phase angle on turbine

[Adam001]

If we have two probes on a turbine on one bearing and they are 90 degree apart now if the shaft is rotating in a pure ideal circular motion the phase angle between two readings is 90 degree , but if the shaft moves in elliptical motion or any other motion does the phase angle remains 90 or change ? and why ? ( Assume key phasor has a constant position in all cases )

 

[SomptingGuy]

If your probes are measuring linear motion past them (or a phase/frequency modulated signal from teeth), you will need three located around the circumference to resolve the three independent degrees of freedom (X, Y, Rotation).

Steve

 

[Sofistioelevib]

Adam001,
you are talking about two different things.
The phase relationship between two sensor is mechanical forced at 90 degrees and still 90 degrees in all shaft motion situation.
Different is phase related on the shaft motion that can change as the shaft motion change.
To clarify: suppose a normal fan, with ideal unbalance and you are going to measure horizontal and vertical measurement (90 degrees apart).
In this case (ideal unbalance) the phase measurement is coincident with mechanical 90 degrees so phase in vertical will be 90 degree shift from phase in horizontal exactly as the position of your sensor (vertical and horizzontal).
Now suppose you are in resonance and should be present only 10 degrees apart between horizzontal and vertical phase readings (but you still measure in horizontal and vertical position.

As previous described you will find in second case there are no match between phase readings and mechanical phase.

Hope to be clear.