In the field of fan bearing vibration, the vibration of rotor mass unbalance accounts for the majority
Impeller wear (mainly blade) is not uniform or corrosion;
Uneven ash accumulation or attachment (e.g. rust) on blade surface;
Wing hollow blade or other parts of the cavity adhesive ash;
Local high temperature makes the shaft bend;
Impeller is not balanced after maintenance;
Impeller strength is insufficient to cause impeller cracking or local deformation;
Parts on the impeller are loose or connectors are not fastened.
Characteristics of vibration caused by rotor imbalance:
The vibration value is in the horizontal direction. Large, but the axial is small, and the bearing seat bearing vibration is greater than the thrust bearing;
Amplitude increases with revolution.
Vibration frequency is equal to speed frequency;
Vibration stability is good, not sensitive to load changes;
The measured phase Angle is unstable and the vibration frequency is 30% ~ 50% working speed when the hollow blade is displaced due to the gray inside or some parts are not welded firmly.