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Shaft aliment

1. By : Eng.MotazabdelsalamMohamed
1
SHAFT
TO SHAFT
ALIGNMENT

2. Coupling types and function
2

3. Purpose :-
Is to transmit rotary motion and torque from the driving
equipment to the driven.
•Secondary functions :-
–Accommodating misalignment between shafts.
–Transmitting axial thrust loads from one machine to
another.
–Maintaining precise alignment between connected shafts.
3
Couplings

4. Rotating Machinery “Driver”
•Turbines
–Gas
–Steam
–Water
–Wind
•Reciprocating
–Diesel
–Gas
4
Electric Motors
–Star Delta
–Variable
speed/variable
frequency

5. •Compressors
•Mixers
•Fans
•Propellers
•Centrifugal pumps
•Gear Pumps
•Screw Pumps
•Piston Pumps
•Reciprocating Pumps
•Electrical machines (generators)
5
Rotating Machinery “Driven”
Couplings

6. 6

7. •Rigid
•Flexible
•Mechanical
•Material
•Elastomeric
•Metal Membrane
All types transmit power
without speed change.
•Gearboxes
•Belt drives
All types change the speed.
7
Couplings Modifiers
Couplings

8. •Coupling misalignment tolerances quoted by flexible
coupling manufacturers specify the mechanical limits of
the coupling or components of the coupling.
•These misalignment tolerances are excessive compared
to shaft misalignment.
8
Couplings & Shaft Misalignments Tolerance

9. 1.Allow limited amount of parallel and angular
misalignment.
2.Transmit power.
3.Insure no loss of lubricant in grease packed types
despite misalignment.
4.Be easy to install and disassemble.
5.Accept torsional chocks and dampen vibration.
6.Minimize lateral loads due to misalignment.
7.Withstand temperature from exposure to environment
or coupling components friction.
8.Ability to run under misalignment when equipment is
initially started.
9.Min. unbalance force and min. effect on critical speed.
10.Be of materials capable of long life and trouble free
service.
9
The Role of the Flexible Coupling

10. •Normal horsepower and speed.
•Max. horsepower being transmitted at max. speed.
•Misalignment accepted limits without failure during
startup.
•Temperature range limit.
•Lubricant type and amount.
•Actual end floats and thermal growth.
•Shafts diameters and distance between shafts ends.
•Type of environment.
•Type of shaft ends (straight, tapered, and threaded)
•Cost, noise and availability of spare parts.
10
Couplings Selection Considerations

11. •Shaft couplings are divided into two main groups.
–Rigid coupling-: It is used to connect two shafts which
are perfectly aligned
a)Sleeve or muff coupling
b)Clamp or split-muff or compression coupling
c)Flange coupling
11
Coupling types

12. 1.Rigid coupling (precise alignment is necessary)
-Used to connect machines where it is desired to maintain shafts
in precise alignment.
-The rotor of one machine is used to support and position the
other rotor in a drive train.
-Very little misalignment is accepted.
-High horsepower is transmitted.
-Vertical pump applications where one of the driver bearing
(thrust bearing) is carrying the weight of the armature and the
weight of the pump rotors.
-The misalignment tolerance of the rigid coupling is the same
tolerance that applies for accepted runout conditions for single
shaft.

13. Couplings

14. Rigid coupling
Types of rigid couplings:-
1.Flanged rigid coupling
-Two flanged rigid members, each mounted on one of the connecting
shafts.
-The flanges are provided with a number of bolts for the purpose of
connecting the two coupling haves.
2.Split rigid coupling
-split along horizontal centerline.
-The two halves are clamped together by a series of bolts arranged
axially along the coupling.

15. Rigid coupling
DriverEquipment

16. 16
Rigid Coupling
Flange

17. 17
▪Flexible coupling Flexible couplings are used to
transmit torque from one shaft to another when
the two shafts having both lateral and angular
misalignment.
Vibration& Shock
Flexible Coupling

18. 18
Jaw Coupling
Gear Coupling Elastomeric Flexible
Coupling
Chain Coupling
Flexible Coupling

19. Heavy duty coupling
19
Pin and push coupling

20. 20
Flexible Disk (Shim) Coupling

21. •Consists of two sets of thin sheet metal disks bolted to the
driving and driven hub members.
•Each set of disks is made up of a number of thin laminations
which are flexible and compensate for shaft misalignment
by means of this flexibility.
•Required no lubrication and alignment of the equipment
must be maintained within acceptable limits.
21
Flexible Disk Coupling

22. •Capacity up to 65000 hp
•Max recommended speed up to 30000 rpm
•Shaft bores up to 12 in
•Shaft spacing up to 20 in
22
Flexible Disk Coupling

23. 23
Flexible Disk Coupling

24. 24
Flexible Diaphragm Coupling
Diaphragm
Pack
OD
Bolts
Spacer Bolts
Shippin
g Screw
Space
r
Rigid
Hub

25. Pre Alignment Checks
25

26. Before Alignment Check Steps
•Soft foot check
–Types
–Detection
–Correction
•Shaft and coupling run out
•Pipe strain or deflection
•Foundation leveling
26
Pre Alignment Checks

27. Soft foot types
Pre Alignment Checks –Soft Foot
27

28. Pre Alignment Checks –Soft Foot
Effect of Soft Foot
Total Shaft Deflection at
Rotation
180
o
Later
Parallel
soft
foot
Angula
r soft
foot
28

29. •We can detect soft foot by:
•Using vibration analysis
•Using dial gage
–On foot
–On coupling
•Using filler gage
29
Pre Alignment Checks –Soft Foot

30. Detecting Using Vibration Analysis
•We can detect soft foot by fix three bolts and loose the fourth one
and compare vibration measurement before and after .
•Repeat this process for all the motor legs finding the highest
effect leg that mean it`s the most soft foot one
•Loose this leg and tighten the other three
•Run the machine and take complete vibration survey making sure
that every thing is secured .
30
Pre Alignment Checks –Soft Foot

31. Soft foot check using foot dial.
Pre Alignment Checks –Soft Foot
Even Space
31

32. Soft foot check using rim dial.
Pre Alignment Checks –Soft Foot
Machine to be
moved
Fixed
machin
e
32

33. Soft foot check using filler gage.
Pre Alignment Checks –Soft Foot
33

34. Special Shims.
Pre Alignment Checks –Soft Foot
a. Stepped shim b. Elastomer shims
Elastomer
shim
Elastomer
shim
Metal shims
34

35. Mounting Foot Details.
Pre Alignment Checks –Soft Foot
Heavy-duty or special washer
to spread load over clearance
hole
Clearance hole for
horizontal alignment
Reduce diameter
here to increase
clearance
35

36. Alignment moving bolts
Pre Alignment Checks
Machine to be
moved (MTBM)
MTBM
Plate bolted or
welded to
baseplate
Jacking
Bolt
Tapped hole
Through
plate
Dial
Indicator
a. Section through mounting
feet
b. Plan view
36

37. Shims Sizes
37
Pre Alignment Checks

38. Shaft and coupling run-out
Pre Alignment Checks
a. Concentric shaft b. Eccentric shaft
c. Eccentric run-out d. Angular run-out
No run-
out
Run-out
38

39. Shaft and coupling run-out (Cont.):
Pre Alignment Checks
Coupling hub
bored off
center
Bent shaft
39

40. 40

41. Leveling
41
Pre Alignment Checks
Axial and
radial
moving
Bolts
Up&down
moving
bolt
Shims

42. Leveling
(Cont.):
42
Pre Alignment Checks

43. D.B.S.E distance between shaft ends
Pre Alignment Checks
CompressorGas Turbine
D.B.S.
E
43

44. Thermal Growth
44
Before Alignment Checks –Thermal Growth

45. Thermal Growth (Cont.):
45
Before Alignment Checks –Thermal Growth

46. Before Alignment Checks –Thermal Growth
Thermal Growth Calculation
46

47. Example
Before Alignment Checks –Thermal Growth
47

48. Alignment at Cold Condition
48
Alignment at Cold Condition
Ambient conditions –before start-up
Flexible coupling
will accommodate
growth
Compressor
Thermal
Growth
Thermal
Growth
Coupling
Face
Access
Gear Turbine
Coupling
Growth
Rotating Filed
Growth
Generator
Thermal
Growth
1-Beam Base
1- Beam Base
1-Beam Base
Foundation Interface
Steel Reinforced Concrete
Foundation
Coupling
Face
Thrillist bag
ASM
Before Alignment Checks –Thermal Growth

49. Alignment at load condition (hot condition)
49
Alignment at load condition (hot condition)
Base Load Steady State Operation
Compressor
1-Beam Base 1-Beam Base
1- Beam Base
Access
Gear
Gear
Operating
Temp
= 200-300
℉
Ambient
Air Inlet
Temp = 60
℉
Turbine
Hot Rotor
Theoretical Straight Line
Exhaust Temp
= 5000 ℉
Generat
or
Operatin
g Temp =
300 ℉
Generato
r
Rotating Filed
at Magnetic
Foundation Interface
Steel Reinforced Concrete
Foundation
Casing
Growt
h
Rotor
Growt
h
Casing
Axial
Growth
Casing Axial
Growth
Thrillist bag
ASM
Before Alignment Checks –Thermal Growth

50. Pipe strain check.
Before Alignment Checks –Pipe Strain
Machine
being
checked for
pipe strain
Pipe Strain
Pipe Strain
Pipe Strain
Pipe Strain
50

51. Measurement of dial bar sag.
Shaft to Shaft Alignment –Bar Sag
51

52. Measurement of dial bar sag
(Cont.):
Clam
p
Mandre
l
Dial BarKnuckle
Dial Indicator
A. Measurement at 12
o’clock
B. Measurement at 6 o’clock52
Shaft to Shaft Alignment –Bar Sag

53. Misalignment Correction Methods
Laser
Alignment
Reverse Dial
Rim & FaceAlignment Method
53

54. Filler and straight peace
54
This method can be described as coupling
alignment not shaft alignment as defined earlier
Misalignment Correction –Rough Alignment

55. Filler Vertical Alignment Calculation
55
Misalignment Correction –Rough Alignment
Driver
A
B
Driven
Coupling diameter = D
Measure from coupling to driver mounting
feet
x feeler calculation = back shin change
x feeler calculation = front shin change
A
D
B
D

56. Bracket sag reason
Setup Alignment Tools Correctly
56

57. Measurement of dial bar sag
Bracket sag (Cont.):
Setup Alignment Tools Correctly
Clam
p
Mandre
l
Dial BarKnuckle
Dial Indicator
A. Measurement at 12
o’clock
B. Measurement at 6 o’clock
57

58. Bracket sag (Cont.);
Setup Alignment Tools Correctly
58

59. How To Remove Sag Error From The Alignment Readings
Setup Alignment Tools Correctly
59

60. Setup Alignment Tools Correctly
Measuring Bracket Sag
Reading
Bracket Sag
Misalignmen
t
60

61. Important rules for right alignment
•Total indicator reading
•validity rule
•True position sensing
61
Dial Gage Balancing

62. Total Indicator Readings
62
A
B
C
D
TIR (vertical)= A -
C
TIR = Total indicator
reading
TIR (horizontal)= D -
B
Dial Gage Balancing

63. Validity Rules
63
Validity rule : D + B = A + C
Dial Gage Balancing
A
B
C
D

64. Validity Rules (Cont.):
•Dial Pointer Should PrefrablyBe Kept On The
MacineTo Be Moved.
•The Sum Total Of Both Side Readings Should Be
Same As Sum Total Of Top Bottom Readings.
•In Actual Practice ,We Can Allow A Difference
Of About 15%. This Rule Is Called Validity Rule.
•Sum Total Of Side Readings =
–0.15 + 0.25 = 0.40
•Sum Total Of Top Bottom Readings =
–0.00 + 0.36 = 0.36
•Difference = 0.40 –0.36 = 0.04 This Difference
Should Be Less Than 15 % 15 % Of 0.40 = 0.06
Thus Difference Is Less Than 15 %.
•Hence Alignment Reading Is Valid.
64
Dial Gage Balancing

65. What Checks to do If Alignment Readings are Found Invalid
•Check The Clamp For Looseness. If Found Loose, Tighten.
•Check The Dial Pointer Is Leaving Contact During Rotation. If So, Do
Rough Alignment With Straight Edge First.
•Check The Coupling For Eccentricity / Ellipticity And Shaft For Runout.
Rectify, And Rotate Both Shafts Together. If Still Alignment Readings
Are Found Invalid, It Means That There Is Sag In The Dial Clamp.
65
Dial Gage Balancing

66. True Position
66
0
0
C-A
D-B
Vertical true position
C-A
Horizontal true position
D-B
Dial Gage Balancing

67. Dial Gage Balancing
67

68. 68
Reverse Dial Method :
Alignment Using Dial Gage
Advantages of reverse dial method:
▪Relatively inexpensive and has been carried out
by tradesmen for years
▪Most plants have dial gauges at hand
Disadvantages are:
▪Moves must be manually calculated
▪Possibility of reading errors
▪Coupling run out errors
▪Bracket or bar sag

69. Alignment Using Dial Gage
▪Dial gauges
mounted on each
shaft
▪Machine dimensions
are recorded
▪Machine moves are
calculated
mathematically or
by scaling
DIS DIM
69

70. Alignment Using Dial Gage
Reverse Dial Graphical Method
▪Pick a suitable scale on the graph paper and
plot similar as below
▪The machine on the right hand side in red we
will consider as our movable machine
70

71. Alignment Using Dial Gage
Reverse Dial Graphical Method –E.g
71

72. Alignment Using Dial Gage
Reverse Dial Graphical Method –E.g
72

73. Alignment Using Dial Gage
Reverse Dial Graphical Method –E.g
73

74. Alignment Using Dial Gage
Reverse Dial Graphical Method –E.g
74

75. Alignment Using Dial Gage
Reverse Dial Graphical Method –E.g
75

76. Cross Dial Method Arrangement
76
Alignment Using Dial Gage

77. Example:
77
Cross Dial Method
Alignment Using Dial Gage
All values shown in mm

78. Alignment Using Dial Gage
78

79. Alignment Using Dial Gage
79

80. Alignment Using Dial Gage
80

81. Alignment Using Dial Gage
81

82. Alignment Using Dial Gage
82

83. Rim and face method
83

84. RIM and FACE alignment method
84

85. Measuring Vertical Misalignment
85
Alignment Using Dial Gage
▪Coupling Offset = Rim Dial (DIR) TIR
▪Shaft Angularity = Face Dial (DIF) TIR
2
Dimension A

86. Calculating the front and rear feet positions
86
Alignment Using Dial Gage

87. Measuring horizontal Misalignment
87
Alignment Using Dial Gage
▪Coupling Offset = Rim Dial (DIR) TIR
▪Shaft Angularity = Face Dial (DIF) TIR
2
A dimension

88. Rim and face graphical method
88
Alignment Using Dial Gage

89. 89
Plot the offset from the rim dial indicator on line DIR
Plot the second offset point using the shaft slope (Face TIR / A
dimension).
Alignment Using Dial Gage

90. 90
Alignment Using Dial Gage