va ii training
DESCRIPTION
VA II TrainingTRANSCRIPT
-
Intermediate Vibration Analysis
IMRAN AHMAD
Director Technical
SUMICO Technologies (Pvt) Ltd+92 321 427 6092
www.sumico.com.pk
-
Timings
1st Session 9000-1030
Tea Break 1030-1045
2nd Session 1045-1300
Lunch Break(Prayer) 1300-1400
3rd Session 1400-1530
Tea Break 1545-1600
4th Session 1600-1700
-
Basics of VibrationIntroduction:
What is Vibration?
-
Principle of Vibration Analysis
Mechanical faults generateunique vibration
Geometry of the machine
diameter of the shaft, number of bearing elements, etc.
Turning speed (e.g. RPM)
Mechanical Defects detected
with vibration analysis
Belt drive faultsImbalanceMisalignmentBent shaftLoosenessMachine resonanceCavitationShaft RubBearing Defects including:
cage defect
outer race defect
inner race defect
rolling element defect
Gear defectsElectrical faults
-
What is Vibration?
In simple terms vibration is :-
A response to some form of excitation
The free movement of the shaft in a journal bearing will cause it to vibrate when a forcing function is applied
What is Vibration ?
Vibration is the motion of a body about a reference position caused by a force
-
What is Vibration?
Vibration is a pulsating motion of a machine or a machine part from its original position of rest and can be represented by the formula:
Vibration Amplitude Response =
Dynamic Force
__________________
Dynamic Resistance
-
Vibration from Mechanical Faults
-
Vibration from Mechanical Faults
-
Vibration from Mechanical Faults
-
Vibration from Mechanical Faults
-
Vibration from Mechanical Faults
-
Vibration from Mechanical Faults
-
How Much Vibration is Too Much ?
1. Use Absolute Vibration Levels
- Given by machine makers
- Published Vibration Severity Standards
eg. ISO 2372, VDI 2056, BS 4675
2. Use Relative Vibration Levels
Vibration Fundamentals
-
11 0.44
7.1 0.28
4,5 0.18
3,5 0.11
2,8 0.07
2,3 0.04
1.4 0.03
0,71 0.02
mm/s rms inch/s rms
rigid flexible rigid flexible rigid flexible rigid flexible Foundation
pumps > 15 kW medium sized machines large machines
radial, axial, mixed flow 15 kW < P 300 kW 300 kW < P < 50 MW Machine Type
integrated driver external driver motors motors
160 mm H < 315 mm 315 mm H
Group 4 Group 3 Group 2 Group 1 Group
A newly commissioned
B unrestricted long-term operation
C restricted long-term operation
D vibration causes damage
ISO 10816-3
-
140 5.51
113 4.45
90 3.54
71 2.80
56 2.20
45 1.77
36 1.42
28 1.10
22 0.87
18 0.71
11 0.43
m rms mil rms
rigid flexible rigid flexible rigid flexible rigid flexible Foundation
pumps > 15 kW medium sized machines large machines
radial, axial, mixed flow 15 kW < P 300 kW 300 kW < P < 50 MW Machine Type
integrated driver external driver motors motors
160 mm H < 315 mm 315 mm H
Group 4 Group 3 Group 2 Group 1 Group
A newly commissioned
B unrestricted long-term operation
C restricted long-term operation
ISO 10816-3
-
Vibration standards are guidelines
Not
Permissible
Not
Permissible
Not
Permissible
GoodLarge Machines
with rigid and heavy
foundations whose
natural Frequency
exceeds
machine speed
Just Tolerable
Allowable
GoodSmall
Machines< 15 kW
Just Tolerable
Allowable
Just
Tolerable
Allowable
Good15 kW