Balancing speed

Question: Do I have to balance at operational speed?



Answer: No, usually not. The unbalance of rigid rotors does not change with the speed.



The centrifugal force which results from the unbalance does increase with the speed. When the rotating component (rotor) is not rigid enough to withstand the centrifugal forces caused by the unbalance, then the rotor is classified as Flexible.



In this case special procedures are required including checking the unbalance at operational speed.