3. What is Alignment?
It is the processofpositioning two (or more) machines
that are coupled, so that Centerlines ofrotating
shaftsform a single line, when the machinesare
working at normal operating temperature.
DEW/CBPM LAB
4. Causes Of Misalignment
Thermal expansion - Most machines align cold.
Machinevibrations.
Forcestransmitted to the machineby pipe or
support structure.
Soft foot.
Direct coupled machinedare not properly aligned.
Poorworkmanship.
5. Effects Of Misalignment
More than50% problems are due tomisalignment.
Causesvibration onthemachine
Vibration destroys critical parts ofmachineslike bearings, gears,
seals,couplingetc.
Breaks lubricant film inside thebearing andincrease friction.
Increases load onthebearing.
Increase2 - 17%powerconsumption.
Generates heatinside thecoupling.
8. Offset Misalignment
DEW/CBPM LAB
If the misaligned shafts
centerlines are parallel but not
coincident, then the
misalignment is said to be
parallel (or offset) misalignment.
11. 0.02
0.04
0.06
0. 12
1 2 3 4 5 6 7 8 9 10
0.14
0.08
0.10
0.16
1X
2X
DEW/CBPM LAB/JV
ORDER FREQUENCY
Parallel Misalignment
High vibration levels at 2X as well as
1X are produced in the radial directions
on the bearings on each side of the
coupling. Most often the 2X component
will be higher than 1X.
Marked by 180 degree phase shift across
the coupling in the radial direction.
Horizontal
&
Vertical
12. 0.02
0.04
0.06
0. 12
1 2 3 4 5 6 7 8 9 10
0.14
0.08
0.10
0.16
1X 2X
DEW/CBPM LAB/JV
ORDER FREQUENCY
Parallel Misalignment
Axial
Axial 1X and 2X levels will be low
for pure parallel misalignment.
14. Angular Misalignment
DEW/CBPM LAB
If the misaligned shafts
meet at a point but are not parallel,
then the misalignment is called
angular misalignment.
16. 0.02
0.04
0.06
0. 12
1 2 3 4 5 6 7 8 9 10
0.14
0.08
0.10
0.16
1X
2X
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ORDER FREQUENCY
Angular Misalignment
Axial
Angular misalignment produces a
bending moment on each shaft,
and this generates a strong
vibration at 1X and some
vibration at 2X in the AXIAL
direction at both bearings.
Marked by 180 degree phase shift
across the coupling in the axial direction
17. 0.02
0.04
0.06
0. 12
1 2 3 4 5 6 7 8 9 10
0.14
0.08
0.10
0.16
1X 2X
DEW/CBPM LAB/JV
ORDER FREQUENCY
Angular Misalignment
Vertical
&
Horizontal
There will also be fairly strong
radial 1X and 2X levels,
however these components will
be in phase.
20. Angular-Axial vibrationat 1XRPM
Offset -Radialvibration at 2Xor 3X RPM
Harmonics (3X-10X)generates as severity increases.
•Ifthe2Xamplitudemorethan50%of1X then coupling damage
starts.
•Ifthe2Xamplitudemorethan150%of1X thenmachineshould be
stoppedfor correction.
1. Vibration Spectrum Analysis
21. Angular-1800 phaseshift in theaxialdirection acrossthecoupling.
Offset -1800 phaseshift inthe radialdirection across thecoupling.00 to 1800 phase
shift occuras thesensor movesfromhorizontalto thevertical direction ofthesame
machine.
Skew -1800 phaseshift in theaxialor radial direction across thecoupling.
2. Vibration Phase Analysis
22. Angular - Axial vibration at 1X RPM
Offset - Radial vibration at 2X or 3X RPM
Harmonics (3X-10X) generates as severity increases.
If the 2X amplitude more than 50% of 1X then
coupling damage starts.
If the 2X amplitude more than 150% of 1X then
machine should be stopped for correction.
Vibration Spectrum Analysis..Recap..
DEW/CBPM LAB
25. Flexible Coupling
Can flexiblecoupling takemisalignment?
Flexible coupling can be used to take minor
misalignment but it will generate heat and
flexible memberswill fail prematurely.
26. Alignment Methods
1. Rough Alignment
(a) Using straight edge
(b) Twin wire method
2. PrecisionAlignment
(a) Face & Rim
(b) Reverseindicator
29. Face& Rim Method
Advantages:
1.Goodfor large dia.coupling hubswhere theshafts are closetogether.
2.To beused where oneof theshaftscannot rotate during alignment.
3.Easytouse.
Disadvantages:
1.Difficultto takefacereadings, if there isaxial floatin theshaft.
2.Requires removal of couplingspool.
3.Morecomplexalignmentcalculation.
31. ReverseIndicator Method
Advantages:
1. Moreaccurate than face & rim method.
2. Readings are not affected by axial float.
3. Possible to keepthe coupling spool.
Disadvantages:
1. Both shafts have to be rotated.
2. Should notbe used onclose coupled shafts.
3. Difficult to take readings on long shaft.
34. Off Set Angular
RPM mm mm / 100 mm
0000 - 1000 0.13 0.10
1000 - 2000 0.10 0.08
2000 - 3000 0.07 0.07
3000 - 4000 0.05 0.06
4000 - 5000 0.03 0.05
Alignment Tolerance
35. Disadvantages Of Dial
Indicator Method
Moretime consuming.
Too much manual work.
Indicator sag.
Difficult to perform on long shaft.
Difficult to determine soft foot.
Difficult to perform vertical shaft alignment.
39. Rules For GoodAlignment
Clean the machine base. Remove rustburrsetc.
Usesteel or brassshims.
Check indicator sag.
Check soft foot.
Check dial gauges before taking readings.
Usecorrectbolt tightening procedure.
Don’t lift the machine more thannecessary.
Tryto put the stem of dial gauge perpendicular to
the surfaceofcoupling.
Usejack bolts.
41. Light Amplified By Stimulated Emission Of Radiation
Laser was originally emitted by chargesent through
a gas mixture of Helium & Neon.
Now it emitted by a low power semi conductordiode
with collimating lenses.
Modulated toavoid interferencefromotherlight
source
It is collinear.
Single wave length of670 nm.
Class II Laser is used for Laser Alignment System.
Laser
