methodical phase analysis

8/11/2019 Methodical Phase Analysis

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Methodical Phase Analysis

by

Franois (Frank) Gagnon

2007 by Frank Gagnon

April 2007 / Frank Gagnon
http://www.vibra-k.com/mailto:[email protected]:[email protected]://www.vibra-k.com/http://www.vibra-k.com/http://www.vibra-k.com/


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Breaking Down PHASEANALYSIS into EASY

STEPS

1999, 2007 by Franois Gagnon

Vibra-K Consultants Ltd.

[email protected]

The machine illustration is 1997 Technical Associates of Charlotte and is used under Fair Use as a

teaching adjunct to expanded material developed by Frank Gagnon


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Phase &

Unbalance

Taking the pain

OUT of phaseanalysis


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Phase implies a comparison

Measured Phase in relation to

Rotor position (for balancing)

Another point or locations measuredphase

What it was before


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Phase Measurement

Two-channel execution (comparativephase or complex spectra) offer thesimplest approach

No need for a visible reference off

the rotor


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Phase Analysis Tolerance

The phase difference seen in the lasttwo slides (tables) of thispresentation allow for a variation

Typically 30 degrees

So 60o is equivalent to 90o


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Phase Analysis Tolerance

More than one phenomenon may be drivingphase!

Some authors suggest up to 40o

difference as a tolerance: we findTHIRTY is enough

The caveat about two or more phenomenaacting simultaneously does apply (such as,

for example, unbalance AND misalignment)


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Complete Machine


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FIRST ROTOR / the motor

One rotor at a time in 6 easy steps


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First Step / OB Axial


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2nd Step / IB Axial


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3rd Step / H Phases together


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4th Step / Vertical Phases


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5th Step / Axial Phases Together


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6th Step / H and V


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So far, what have we found ?

?


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Second Rotor / the pump

Same six easy steps


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1- IB Axial


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2- OB axial


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3- Horizontal Phases


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4- Vertical Phases


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5- Axials together


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6- H & V Together


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Both Rotors Together

ACROSS THE COUPLING in

two easy steps


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2) Radial Phases across the

coupling


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Conclusion ???

Motor has abnormal vertical

phase behavior (180o)

Axial phases across the

coupling are opposed (180o)

Vertical phase across thecoupling are opposed (180o)


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Radial Phase Analysis


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Phase

Difference

0o 30 to

60o90o 120 to

150o180o

Unbalance

(general)H & V

Static(force)

H & HV & V

H & V

Couple H & V H & HV & V

Dynamic H & HV & V

H & V H & HV & V

Eccentric H & V H & V

Resonance H & V H & V

Acrosscoupling

Normal Misalignment(parallel)

Radial Phase Analysis


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Axial Phase AnalysisAxialPhase

0o 30 to60o

90o 120-150o

180o

BearingFace

NormalAll points

Abnormal(4 point

system)

Abnormal(2 point

system)

AcrossRotor

Normal Bent Shaft

AcrossCoupling

Normal AngularMisalignment

methodical phase analysis

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