Over the past twenty years, the level of awareness concerning the importance of accurate and precise shaft alignment has increased dramatically. In would therefore appear that shaft alignment seems to have taken a more important role when installing and maintaining machinery.

The alignment is considered to be satisfactory when it is possible to ensure the shaft parameters within the required limits under all operating conditions of the vessel.

Effects of Misalignments:

• Excessive axial and radial forces on the bearings, which reduce longer bearing life and rotor stability under dynamic operating conditions.
• Increase shaft bending from the point of power transmission in the coupling to the coupling end bearing.
• Increases wear in the coupling components.
• Possibility of shaft failure from cyclic fatigue.
• Possibility of increase vibration levels in machine casings, bearing housings, and rotors
• Premature bearing, seal, shaft, or coupling failures.

• High casing temperatures at or near the bearings or high discharge oil temperatures.
• Excessive amount of oil leakage at the bearing seals.
• Loose foundation bolts.
• High number of coupling bolts failures, coupling bush failures, gear teeth of coupling failures or they wear quickly.
• Excessive amounts of grease (or oil) on the inside of the coupling guard