for data acquisition and processing.
