Vibration Analysis Services

Autocorrelation Instructions for AMS Machinery Manager Version 5.5 or higher. Images from Emerson for demonstration purposes In this above example, we have two Acceleration Time Wave Forms (TWF) from two different machines. The first or top TWF is from a Blower inboard bearing in the vertical plane. The second is a cooling water centrifugal pump inboard bearing in the vertical plane. Notice in both TWF’s it is hard to detect if there is any repetitive impacting To Auto correlate, select the time waveform. In the above example, we click on the first TWF blower. Once selected then right-click – (see below Autocorrelation,) After the right-click the above menu box will appear. (Select Auto correlate. See results below) In this example for the blower, the autocorrelation is near 1 so the impacts are repetitive and is most likely related to a bearing defect. The second example below is a centrifugal cooling pump. Again, once the TWF is selected we again right-click and select autocorrel

 Vibration Analysis of a Bent Shaft. A bent shaft predominantly causes high 1X axial vibration. The dominant vibration is normally at 1X if the bend is near the centre of the shaft, however, you will see 2X vibration if the bend is closer to the coupling. The axial measurement is the key indicator. Spectrum : Look for a high 1X peak in the axial plane.  If the bend is close to the coupling then you will see a higher 2X peak.  You may also observe higher than-normal 1X and 2X peaks in the radial direction. The phase is also a good indicator to diagnose a bent shaft. The phase at 1X measured in the axial directions at opposite ends of the component will be 180° out of phase. Please note if measurements are taken at the face of the component they will be in phase. TimeWave Form : The TWF is not a good indicator, however, a sinusoidal waveform is expected in the axial plane. Bent Shaft Spectrum in the axial direction. Please note the 2Xrpm will tend to appear if the shaft bend is closer t

  Vibration Data for Shaft  Misalignment  Offset/Parallel Misalignment 1X,2X,3X & sometimes 4X & 5X in the radial direction at Motor Running Speed, RPM Angular Misalignment: 1X & 2XRPM in the axial direction. 1X,2X & sometimes 3X in the radial direction. This can depend on the type of coupling in service. Offset/Parallel Misalignment The Centerlines are parallel but offset.  Offset Misalignment Spectrum. Be aware 3X & 4X RPM also be present. Note the 180 deg out of phase across the Coupling This is why phase measurements are needed to help confirm parallel misalignment. The 2X RPM is usually higher than 1X RPM. Readings taken radially in the horizontal and vertical planes should be similar. Angular Misalignment Spectrum :  Basically stated, angularity is the gap difference across two coupling faces-normally top to bottom or side to side. Angular misalignment in the radial direction Spectrum: Angular misalignment produces a bending moment on each shaft, and this g