Balancing is the process of correcting the uneven distribution of geometric mass (see Unbalance). In the case of a centrifugal pump, perform this operation in such a way that the rotation axis of the pump rotor is a free axis (there is no free inertia effect during rotation). There is a difference between static and dynamic balance.
In static balance, the center of mass of the pump rotor is placed on the rotating shaft of the pump shaft as accurately as possible, thus eliminating the resultant force of centrifugal force (not to be confused with the resultant force). This is also called "single plane balance" and is usually applied when the axial dimension of the rotating mass is significantly smaller than its diameter.
When performing dynamic balancing on a balancing machine, the rotating shaft of the pump rotor becomes the inertial main shaft. As a result, not only the resultant force is eliminated, but also the resultant static moment of the centrifugal force is eliminated. This is called two-plane balance i (see also hydraulic imbalance of centrifugal pumps).