Axial Phase Analysis Around A Single Bearing
Phase analysis can also reveal some important information when performed in the axial direction. Let's examine what is happening in the animation here:
  • There are 6 transducers mounted axially - the movement being measured is axial only.
  • We are measuring phase in the same manner as for radial phase - namely triggering the strobe light at a peak amplitude and freezing some reference mark (a key ?).
"Planar" Motion
  • With the transducers mounted in this manner, the peak signal will arrive when the bearing is displaced its maximum to the right.
  • Each of the 6 transducers are displaced the maximum amount to the right at the same moment. 
  • Therefore, regardless of which transducer you are analyzing from, the phase angle (location of the mark) will be the same.
Just as our radial phase analysis provides important information on the 'shape' of the movement radially, an axial phase analysis provides important information on the 'shape' of the movement axially. In the above animation, we have found there is no phase shift as we move the transducer around the face of the bearing. But how else could it be moving ?
 
The Bearing Is Moving Axially In A "Planar" Motion (Not Twisting On The Shaft)

What is the significance of this ?
 

The Source Of The High Axial Vibration Is Not Caused By Incorrect Installation Of This Bearing