Which misalignment types are corrected by shaft alignment?

• A. Angular and parallel
• B. Radial and axial
• C. Vertical and horizontal
• D. Circular and diagonal

Answer: (A)

Shaft alignment targets two basic misalignment modes between connected shafts: angular misalignment, where the two shaft axes form a angle, and parallel (offset) misalignment, where the axes are parallel but displaced from each other. Correcting both types means the shafts’ axes line up along the same straight line, which minimizes bending moments in the shaft and coupling, reducing vibration, wear, and energy loss. The other terms describe directions or nonstandard labels rather than the two fundamental misalignment categories used in practice (vertical/horizontal are directions, circular/diagonal aren’t recognized categories, and radial/axial refer to other issues like runout rather than the primary shaft-to-shaft misalignments).