Misalignment occurs when the motor drive shaft is not in correct alignment with the load, or the component that couples the motor to the load is misaligned. This misalignment may be caused during assembly or develop over time due to thermal expansion, components shifting or improper reassembly after maintenance. Unless corrected, misalignment leads to increasing wear in mechanical drive components and likely premature failures.
Many professionals believe that a flexible coupling eliminates and compensates for misalignment, but a flexible coupling only protects the coupling itself. Even with a flexible coupling, a misaligned shaft will transmit damaging cyclical forces along the shaft and into the motor, leading to excess wear on the motor and increasing the apparent mechanical load.
In addition, misalignment may feed vibration into both the load and the motor drive shaft. There are a few types of misalignment:
- Angular misalignment: shaft centerlines intersect but are not parallel.
- Parallel misalignment: shaft centerlines are parallel but not concentric,
- Compound misalignment: a combination of parallel and angular misalignment. (Note: almost all misalignment is compound misalignment, but practitioners talk about misalignment as the two separate types because it is easier to correct a misalignment by addressing the angular and parallel components separately.)
A Fluke 830 Laser Shaft Alignment Tool can measure and diagnose misalignment issues as well as easily guide a technician to realign a shaft to its proper working order.