MI MILITARY S SEA EALIFT COMM COMMAND VIBRATION ANALYSIS N7 - - PowerPoint PPT Presentation

MI MILITARY S SEA EALIFT COMM COMMAND

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VIBRATION ANALYSIS

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LEAR ARNING O OBJ BJECTI CTIVES

• Define a VTAG page and use the VTAG page to identify

vibration block replacement locations.

• Locate and view collected data using the browse

menu in the CMS Module

• Identify Invalid Vibration data

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Learn rning O g Objecti ctives

• Match the Repair Priorities to their

definitions

• Desirable
• Important
• Mandatory
• Update and save an equipment repair action

based on vibration analysis alarm test results.

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The e Human Vi Vibration An Analyzer

• Hearing and Touch are Sensitive – Experienced Engineers,

familiar with vessel, will detect when an issue is present.

฀ Disadvantages

• Limited Memory
• No Electrical Output
• Takes Frequent Vacations
• Retires at Peak of Productivity

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What i is V s Vibration?

“Vibration is periodic motion; the movement of a body about a reference position, which repeats itself after a certain interval of time.”

Time Peak A SINE WAVE IS THE SIMPLEST FORM OF VIBRATION

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Mea easuring g Machinery v vibration

Paper Let’s measure the height of the peak generated by machine rotation This will be called the “Amplitude”

Sensor

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Mea easuring g Machinery v vibration

Vibration Measurement Parameters

• Amplitude (Magnitude) –

How much

• Expressed as Displacement, Velocity or Acceleration
• Time component: Example: Travel 5 miles in 5 minutes –

velocity is 1 mile per minute, 60 miles/hour.

• Frequency (Period)
• How often
• Expressed as Cycles Per Minute (CPM), Hertz (cycles per

second) or Orders (as compared to a reference RPM)

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Simple Vi e Vibration

3 cycles p per er s sec econd

1 sec

Frequency in CPS

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Sim imple le V Vibratio ion

1 sec

Frequency in CPS

This value, regardless of the units, is the Amplitude.

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Simple Vi e Vibration

3 cycles p per er s sec econd

1 sec

Frequency in CPS

This value, regardless of the units, is the Amplitude.

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Co Complex Vi x Vibration

.5 sec

1 cps 3 cps

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Time D e Domai ain v vs Frequen ency cy D Domai ain

A m p l i t u d e Time 1 cps 3 cps

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Piezo zo-Elect ctric A c Accelerometer

1 5

• Compression Type

Seismic Mass Crystal Element Base ICP Amplifier Mounting Stud Pre-loading Spring This crystal will amplify or dampen an applied DC voltage based

• n it’s rate of

Acceleration (In/sec/sec)

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Vi Vibration T Theo eory - re relat ationship

Rotation

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Picture e this h happening

.5 sec

1 cps 3 cps

Steady DC Voltage applied

Time Heavy Spot

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Vi Vibration An Analysis - Bas asic F Fac acts ts

• A typical Rotating Machine’s failure modes create

distinct vibration characteristics

• Any change in the vibration signature on a typical

machine indicates a change in the dynamic

• peration of the machine – Doubling of

Amplitude normally indicates a problem.

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Vibration A Anal alysi sis i s is a Process ss

Vibration Data What, if anything, is wrong with this machine and how bad is it? Machinery Fault Report Machinery Knowledge Base Average Spectra Data Base Spectral Analysis Rule Base Maintenance Planning How does this data compare to that of a healthy machine? What are the vibration sources within this machine?

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Rules a s and E Expert ert S System em

Vibration Analysis

Rules and the Expert System

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Co Common P Problems I Iden entified

The BIG Three

• Imbalance
• Misalignment
• Bearings (BAD /COCKED / WORN)
• Out-of-round Journal
• Gear Problems
• Impeller Blade Problems
• Magnetic Noise
• Electrical Noise
• Bent shaft
• Looseness

Motor Gear Cprsr

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Di Diagn gnostics ( s (Principles)

1.

Specific mechanical faults such as imbalance, misalignment, looseness, etc., generate mechanical vibration in a well-defined frequency band or pattern.

• 2. Multiple faults are common. Find and fix one problem

at a time. Start with the worst problem.

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Diagnostics ics ( (Prin rincip iple les)

• The next few slides will discuss Vibration Symptoms of

specific problems.

• We will call each one a “RULE”
• Each “RULE” is contained in your database.
• “Rules” are used to allow the computer to

Diagnose the problem.

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Vi Vibration An Analysis Spec ectral An Analysis

• Each mechanical or electrical fault appears at a certain

frequency or pattern of frequencies.

<1x 2x-3x 4x-6x >6x 1x

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Prob

• blem D

Diagnos

• stics

cs - Imbalance

• High 1x RPM in the Radial direction
• Almost equal in all Radial directions
• Amplitude and location increase with speed

Heavy Spot Reference

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Problem Di Diagnostics - Imb mbalanc nce o

• n a

a Variable S Spee eed M Machine

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Problem Di Diagnostics -Mis isalig lignment

• Caused by improper assembly or bent shaft
• Large peaks at 1xRPM and 2xRPM especially in the axial

direction

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Problem Di Diagnostics -Mis isalig lignment

Angular Misalignment Parallel Misalignment

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Problem Di Diagnostics -Mis isalig lignment

Bent Shaft Bearing Misalignment

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Problem Di Diagnostics - Be Beari rings

• Bearings are the point of contact between the

moving part and the stationary part

• Bearings are the weak link in the machine train
• Usually, bearings are the first to fail but usually,

they are not the cause of the problem

• Two types of bearings
• Fluid-Film (Sleeve or Babbit)
• Rolling Element (Anti-friction)

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Bear aring C Con

• nstru

tructi tion

Snap ring groove Inner race Inner ring Cage Outer race Outer ring Seal/shield groove & notch Bore Inner ring face Outer ring face Outside diameter Ball

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Rolling E g Elem ement Be Bearings s - Failur ure Mo Modes

• First Stage: Earliest indication of bearing problems

appears in the Higher Frequencies typically between 1250 - 15000 Hz

1x 2x

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Rolling E g Elem ement Be Bearings s - Failur ure Mo Modes

• Second Stage: Bearing problems propagate to the

lower frequencies typically between 60 - 312 Hz or 3x to 8x shaft rotation

** Non-integer multiples of shaft rotation 1x 2x

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Rolling E g Elem ement Be Bearings s - Failur ure Mo Modes

• Third Stage: Multiple harmonics of bearing

frequencies are present and possibly sidebands.

1x 2x BFPO BFPI

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Rolling E g Elem ement Be Bearings s - Failur ure Mo Modes

• Fourth Stage: An overall increase in the noise floor and excessive

machine looseness with high energy levels under the curve

1x 2x BFPO BFPI

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Intr trod

• ducti

tion

• n t

to the e Expert A Analy lysis is Prog

• gram

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Severity & Repair Recommendation Machine Faults Supporting Vibration Characteristics

Expert Analysis System

HOW DID WE GET TO THIS POINT?

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Vibrati tion A Analysis P Process

Vibration Data What, if anything, is wrong with this machine and how bad is it? Machinery Fault Report Machinery Knowledge Base Average Spectra Data Base Spectral Analysis Rule Base Maintenance Planning How does this data compare to that of a healthy machine? What are the vibration sources within this machine?

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SLOTS=61 BARS=43 POLES=4 FAN BLADES=11 SHAFT=1 IMPELLER VANES=7

Step 1 – Know your machine

Machinery Knowledge Base

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Vibration Spectra in 3 Axes Data from ALL Pickup Locations / Verify blocks are installed prior to test Proper Speed & Test Conditions

Step 1 – Know your machine

MachineryKnowledge

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VTAG

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Frame e of Refer eren ence

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Tri-Axial al S Senso sor

ACCELEROMETER

PLAN VIEW

ACCELEROMETER

ELEVATION

MOUNTING PAD

ELEVATION

MOUNTING PAD

PLAN VIEW ALIGNMENT NOTCH ALIGNMENT KEY CAPTURE SCREW CHANNEL IDENTIFICATION & ORIENTATION ARROWS CAPTURE SCREW

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RAT Orienta ntation

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ART RT Orienta ntation

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SAMPL PLE O E ORI RIENTATI TIONS

A T R RA RAT RA RAT RT RTA RT RTA TA TAR TRA RA ATR TR ART RT

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Test t Loc

• cati

tion N Numbers

Motor Pump Motor 3 4 1 2 3 4 1 2 Motor 1 2 Pump Gear 3 4 5 6 7 8 Motor 1 2 3 4 (4) 5 6 Pump Gear Pump

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Ex Expert rt Al Alert rt Screening S Sheet

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Major Machine Components

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Or Orde ders 60 60 70 70 1 2 3 4 5 6 7 8 9 10 10

Order ders Order ders

CHI CHILL W WATE TER P PUM UMP AV AVERA RAGE D DAT ATA

Or Orde ders

VdB dB 80 80 90 90 10 100 11 110 12 120 13 130

Unit 4 4 J Jul 9 l 96 Chill W Wtr P Pmp Unit 2 2 J Jun 9 n 96 Chill W Wtr P Pmp

14 140 VdB

dB

Unit 1 1 J Jan 9 96 Chill W Wtr P Pmp Unit 1 1 M Mar 9 96 Chill W Wtr P Pmp Unit 3 3 M Mar 9 96 Chill W Wtr P Pmp Uni nit 1 1 J Jun 9 n 96 Chill W Wtr P Pmp

Or Orde ders

VdB dB

Or Orde ders

VdB dB

Or Orde ders

VdB dB

Or Orde ders

VdB dB

Or Orde ders

VdB dB

Averaged Spectra or Baseline Information

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1 2 3 4 5 6 7 8 ORDERS VdB

120 110 100 90 80 70 60 MIL-STD-167-I

~1000RPM 107 VdB

107 VdB above 1200 rpm

Note: Curve is based on Mils (peak) vs CPM

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Commercial Standard

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Severity & Repair Recommendation Machine Faults Supporting Vibration Characteristics

Expert Analysis System

That’s how we got to this point. Amplitude of vibration is expressed as VDB

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Why u use L Log

• garith

thmic S Scal ale?

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De Decibel Rules o

• f Thumb

dB Change Power Ratio Level Ratio

3 2 1.4 6 4 2 10 10 3 20 100 10

**NOTE: Adding dB is like multiplying amplitude ratios

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Severity & Repair Recommendation Machine Faults Supporting Vibration Characteristics

Expert Analysis System

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Vibration D Data ta C Collection

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Vibration

• n C

Collec ection

• n S

System em

1 Hard Carrying Case 7 RS-232 Communications Cable 2 Soft Carrying Case & Strap 8 Internal Memory Card & Adapter 3 ViPRe Data Collector 9 Hand Strap 4 External Battery Charger 10 USB Communications & Charging Cable 5 Spare Battery 11 ViPRe Battery (internal not shown) 6 Internal Battery Charger 12 Tri-Axial Vibration Sensor (others)

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Prog

• gram S

Suppor

• rt
• Equipment
• ViPRe Data Collector
• PR-1 Signal Generator
• Triax. Accelerometer
• Manuals
• Daily Op. Guide
• VTAG’s
• Training
• Shipboard Training
• CMEO Training
• Consumables
• Adhesives
• Mounting Pads
• Bar Code Labels

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VTA TAG

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Bloc

• ck Location
• n - Collecti

tion

Ensure all pickup locations are installed in accordance with the VTAG prior to starting tests.

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COLLE LLECT D DATA

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COLLE LLECT D DATA

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COLLE LLECT D DATA

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COLLE LLECT D DATA

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COLLECT DATA

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COLLECT DATA

If this screen pops up – you have a problem.

• Do not proceed with

data collection, follow the instructions on the next few screens

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COLLECT DATA

• 1. Plug in the ViPRE
• 2. Click on the Active Synch

Icon in the Active Toolbar

• 3. Select “Explore”

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COLLECT DATA

At this screen, select “Storage Card”

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COLLECT DATA

Highlight both files, then Delete

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COLLE LLECT D CT DATA

The screen will then look like this. Good Thing

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COLLECT DATA

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COLLE LLECT D DATA

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TRIAXIAL S SENSOR OR

Attach the Sensor to the block you selected from the TREE

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COLLE LLECT D DATA

Enter Key – Starts the process

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COLLE LLECT D CT DATA

If the ViPRe screen provides this warning: ALWAYS answer YES THERE IS A WAY TO PREVENT THIS – Restore the database prior to starting!!

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COLLE LLECT D DATA

• Collect Data from ALL Pickup Locations

within 30 minutes of each other

• Check the DONE and LEFT sections to see if

all points are completed

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Un Unloa

• ading t

g the ViPR PRe

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Download d Data

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Com

• mmon
• n P

Prob

• blem

At times, the communications do not happen automatically

• Re-Boot the ViPRE
• Ensure the ViPRE is disconnected from the COMM cable
• Power on the ViPRE
• Press 2,7,8, 9 keys simultaneously
• Plug ViPRe back into the computer

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View S Spectra f for V r Validity ty

• After Downloading – View Data from

the WORKBOOK module in SAMM

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Vi View S Spec ectra f for Validity

Locate the SAMPLE VIBRATION task Click on the Link to view Data

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Data Validity Checks

• Improper Test conditions
• Improper Test Speed
• Test Load
• Equipment Warm-up
• Pump Cavitation
• Varying Turbine Speed

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Iden entifying F g First Order er P Peak

Motor Rate RPM 1780

2 4 6 8 10 12

CPM (x 1000)

60 70 80 90 100 110 120 130 140

VdB

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Iden entifying F g First Order er P Peak

2 4 6 8 10 12

CPM (x 1000)

60 70 80 90 100 110 120 130 140

VdB

Motor Rate RPM 1780

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Mu Multi-shaft M Machine

1 2 3 4 5 6 60 70 80 90 100 110 120 130 140 VdB ORDERS Motor Rated RPM = 1780

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Mu Multi-shaft M Machine

1 2 3 4 5 6 60 70 80 90 100 110 120 130 140 VdB ORDERS Motor Rated RPM = 1780 Pump RPM = 774 Pump Vanes = 6

P P P P P M M M M M M P P PV 2PV

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Iden entifying F g First Order er P Peak

1 2 3 4 5 6 60 70 80 90 100 110 120 130 140

VdB

Invalid Data – Improper Test Conditions – No Peak at the 1X, Everything is shifted left

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Valid lid o

• r Invalid

lid?

1 2 3 4 5 6 60 70 80 90 100 110 120 130 140

Orders VdB Bearing Tone -- 4.6X

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Ch Chec eck f for Da Data V Validity

• Improper Test Conditions
• Improper Sensor Attachment
• Wrong Orientation
• Striking the Wrong Barcode
• Loose Sensor Attachment

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Improper S er Sen enso sor A r Attachment

2 4 6 8 12 10 CPM x 1000 50 60 70 80 90 110 120 130 100 VdB

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Ch Chec eck f for Da Data V Validity

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Overh erheated S Sen enso sor

2 4 6 8 10 12 60 70 80 90 100 110 120 130 VdB CPM x 1000

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Rev eview ew W Workbook

Locate the SAMPLE VIBRATION task Click on the Link to view Data

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Valid id or

• r I

Invalid lid?

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Valid id or

• r I

Invalid lid?

NOTE: Expert system automatic analysis results – Please read carefully. NOTE: DLI will manually analyze all tests Important or Mandatory – Do not take action until confirmation by DLI.

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Valid id or

• r I

Invalid lid?

NOTE: ANALYST COMMENTS: DLI will manually analyze all tests Important or Mandatory – Please wait and review prior to any repair recommendation.

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Valid id or

• r I

Invalid lid?

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Valid id or

• r I

Invalid lid

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Da Data R Revi view

103

UTILITIES

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Ha Hands O s On Application

• Collect vibration data, using the Test Machine, store

under one of these points.

• Forward Segregated Ballast Pump
• No.1 Cargo JP5 Pump
• No.1 Cargo Fuel Oil Pump
• No.3 Lube Oil Service Pump
• No.2 Reduction Gear Lube Oil Pump

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Calib librate El Electronic ic E Equip ipment