Why static balance and dynamic balance check should be done on the rotor of centrifugal compressor

The impeller on the main axis of centrifugal compressor and other parts and parts rotate at high speed along with the coaxial, which is collectively referred to as the rotor of centrifugal compressor. Before assembling the rotor, although every impeller and other parts and parts have done static balance inspection respectively, the rotor as a whole still needs strict dynamic balance inspection. This is because the rotating speed of the rotor is very high, and extremely tiny unbalance will cause great vibration.
As mentioned above, balance includes static balance and dynamic balance. Static balance is the basis of dynamic balance, which is mainly used to check and correct the independent balance situation of components such as impellers on the rotor. The content of static balance check is to check whether its center of gravity coincides with the rotating axis. If it overlaps, it can keep balance at any corner, otherwise it will rotate, and it can only stay still at a certain position (when the center of gravity is just below the axis; static balance correction refers to the method of finding out unbalanced mass (adding this mass to make it reach balance) through static balance test, and trying to get rid of equivalent unbalanced mass in symmetrical position, make the checked parts and parts reach static balance.
Although the rotor of centrifugal compressor has gone through strict static balance, it still inevitably has extremely tiny eccentricity, and there will still be unbalanced force when the rotor rotates. Especially because the unbalanced mass of each part is not in the same plane, they will generate a moment of torque, which makes the axis bend and thus generate vibration. Therefore, dynamic balance test on the rotor is also needed. The dynamic balance test is carried out on the dynamic balance machine. When the rotor is rotating (it is better to reach the working speed), check its unbalance and try to eliminate the influence of its unbalance torque.
The dynamic balance requirement of centrifugal compressor rotor is usually high. The specific value mainly depends on its rotating speed, generally in the order of micrometer.