Balancing; Onspeed Balancing of a Rotor

Balancing generally refers to the balancing of a turbomachinery rotor. Balancing can, in some cases, be done in the field. Maintenance staff can be trained, for instance, to balance a pump in situ in the plant, if their readings with their vibration analysis equipment confirm that this is what needs to be done. For more critical items, such as process compressors, this process is best done in the overhaul facility of the original equipment manufacturer (OEM). The exception to this would be if the end user had his or her own balance equipment and had trained staff that was capable of handling the rotor in question.

Most balancing of rotating machinery rotors or components of rotors (such as turbine wheels and so forth) is done in a balancing machine at speeds in the neighborhood of 1800 to 2000 r/min in atmospheric conditions. In certain rare instances, balancing at these speeds does not remove the imbalance (that was causing rotor vibration in the first place). As a last resort, the process engineer may have to specify onspeed balancing of this rotor. This needs to be done in a vacuum chamber and is expensive. Also, there are very few suitable vacuum test facilities in the world. Before getting into this additional expense, the process engineer is probably well advised to consult a rotating machinery engineer.

Balancing Problems, Troubleshooting (Turbomachinery) ( see Condition Monitoring)

Batteries ( see Cells)

Bearings ^[*] ( see also