A SYSTEM THAT MONITORS THE MECHANICAL PARAMETERS OF A MACHINE VIZ:

1) Vibrations

2) Axial shift

3) Differential expansion

4) Absolute expansion

5) Shaft Eccentricity

“MACHINERY SUPERVISORY SYSTEM”

Main objectives

1. Monitoring machine healthiness

2. Reducing the maintenance time by conditional / predictive maintenance

3. Extending machines working life

4. Preventing destructive failures

Basics of Vibration

Three very basic yet very important questions

• What is vibration?

• How vibrations are caused?

• Why at all should we measure it?

Some Definations of Vibration

1.Vibration is an oscillation about a reference position wherein the quantity is a parameter defining a motion of a

mechanical system.

2.Vibration is a form of wasteful energy which is caused by mechanical problems in a machine.

3.Vibration is a result of dynamic forces in machines which have moving parts and are connected to the machine.

We can understand severity of mechanical problems in a machine by measuring the vibrations accurately.

By measuring vibrations, we are gauging the MECHNICAL HEALTH of an equipment.

And off course by using it properly we can

SAVE TIME , ENERGY & MONEY

Troubleshooting-Vibration problemsSome Ideas

1. Due to unbalancing

2. Due surface roughness.

3. Inadequate oil flow to bearing.

4. Bearing supporting system disturbance.

5. Wrong assembly of bearing.

6. Disturbance in centring of turbine or

disturbance in alignment.

7. Wrong way assembly of coupling.

8. Using of improper coupling bolts.

9. Touching of loose components.

10. Condensate formation near glands.

11. Casing drains choking.

12. Piping problem

`

UNBALANCEMISALIGNMENTLOOSENESSRUBBINGSHAFT CRACKDEFECTIVE ROLLING ELEMENTS ETC

Un-balance

MissAlignment

Loose-ness

Mounting Base

Etc.

ABNORMAL CONDITIONS

Basics

• Rotating body

ROTOR

ANGLE BETWEEN CENTRE OF AXIS & ROTATING AXIS

Understanding characteristics of vibration

Two main components

1.Amplitude - Amount of vibration

2. Frequency – Number of cycles per second

When expressing machine vibration, it is expressed by three kinds, displacement, speed, and acceleration, and each relation becomes as it is shown in the following figure.

Amplitude

　　 ;D

Dis-placementDisplacement D ＝ Half of

amplitude （ μm ）

Cycle T(=1/Frequency)

Accel.

Acceleration A ＝ ( 2pf )2 D 　（ m/s2)

90°

Velo-city

Velocity V = 2pf D 　（ mm/s)

Phase difference

90°

Time

Amplitude

Amplitude can be explained by three ways

1. Displacement in units - Mils or mm

2. Velocity in units - inches/sec or mm/sec

3. Acceleration in units - G or mm/sec2

Relationship between displacement,velocity & acceleration

Engineering Units

Typically three units of measurement,

a) 0 to Peak (0-P)

Both Velocity (in/sec, mm/sec) and Acceleration (g's) by definition are measured in 0 to Peak or one/half the Peak to Peak signal as viewed on an oscilloscope.

b) Peak to Peak (P-P)

Displacement by definition is measured in Peak to Peak or the actual Peak to Peak Motion of the Shaft.

c) Root Mean Square (RMS)

Root Mean Square (RMS) is a popular method of measuring Case or Bearing Cap Vibration as many vibration engineers have found that RMS is more indicative of actual rolling element bearing condition. A pure sine wave RMS would be 0.707 times the 0 to Peak Value.

SENSORS

Non-contact

Contact

Eddy Current

Capacity

Ultrasonic

Laser

Moving Coil

Piezoelectric

Strain Gauge

Servo

Displacement

Displacement

Displacement or Velocity

Velocity

Acceleration

Acceleration

Displacement

Acceleration

VARIOUS SENSORS FOR MEASURING VIBRATION

A Word About BearingsThe vast majority of bearings are one of two types:

Rolling Element, or “Anti-Friction” Bearings and Fluid Film Bearings

bearing

bearing

housing

bearing

bearing

housing

Oil Wedge (load zone)

Soft Metal

(Babbitt)

Eddy Current Probe

Accelerometer

Fluid Film: Capable of supporting very high loads, high temperatures, high speed. Expensive and associated rotor dynamics are very complex.

Rolling Element: Low cost, simple to apply. But are capable of only moderate speeds and relatively light loads. Rotor dynamics aren’t bad but diagnostics can be complex due to all those spinning balls!

Continuous vibration monitoring system

By SHINKAWATRANSDUCERS & DRIVERS

CONTACT TYPE NON-CONTACT

VK SeriesVibration Transducer

RD SeriesTacho Driver

CA Series Acceleration Transducer

LVDT SeriesDifferential Transformer

PRINCIPLE - EDDY CURRENT SENSORS

`

Target(Metal)

Magnetic Flux

Sensor Coil

.

.

Driver

Eddy Current

.

Conditioner

Oscillator

. Amplifier

Linerizer

Phase Detection

Bridge Circuit

Voltage ∞ Displacement

Output

TIME

TIME

IN-OUT CHARACTERISTICSOUTPUT VOLT

0 DISTANCE (GAP)

SENSORTARGET

CHARACTERISTICS

おもり板バネ

N

S

N

S

N

S

N

S

N

S

N

S

N

S

N

S

N

S

N

S

TARGET OBJECT Vibration

STUD BOLT

SPRING(PLATE) BOBBIN

DETECTION COIL

MAGNETDAMPING COIL

CASING

Output Voltage ∝Velocity Vibration

PRINCIPLE OF MOVING COIL TYPE VELOCITY VIBRATION TRANSDUCER

Output Voltage Force ∝ ∝Acceleration Vibration

Vibrating Object Vibration

Stud Bolt

Mass Weight

Electrode

Piezoelectric Device

CasingElectrode

e

PRINCIPLE OF PIEZOELECTRIC ACCELERATION TRANSDUCER

Radial Shaft Vibration in X & Y direction

45 Deg

Sensors

Shaft

Mounting arrangement

Axial Shaft Vibration Measurement

Mounting bracketSensor

Shaft

disc

Axial Position

ThrustMonitor

Sensor

Rotor

Oscillator-Demodulator(Driver)Extension

cable

AXIAL POSITION

STANDARD MOUNTING TECHNIQUES

-- SINGLE SENSOR --

-- TWO SENSORS --

RADIAL SHAFT VIBRATION

Driver

Field Installation

Junction box

Driver

Extension cableSensor

Target

SPEED SENSOR

Differential Expansion

A) Disc Type

Disc on shaft

Sensor

B) Ramp Type

Mounting Bracket

Sensors

Ramp arrangement

Differential Expansion

DIFFERENTIAL EXPANSION

Differential Expansion

Ramp targettype

DifferentialExpansion

Monitor

Driver

SensorRotor

Rotor

RotorComplementary input type

Ramp targettype

Case Expansion

LVDT

VM -11P

Signal Conditioner

Sensor

CaseDual case

exp. Monitor

STANDARD MOUNTING TECHNIQUES

CASING VIBRATION

VMS APPLICATIONS

1. MOTORS ABOVE 100 KW……LT & HT.2. PUMPS – BFP,CEP,ECW,CWP……CRITICAL PLACES.3. ID, FD , PA FANS & BLOWERS…..4. GEAR BOXES.5. CRUSHERS.6. MILLS.7. COMPRESSERS.8. PAPER ROLLERS.9. CRITICALS MACHINES IN AUTOMOBILES.

APPLICATION TO UNDERSTAND CASING VIBRATION

MONITORING.

Motor coupled with Horizontal

Pump

Motor – 200KW & Above• Motor is having 02 Bearings ( 1 Drive end

called DE and 1 Non Drive End called NDE )

Motors

Motor

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( Accelerometer / Velocity )

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( Accelerometer / Velocity )

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( Accelerometer / Velocity )

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( Accelerometer / Velocity )

JB JB

B1

B4

B 3B2

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( NL LP 202 / Accelerometer )

JB JB

B1

B4

B 3B2

Inp

ut

23

0V

AC

1

6 R

ela

y O

/p2

No

s P

er

i/p

1

6 4

-20

mA

O

/p

Motor Coupled with H. Pump

Centrifugal Pumps

Motor is already having 2 Bearing and Pump is having 2 Bearing ( DE & NDE )Every Bearing need to have 02 Sensors ( Accelerometer / Velocity )

JB JB

B1

B4

B 3B2

Inp

ut

23

0V

AC

1

6 R

ela

y O

/p2

No

s P

er

i/p

1

6 4

-20

mA

O

/p

INSIDE VM-5 RACK

SIGNAL PROCESSING

Alarm/Shutdown/Integrity logic processing

POWER SUPPLY(IES)

DISPLAY INDICATION

INPUTS/OUTPUTS

PROTECTIVE RELAYS

• SIGNAL CABLE

• RADIAL VIBRATION

• AXIAL POSITION

• CASING VIBRATION

• TEMPERATURE

• PISTON ROD DROP

• SPEED INDICATION

• OVER SPEED

DETECTION

MONITORSYSTEM

MEASURED VALUE(4 - 20MA OR 1 - 5VDC)

SIGNALS FROMSENSORS

DANGER /ALERT STATUS (RELAY CONTACT OUTPUT)

BUFFERED OUTPUT(VIBRATION WAVE FORM)

INPUT OUTPUT

PRIMARY FUNCTIONS OF MONITOR

Indicator1. Measuring value

2. Bar graph

3. Gap voltage

4. Alarm values

5. Sensor condition

SELF-DIAGNOSTIC FUNCTIONPRESS CHECK KEY ( IN NORMAL OPERATING MODE )

LCD, LED DISPLAY TEST (ALL LAMPS LIGHTS) SELF DIAGNOSIS DISPLAY OF DIAGNOSIS RESULT AS (NORMAL) OR (ABNORMAL)

CH1 OK (INPUT ABNORMAL) ALARM HIGH ---------------

CH2 OK (INPUT ABNORMAL) ALARM HIGH ---------------

CH1 OK (INPUT ABNORMAL) ALARM LOW --------------

CH2 OK (INPUT ABNORMAL) ALARM LOW ----------------

CH1 A/D INPUT 5V SIDE OVER -------------------

CH2 A/D INPUT 5V SIDE OVER -------------------

CH1 A/D INPUT 0V SIDE OVER ------------------

CH2 A/D INPUT 0V SIDE OVER -------------------

EASY ACCESS

1) TURN SCREWS AT TOP AND BOTTOM OF FACE PLATE.

2) PULL OUT THE FACE PLATE TILL THE DEPTH OF THE SLIDE FRAME.

3) TWIST IT SLIGHTLY TOWARD THE RIGHT.

BASIC KEY OPERATIONS

DIP SWITCH SETTING

1) 1BY (1CH BYPASS) S.W.2) 2BY (2CH BYPASS) S.W.3) DBY (DANGER BYPASS) S.W.4) MS1 (MODE-SELECT1) S.W.

(NORMALLY OFF )5) MS2 (MODE-SELECT2) S.W.6) N·A (NOT AVAILABLE)

(SET) KEY: TO CHANGE DISPLAY MODE AND TO FINALIZE INPUT.

(UP) KEY : TO INCREMENT SET VALUES.

(DOWN) KEY : TO DECREMENT SET VALUES.

(RESET) KEY : TO RESET SELF HOLDING ALARMS.

(CHECK) KEY : TO ADJUST THE GAIN WHILE USING UP AND DOWN KEY.

YOUR INPUTS / COMMENTS PLEASE !!!