The most cause of machine vibration that created energy loss and less efficiency is misalignment. It occurs during the machine operation where stator and rotor have no linear position. It’s still elusive to detect the misalignment problem, because it has influenced by machine speed and stiffness of the system.
Basically, misalignment can be classified into parallel and angular misalignment. Parallel misalignment is detected by high radial vibration at 2x rpm where the amplitude value is a half of the amplitude of 1x rpm in radial direction. Angular misalignment is detected by high axial vibration at 1x rpm and its harmonics frequency may appear. The amplitude value of this type misalignment is about 30% to 50% of amplitude from 1x rpm.
Mostly, in all-over rotating equipment, misalignment occurs due to the combination of both types. To handle this phenomenon, laser precision alignment is the best choice. This alignment method is utilizing the laser beam that perpendicular shooting each other as detector to indicate the deviation from stator and rotor, then bring them into its line properly.