Shaft alignment

Shaft alignment is the process to align two or more shafts with each other to within a tolerated margin. It is an absolute requirement for machinery before the machinery is put in service.

When a driver like an electric motor or a turbine is coupled to a pump, a generator, or any other piece of equipment, it is essential that the shafts of the two pieces are aligned. Any misalignment between the two increases the stress on the shafts and will almost certainly result in excessive wear and premature breakdown of the equipment. This can be very costly. When the equipment is down, production might be down. Also bearings or mechanical seals may be damaged and need to be replaced. Flexible couplings are designed to allow a driver (electric motor, engine, turbine, hydraulic motor) to be connected to the driven equipment. Flexible couplings use an elastomeric insert to allow a slight degree of misalignment. Flexible couplings can also use shim packs. These couplings are called disc couplings. Tools used to achieve alignment may be mechanical or optical, like the Laser shaft alignment method, or they are gyroscope based. The gyroscope based systems can be operated very time efficient and can also be even used if the shafts have a large distance (e.g. on marine vessels).