Pulley misalignments cause excessive belt and sheave wear, reduced bearing life, increased power consumption and high vibration levels. There are multiple types of misalignments that occur when the drive and driven shafts are not parallel and the sheaves are not axially aligned on the drive and driven shafts. Misalignments can be caused by improper belt tension and ineffective alignment procedures.

When machines are properly aligned the chance of machine failure is significantly reduced and the operating life is extended. Misalignment can cause bearing failure, coupling wear, high vibration, seal failures and reduced operating efficiency.

Misalignment is one of the two major causes of machine failure. The other is unbalance. Bearing failure is usually not the cause of machine failure, but actually the result of unbalance or misalignment. Typically misalignment will cause inboard or coupled end bearing failures. Inexperienced individuals might assume that a straight edge and a flexible coupling is all that is needed when performing an alignment. This is simply not the case., especially on larger, high speed machines. Proper alignment require the use of reverse dial indicators or laser alignment systems and the ability to recognize and correct for thermal growth, run-out, soft foot, sprung foot, unstable foundations and other conditions that will affect the final alignment. The PAT enables thr user to practice and become proficient in the use of different alignment instruments and methods. PAT can also be used to verify the accuracy and repeatability of the equipment and method used to perform the alignment.