1. Vibration caused by rubbing between dynamic and static parts

For example, the collector outlet and the impeller inlet rub, the impeller and the casing rub, the spindle and the sealing device rub. Its vibration characteristics are as follows:

          Vibration instability;

          Vibration is self-excited vibration independent of speed;

          When friction is severe, reverse vorticity occurs.

          2. Vibration caused by abnormal rolling bearing

         Vibration of poor bearing assembly:

         If the journal or shoulder is badly processed, the journal is bent, the bearing is tilted, and the inner ring of the bearing is not overlapped with the axis line after assembly, so that the bearing produces an alternating axial force every turn, and the fixed round nut of the rolling bearing is loosened, resulting in local vibration. Its vibration characteristics are as follows:

         The vibration value is the largest in axial direction.

         The frequency of vibration is equal to the frequency of rotation.

         3. Vibration caused by insufficient stiffness of bearing seat foundation

         Poor grouting of foundation, loose anchor bolts, loose gaskets and weak connection of machine base will cause severe forced resonance phenomenon. The characteristics of this vibration are:

Vibration of bearing seat at faulty anchor bolt. Large and in radial component. Big;

Vibration frequency for the speed of 1, 3, 5, 7 and other odd frequency combination, 3 times the component value of the highest frequency domain characteristics.