VIBRASI_Level 1

Condition Monitoring & Vibration Fundamentals

Copyright Copyright 2004- PT. Putrana Putranata ta Adi Adi Mandiri Mandiri – sole agent agent Prüfte Prüftechnik chnik AG, Germany Germany

1

Kena Kenapa pa perl perlu u condi conditi tion on monit monitori oring ng ?

Biaya Biaya mainte maintenan nance ce setela setelah h pengen pengenala alan n condit condition ion monito monitoring ring


2

Kena Kenapa pa perl perlu u condi conditi tion on monit monitori oring ng ?

Biaya Biaya mainte maintenan nance ce setela setelah h pengen pengenala alan n condit condition ion monito monitoring ring


2

Peny Pe nyeb ebab ab dari dari brea breakd kdow own n mesi mesin n


3

Apakah itu, Condition Monitoring ? Monitoring Parameters

Temperature Output Phase Motor Current Casing Expansion Eccentricity Valve position

Suara ! Apa lagi ?

Pressure Speed Vibration Oil Quality & Condition Differential Expansion Rotor position

Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

4

Tipe Monitoring Kerusakan pada mesin – Penyebab utama kerusakan Unbalance Misalignment

Temperature X

Lubrication Oil contam

X

Gear mesh defect

Blade defects

Stator defect

X

X

X

X

X

X

X

X

Component resonance

X

Belt vibrations Rotordefect

X

X

X

X

X

X

Bearing defect

Suara X Oil Analysis X

X

X

X

X

Vibration Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

5

Pengukuran vibrasi


6

Kondisi bearing : lokasi & persiapan


7

Pengukuran kavitasi


8

Pengukuran RPM


9

Pengukuran temperatur


10

Contoh alat - 1


11

Contoh alat - 2


12

Contoh alat - 3


13

Apakah ‘v i b r a s i ’ itu ?

V i b r a t i o n is a mechanical oscillation around a reference position.

In a machine, vibration is the result of internal dynamic forces created by the rotating elements. R ef er e n c e : In t r o d u c t i o n t o M a c h i n e ry A n a ly s i s a n d M o n i t o r i n g – S ec o n d E d i t i o n - b y J o h n S . M i tc h e l l


14

Parameter-parameter vibrasi A = Amplitudo, T = Perioda waktu, f = 1/T = frekuensi φ = Phase

Harmonic motion is the simplest form of vibration, when plotted as a function of time, it is represented by a sinusoidal curve.


15

Frekuensi rotasi


16

Parameter umum pengukur vibrasi

Rms = Root Mean Square M = mean (rata-rata) P = Peak (puncak)

x (t ) = x p sin

⋅ t

x m

=

= 2 ⋅ f f =

1 T

x r ms

1

∫ T

=

T

0

1

x (t ) dt

Crest factor =

peak r ms

K factor = peak × r ms

∫ T

T

0

2

x (t )dt

Form factor =


r ms mean 17

Faktor-faktor konversi untuk gelombang sinus Conversion

ke : Peak-to-Peak value

Peak value

Mean value

Effective / RMS value

Peak-to-Peak value

1

0.5

0.32 = 1/

0.35 = 1/2 2

Peak value

2

1

0.64 = 2/

0.71 =1/ 2

1

1.11 = /2 2

0.90 = 2 2/

1

Dari : Faktor

Median value

Effective/RMS value

3.14 =

2.83 = 2 2

1.57 = ½

1.41 = 2


18

Nilai Peak dan RMS


19

Layar VIBROTIP ®


20

Lokasi penempatan transducer yang cocok


21

Typical Uses of Vibration Transducers Radial Shaft Vibration & Position Radial Casing Vibration

Axial Shaft Vibration & Position


22

Contoh alat - 1


23

Displacement, velocity & acceleration

x (t ) = x p sin

⋅ t

⎞ ⋅ x p cos ⋅ t = v p sin ⎛ ⋅ + t ⎜ ⎟ 2 ⎝ ⎠ 2 a ( t ) = − x p sin ⋅ t = a p sin ( ⋅ t + ) v (t ) =

x p = 1

2

⋅ x pp

v p = 2

⋅ f ⋅ x p = 6.28 ⋅ f ⋅ x p

a p = 4

2

⋅ f 2 ⋅ x p = 39.47 ⋅ f 2 ⋅ x p


24

Bagaimana mengukur amplitudo vibrasi ?

x (t ) = x p sin

⋅ t

⎞ ⋅ x p cos ⋅ t = v p sin ⎛ ⎜ ⋅ t + ⎟ 2 ⎠ ⎝ 2 a ( t ) = − x p sin ⋅ t = a p sin ( ⋅ t + ) v (t ) =


25

Transducer Vibrasi Sensor…Transducer…Probe…Apakah ini ?

….Pada dasarnya peralatan ini merubah vibrasi mekanis ke signal electric

Accelerometer Charge Type & Line Drive Constant Voltage & Constant Current

Velocity Transducer

Displacement Shaft Riders Proximity Probes (Eddy Current Probes)


26

Tipe transducer vibrasi


27


28

Fundamental Vibrasi

Seberapa besar vibrasi diijinkan ? 1. Gunakan Batas Vibrasi Absolut - diberikan oleh pembuat mesin - gunakan Standard Vibrasi Internasional, misalnya ISO 2372, VDI 2056, BS 4675 (Canadian Government Vibration Limit for Maintenance) 2. Gunakan Batas Vibrasi Relatif - gunakan histori mesin - gunakan batas dari pengalaman sendiri - lihat kondisi baru Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

29

Formula umur bearing

C ⎛ ⎞ H =⎜ ⎟ ⎝ L + Konst ⋅ M ⋅ V ⋅ N ⎠

3

16667 ⎞ ⎛ x⎜ ⎟ ⎝ N ⎠

H = umur bearing (jam) C = kapasitas bearing (kg) (dari spesifikasi manufactur er) L = beban bearing in - service (kg) Konst = 2.6674 ⋅10 -6 M = berat (kg) V = vibrasi (mm/s) N = speed (RPM) (Jika V dalam inch/s dan C, L, M dalam lbs, maka Konst berubah menjadi : Konst = 6.7753 ⋅10 -5 ) Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

30

Contoh menggunakan formula umur bearing

9,000 ⎛ ⎞ ⎟ -6 ⎝ 450 + 2.6674 ⋅10 ⋅ 5,850 ⋅15.24 ⋅1,800 ⎠

3

H=⎜

=

9,971 (24 ⋅ 365)

⎛ 16667 ⎞ ⎟ = 9,971 jam ⎝ 1,800 ⎠

x⎜

= 1.13 tahun

H = umur bearing (jam) C = kapasitas bearing = 9,000 (kg) L = beban bearing in - service = 450 (kg) Konst = 2.6674 ⋅10-6 M = berat = 5,850 (kg) V = vibrasi = 15.24 (mm/s) N = speed = 1,800 (RPM)


31

Monitoring Vibrasi Mana mesin yang bagus ? Batas Bahaya

Batas Bahaya

Batas Peringatan

Batas Peringatan

Ref

Ref

Mesin ‘A’

Mesin ‘B’


32

Monitoring Vibrasi Mana mesin yang bagus ? Tingkat Vibrasi

Batas Bahaya

Mesin ‘A’

Batas Peringatan

Mesin ‘B’

Waktu


33

Monitoring Vibrasi

Mana mesin yang bagus ? Tingkat Vibrasi

Batas Bahaya Batas Peringatan Mesin ‘A’

Mesin ‘B’

Waktu

Copyright Copyright 2004- PT. Putrana Putranata ta Adi Adi Mandiri Mandiri – sole agent agent Prüft Prüftechni echnik k AG, Germany Germany

34

Overall Measurement

Vibration um mils mm/s

x

Danger Limit

x

xx

x x

x

x x

x

x x

x

Alert Limit

Vibration um mils mm/s

Ref

Lead Time

Time


35

Manual & Automatic Trending

Trending with a Difference Vib

Vib

Danger Limit

Alert Limit

Alert Limit Limit * * *

* *

Danger Limit

* *

*

* * *

* * * * * *

*

*

* *

*

* * *

* * * * * * *

Time

Time

Poor Trend accuracy with no control (Takes all data & makes trend)

Improve Trend accuracy with Manual & Automatic Trending (User define trend conditions)


36

Trending Vibration RMS velocity


37

Trending shock pulse method

50

Path of Location : PT. Caltex\Water Plant\Fresh Water Pump\Centrifugal Pump\Impeller Side\shock pulse m. >120

45

Number of Meas. Values : 6

ShockPulsedBn

Meas. Task : Bearing

40 AlarmM ax

Meas. Type : Sum

35

Unit: dBn

30 W arningM ax

dBc dBa

Ø (mm)

9:21:40 PM 9 20 0

1

80.00

-

6/2/98

8:46:42 PM 9 20 0

5

80.00

-

dBm

7/2/98

8:21:40 PM 11 20 0

3

80.00

-

dBc

8/8/98

6:03:53 PM 9 1500 20

3 0

80.00

9/18/98

1:18:12 AM 11 1500 20

4 0

80.00

3/23/99

11:48:27 PM -3 1500 20

-10 0

80.00

25 20

AlarmC arpet

15

SIM Date

Time RPM

5/3/98

W arningCarpet 10 5 0 -5 10

5/25/98 6/22/98 7/20/98 8/17/98 9/14/98 10/12/98 11/9/98 12/7/98 1/4/99 2/1/99 3/1/99 3/29/99 date

dBm dBia


38

Trending bearing condition


39

Standar ISO 2372 A m p l i t u d o v e l o c i t y R M S ( m m / s )

Daya < 15 kW atau < 20 HP

15 kW - 75 kW atau 20 – 100 HP

Daya > 75 kW atau > 100 HP

Turbomachinery (Turbine/Comp dll)


40

Standar ISO 10816-3


41

Standard ISO 10816-3


42

Persiapan untuk pengukuran vibrasi


43

VIBCODE: pengenalan lokasi dengan cara otomatis


44

Sistem VIBCODE


45

Vibrasi dominan vertikal

MOTOR/DR

POMPA/DN

Penyebab Utama : 1. Pondasi (karatan, dudukan lemah, melengkung, baut kendor)


46

Vibrasi dominan horizontal

MOTOR

BLOWER

Penyebab Utama : 1. Unbalance 2. Housing bearing 3. Gaya aerodinamik Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

47

Vibrasi dominan aksial

MOTOR

BLOWER

Penyebab Utama : 1. Misalignment 2. Sleeve bearing 3. Housing bearing Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

48

Vibrasi dominan vertikal, horizontal, aksial

MOTOR

BLOWER

Penyebab Utama : 1. Antifriction bearing 2. Shaft bengkok 3. Pondasi melengkung Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

49

Fase


50

Contoh fase - 2


51

Contoh fase - 3


52

Vibrasi gabungan

1

2

1+2

Amplitudo(1) = 10, Amplitudo(2) = 5, Amplitudo(1+2) = ???


53

Vibrasi gabungan 1 frekuensi


54

Vibrasi gabungan 1 frekuensi beda fase


55

Machine Vibration Signal

Time Signal S1 + S2 + S3

+

+ S1

S2


S3

56

Spectrum frekuensi dari gelombang sinus

Frekuensi = 1 / T


57

Time signal & Spectrum frekuensi


58


59


60


61

Vibration Fundamentals Machine Vibration Signal

Time Signal

Freq. Spectrum

Hz Copyright 2004- PT. Putranata Adi Mandiri – sole agent Prüftechnik AG, Germany

62

FFT Analysis FAST FOURIER TRANSFORMATION

+

+

T

Eg. 1x = 1/T

Converting time signal to freq. spectrum 1X

5 kHz


63

Spectrum Analysis


64

FFT - Fast Fourier Transformation

Sample 1

Sample 2

Filtering

Filtering

Window Function

Window Function

Detectors

Detectors

FFT

+

FFT

= Avg

FFT Spectrum 1

FFT Spectrum

FFT Spectrum 2


65

Time vs FFT Time Signal:

FFT Fast Fourier Transformation

transient signals, repeat frequencies, beats and sine waveform good visible → but: Individual Frequencies of the Vibration Spectrum almost not visible

Amplitude Spectrum: good visibility of the dominant frequencies of the vibration signal → but: transient Signals, shocks with repeat frequency and beat signals almost not visible


66

Spectrum frekuensi dari signal yang kompleks


67

Contoh : Pompa centrifugal


68

Spectra untuk bentuk gelombang yang standard


69

Displacement, velocity & acceleration spectra


70

Fungsi window


71

Skala linear dan logaritmis

Logaritmis


72

Spectrum dengan alarmband

vmm/s 5.0

Location :PT. Caltex\Water Plant\Fresh Water Pump\Centrifugal Pump\Impeller Side\mach.

4.5

spectr. >600 including band alarm

4.0

#

X

Y

3.5

0

25.00

0.78

3.0

1

49.75

0.49

2.5

2

99.75

0.40

2.0

3

74.75

0.23

4

124.75

0.19

Alarm

5

97.25

0.15

Warning

6

10.25

0.09

7

9.00

0.09

8

122.00

0.09

9

11.75

0.07

1.5 1.0 0.5 0.0

0

5

10 15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95 100 f Hz


73

VIBRASI_Level 1

Recommend Documents