Pump and motor misalignment is one of the main causes of breakage and premature wear of bearings, joints and seals and produces excessive vibrations, noise and increases in coupling temperature.
Misalignment is considered to be the cause of a percentage that is between half and two thirds of the failures of the rotating equipment.
From the loosening or breaking of the foundation and coupling bolts, these are a prelude to greater damage such as the premature failure of gaskets and even of the shaft
Alignment of the motor pump is essential because it minimises the misalignment forces acting on the bearings and the seals of the gaskets, minimises the wear of the joint and in addition lengthening the life of the components. Increasing of the time between failures and reducing vibrations also has benefits in terms of efficiency, reducing energy costs.
Larger motors are usually coupled directly to their loads with rigid or flexible couplings; the former do not compensate for misalignment of the motor while the flexible ones tolerate small amounts of misalignment and can also partially reduce the vibrations transmitted from one appliance to another.
However, coupling flexibility is not the solution to misalignment as it transmits stresses to the motor and to the bearings and/or to the pipes connected downstream of the motor.
The alignment of the motor pump involves re-alignment of the central lines of the shafts between a motor and a pump, through the use of lifting bolts or via lever bars, hammers or other tools.
For correct alignment, however, it is necessary to use alignment tools such as selection indicators or laser alignment tools.
The causes of misalignment include sedimentation of the base after prolonged operation, insufficient tightening of the bolts or installation errors.