Explain shaft alignment and the consequences of misalignment.

• A. The process of aligning belt pulleys.
• B. Aligning gears in a gearbox.
• C. The process of aligning motor and driven shaft axes; misalignment causes excessive bearing wear, vibration, energy loss, and premature failure.
• D. Balancing the rotor.

Answer: (C)

Shaft alignment means making sure the axis of the motor shaft and the axis of the driven shaft run on the same straight line and are oriented so the coupling carries power without introducing bending moments. When alignment is correct, the shafts, coupling, and connected components share the load smoothly as the machine rotates.

If alignment is off, the misalignment creates bending forces in the shafts and in the coupling. Those extra forces translate into higher bearing loads, which speeds up wear and can cause overheating and premature bearing failure. The uneven loading also induces vibrations, which ripple through the machine, increasing noise, reducing efficiency, and contributing to fatigue of structural parts. All of this means energy is wasted in the form of heat and friction, and seals, gears, or other connected components can wear more quickly or fail. Proper alignment, checked and corrected with the right tools, keeps loads balanced, extends bearing life, reduces vibration, and improves overall reliability.