Requirements of good shaft alignment / good coupling set-up

Easy to connect or disconnect the coupling.

This does allow some misalignment between the two adjacent shaft rotation axes.

No projecting parts

Goal should be to minimize the remaining misalignment in running operation so as to maximize power transmission and to maximize machine runtime (coupling, bearing and sealing's lifetime).

It is recommended to use manufacturer's alignment target values to set up the machine train to a defined non-zero alignment, due to the fact that later, when the machine is at operation temperature, the alignment condition is perfect