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