45 years in cm (slide share2013)

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Ray Beebe

Lessons learnt in 45 years of condition monitoring……..

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Condition monitoring is a type of maintenance inspection where

operational assets are monitored, on or off-line, and the data

obtained is analysed to -

– detect signs of degradation,

– diagnose cause of any fault,

– predict for how long the items can be safely (or economically)

run, and

– lead to the root cause being identified and if economical,

engineered out.

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Predictive Maintenance is a process that requires

technologies and people skills that integrates all

available equipment condition indicators (diagnostic

and performance data, operator logged data),

maintenance histories and design knowledge to

make timely decisions about maintenance

requirements of important equipment. (EPRI)

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My start: Yallourn

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• Basic vibration analysis and balancing• Performance monitoring: turbines, pumps,

boilers• Inspiring bosses gave me the CM virus!

• Lesson #1 Choose your bosses well• Lesson #2 Plant new, or THE major

asset? What is current hot issue for your management? Easier to get proposals accepted.

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Hazelwood

8 x 200MW (then)

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Case 1

Example of how an image would be positioned. Please refer to 4.1 – 4.5 of the Brand Guidelines (www.adm.monash.edu.au/mapa/brand) for guidance on imagery.

New 200MW unit: erratic vibration. 38 weeks offline to fix!

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Vector effect of loose mass is like a balance calibrating run (simple vibration meter with tuned filter/strobe used)

PHASE gives the clue, e.g.– Time A: 100 μm

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Vector effect of loose mass is like a balance calibrating run

PHASE gives the clue, e.g.– Time A: 100 μm – Time B: 50 μm

Loose rubber bung inside rotor centre counter-bored section! All bungs removed –OK.

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Pump vibration so high that outlet valve wobbled shut. Operations tied it open!

Solution – stiffen up bearing support to raise resonance away from rotation speed

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• Lesson #3 Simple instruments and

approaches can do a lot.

• Lesson #4 Use “5 Whys” right back to a

component’s manufacture.

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Case 2 Balancing mill wheel

Timed-oscillation method, off-speed. Plot of swing times to find balance mass, location

Typical vibration meter with tuned filter, strobe output for phase. Several balances gave sensitivity (amplitude/phase), enabled

one-shot balance and great time saving.

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Case 3

Example of how an image would be positioned. Please refer to 4.1 – 4.5 of the Brand Guidelines (www.adm.monash.edu.au/mapa/brand) for guidance on imagery.

Points at around normal duty are enough for CM. So, ceased the long full Head-Flow tests

Try using DCS to obtain data points, minimising special tests.

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• Lesson #5 Review monitoring

procedures regularly:

– Still needed?

– Can be simplified?

– Stretch interval ?

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2 years in UK (Babcock, Parsons, CEGB, plus several plant visits in UK, Europe, USA. Wrote reports on return, bought advance vibration analysis gear. Application involved reps from our several power plants)

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• Lesson #6 If worthwhile learning can only be

obtained outside, make proposal, BUT ensure

that only you can be selected!

• Lesson #7 To get buy-in, involve locals

deeply.

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• Lesson #8 Document the procedures, make

available to all

• Lesson #9 Estimate costs/benefits and keep

running score (sample period each year may be

enough). Publicise your activities widely, but admit

shortcomings.

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• Lesson #10 Engineers do initial set-up well.

Ongoing routine CM is better run by technicians.

• Lesson #11 Check your cupboards for under-

utilised equipment!

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An FFT!One set of gear bought to be used by people at 6 sites - simple user manual written.

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Case 4

High vibration on booster pump bearing

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Analysis showed vibration was at main pump blade pass frequency.

Cause diagnosed as acoustic resonance.

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• Lesson #12 Specialist test equipment needs regular owner, full-time skilled operators

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• Lesson #13 Don’t fully believe the data

unless it looks about right!

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Case 5

HPP

LP

Generator Gearbox andExciter

Journal bearings

Coupling

120MW unit – generator trim balanced at speed after disconnected from turbine: exciter used as motor.But, massive vibration when returning to service…

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Case 5

HPP

LP

Generator Gearbox andExciter

Journal bearings

Coupling

Note that generator bearings are longer than diameter- unusual…

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0 20 50 Vibration frequency Hz

Vibration velocity

Vibration increasing @ 19.5Hz

At near to synchronising, vibration rapidly increased. Held on PEAK mode, found to be at rotor first critical speed….

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Luckily, had this ESDU chart(IMechE research)

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Load parameter W’

0.1

1.0

10

0.1 0.5 0.9

Eccentricity ratio

Oil 71°C

Oil 40°C

Increased risk of half-frequency whirl

Original operation

Operation when bearings modified

Recommended area

Lines of increasing constant b/d

Bearing too short

ESDU66023

2

/

d

c

Nbd

WW d

e

(Shorter bearings fitted)

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Case 6 Reduced Valve Wide Open output found on test….

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Cause diagnosed as deposition on blades. Steam Forced Cool had washing effect.

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• Lesson #14 Consider OEM

recommendations carefully, but do not

follow them blindly.

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Case 7 Comparison- high accuracy tests vs plant instruments

460

470

480

490

500

510

520

530

31-Jan-93 28-Oct-95 24-Jul-98 19-Apr-01 14-Jan-04

Date of test

Co

rrec

ted

VW

O O

utp

ut

MW Upper points - accurate tests

Lower points - DCS tests

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• Lesson #15 Find if plant instruments can

give usable trend for CM. If a DCS or

SCADA exists, then try data extraction and

utilisation.

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Case 8

2” air gap to bearing

Post-overhaul – excessive vibration – but on bearing cover, not on bearing as shown in control room

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• Lesson #16 Do not believe everything

you read in the control room! Verify actuality

at, and inside, the machine.

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• Lesson #17 Training is essential, at start

and ongoing. Certification will help.

  I am Chair of CMSkills

Peter Todd is Chair Condition Monitoring Certifying Board within the AINDT is working on processes (in Australia).

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• Lesson #18 Share your learning via on-line

forums, networking, conferences, articles

for magazines , even a book (e.g. this

session presented 6 times : USA, Asia and

Australia)

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•  Lesson #19 Make recommendations clear and concise:

• Lesson #20 THE MAJOR ONE. Condition monitoring is not an end in itself, and should be applied along with other maintenance strategies as decided by an RCM or similar analysis.

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Questions or comments?

Thank you for sharing my 45 years in 45 minutes with around 45 slides!

AND, thanks to all of the many who worked along with me!

Happy monitoring!

email for free [email protected]

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• 55 000 students, 7 campuses

• Gippsland campus at Churchill

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The Lessons in full

– Lesson #1 Choose your bosses well

– Lesson #2 Lesson #2 Plant new, or THE major asset? What is current hot issue for your management? When a plant is new and/or the major asset makes it easier to get proposals for CM etc. accepted

– Lesson #3 Correct and confident diagnosis is often possible without complex instruments.

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-Lesson #4 Persist with the “5 Whys” until every possibility for a cause has been exhausted - right back to the intimate detail of a component’s manufacture.

-Lesson #5 Review monitoring procedures regularly, to find if a test or procedure is in fact still needed, or can be simplified, or have its interval stretched.

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- Lesson #6 If you find that worthwhile learning for your organization can only be obtained outside it (whether in another country or not), make the proposal, but ensure that it is only you that can be selected to go!

- Lesson #7 To get buy-in, involve locals deeply in any development.

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- Lesson #8 For staff training and for briefing of relevant staff, document the procedures (include digital pictures) and make them available to all on the company intranet. -Lesson #9 To ensure continuity of the CM program, estimate costs/benefits and maintain a running score sheet. Even if only done for a sample period each year, worthwhile payback will be shown. Publicise your activities widely, admitting any shortcomings.

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- Lesson #10 Initial development of CM applications is well done or managed by professional engineers, but ongoing routine CM is better run by technicians whose career expectations are likely to be less ambitious. Trades/crafts people can also find this a fulfilling career.

- Lesson # 11 Check your cupboards – you may have under-utilised equipment with as yet unknown capability!

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• Lesson #12 Specialist test equipment needs to have a regular owner and full-time skilled operator

• Lesson #13 Check, and recheck, critical data values if any look to be unusual

• Lesson #14 Take OEM recommendations into careful consideration, but do not follow them blindly.

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• Lesson #15 Assess whether the plant instruments can be used to give a usable trend for CM. If a DCS or SCADA exists, then try data extraction and utilisation.

• Lesson #16 In critical cases, do not believe everything you read in the control room without verification of labels and actuality at and inside the machine.

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• Lesson #17 Training is essential before starting CM work, followed by regular reinforcement via courses, conferences. Consider getting certification to verify capability.

 • Lesson #18 Share your learning via on-line

forums, networking, conferences, articles in engineering magazines.

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•  Lesson #19 Make recommendations clear and concise: put the technical complexity in appendices.

 • Lesson #20 THE MAJOR ONE. Condition

monitoring is not an end in itself, and should be applied along with other maintenance strategies as decide by an RCM or similar analysis.