Vibration Analysis for Rotating Machine
-
Upload
pond-wasin -
Category
Documents
-
view
246 -
download
0
Transcript of Vibration Analysis for Rotating Machine
-
7/26/2019 Vibration Analysis for Rotating Machine
1/46
Vibration monitoring and analysisfor rotating machine
Introduction to mechanical vibration
-
7/26/2019 Vibration Analysis for Rotating Machine
2/46
Outline
Introduction
Vibration monitoring and analysis
Vibration : Measurement
Data Acquisition
Types of transducer
Mounting method
FFT analysis
Example
Unbalance
Misalignment
Spur gear
Centrifugal pump
-
7/26/2019 Vibration Analysis for Rotating Machine
3/46
Introduction
Static equipment Ex. Pressure vessel, Tank
Rotating equipment Pump, Compressor, turbine
-
7/26/2019 Vibration Analysis for Rotating Machine
4/46
Vibration monitoring and analysis
Raw Data
Time domain
Analysis data
Frequency domain
FFT analyzer
Sensor
-
7/26/2019 Vibration Analysis for Rotating Machine
5/46
Vibration : MeasurementAmplitude Units
Displacement, D Micrometer peak to peak
Velocity, V mm/s - peak or rms
Acceleration, A mm/s2- peak or rms
-
7/26/2019 Vibration Analysis for Rotating Machine
6/46
Types of transducer
Proximity Probe Seismic Velocity
ProbeAcceleration Probe
Relative displacement Velocity Acceleration
01,500 Hz 81,500 Hz 120,000 Hz
-
7/26/2019 Vibration Analysis for Rotating Machine
7/46
Mounting method
Method Frequency
limit (Hz)
Hand held 500
Magnet 2,000
Adhesive2,500
4,000
Bees wax 5,000
Stud6,000
10,000
-
7/26/2019 Vibration Analysis for Rotating Machine
8/46
FFT analysis
Fast fourier
transform (FFT)
-
7/26/2019 Vibration Analysis for Rotating Machine
9/46
Vibration monitoring and analysis
Raw Data
Time domain
Analysis data
Frequency domain
FFT analyzer
Sensor
-
7/26/2019 Vibration Analysis for Rotating Machine
10/46
Example
Unbalance
Misalignment
Spur gear
Centrifugal pump
-
7/26/2019 Vibration Analysis for Rotating Machine
11/46
Type of unbalance1. Static unbalance2. Couple unbalance3. Dynamic unbalance
-
7/26/2019 Vibration Analysis for Rotating Machine
12/46
12
Static Unbalances
Corrected
balance weight in one plane at rotor centre of gravity (CG).
-
7/26/2019 Vibration Analysis for Rotating Machine
13/46
Couple Unbalances
180
Corrected
balancerequires correction in two planes at 180.
-
7/26/2019 Vibration Analysis for Rotating Machine
14/46
Dynamics Unbalances
static couple Staticunbalance Couple
-
7/26/2019 Vibration Analysis for Rotating Machine
15/46
Special case of Dynamics Unbalances
Corrected
Overhung rotors often have both static and couple unbalance eachof which may require correction.
Overhung Rotor Unbalance
-
7/26/2019 Vibration Analysis for Rotating Machine
16/46
Balancing
cooling tower
-
7/26/2019 Vibration Analysis for Rotating Machine
17/46
Cooling Tower
1. (transducer) (Tachoprobe)
2. 1- (Magnitude :mm/sec)- (phase angle)
3. (trial weight) Rotor
4. 2- (Magnitude :mm/sec)- (phase angle)
5. Polar graph
-
7/26/2019 Vibration Analysis for Rotating Machine
18/46
(Trail weight) Wt = 30 x Wr/ r
Wr Static weight : gr (radius of trial weight : mm)
(correct weight) Vc= Vox Wt/Vt
Vo Unbalance : mm/secVt : mm/sec
Reference by : Machinery vibration & Balancing /Victor Wowk.
-
7/26/2019 Vibration Analysis for Rotating Machine
19/46
spectrum cooling #4 1X rpm Amplitude Unbalancing
Frequency : 355.3
Amplitude: 4.379Phase : 84 degree
()
-
7/26/2019 Vibration Analysis for Rotating Machine
20/46
Vector correct & angle phaseon Polar graph
Data: 1.Rotor & Fan weight : 26 kg ,(4x32 kg)
2. Radius of trial : 220 mm.
Vector unbalance Vo: 4.379 mm/sec
Phase Vo: 84 degree.
Trial weight : 25 g (21 g)
Vector unbalance +weight V1: 7.4 mm/sec
Phase V1: 215 degree.
Vector from trial weight Vt: 10.8 mm/sec
Phase : 329 degree. (Vt-Vc)
-
7/26/2019 Vibration Analysis for Rotating Machine
21/46
Position of point to correct (Balancing)
Trial weight : 25 g (21 g)
Phase : 84 degree.
Correct weight ,Mc : 10.1 g
Correct phase : 31 degree.
Before..
After..
-
7/26/2019 Vibration Analysis for Rotating Machine
22/46
Amplitude: 1.684 mm/sec
4.375
()
-
7/26/2019 Vibration Analysis for Rotating Machine
23/46
Misalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
24/46
MisalignmentIntroductio
n
What is it? Misalignment is a conditionwhere the centerlines of
coupled shafts do notcoincide.
-
7/26/2019 Vibration Analysis for Rotating Machine
25/46
EX.
Introductio
nMisalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
26/46
Introductio
n
Bearing, Coupling, Seal and Shaft failure
Lost time to repair machine
Lost opportunity to run process
Lost Maintenance Cost
Misalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
27/46
Type of
misalignmen
tMisalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
28/46
Detection
methodMisalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
29/46
Introductio
nMisalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
30/46
MisalignmentDetection
method
Time- Frequency Domain
Fast fourier
transform (FFT)
-
7/26/2019 Vibration Analysis for Rotating Machine
31/46
Type of
misalignmen
tMisalignment
-
7/26/2019 Vibration Analysis for Rotating Machine
32/46
Type of
misalignmen
tMisalignment
Shear force
Bending moment
2X component will
be higher than 1X.
Depend on thecoupling type
Axial 1X and 2Xlevels will be low
Symptoms: 2X radial, smaller 1X
radial
-
7/26/2019 Vibration Analysis for Rotating Machine
33/46
Type of
misalignmen
tMisalignment
Bending moment
Also be fairly
strong radial
1X and 2X levels
Symptoms: High axialvibration: 1X
strong (but 2X and 3X can also be
strong)
-
7/26/2019 Vibration Analysis for Rotating Machine
34/46
Type of
misalignmen
tMisalignment
Can be 3X, 4X all the
way up to 8X peaks
The noise floor is
not raised(unlike
rotating looseness)
Frequency: 1X and 2X (and 3X and
4X) axial and radial
-
7/26/2019 Vibration Analysis for Rotating Machine
35/46
Spur Gear
Failure Mode :Backlash, Tooth wear and Broken teeth etc.
-
7/26/2019 Vibration Analysis for Rotating Machine
36/46
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
37/46
Backlash
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
38/46
Tooth wear
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
39/46
Tooth load
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
40/46
Broken Tooth
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
41/46
Broken Tooth
Normal
-
7/26/2019 Vibration Analysis for Rotating Machine
42/46
Vibration in centrifugal pump
-
7/26/2019 Vibration Analysis for Rotating Machine
43/46
Loosen components
-
7/26/2019 Vibration Analysis for Rotating Machine
44/46
Gap between blade vanes and case is too small
-the BPF will increase
-
7/26/2019 Vibration Analysis for Rotating Machine
45/46
Turbulence flow
-random amplitude
at low frequency
-
7/26/2019 Vibration Analysis for Rotating Machine
46/46
Cavitation
-random amplitude
at high frequency