The characteristics of poor performance of dynamic balance and unbalance problem were confirmed
Let's look at the vibration characteristics of unbalance and some proven analytical techniques to discuss how to determine unbalance:
First, unbalanced vibration characteristics
The basic characteristics of unbalance are intuitive and easy to understand. When the rotor with uneven mass distribution rotates, the unbalance rotation characteristics are reflected by the vibration characteristics
The periodicity of vibration is the same frequency as the working speed, and the main vibration energy is concentrated in the double rotation speed of the equipment
The degree of vibration intensity is sensitive to the change of working speed
Maximum radial vibration amplitude
The amplitude and phase Angle of vibration are stable and repeatable
The phase Angle of the vibration varies by about 900 in the horizontal and vertical directions
Second, how to analyze and confirm the cause of equipment failure is caused by imbalance
Double the frequency spectrum with large amplitude and very small harmonics
No other peaks are included in the significant amplitude
Verify accurate double speed characteristics with high resolution amplification or time synchronization averaging
The amplitude of the double speed frequency does not differ greatly in the horizontal and vertical directions, unless there is an asymmetric steel feature in the structure
The vibration intensity of axial frequency doubling is less than that of radial frequency doubling
Each rotation cycle produces a symmetrical waveform with no clipping or top discontinuity
In the phase analysis, the horizontal and vertical difference between the same bearing seat is about 90 degrees
When there is poor dynamic balance in the equipment, we must carry out the action balance correction, but before the dynamic balance correction, the analysis and identification of the causes of poor dynamic balance is the necessary step for us to carry out the action balance correction