7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 1/23

Prepared by Toheed Ahmed 29 March 2015

Vibration Concept

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 2/23

No. 1

What is Vibration ?

o Vibration the motion of a body about a reference point.

o At its simplest vibration is displayed as displacement over time.

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 3/23

No. 2

Machine Monitoring

Why do we need to Measure the Vibration ?For Protection of machineryTo predict crucial machinery Problems

•Imbalance

•Misalignment

•Shaft crack•Bearing FailuresParameters to measure

•Thrust

•Vibration (varying gap measurement)

•Speed

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 4/23

No. 3

How do we measure vibration?

Three types of sensors

Displacement, Velocity, Acceleration

Signal processor of some type (CSI 2130)

Local or portable display for field analysis

RemoteSoftware for viewing and storing collected vibration data

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 5/23No. 4

Displacement accentuatesthe low frequencies – Mils

Velocity is consistent acrossa larger range of frequencies

  ccelerationaccentuatesthe higher frequencies (g’s)

Most vibration is analyzed in Velocity since the energy level is consistentthroughout the frequency range,

The Units

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 6/23No. 5

Displacement Probes

Typical ApplicationsShaft vibration measurement

Key phaser marker

Shaft center line position

Best suited for 1 to 500 hz

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 7/23No. 6

OR

MeasuringAmplifier

45O 45O

PROXIMITYPICK-UP

L RSHAFT

MeasuringAmplifier

VERTICAL

HORIZONTALL R

SHAFT

RECOMMENDED LOCATIONS OF SHAFT VIBRATION MEASUREMENTS AS PER ISO

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 8/23No. 7

Velocity Pickup

Velocity Sensor Application

Mounted on case of machine for bearing and structural vibrationbest suited for 10 to 1000 hzdepending on the application when integration to displacement is required

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 9/23

No. 8

 Accelerometer 

Accelerometer ApplicationsCase mounted or magnet mountedPrimarily Roller‐element Bearings and GearsWhen analysis and diagnostics are important

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 10/23

No. 9

Signal processing

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 11/23

No. 10

Vibration Monitoring System Overview

ProbeRadiates Magnetic

Field

Extension

CableProximitor 

Generate RF signal

Produce Amplitude

Demodulated output

with respect shaft movement

Barrier 

Monitor Shaft

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 12/23

No. 11

Average  RMS 0 - Peak  

Peak - Peak 

Units of Vibration

RMS = 0.707 x (0-Peak) 

Average = 0.637 x (0-Peak) 

Peak to Peak = 2 x (0-Peak) 

Frequency Acceleration(Peak or RMS) Velocity (Peak) Displacement(Peak to Peak)

CPM

Hz

g pk

g RMS

m/s2 pk

m/s2 RMS

in/s pk

mm/s pk

mils pk – pk

mm pk - pk

English and Metric units:

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 13/23

No. 12

Wiring Terminology

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 14/23

No. 13

Wiring Terminology

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 15/23

No. 14

Proximity Transducer System

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 16/23

No. 15

Proximity Probes

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 17/23

No. 16

Proximity Probes

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 18/23

No. 17

Proximity Probes

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 19/23

No. 18

Proximity Probes

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 20/23

No. 19

Vibration

Characteristics of vibration signal

AMPLITUDE

FREQUENCY

PHASE

ORBIT

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 21/23

No. 20

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 22/23

No. 21

Reasons of Vibration

If the measurement is healthy, following may be the reasons of vibration

 problem   UNBALANCE

  MISALIGNMENT

  LOOSENESS

  PIPE PULLS

  SHAFT CATENARY / BEARING LOADING

  RESONANCE

  UNEQUAL FLOW PATH CLEARANCES

  RUBBING

  SHAFT BOW

  OIL / STEAM WHIRL

  DEVIATED OPERATING PARAMETERS

  DEFECTIVE BEARING / ASSEMBLY OF BEARING

  VIBRATION TRANSMITTION FROM OTHER SOURCE

  GEAR INACCURACIES

  CASING DISTORSTION

  CAVITATION

7/23/2019 vibration presentation .pdf

http://slidepdf.com/reader/full/vibration-presentation-pdf 23/23

No. 22

QUOTE OF THANKS

Efforts find their way towards success…