CAM ANALYSIS APPARATUS

Cams are used in machines to move a component in a prescribed path e. g.

textile machine tools, I. C. engines, printing machines etc. Cam is a

mechanical member for transmitting desired motion to follower by direct

contact. Various types of cams and followers are used in practice like wedge,

radial or cylindrical cams and reciprocating or oscillating followers with flat

face, mushroom face or roller. The apparatus provides study of three types of

cams and followers with dial gauge, follower displacement diagrams can be

plotted and by rotating the cam, ‘jump’ phenomenon can be observed.

AIM:

To determine the speed at which cam jump occur for various spring loading

CONDITION.

SPECIFICATIONS :

1) Cams - Eccentric, tangent & circular arc cam one each.

2) Followers - Flat faced, Mushroom , and Roller followers one each.

3) Push rod assembly with spring and dead weights.

4) Variable speed motor to drive the cams.

5) Angular scale and dial gauge - 1 each.

EXPERINMENTAL PROCEDURE : -

1) Fit the required cam over the cam shaft and required follower to the push

rod.

2) Set angular scale at required position.

3) Adjust the weight seat and dial gauge.

4) Rotate the cam by hand and note down the dial - gauge reading at every

300 intervals.

5) Remove the dial gauge. Switch ‘ON’ the power supply. Slowly increase

the motor speed.

6) At particular speed a peculiar striking sound is heard. This speed is called

‘Jump Speed’. At this speed, follower does not follow the exact path

guided by cam contour. Note down this speed. Use of this cam-follower

system beyond this speed is useless, because desired follower motion is

not obtained.

7) Repeat the procedure for different dead weight and spring tension

configurations at different cam - follower configurations.

OBSERVATIONS : -

Cam --------- Follower----------

Sr

No.

Cam

Angle

Follower displacement

mm

1. 0

2. 30

3. 60

4. 90

⇓ ⇓

⇓ ⇓

12. 360

Jump Speed = rpm. Dead weight = N

Spring stiffness = 400 N/ m

PRECAUTIONS : -

1) Fix the key and bolt, for cam tightening properly.

2) While starting the motor, ensure that the dial gauge has been removed.

3) Tighten the weights loaded, by the check nut.

WHIRLING OF SHAFT

INTRODUCTION: IN ROTATING MACHINERY, IF SPEED ROTATION IS NEARER TO NATURAL FREQUENCY OF SYSTEM, THEN THE

AMPLITUDE OF VIBRATION WILL BE VERY HIGH. THE PHENOMENON IS CALLED WHIRLING OF SHAFTS AND

THE SPEED AT WHICH WHIRLING OCCURS IS CALLED WHIRLING SPEED OR CRITICAL SPEED. IN ANY

MACHINERY, IT IS TO BE ENSURED THAT THE MACHINERY IS NOT RUNNING NEAR THE CRITICAL SPEED.

CONSIDER A SINGLE ROTOR SYSTEM HAVING MASS ‘M’ AT CENTRE. IF ‘Q’ IS LATERAL STIFFNESS OF SHAFT IS

N/M IF E IS ECCENTRICITY OF MASS AND Y IS DEFLECTION.

AIM:

TO DETERMINE THE CRITICAL(WHIRLING) SPEED OF THE GIVEN ROTOR.

EXPERIMENTAL SETUP:

THIS CONSISTS OF A SHAFT Y DIAMETER‘D’ AND CENTRAL MASS ‘M’. THE SHAFT IS SUPPORTED ON TWO

BEARINGS AND DISTANCE BETWEEN BEARINGS CAN BE ADJUSTED. THE SHAFT IS DRIVEN BY A VARIABLE

SPEED MOTOR WITH SPEED INDICATOR. THE WHOLE ARRANGEMENT IS MOUNTED ON A BED.

SPECIFICATION:

SHAFT DIAMETER = 8 MM

MAXIMUM SHAFT LENGTH(BETWEEN CENTRE) = 750 MM.

ROTOR DIAMETER = 110 MM

ROTOR THICKNESS =14 MM.

ROTOR WEIGHT (M) = 1 KG.

EXPERIMENTATION:

1. INITIALLY SET THE BEARING BLOCK AT LAST HOLE SO THAT IT WILL BE MAXIMUM CENTRE DISTANCE

BETWEEN PEDESTALS AS MM.

2. CALCULATE LATERAL STIFFNESS OF SHAFT CONSIDERING THUS AS BOTH END FIXED BEAM

3. CALCULATE CRITICAL SPEED OF SHAFT

4. RUN THE SHAFT AND GRADUALLY INCREASE SPEED.

5. NOTE THE CRITICAL SPEED BY OBSERVING AMPLITUDE OF ROTOR.

6. INCREASE THE SPEED AND ENSURE THAT AMPLITUDE DECREASES.

7. CAUTION: DO NOT RUN THE SHAFT LONGER TIME ATCRITICAL SPEED.

8. DO THIS FOR CENTRE DISTANCE VARIANCE OF 25 MM, 50 MM…... ( PITCH OF THE HOLE WAS 25 MM)

RESULT:

THUS THE CRITICAL SPEED OF GIVEN ROTOR IS DETERMINED.

WHIRLING OF SHAFT

DESCRIPTION :

THIS APPARATUS IS DEVELOPED FOR THE DEMONSTRATION OF WHIRLING PHENOMENON. THE SHAFT CAN BE TESTED FOR DIFFERENT

END CONDITIONS.

THE APPARATUS CONSISTS OF A FRAME TO SUPPORT ITS DRIVING MOTOR, END FIXING AND SLIDING BLOCKS ETC. A SPECIAL DESIGN

IS PROVIDED TO CLEAR OUT THE EFFECTS OF BEARINGS OF MOTOR SPINDLE FROM THOSE OF TESTING SHAFTS. THE SPECIAL DESIGN

FEATURES OF THIS EQUIPMENT ARE AS FOLLOWS.

A) COUPLING :

A FLEXIBLE SHAFT IS USED TO DRIVE THE TEST SHAFT FROM MOTOR.

B) BALL BEARING FIXING ENDS :

THESE ENDS FIX THE SHAFTS WHILE IT ROTATES. THE SHAFT CAN BE REPLACED WITHIN SHORT TIME WITH THE HELP OF THIS UNIT.

THE FIXING ENDS PROVIDE CHANGE OF END FIXING CONDITION OF THE ROTATING SHAFT AS PER THE REQUIREMENT.

SHAFT SUPPLIED WITH THE EQUIPMENT :

POLISHING STEEL SHAFTS ARE SUPPLIED WITH THE MACHINE, THE DIMENSIONS BEING AS UNDER,

SHAFT NO. DIAMETER IN IN. (APPROXIMATELY) LENGTH ( APPROXIMATELY)

1 3/16” , 0.47 CM. 35.5”, 90.00 CMS.

2 ¼” , 0.64 CM. 35.5”, 90.00 CMS.

3 5/16” , 0.79 CM. 35.5”, 90.00 CMS.

END FIXING ARRANGEMENT :

AT MOTOR END AS WELL AS TAIL END DIFFERENT END MAKING USE OF DIFFERENT FIXING BLOCKS CAN DEVELOP CONDITIONS.

1) SUPPORTED END CONDITION – MAKE USE OF END BLOCK WITH SINGLE SELF ALIGING BEARING.

2) FIXED END CONDITION – MAKE USE OF END BLOCK WITH DOUBLE BEARING.

GUARDS D1 AND D2 :

THE GUARDS D1 AND D2 ( FIG. 1 ) CAN BE FIXED AT ANY POSITION ON THE SUPPORTING BAR FRAME WHICH FITS ON THE SIDE

SUPPORTS. ROTATING SHAFTS ARE TO BE FITTED IN BLOCKS IN A AND B STANDS.

SPEED CONTROL OF DRIVING MOTOR :

THE DRIVING MOTOR IS 250 VOLTS, DC ¾ HP., 6000 RPM, 50 HZ., AND SPEED CONTROL UNIT IS A DIMMERSTAT OF 240 VOLTS,

4 AMP. 50 HZ.

MEASUREMENT OF SPEED :

TO MEASURE THE SPEED OF THE ROTATING SHAFT A SIMPLE TACHOMETER MAY BE USED ( WILL NOT BE SUPPLIED WITH THE

EQUIPMENT ) ON THE OPPOSITE SIDE OF THE SHAFT EXTENSION OF THE MOTOR.

WHIRLING OF ELASTIC SHAFT :

IF,

L = LENGTH OF THE SHAFT IN CMS.

E = YOUNG’S MODULUS KG/CM2 2.060 X 10

6

I = 2ND

MOMENT OF INERTIA OF THE SHAFT CM4.

W = WEIGHT OF THE SHAFT PER UNIT LENGTH KG /CM.

G = ACCELARATION DUE TO GRAVITY IN CM/SEC2 = 9.81.

THEN THE FREQUENCY OF VIBRATION FOR THE VARIOUS MODES IS GIVEN BY THE EQUATION,

E I g

F = K X

W L4

THE VARIOUS VALUES OH K ARE GIVEN BELOW,

SR. NO. End Conditions Value of k

1ST

MODE 2ND

MODE

1 SUPPORTED, SUPPORTED 1.57 6.28

2 FIXED, SUPPORTED 2.45 9.80

3 FIXED, FIXED 3.56 14.24

Data :

SR. NO. SHAFT DIA. I = CM4 W = KG/CM

1 3/16” = 0.47 CM. 25.39 X 10-4

0.15 X 10-7

2 ¼” = 0.64 CM. 79.91 X 10-4

0.28 X 10-7

3 5/16” = 0.79 CM. 194.78 X 10-4

0.424 X 10-7

PRECAUTIONS TO BE OBSERVED IN EXPERIMENTS :

1) IF THE REVOLUTION OF AN UNLOADED SHAFT ARE GRADUALLY INCREASED IT WILL BE FOUND THAT A CERTAIN SPEED WILL

BE REACHED AT WHICH VIOLENT INSTABILITY WILL OCCUR, THE SHAFT DEFLECTING INTO A SINGLE BOW AND WHIRLING

ROUND LIKE A SKIPPING ROPE. IF THIS SPEED IS MAINTAINED THE DEFLECTION WILL BECOME SO LARGE THAT SHAFT WILL

BE FRACTURED, BUT IF THIS SPEED IS QUICKLY RUN THROUGH THE SHAFT WILL BECOME STRAIGHT AGAIN AND RUN TRUE

UNTIL AT ANOTHER HIGHER SPEED THE SAME PHENOMENON WILL OCCUR, THE DEFLECTION NOW HOWEVER, BEING IN A

DOUBLE BOW AND SO ON. SUCH SPEEDS ARE CALLED CRITICAL SPEEDS OF WHIRLING.

2) IT IS ADVISABLE TO INCREASE THE SPEED OF SHAFT RAPIDLY AND PASS THROUGH THE CRITICAL SPEED FIRST RATHER

THAN OBSERVING THE 1ST

CRITICAL SPEED WHICH INCREASE THE SPEED OF ROTATION SLOWLY. IN THIS PROCESS THERE IS

POSSIBILITY THAT THE AMPLITUDE OF VIBRATION WILL INCREASE SUDDENLY BRINGING THE FAILURE OF THE SHAFT.

IF HOWEVER THE SHAFT SPEED IS TAKEN TO MAXIMUM FIRST AND THEN SLOWLY REDUCED, ( THUS NOT ALLOWING TIME

TO BUILD-UP THE AMPLITUDE OF VIBRATION AT RESONANCE ) HIGHER MODE WILL BE OBSERVED FIRST AND THE

CORRESPONDING SPEED NOTED AND THEN BY REDUCING THE SPEED FURTHER THE NEXT MODE OF LOWER FREQUENCY

CAN BE OBSERVED WITHOUT ANY DANGER OF RISE IN AMPLITUDE AS THE SPEED IS BEING DECREASED AND THE INERTIA

FORCES ARE SMALLER IN COMPARISON WITH THE BENDING SPRING FORCES HENCE POSSIBILITY OF BUILD UP DANGEROUS

AMPLITUDES AT RESONANCE OR NEAR RESONANCE IS AVOIDED.

3) THUS IT CAN BE SEEN THAT IT IS A DESTRUCTIVE TEST OF SHAFTS AND IT IS OBSERVED THAT THE ELASTIC BEHAVIOR OF THE

SHAFT MATERIAL CHANGES A LITTLE AFTER TESTING IT FOR A FEW TIMES AND IT IS ADVISABLE THEREFORE, TO USE FRESH

SHAFT SAMPLES AFTERWARDS.

4) FIX THE APPARATUS FIRMLY ON THE SUITABLE FOUNDATION.

TYPICAL TEST OBSERVATION :

1) BOTH ENDS OF SHAFTS FREE (SUPPORT) 1ST

AND 2ND

MODE OF VIBRATION CAN BE OBSERVED ON SHAFTS WITH 3/16”:

DIA. AND ¼” DIA.

2) ONE END OF SHAFT FIXED AND THE OTHER FREE, 1ST

AND 2ND

MODE OF VIBRATION CAN BE OBSERVED ON THE SHAFT

WITH 3/16” DIA.

3) BOTH ENDS OF SHAFT FIXED – 2ND

MODE OF VIBRATION CANNOT BE OBSERVED ON ANY OF THE SHAFTS AS THE SPEEDS

ARE VERY HIGH AND HENCE BEYOND THE RANGE OF THE APPARATUS.

4) THERE IS DIFFERENCE BETWEEN THEORETICAL SPEED OF WHIRLING AND ACTUAL SPEED OBSERVED, DUE TO FOLLOWING

REASONS :

a) THE END CONDITIONS ARE NOT SO EXACT AS ASSUMED IN THEORY.

b) PRESSURE OF DAMPING AT THE END BEARINGS.

c) ASSUMPTIONS MADE IN THEORETICAL PREDICTIONS.

d) LACK OF KNOWLEDGE OF EXACT PROPERTIES OF SHAFT MATERIAL.

e) A UNIFORMLY LOADED SHAFT HAS, THEORETICALLY INFINITE NO. OF NATURAL FREQUENCIES OF TRANSVERSE

VIBRATION FOR FUNDAMENTAL MODE OBSERVATION OF THE FIRST MODE OF WHIRLING IS THEREFORE NOT SO

DEFINED AND THUS DIFFICULT 2ND

CAN BE VERY EASILY OBSERV

PORTER GOVERNOR

AIM :TO DETERMINE THE CONTROLLING FORCE OF PORTER GOVERNOR

APPARATUS :UNIVERSAL GOVERNOR APPARATUS ,TACHOMETER

PROCEDURE:

1. ARRANGE THE SETUP AS A PROELL GOVERNOR. THIS CAN BE DONE BY REMOVING THE UPPER SLEEVE ON THE

VERTICAL SPINDLE OF THE GOVERNOR AND USING PROPER LINKAGES PROVIDED.

2. INCREASE THE SPINDLE SPEED SLOWLY AND GRADUALLY.

3. NOTE THE SPEED AND SLEEVE VS SLEEVE DISPLACEMENT.

4. PLOT THE GRAPH OF SPEED VS GOVERNOR HEIGHT.

5. PLOT THE GRAPH OF SPEED VS GOVERNOR HEIGHT.

6. PLOT THE GOVERNOR CHARACTERISTIC AFTER DOING THE NECESSARY CALCULATIONS.

PRECATIONS:

1. INCREASE THE SPEED GRADUALLY.

2. TAKE THE SLEEVE DISPLACEMENT WHEN THE POINTER IS STEADY .

3. ENSURE THAT THE LOAD ON SLEEVE DOES NOT HIT THE UPPER SLEEVE OF THE GOVERNOR.

4. BRING DIMMER AT ZERO POSITION THEN SWITCH OFF THE UNIT.

OBSERVATION AND CALCULATION:

DIMENSIONS

A) LENGTH OF EACH LINK - L = 0.125 M.

B) INITIAL HEIGHT OF GOVERNOR – HO= 0.105 M.

C) INITIAL RADIUS OF ROTATION – RO = 0.120 M.

D) WEIGHT OF EACH BALL - W = 0.6 KGS.

E) WEIGHT OF SLEEVE WEIGHT = 0.5 KGS.

RADIUS OF ROTATION `R` AT ANY POSITION COULD BE FOUND AS FOLLOWS

A) FIND HEIGHT H = HO – X/2 MTR. HO = 0.10 M

B) FIND “ A “ BY USING A = COS –1 (H/L) IN DEGREES

C) THEN R = 0.05 + L SIN A MTR.

D) ANGULAR VELOCITY ‘W ’ = 2P N/60 RAD/SEC

SL.NO. SPEED

N

RPM

SLEEVE

DEPTH(X)M

HEIGHT

(‘H’)M

RADIUS OF

ROTATION (R)

M

FORCE ‘F’

=(W/G)*2R

GRAPH: 1. FORCE VS RADIUS OF ROTATION

2. SPEED VS SLEEVE DISPLACEMENT

RESULT: THE CONTROLLING FORCE OF A PORTER GOVERNOR IS DETERMINED

PROELL GOVERNOR

AIM : TO DETERMINE THE CONTROLLING FORCE OF PROELL GOVERNOR

APPARATUS : UNIVERSAL GOVERNOR APPARATUS, TACHOMETER

PROCEDURE:

1. ARRANGE THE SETUP AS A PROELL GOVERNOR . THIS CAN BE DONE BY REMOVING THE UPPER SLEEVE ON THE VERTICAL

SPINDLE OF THE GOVERNOR AND USING PROPER LINKAGES PROVIDED.

2. INCREASE THE SPINDLE SLOWLY AND GRADUALLY.

3. NOTE THE SPEED AND SLEEVE DISPLACEMENT.

4. PLOT THE GRAPH OF SPEED VS SLEEVE DISPLACEMENT.

5. PLOT THE GRAPH OF SPEED VS GOVERNOR HEIGHT.

6. PLOT THE GOVERNOR CHARACTERISTIC AFTER DOING THE NECESSARY CALCULATIONS.

PRECAUTIONS:

1. INCREASE THE SPEED GRADUALLY.

2. TAKE THE SLEEVE DISPLACEMENT WHEN THE POINTER IS STEADY.

3. ENSURE THAT THE LOAD ON SLEEVE DOES NOT HIT THE UPPER SLEEVE OF THE GOVERNOR.

4. BRING DIMMER AT ZERO POSITION THEN SWITCH OFF THE UNIT.

OBSERVATION AND CALCULATION:

LENGTH OF EACH LINK L= 0.125MT

INITIAL HEIGHT OF THE GOVERNOR HO = 0.100MT

INITIAL RAD OF ROTATION RO =0.127MT

WEIGHT OF BALL ASSEMBLY W1=7.4N

WT OF SLEEVE W2 = 9.81 N

TOTAL WT OF ASSEMBLY W=W1+W2

EXTENSION OF LENGTH BG= 0.075M

DIMENSIONS

A) LENGTH OF EACH LINK - L = 0.125 M.

B) INITIAL HEIGHT OF GOVERNOR – HO= 0.100 M.

C) INITIAL RADIUS OF ROTATION – RO = 0.127 M.

D) WEIGHT OF BALL - W = 0.6 KGS.

E) EXTENSION OF LENGTH BG = 0.075 M.

OBSERVATION TABLE:

SL.NO. SPEED

N

RPM

SLEEVE

DEPTH(X)M

HEIGHT

(‘H’)M

RADIUS OF

ROTATION (R)

M

FORCE ‘F’

=(W/G)*2R

GRAPH: 1. FORCE VS RADIUS OF ROTATION.

2. SPEED VS SLEEVE DISPLACEMENT.

RESULT : THE CONTROLLING FORCE OF A PROELL GOVERNOR IS DETERMINED.

WATT GOVERNOR

AIM : TO DETERMINE THE FORCE OF WATT GOVERNOR

DIMENSIONS :

a) LENGTH OF EACH LINK : L = 125MM =0.125M

b) INITIAL HEIGHT OF GOVERNOR = H0 = 96 MM =0.105M

c) INITIAL RADIUS OF ROTATION = 0.120M

d) WEIGHT OF EACH BALL ASSEMBLY = 0.520 KG OR 0.6 KG

GO ON INCREASING THE SPEED GRADUALLY AND TAKE THE READINGS OR SPEED OF ROTATION ‘N’ AND CORRESPONDING SLEEVE

DISPLACEMENT ‘X’ RADIUS OF ROTATION ‘R’ AT ANY POSITION COULD BE FOUND AS FOLLOWS:-

i) FIND HEIGHT = H = H0 – X/2

ii) FIND ‘α’ BY USING COS’α = H / L = COS –1

(H/L) IN DEGREES

iii) THEN R = 50 + L SIN α

ANGULAR VELOCITY ‘’ = 2N/60 RAD/SEC

PROCEDURE:

WATT GOVERNOR:

1. THE GOVERNOR SETUP IS CONNECTED TO THE POWER SUPPLY.

2. THE SET UP IS STARTED AT MINIMUM SPEED USING A SPEED CONTROLLER.

3. THE SPEED AT WHICH THE GOVERNOR JUST STARTS TO LIFT IS THE MINIMUM

EQUILIBRIUM SPEED.

4. THE SPEED IS GRADUALLY INCREASED AND THE SPEED CORRESPONDING TO THE

MAXIMUM HEIGHT OF THE GOVERNOR IS THE MAXIMUM EQUILIBRIUM SPEED.

OBSERVATION TABLE :

SR. NO. SPEED IN RPM SLEEVE DISPLACEMENT HEIGHT COS α = H / L RADIUS OF

ROTATION

FORCE F = W /

G ω2 X R.

FOLLOWING GRAPHS MAY THAN BE PLOTTED TO STUDY GOVERNOR CHARACTERISTICS

1) FORCE V/S RADIUS OF ROTATION.

SPEED V / S SLEEVE DISPLACEMENT

RESULT : THE CONTROLLING FORCE OF A WATT GOVERNOR ARE DETERMINED

STATIC AND DYNAMIC BALANCING

INTRODUCTION :

IT IS BASIC EQUIPMENT USED FOR ANALYZING THE CONCEPT OF STATICALLY AND DYNAMICALLY

BALANCING OF ROTATING MASSES.

BASIC SETUP :

THE EQUIPMENT CONSISTS OF RIGID FRAME OF ‘T’ SHAPE. WE MAY CALL THIS AS SUPPORTING FRAME.

THREE NUTS ARE PROVIDED ON IT TO HOLD THE EQUIPMENT ON HORIZONTAL LEVEL BY TIGHTENING

SCREWS. A MAIN FRAME CONSIST OF FOUR STEEL FLAT IS ALSO PROVIDED WITH THE EQUIPMENT. THIS IS

BASIC AND IMPORTANT PART WITH TO OUR EXPERIMENT. THIS FRAME CONSISTS OF HORIZONTAL

SHAFT MOUNTED BETWEEN TWO BEARINGS. A PULLEY ALLOWS WITH A HOCK AND A POINTER IS

PROVIDED ON THIS PULLEY. A GRADUATED SCALE OF 3600 IS PROVIDED ON THIS SIDE OF MAIN FRAME.

SIX ROTATING WEIGHTS WITH MARKING OF NUMBERS LETTERS HAVING DIFFERENT HOLES ARE

PROVIDED.

PROCEDURE : CLAMP THE MAIN FRAME ON THE SUPPORTING FRAME BY A NUT AND BOLT. CLAMP ROTATING WEIGHT

HAVING MARK AS 1/A ON THE MAIN SHAFT BY ALLEN KEY PROVIDED WITH THE MACHINE. ENSURE

THAT WEIGHT IS FIRMLY CLAMPED. IT SHOULD MOVE ALONG WITH THE SHAFT ONLY. WHILE DOING

THIS, CARE SHOULD BE TAKEN TO HAVE THE POINTER AT 00. NOW ATTACH TWO WEIGHT PANS BY A

LIGHT FLEXIBLE STRING TO THE HOOK PROVIDED ON THE PULLEY. LET THIS STRING PASS THROUGH

THE GROOM PROVIDED ON PULLEY. NOW ADD STEEL BALLS IN ANY ONE OF THE WEIGHT PANS ENSURE

THAT BOTH THE WEIGHT PANS ARE IN HORIZONTAL LEVEL. GO ADDING WEIGHTS UNTIL THE

ROTATING WEIGHT FALLS FREELY. AT THIS TIME POINTER SHOW 900

+ 100. COUNT DOWN THE STEEL

BALLS.

CONTINUE THIS PROCEDURE FOR ALL OTHER FIVE WEIGHTS. RECORD THIS WEIGHTS IN A TABLE.

WT. NO. NO. OF STEEL BALLS

1 2 3 4 5

6 TO DETERMINE STATIC BALANCING :

SELECT ANY FOUR ROTATING WEIGHTS AT RANDOM. SELECT ANY RANDOM DISTANCE BETWEEN THEM. FIND THE COUPLE OF ALL THE FORCES (WEIGHTS) WITH RESPECT TO ANY ONE OF THE FORCES. THE

GENERAL IDEA OF THIS COUPLE BINDING WILL BE AS UNDER,

4 2 3 6 ----- A ----------- B ------------- C ------ TABULATE THE RESULTS AS PER FOLLOWING –

WEIGHT NO. WR DIST. W.R.T.WEIGHT Couple WR X D

4 0 0 2 A 3 (A + B) 6 (A + B + C)

NOW DRAW COUPLE POLYGON. HERE WE WILL GET THE ANGLE OF WEIGHT NO. 2 & 3.

FORCE POLYGON IS ALSO DRAWN BY TAKING A SUITABLE SCALE FOR WR VALUES WITH ANGLE OF

FORCE 4 AS 0. ANGLES OF FORCES 2 & 3 AS FOUND IN COUPLE POLYGON. HERE YOU WILL FIND OUT

THE ANGLE OF FORCE 6.

NOW TABULATE THE ANGLES OF EACH FORCES.

FORCE Angle

4 0 2 3 6

ATTACH THESE WEIGHTS AS PER THESE ANGLES. ON THE SHAFT WITH THE USE OF WEIGHT SETTING

GAUGES AND SCALE PROVIDED ON THE MAIN FRAME. FOR TIGHTENING THE SHAFT AT REQUIRED

ANGLE USE OF KNOB MAY BE DONE. ENSURE THAT THE WEIGHT ATTACHED IS AT RIGHT ANGLE TO THE

WEIGHT SETTING GAUGE AND IT IS EXACTLY AT THE DISTANCE TAKEN FOR CALCULATING COUPLE.

REMOVE WEIGHT SETTING GAUGE AND KNOB. ROTATE THE PULLEY BY HAND. IT SHOULD STOP AT ANY

POSITION.

DYNAMIC BALANCING :

REMOVE THE MAIN FRAME FROM SUPPORTING FRAME. ATTACH HOOK AND CHAIN TO THE MAIN

FRAME AT THE GIVEN TAPINGS. LIFT THE MAIN FRAME AND ATTACH IT TO THE SUPPORTING FRAME BY

CHAIN AND STUD. TIGHTEN THE NUT. NOW THE MAIN FRAME IS HANGING. ADJUSTS ITS LEVEL BY

CHAIN AND NUT ARRANGEMENT.

PUT A BELT ON THE MOTOR PULLEY AND PULLEY PROVIDED ON SHAFT. USE SMALL DIAMETER OF THE

PULLEY TO PUT BELT ON IT. NOW START THE MOTOR AND OBSERVE THE PERFORMER.

WE CAN SAY THE ROTATING MASSES ARE PERFECTLY DYNAMICALLY BALANCED WHEN THERE EXISTS

ZERO VIBRATION TO THE FRAME.

LIMITATIONS :

CARE IS TAKEN TO MINIMIZE FRICTION BETWEEN THE SHAFT AND MAIN FRAME BUT HOWEVER ZERO

FRICTION IS NOT POSSIBLE AT ALL.

BY SELECTING ANY FOUR WEIGHT RATHER THAT THE ABOVE WE CAN FIND THE SAME STATIC AND

DYNAMICALLY BALANCING OF ROTARY WEIGHTS.