training course on vibration analysis level-1paec.gov.pk/documents/dnper/cvcm/cmt.pdf · training...

Training Courseon

Vibration Analysis Level-1

Centre for Vibration Analysis & Condition Monitoring (CVCM)

N-Block, Opp.: National Achieve Centre,

Pak Secretariat, Islamabad

Condition Monitoring

“Monitors the condition of the machine, if you

know the condition you can plan your response”

• Your rotating machine is tryingto tell you its condition via:

Vibration

Temperature

Oil samples

Sound

Motor voltage/current

• You have to choose thetechnologies required toassess the condition

Condition Monitoring (2)

Condition Monitoring = Health Monitoring

Vibration:

The ‘pulse’ of the

machine

Oil:

The ‘life blood’ of

the machine

Thermography:

‘Taking its

temperature’

Motor Current:

The ‘brain waves’

of the machine

Total

Picture

• Its all about money!

• When a machine fails:

Production may stop.

There may be secondary damage.

There may be safety or environmental issues.

Repair/labour costs can increase.

Why monitor the condition?

• If we can assess the risk of failure we can plan therepair at most cost effective time. Parts can be orderedand labour organized.

• We do not need to perform expensive preventivemaintenance.

• We can reduce number of parts held in store

Condition Monitoring Benefits

• Some technologies can tell us that aproblem exists now, and they help toassess the severity.

• Some tests will also tell us if a situationexists that could cause a problem infuture:

Contamination in lubricant

Resonance

Misalignment

Condition Monitoring: Early warning system

• We do not always know what levels are acceptable

• Instead we watch for change in level

We trend levels over time

We can use statistics to set alarms

Condition Monitoring: Watch for a change

• Each technology tells you something about the machine.

• Select the technologies and test frequency carefully.

• Best results are achieved when results from multipletechnologies are integrated into one report .

Condition Monitoring: The whole picture

Overview of Technologies

Condition Monitoring Technologies

• Oil Analysis

• Thermography

• Acoustic Emission

• Wear Particle Analysis

• Motor Testing

• Vibration Analysis

Role of Condition Monitoring Technologies

Thermography19 %


Oil Analysis is a non-destructive test used to assess the condition of lubricants and determine the type and amount of contamination present.

Criticality of lubrication to most industrial equipment, oil analysis trending over time is one of the most powerful predictive tools for identifying potential failures.

3 basic categories of elements affecting the lubrication effectiveness: wear metals, contaminants, and additives.

Oil Analysis – What does it offer ?

• Designed to keep track of the health of lubricants as well as the equipment.

• Detecting and avoiding Contamination

• Detecting and avoiding lubricant degradation

• Detecting and avoiding Wear

Therefore• Extending Lubricant Life

• Extending equipment life

• Improving Uptime performance

• Improving Profitability

Oil Analysis is not a tool for blaming someone !

Benefits of Oil Analysis

– Reduce maintenance costs

– Reduce unexpected downtime

• Indication of component failure

• Locations of the damage

• Identify type of damage (chemical, abrasion, fatigue, or other)

– Increase equipment availability

Potential Cost Saving from Oil Analysis

– Lubricant consolidation

– Extended oil change intervals

– Extended machine life

– Power consumption

1. Benchmark the New Oil

2. Correctly Located Sampling Points

3. Consistent & Correct Sampling Procedure

5. Correct Selection of Appropriate Tests

6.. Immediate dispatch of samples to Lab

4. Clean & Appropriate Sampling Bottles

7.Quality testing by the Lab

8. Quality Interpretation & immediate action to any

abnormal feedback

Strengths & Weaknesses of Oil Analysis

• Detects normal wear particles up to 6-10 microns.

• Determines lubricant additive depletion

• Detects fluid contamination

• Does not detect the onset of abnormal wear – wear particles

in excess of 10 microns

• Does not detect the sources of wear ( bearings, gears, seals,

rings, etc)

• Does not provide information regarding machine condition


Wear Particle Analysis

– Wear particle analysis is a machine condition analysis technologythat is applied to lubricated equipment.

– It provides an accurate insight of a machine’s lubricatedcomponents by examining particles suspended in the lubricant.

– By trending the size, concentration , shape and composition ofparticles contained in a systematically collected oil samples,abnormal wear related conditions can be identified at an earlystage.


Particle Sources

– Bearing

– Gears

– Seals

– Interior surfaces

– External particulates (contaminants)

– Chemical corrosion

– Additives degradation


Wear Metals

Wear Metal Possible OriginAluminum Bearing, Blocks, Blowers, Bushings,

Clutches, Pistons, Pumps, Rotors

Chromium Bearing, Pumps, Rings, Rods

Copper Bearing, Bushings, Clutches, Pistons, Pumps

Iron Bearing, Blocks, Crankshafts, Cylinders, Discs, Gears, Pistons, Pumps, Shafts

Tin Bearing, Bushings, Pistons


Acoustic Emission:

– Rotating equipment and other assets emit high-frequency sound that

provides clues to potential problems:

• Excellent tool for finding air leaks

• Good tool for finding bearing problems

• Lubrication problems can be detected and corrected

• Good tool for finding steam leaks in steam traps

• Can be used to detect electrical faults and many others


What is ultrasound:

– The human ear can only detect sound in the sonic range 20 to 20,000 Hz

– Any sounds that are above the human hearing capabilities are referred toas “ultrasounds”

– A few facts:

• The sounds are directional

• The volume depends on distance from the source

• Sound travels through air and solids


How do you use it:

– An Ultrasonic Gun is required to measure the signal and then heterodynethe signal to an audible signal

Air leak Steam leak Steam Trap


What do you do with it:

– There are two ways to use the ultrasound data.

You can listen to it

Search for leaks, search for faults etc.

– You can measure it

The units are displayed in dB

You can also view a time waveform and spectrum


Thermography:

– Thermography is the study of radiated energy using a thermal infraredimaging system

– Heat can indicate a fault condition

– Temperature can be measured at a point but we will focus on thermographic image


Infrared Thermography

– The camera detects the radiated energy and displays the temperaturegradients. A scale indicates the relationship between colour andtemperature

– The radiated energy is interpreted by the camera to display atemperature at a point or area

The actual temperature indicated may be incorrect

Surface type, wind condition and other factors effects accuracy

THERMOGRAPHY SURVEY

What can Thermography find?

What you see What thermography sees

Overheating electrical connection indicates a serious fire hazard.

THERMOGRAPHY SURVEY

Can you afford not to have a Thermography Survey?

Fire damaged electrical systemCruise Ship Fire

Damage

Applications of Infrared Thermography

– Mechanical

Machines, pipes, bearing and belts

– Electrical

Overhead lines, transformers, motors and control panels

– Steam Systems

– Security Systems

– And many others!

Thermal Comparison to Photographic Image

– Comparing the visual image to thermo-

graphic image reveals the nature of fault

condition

– The temperature scale indicated severity

A few thing to know

– The source of heat may comes from inside the object (tank, machine,

cabinet), but the detector only see the energy emitted from the

surface.

– It is therefore necessary to open cabinets to detect electrical faults

Overheated motor bearing Over 80 °C on bearing housing

50,1°C

81,8°C

60

70

80

66.9°F

202.3°F

80

100

120

140

160

180

200Hot v-belt

stressed due

to wear and/or

misalignment

• Over-heating due

to:

Belt wear

Pulley wear

Pulley misalignment


Motor Testing

– Motor Current Signature Analysis (MCSA) is a conditionmonitoring technique used to diagnose problems in inductionmotors.

– It was first proposed for use in nuclear power plants forinaccessible motors and motors placed in hazardous areas.

– MCSA can be used as predictive maintenance tool for detectingcommon motor faults at early stage and as such preventexpensive catastrophic failures, production outages and extendmotor lifetime.

MCSA – Motor Current Signature Analysis

• Used to generate analyses and trend of electric machines dynamically.

• They aim to detect predictive problems in a rotating electric machine, such as:

Static eccentricity ( Stator)

Dynamic eccentricity (Rotor)

Broken rotor bar problems

Voltage unbalance

Shorted stator turns

Problems on the windings

Induction Motor Fault

Electrical Fault Mechanical Fault

Stator fault Rotor fault Bearing fault Eccentricity

Winding external faults

Broken rotor bars, end rings

Motor Current Signature Analysis

Motor Testing

– Current spectra can be collected on each power leg at the panelusing a current clamp.

– One general comparison that can be made is the amperage drawfrom each leg.

– These should be approximately the same for proper loadbalancing.

– An exceptionally high or low load indicates problems.

– The flux coil is used on the motor rather than on panel. It collectsdata from the flux field generated by the motor. The data can beviewed on a spectrum.

– Flux measurement Indicate Potential problems in windings.


Vibration Analysis

– Can tell us a great dealabout a machine.


Vibration Analysis

– Used to Detect, Analyse and Confirm plant machinery problems. This canbe done in three ways:

• On-line for automated and continuous monitoring and protection ofcritical plant items

• Portable route based data collection and analysis

• Wireless used for remote monitoring of moving or inaccessibleequipment

Typical Machinery Problems that Can Be Found Using Vibration Analysis:

• Unbalance

• Misalignment

• Mechanical looseness

• Structural problems

• Bent shaft

• Bearing faults


• Gear faults

• Belt problems

• Lubrication problems

• Electrical motor faults

• Cavitation and turbulence

• others

Typical Machinery Problems that Can Be Found Using Vibration Analysis:


Which Technology is Applicable?

training course on vibration analysis level-1paec.gov.pk/documents/dnper/cvcm/cmt.pdf · training...

Documents