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Vibration AnalysisVibration Analysis
& Balancing& Balancing
What is Vibration AnalysisWhat is Vibration Analysis
The study of Collected data taken The study of Collected data taken with the analyzer, of a machine while with the analyzer, of a machine while it is running. it is running.
Data is collected at each location or Data is collected at each location or point in the horizontal, vertical and point in the horizontal, vertical and the axial plans.the axial plans.
Numerous bearing, motor and Numerous bearing, motor and condition fault frequencies are condition fault frequencies are checked and compared. checked and compared.
Vibration AnalysisVibration Analysis What is vibration?What is vibration?
• Forces that vary in amplitude or Forces that vary in amplitude or direction over time cause direction over time cause repetitive motions called repetitive motions called vibrationvibration
When is vibration bad?When is vibration bad?• All rotating machinery generates All rotating machinery generates
some vibrationsome vibration• Only vibration that exceeds Only vibration that exceeds
certain amplitude levels is bad.certain amplitude levels is bad.
Vibration TerminologyVibration Terminology
AmplitudeAmplitude• The measure of energy or movement in The measure of energy or movement in
a vibrating objecta vibrating object
• Three common ways of expressing:Three common ways of expressing: Displacement in mils peak to peakDisplacement in mils peak to peak Velocity in inches/second peakVelocity in inches/second peak Acceleration in g’s rmsAcceleration in g’s rms
Vibration TerminologyVibration Terminology
FrequencyFrequency• The number of times that a vibrating The number of times that a vibrating
object repeats its motion per unit of object repeats its motion per unit of timetime
• The rotational frequency is often The rotational frequency is often called 1Xcalled 1X
• Other frequencies are often identified as Other frequencies are often identified as multiples of 1X, such as 2X, 3X, 4X, etc.multiples of 1X, such as 2X, 3X, 4X, etc.
Vibration MeasurementVibration Measurement
We analyze vibration profiles from, We analyze vibration profiles from, motors, fans and pumps, chillers, motors, fans and pumps, chillers, bearings and overall machine health.bearings and overall machine health.
Were looking for bearing condition, Were looking for bearing condition, mechanical looseness, motor mechanical looseness, motor electrical problems, resonance issueselectrical problems, resonance issues
Overall vs. Running speed-1XOverall vs. Running speed-1X
Overall amplitude is a measure of the Overall amplitude is a measure of the vibration energy over a wide vibration energy over a wide frequency rangefrequency range
1 times amplitude usually refers to 1 times amplitude usually refers to the vibration at operating/running the vibration at operating/running speedspeed
Overall amplitude includes the Overall amplitude includes the effects of all sources—even those effects of all sources—even those external to the fanexternal to the fan
Vibration TerminologyVibration Terminology
Vibration Spectrum: Vibration Spectrum:
(a display of frequency vs. amplitude)(a display of frequency vs. amplitude)
Profile PlotProfile Plot
PROFILE PLOT(More Than One Equipment)
24-Sep-1009:48:08
To
01-Oct-1013:15:31
Full Scale
280. %
of Fault
EQUIPMENTAREA
M1H
AA
M1V
AA
M1A
AA
M2H
AA
M2V
AA
FNV
AA
M1H
BA
M1V
BA
M1A
BA
M2H
BA
M2V
BA
FNV
BA
M1H
CA
M1V
CA
M1A
CA
M2H
CA
M2V
CA
FNV
CA
M1H
DA
M1V
DA
M1A
DA
M2H
DA
M2V
DA
M1H
EB
M1V
EB
M1A
EB
M2H
EB
M2V
EB
M1H
FB
M1V
FB
M1A
FB
M2H
FB
M2V
FB
M1H
GB
M1A
GB
M2H
GB
M1H
HB
M1A
HB
M2H
HB
M1H
IB
M1V
IB
M1A
IB
M2H
IB
M2V
IB
1xTS
2xTS
3xTS
4XTS
FAN MOTOR POINTS
Dynamic UnbalanceDynamic Unbalance
Dynamic (couple) unbalance Dynamic (couple) unbalance requires correction in two or requires correction in two or more planesmore planes Heavy spot Heavy spot will will notnot “bottom “bottom out” when out” when rotor is rotor is placed in placed in bearingsbearings
Achieving Lower Vibration LevelsAchieving Lower Vibration Levels Involves better precision of many Involves better precision of many
componentscomponents• Better balance of all rotatingBetter balance of all rotating
componentscomponents Fan wheel (balance with fan shaft)Fan wheel (balance with fan shaft) SheavesSheaves CouplingsCouplings MotorsMotors
• Straighter shafts with precision diameter Straighter shafts with precision diameter tolerance and roundness tolerance and roundness
• Less hop and wobble in fan wheelLess hop and wobble in fan wheel• Better fits in attached componentsBetter fits in attached components
Achieving Lower Vibration LevelsAchieving Lower Vibration Levels
Involves better precision of many Involves better precision of many components (continued)components (continued)• Reduced internal clearance in bearingsReduced internal clearance in bearings• Bearing mounting surfaces machined Bearing mounting surfaces machined
flatflat• Premium quality v-belt drivesPremium quality v-belt drives• Precision alignment of v-belt drives or Precision alignment of v-belt drives or
couplingscouplings• Precise tensioning of beltsPrecise tensioning of belts
Achieving Lower Vibration Levels Achieving Lower Vibration Levels
Involves other special design Involves other special design considerationsconsiderations• Heavier and more rigid components: Use Heavier and more rigid components: Use
Class III instead of Class IIClass III instead of Class II• Aluminum fan wheel (reduced rotor weight)Aluminum fan wheel (reduced rotor weight)• Use inertia base for flexibly mounted fanUse inertia base for flexibly mounted fan• Select lower speed fans if possibleSelect lower speed fans if possible• Avoid operation at any critical Avoid operation at any critical
resonance speeds- vibration can resonance speeds- vibration can increase up to 10X amplitudeincrease up to 10X amplitude
BalanceBalance BalancingBalancing
• The process of adding or removing The process of adding or removing weight on a rotor in order to move the weight on a rotor in order to move the center of gravity towards the axis of center of gravity towards the axis of rotationrotation
• The purpose of balancing is to reduce The purpose of balancing is to reduce the unbalance forces that damage the unbalance forces that damage machines, there surroundings and machines, there surroundings and reduce noise transmitted to tenants reduce noise transmitted to tenants
Balance TolerancesBalance Tolerances
Defines the maximum amount of Defines the maximum amount of residual unbalance remaining after residual unbalance remaining after balancingbalancing
Originally defined in international Originally defined in international standard ISO 1940/1standard ISO 1940/1
Many new standards exist today. Many new standards exist today. We use the manufactures specifications We use the manufactures specifications
along with years of experience to along with years of experience to achieve best balance possibleachieve best balance possible
Balance and Vibration tolerancesBalance and Vibration tolerances
• Proper balance Proper balance • Provides for long Provides for long
life, life, • Higher efficiency Higher efficiency
and and • Reliable operation Reliable operation
without excessive without excessive costcost
Static UnbalanceStatic Unbalance Static unbalance can be Static unbalance can be
corrected by adding a single corrected by adding a single weightweight
Heavy spot Heavy spot will “bottom will “bottom out” when out” when the rotor is the rotor is placed in placed in bearingsbearings
Dynamic UnbalanceDynamic Unbalance
Dynamic (couple) unbalance Dynamic (couple) unbalance requires correction in two or requires correction in two or more planesmore planes
Heavy spot Heavy spot will will notnot “bottom “bottom out” when out” when rotor is rotor is placed in placed in bearingsbearings
END
503 657-4467