What is the purpose of shaft alignment in a two-shaft system?

• A. To correct angular and parallel misalignment in two planes, vertical and horizontal.
• B. To maximize gear ratio
• C. To minimize electrical interference
• D. To reduce lubrication requirements

Answer: (A)

Shaft alignment is about making sure the driving and driven shafts run along the same straight line so the coupling can transmit torque without adding bending stresses. In a two-shaft system, misalignment can show up as angular misalignment (shafts at an angle to each other) and parallel or offset misalignment (the axes are not on the same line). These errors can occur in both vertical and horizontal directions. The goal is to correct both angular and parallel misalignment in both planes so the shafts are effectively coaxial, which reduces vibration, wear on bearings and seals, and energy losses from the misaligned load. The other options don’t address this mechanical alignment issue: gear ratio relates to gear design, electrical interference is about electrical systems, and lubrication needs aren’t the primary purpose of alignment (though good alignment can help reduce wear and thus affect lubrication needs).