Purpose of Rotor Balancing

An unbalanced rotor will cause vibration and stress in the rotor itself and in its supporting structure. Balancing of the rotor is therefore necessary to accomplish one or more of the following:

• Increase bearing life
• Minimize vibration
• Minimize audible and signal noises
• Minimize operating stresses
• Minimize operator annoyance and fatigue
• Minimize power losses
• Increase quality of product
• Satisfy operating personnel

Unbalance in just one rotating component of an assembly may cause the entire assembly to vibrate. This induced vibration in turn may cause excessive wear in bearings, bushings, shafts, spindles, gears, etc., substantially reducing their service life. Vibration sets up highly undesirable alternating stresses in structural supports and frames that may eventually lead to their complete failure. Performance is decreased because of the absorption of energy by the supporting structure. Vibrations may be transmitted through the floor to adjacent machinery and seriously impair its accuracy or proper functioning.

(Practical Machinery Management for Process Plants, Volume 3, Second Edition – Machinery Component Maintenance and Repair – Heinz P. Bloch)