What is a limitation of using cross dialing methods in alignment?

The correct choice identifies a significant limitation of cross dialing methods used in alignment. In cross dialing, accurate measurements are taken while both shafts are rotating, which is essential for ensuring that the alignment of the shafts is appropriately assessed. This method depends on the dynamic behavior of the shafts during operation; therefore, the requirement for both shafts to be in motion limits the applicability of cross dialing in situations where a shaft cannot be rotated or is stationary.

This limitation becomes particularly relevant in maintenance or troubleshooting scenarios where equipment must remain idle or when dealing with systems that do not allow for easy rotation of the shafts under inspection. Consequently, if one shaft cannot turn, the cross dialing method cannot be effectively utilized, highlighting how critical the operation of both shafts is for this alignment technique.