POWER-GEN Worldwide, September 2010
The alignment of turbine-generator sets poses unique challenges that only the best laser shaft alignment systems can overcome. Not the least of these is the difficulty of turning the shafts (either coupled or uncoupled) and the methods employed in turning them. The intent of this article is to present a few of these challenges and the solutions to them.
Since a turbine-generator train cannot be readily rotated by hand (unlike most other smaller machine sets), external “helper” forces must be enlisted, such as an overhead crane with a sling around the shaft or coupling. As the crane applies rotational force it also lifts the shafts in the bearings a little, changing their relative alignment and true position in the bearings. This makes using the Continuous Sweep measure mode impractical, since you do not want to corrupt the validity of the alignment data you are collecting as you rotate the shafts. The same concerns also apply to other methods, such as the chainfall and pin method…
Read entire article Turbine-Generator Alignment featuring the Rotalign Ultra laser shaft alignment system