This is a common misconception in some industries surrounding flexible couplings. Some maintenance and production individuals believe that flexible couplings are designed to allow for a few degrees of misalignment. This is not quite the case. While flexible couplings do tolerate some amount of misalignment, this is not their intended purpose. The greater the misalignment, the shorter the life expectancy of the coupling.
Flexible couplings are designed to reduce some of the resulting shock impact that occurs when rotating shafts are started up. Another primary function is to act as a type of “fuse” between the motor and the driven machine. In the event of an abrupt failure or overload on either the motor or the pump, the flexible coupling will be destroyed instead of possibly both machines.
Shaft misalignment is the primary contributing factor in over 50% of rotating equipment breakdowns. A single coupling failure can cost thousands of dollars, just in lost productivity due to downtime. The precision shaft alignment performed in the field needs to be better than what the couplings will tolerate. Machinery has the potential to change position overtime causing misalignment. This is the main justification for precision machine alignment.
Through the proper use of precision shaft alignment equipment, we can be certain that our rotating machinery shaft alignments are done to a far more precise degree then we could ever do it without these instruments. The justification is the cost savings from greatly reduced equipment failures.
Save the Machine!