Rotor Balancing Methods and Instrumentation

Rotor balancing methods may be separated into two categories: rigid rotor balancing and flexible rotor balancing. These generic titles refer to whether or not rotor flexibility is taken into account. That is, flexible rotor balancing procedures take into account rotor flexibility, while rigid rotor balancing procedures do not. Many flexible rotor balancing methods are suitable for balancing rigid rotors. However, rigid rotor balancing methods are, in general, not effective for balancing flexible rotors. Unfortunately, in practice, the use of rigid rotor balancing methods with flexible rotors is not unusual. The result is, at best, an extremely inefficient and costly balancing process and, at worst, a presumably well-balanced rotor which, at its operating speed, is actually very poorly balanced and potentially destructive. Specific rigid and flexible rotor balancing methods are discussed in considerable detail in this and the following several chapters.