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LIST OF EXPERIMENTS

1. TO DETERMINE THE GAIN OF OPEN LOOP AND CLOSED LOOP

CONTROL SYSTEM.

2. EFFECT OF LOAD DISTURBANCE ON OPEN LOOP AND CLOSED

LOOP SYSTEM.

3. TO DETERMINE THE TRANSFER FUNCTION OF A D.C

SERVOMOTOR.

4. TO DRAW THE TRANSFER CHARACTERISTICS OF LVDT.

5. STUDY OF LAG-LEAD COMPENSATOR

6. TO DETERMINE THE TRANSFER FUNCTION OF AC SERVOMOTOR.

7. TO DETERMINE THECHARACTERISTICS OF THE STEPPER MOTOR.

8. STUDY OF LAG COMPENSATOR AND LEAD COMPENSATOR

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EXPERIMENT NO.1

OPEN AND CLOSED LOOP

AIM: To Determine The Gain Of Open Loop And Closed Loop Control System.

APPARATUS REQUIRED:

Open Loop/Closed Loop Trainer Kit, Patch Chords.

THEORY:

Open Loop Control Systems Are Those In Which The Output Has No Effect Upon The Control Action.

That Is An Open Loop Control System, The Output Is Neither Measured Nor Feedback For Comparison With The

Input, Fig(1) Shows The Input Output Relationship Of An Open Loop System. A Practical Example Is A Washing

Machine; The Machine Doesnt Measure The Output Signal, Namely The Cleanliness Of The Clothes. Any Control System That Operates On A Time Basis Is An Open Loop. For Example; Traffic C Control, Which Is Operated On

A Time Basis, Is Another Example Of Open Loop Control.

Input output

The Open Loop Gain G(S) =

= K1 or K2

A Closed Loop Control System is one in which the output signal has a direct effect upon the control

action i.e., a closed loop control systems are feedback control system. The actuating error signal which is the

difference between the input signal and the feedback signal is fed to controller so as to reduce the error and bring the

output of the system to the desired value. In other words the term closed loop implies the use of feedback action in order to reduce system error. The input output relationship of the closed loop system is shown in following figure.

Input output

Controller Plant Or Process

Controller Plant Or Process

Feedback Element

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CIRCUIT DIAGRAM:

L1

Set Point

Adjust

L2

R(s) E(s) Y(s)

X1

Z

X2

PROCEDURE:

i.)MEASUREMENT OF OPEN LOOP GAIN

1. Make Power On To The Unit

2. Connect SP To Open Loop Controller G(S) With K1 (Or K2) Gain By Connecting SP Socket To K1 (Or K2)

Socket [Fig A]

3. Set SP to Value Of 4 Volt And Measure The Output

4. Change The Value Of SP And Take 2-3 More Reading.

5. Calculate Open Loop Gain G(S) =Output/Input=K1

6. Change Open Loop Gain to K2 by Connecting SP To K2 And Repeat Steps 2 To 5

ii.)MEASUREMENT OF FEEDBACK GAIN

1. Make Power On To the Kit

2. Connect SP To Input K1(Or K2) Of H(S) Of Fig (A)

3. Set SP to Say 4 Volt

4. Measure the Voltage at Input and Output of H(S)

5. Feedback Gain H(S) =Output of H(S)/Input of H(S)

iii.)TO DETERMINE THE OUTPUT VOLTAGE OF CLOSED LOOP SYSTEM

1. Make Power On To the Unit

2. Connect SP To Summing Amplifier At R(S)[Fig (A)]

3. Connect E(S) To K1 Of G(S)(For Gain=1)

4. Connect Output Of H(S) To Summing Amplifier By Shorting Point X1 And X2

5. Set SP to Say 4 Volts and Measure The Output Voltage

6. Calculate Output Voltage By Using The Formula.

Y(s) =

*SP value

7. Change the gain of forward controller G(s) and /or feedback controller H(s) and note the input and output voltage.

V+ V- LOAD

DISTURBANCE

Set point

K1 G(s)=k

H(S)=K K1

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FORMULA:

Y(s) =

*SP value

OBSERVATION TABLE:

i.)Measurement of Open Loop Gain

S.No Open Loop Gain K1(Or

K2)

SP Value (V In) Output Voltage

(V Out)

Gain=V Out/V In=K1

(Or K2)

ii.)Measurement of Feedback Gain:

S.No K1(Or K2) of H(s) Input of H(s)

volts

Output of H(s)

volts

Feedback

Gain=H(s)=K1

(Or K2)

iii.)To Determine Output Voltage of Closed Loop System

Y Output Voltage

S.No G(S) H(S) SP Input

Voltage

Observed Calculate

K1

K1

K2

K2

K1

K2

K1

K2

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PRECAUTIONS:

1. If Negative Readings Are Obtained Change The Multimeter Terminal Connection.

2. The Supply Should Be According To The Specifications Mentioned.

3. The Chords Should Be Properly Connected.

4. Supply Should Be Given Only After The Connections Are Made.

APPLICATIONS:

Of Open Loop:

Train Crossing Signal Gates, Any Light Switch At Your Home.

Of Closed Loop:

The Power Supply in A Computer Or Any Electronic Devices, Furnace/Heating System With A Thermostat.

RESULT:

1.) The Open Loop Was Verified To Be K1 Or K2(According To The Connection).

2.) The Feedback Gain Was Verified To Be K1 Or K2(According To The Connection).

3.) The Observed And Calculated Values Of The Output Was Determined To Be The Same For The Closed Loop

System.

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EXPERIMENT NO: 2

LOAD DISTURBANCE ON OPEN LOOP AND CLOSED LOOP SYSTEM

AIM: Effect of Load Disturbance on Open Loop and Closed Loop System.

APPARATUS REQUIRED:

Open Loop/Closed Loop Trainer Kit, Patch Chords.

THEORY:

Open Loop Control Systems Are Those In Which The Output Has No Effect Upon The Control Action. That Is An

Open Loop Control System, The Output Is Neither Measured Nor Feedback For Comparison With The Input, Fig(1)

Shows The Input Output Relationship Of An Open Loop System. A Practical Example Is A Washing Machine; The

Machine Doesnt Measure The Output Signal, Namely The Cleanliness Of The Clothes. Any Control System That Operates On A Time Basis Is An Open Loop. For Example; Traffic C Control, Which Is Operated On A Time Basis,

Is Another Example Of Open Loop Control.

Input output

The Open Loop Gain G(S) =

= K1 or K2

A Closed Loop Control System Is One in Which the Output Signal Has A Direct Effect Upon The Control Action.

That Is, A Closed Loop Control Systems Are Feedback Control System .The Actuating Error Signal, Which Is the

Difference between the Input Signal and the Feedback Signal. It Is Fed To Controller So As To Reduce The Error

And Bring The Output Of The System To The Desired Value. In Other Words The Term Closed Loop Implies The Use Of Feedback Action In Order To Reduce System Error. The Input Output Relation Ship Of The Closed Loop System Is Shown In Fig (2)

Input output

Controller Plant or Process

Controller Plant or Process

Measuring

Element

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CIRCUIT DIAGRAM:

L1

Set Point

Adjust

L2

R(s) E(s) Y(s)

X1

Z

X2

PROCEDURE 1. Adjust Load Disturbance to Say +1 V

2. Connect Load Disturbance To System By Shorting Point L1 And L2[Fig(A)]

3. Note the Output Voltage for the Closed Loop System for Disturbance Of +1 V

4. Now Make the Connections for Open Loop Controller and Short Point L1 and L2 For Providing The Load

Disturbance

5. Note the Effect of +1 Volt Load Disturbance on Output Of Open Loop Controller

6. Compare The Percentage Change In Output For Given Load Disturbance For Open Loop And Closed Loop.

OBSERVATION TABLE:

S.No Open Loop

System

Load

Disturbance

Volts

Output Voltage

Without

Disturbance

Output Voltage

With

Disturbance

Percentage

Change

S.No Closed Loop

System

Load

Disturbance

Volts

Output Voltage

Without

Disturbance

Output Voltage

With

Disturbance

Percentage

Change

V+ V- LOAD

DISTURBANCE

Set point

K1 G(s)=k

H(S)=K K1

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PRECAUTIONS:

1. If Negative Readings Are Obtained Change The Multimeter Terminal Connection.

2. The Supply Should Be According To The Specifications Mentioned.

3. The Chords Should Be Properly Connected.

4. Supply Should Be Given Only After The Connections Are Made.

APPLICATIONS:

Open Loop

Train Crossing Signal Gates, Any Light Switch At Your Home.

Closed Loop

The Power Supply in a Computer or Any Electronic Devices, Furnace/Heating System with a Thermostat.

RESULT: It Was Verified That the Effect of Disturbance for a Closed Loop System Is Less As Compared To the

Open Loop System

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EXPERIMENT NO: 3

D.C SERVOMOTOR

AIM: To Determine The Transfer Function Of A D.C Servomotor.

APPARATUS REQUIRED:

1.) D.C Servomotor

2.) Control Kit

3.) Ammeter 0-500 Ma (M.C Type)

4.) Voltmeter 0-15 V (M.C Type)

5.) Multimeter Digital

6.) Connecting Wires

THEORY:

A D.C Servomotor Is Often Employed In A Control System Where An Appreciable Amount Of Shaft Power Is

Required .The Dc Motor Are Much More Efficient Than Ac Servomotor .The Dc Motor Have Separately Excited

Fields. They Are Either Armature Controlled With Fixed Field Current Or Field Controlled With Fixed Armature

Current. The Performance Characteristics of the Armature Controlled Dc Motor Resemble the Idealized

Characteristic of The Two-Phase Ac Servomotor.

Consider the armature-controlled dc motor is shown in fig.1

=Armature-Winding Resistance, Ohms =Armature -Winding Inductance, Henrys =Armature-Winding Current , Amperes =Field Current, Amperes

=Applied Armature Voltage, Volts =Back Emf, Volts =Angular Displacement of Motor Shaft, Radians T=Torque Delivered By the Motor Kg-Cm

J=Equivalent Moment Of Inertia of The Motor And Load Referred To The Motor kg- F=Equivalent Viscous-Friction Coefficient of the Motor and Load Referred to the Motor kg-cm/red/sec

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CIRCUIT DIAGRAM:

PROCEDURE:

Transfer Function of D.C Servomotor

Speed-Torque Characteristic and Torque-Armature Characteristics

1.) Make Connections as Shown In Circuit Diagram

2.) Connect Motor Unit to Control Using 9 Pin Connector Chords

3.) Make Power On To the Unit .Put RPM Meter Switch at Output Speed Position

4.) Adjust Volt And Adjust the Pot of Dc Power Supply at Say 8 Volts .Keep The Knob K of Spring

Balance Loading System for No Load Position

5.)Note Speed Of The Motor N, Armature Current And And Reading Of Spring Balance ,And

Feedback Voltage Increase The Load On Dc Servomotor By Adjusting Knob K Of Spring Balance

Loading System In Proper Steps And Note The Reading N, , , And

6.) Adjust the Volt and Adjust the Pot of Dc Power Supply for =10 V And Repeat Step 4. 7.) Plot the Graph of Torque against Speed for At least 2-3 Different Values of Armature Voltage.

8.) Plot the Graph of Torque in (gm-Cm) Against Armature Current

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(In Amperes) .From The Graph Calculate Motor Torque Constant K= gm-cm/A

Back-Emf Characteristics:

1.) Keep Minimum Load On Motor By Adjusting Knob K Of Spring Balance Loading System.

2.) Use Same Circuit Connection as In Part A .Vary The Dc Voltage From Minimum To Maximum In

Proper Steps By Volt Adjust Pot And Note Speed N And Feedback Voltage .Tabulate the result.

3.) Calculation of Back Emf

Armature Resistance Ra=-------Ohms

Back Emf as is negligible Graph:

A.)Plot The Graph Of Back Emf Against Speed (Rad/Sec) Calculate Back Emf Constant =

Volt/Rad/Sec.

B.)Plot the Graph of Feedback Voltage Against , Feedback Gain

MODEL GRAPHS:

Back Emf-speed characteristics:

\

FORMULA:

---------- ---------

s (

A.)Motor Gain Constant

= if f is negligible

B.) motor time constant

=

if f is negligible

=0.3 ohms;j=0.4 kg-

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And K as calculated from graph and & j as given in data of motor in above equation

to get transfer function.

OBSERVATION TABLES:

A.)SpeedTorque Characteristics

S.No (Gm) (Gm) T= -

(Gm)

Torque

T= -

)*2(Gm-Cm)

Speed

N(Rpm)

Armature

Current

(Ma)

Feedback Voltage

(Volts)

B.) Back-Emf Characteristics

PRECAUTIONS:

1.) Connection should be neat and clean.

2.) Proper time should be given for the settlement of the reading.

3.) Portable instrument should be selected of proper range.

APPLICATIONS:

Servomotors Are Used In Applications Such As Robotics, servo stabilizers, aircraft control systems,

CNC Machinery Or Automated Manufacturing.

RESULT: The Transfer Function of DC Servomotor Is-----------

S.No Armature

voltage (volts) Armature current

(ma) Speed N (RPM) Speed

(rad/sec)=2 /60 Back Emf (volt)

Feedback

voltage

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EXPERIMENT NO: 04

LINEAR VARIABLE DIFFERENTIAL TRANSFORMER

AIM: To Draw the Transfer Characteristics of LVDT

APPARATUS REQUIRED: LVDT Kit, Multimeter, Patch Chords.

THEORY:

LVDT Or Linear Variable Differential Transformer Is An Inductive Transducer Which Converts Displacement Into

Electrical Signal. This Transformer Consists Of Three Winding, One Primary Winding P And Two Secondary

Windings And .The Secondary Windings Are Exactly Identical I.E., They Have Equal Number of Turns and Are Placed on Either Side of Primary Winding .The Three Windings Are Wound over a Hollow Non-Magnetic

Insulating Material. The Ferromagnetic Core of the Transformer Is Movable and Its Position Determines the Flux

Linkages between Primary And Each Of The Secondary Windings. Primary Windings Is Connected To An A.C

Source Of Voltage 5 To 25V And Frequency 50 Hz To 20 KHz. The Output Voltage Is The Difference of the Emfs induced in the Secondary Windings as They Are Connected in Series Opposition .When The Core Is in the Center, The Output Voltage Would Be Zero. This Is Called Null Position. When The Core Is Moved Towards Left,

More Flux Links With Then .The Magnitude Of The Output Voltage Is Equal To The Difference Between The Two Secondary Voltages And Is In Phase With The Emf Of .When The Core Is Moved To The Right, More Flux Links With The ,The Output Voltage Magnitude Again Equals The Difference Between Two Induced Emfs And It Is In Phase With The Emf Of Coil. Fig (1) Shows the Output Voltage ( ) As A Function of Core Position X.

Fig. 1(A) fig. 1(B)

Fig.1(A) Actual LVDT Characteristics and Fig.1(B)LVDT Characteristics When Measured With Voltmeter.

Fig.1 (A) And (B) Shows That The LVDT Characteristics Is Linear For Most Of The Range Of Operation .Beyond

This Range, The Curve Flattens On Both Sides On Account Of Saturation .At The Null Position ,There Exists Some

Residual Voltage Which Is Less Than 1% Of The Maximum Value Of Output Voltage .The Residual Voltage May Appear Because Of:

(A.) Magnetic and Electrical Imbalance of Windings.

(B.) Presence of Harmonics in the Input Voltage.

(C.) Presence of Harmonics in the Output Voltage.

(D.) Stray Magnetic Fields.

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CIRCUIT DIAGRAM:

Linear variable differential transformer

PROCEDURE:

1.) Connect the Primary Winding Of LVDT to An Excitation Source As Shown In The Fig.2

2.) Connect The Two Secondary Windings In Series Opposition.

3.) Bring The Core To The Center Position.

4.) Note The Residual Voltage.

5.) Display The Core By +50 Mm In Steps Of 10 Mm To The Right Of The Center Position And Note The Output

Voltage.

6.) Repeat Step 4 For Displacement To The Left Of The Center Position.

7.) Plot The Graph Between Output Voltage And Displacement.

FORMULA:

The Transfer Function of LVDT in the Linear Range Is Given As

= constant.

The limitations of LVDT are that is sensitive to stray magnetic fields and temperature variations.

OBSERVATION TABLE:

Left Movement Right Movement

S.No Distance (Mm) Output Voltage

(Mv) Distance(Mm) Output Voltage

(Mv)

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PRECAUTIONS:

1.) Connection Should Be Neat And Tight.

2.) Null Point Should Be Obtained Carefully.

3.) Output Voltage On Either Side Of The Displacement Should Be Noted Carefully.

APPLICATIONS:

It is used in radiation resistance designs for nuclear operations.

RESULT:

The Transfer Function of the LVDT Was Obtained To Be--------

And Hence the Characteristic of LVDT Is Obtained.

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EXPERIMENT-05

STUDY OF LAG-LEAD COMPENSATOR

AIM: Study of Lag-Lead Compensator

APPARATUS REQUIRED: Lead Lag Compensator Kit, CRO and Connecting Probes

THEORY:

Compensation Network Are Often Used To Make Improvement In Transient Response And Small Change In Steady

State Accuracy. The Set Up Is Divided Into Three Parts. Signal Source. It Has A Sine Wave Of 10-1200 Hz Of 0-8

Vpp. Square Wave Of 20, 40, And 80 Hz Of 0-2 Vpp. Trigger Is Available For Triggering Of CRO In External

Trigger Mode. The Amplitude Is 1.2 Vpp. There Are Three Compensation Circuit As Lag. Lead And Lag-Lead with

Transfer Function .The set up Has Two Dc Regulated Power Supply for Signal Source and Systems

CIRCUIT DIAGRAM:

PROCEDURE:

The Experiment Is Divided Into Two Parts

1.)Open Loop Response: Connect Square Wave To Gain And CRO Across Input And Output .Select Frequency To

80Hz At 0.2Vpp .Measure Input Amplitude Vpp As A And Output As Amplitude As B. Calculate Gain

Factor=B/A. Connect Sine Wave With Process Input ,CRO Across Input And Output .Set Input Voltage =8Vpp

From Low Frequency End 10 Hz Note Output Voltage Vpp As B. Note The Phase Difference For Each Test

Frequency Connect The Sine Wave With Lag Input. Connect CRO Across Input And Output. Note The Output

Voltage, Phase Difference For Each Test Frequency. Prepare a Table between Input /Output Voltage, Gain

Magnitude in Db and Phase Angle in Degree .Plot A Graph Accordingly

2.) Closed Loop Response: Connect The Square Wave Signal Of 20Hz, 1Vpp At Input Of Error Detector. Adjust

Gain To The Value Found From plot For Required Shape Of Response And Sketch It In The Paper .From The

Transient Response Measure Maximum Over Shoot Mp, Steady State Error Ess And Peak Time Tp. Select 40 Hz,1

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Vpp And Adjust Gain Control To 60%.Not Gain Control Setting. Trace Wave Form on Paper with Record Of Ess,

Mp, Tp. Select Frequency To 80Hz And Adjust Gain Control For Minimum Ess To 0.Trace The Wave Form With

Set Square Wave Frequency To 20 HZ, 1Vpp At Error Detector Input. Adjust Gain Control To For Similar Ess Note

Gain To Form Dial Setting. Trace The Wave Form On Paper With Record Of Mp, Tp And Ess.

APPLICATIONS: Robotics, satellite control.

RESULT: Hence We Have Studied The Lag-Lead Compensator.

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EXPERIMENT-06

TRANSFER FUNCTION OF TWO-PHASE AC SERVOMOTOR

AIM: To Determine the Transfer Function of Ac Servomotor

APPARATUS REQUIRED:

1.) Transfer Function of Ac Servomotor (Vpet-302) Trainer Kit.

2.) Two Phase Ac Servomotor with Load Setup and Loads

3.) Pc Power Chord

4.) Patch Chords

5.) 9 Pin Cable

THEORY: AC Servomotor I Basically A Two Phase Induction Motor Except For Certain Design Feature .A Two

Phase AC Servomotor Differs In Two Ways From A Normal Induction Motor. The Servomotor Rotor Side Is Built

In High Resistance So The X/R Ratio Is Small Which Results In Linear Mechanical Characteristics Evan If Getting

Higher Efficiency. Another Difference Of AC Servomotor Is That The Excitation Voltage Applied To Two Stator

Winding Should Have A Phase Difference Of 90.Two Phase Ac Servomotor Needs 90 Phase Shift Between Two

Phases To Produce The Torque. If We Use The Capacitor In Series With One Phase Which Will Create 90 Phase

Shift In Our Trainer Kit 90 Phase Shift Is Produced By Using Scott Connection Of The Transformer, Without Using

Capacitor. Servomotor Are Used To Convert An Electrical Signal Applied To Them Into An Angular Displacement

Of The Shift

CIRCUIT DIAGRAM:

STATOR OF AC SERVOMOTOR

ROTOR OF AC SERVOMOTOR

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TRANSFER FUNCTION OF AC SERVOMOTOR

PROCEDURE:

CONNECTION PROCEDURE FOR MOTOR CONSTANT : 1.) Initially Keep All The Switches In Off Position.

2.) Connect the Banana Connector To And To 3.) The Banana Connector Pin Terminal Is Also Connected With Motor Control Winding P Terminal And The

Banana Connector Terminal Is Also Connected With Motor Control Winding N Terminal. 4.) Connect the 9 Pin D Connector from Ac Servomotor to VPET-302 Module Trainer Kit

5.) Keep The Variable Ac Source In Minimum Position.

EXPERIMENTAL PROCEDURE FOR MOTOR CONSTANT 1.) Apply 3 Ac Supply to the 3 Input Banana Connectors at the Backside Of The Module 2.) Switch on the Power Supply

3.) Switch On The Control Winding And Main Winding Switches And Respectively. 4.) Now Slowly Vary the Variable AC Source to the Control Winding Till the Motor Reaches 300 R.P.M

5.) Apply Load One By One till the Motor Stops

6.) Note down The Load Values and Control Voltages.

7.) Now Again Vary the AC Source and Apply Voltage to Control Winding till the Motor Reaches 300 R.P.M

8.) Again Apply Loads Till The Motor Stops.

9.) Repeat the Above Steps and Note down The Values and Tabulate It

10.) Calculate the Torque of the Motor

11.) Draw The Graph Between Control Voltages Vs. Torque.

12.) From the Graph Find Out the Motor Constant K1.

CONNECTION PROCEDURE FOR MOTOR CONSTANT 1.) Initially Keep All The Switches In Off Position.

2.) Connect the Banana Connector To And To 3.) Connect the 9 Pin D Connector from Ac Servomotor to VPET-302 Module Trainer Kit for measuring the speed.

4.) Keep The Variable Ac Source In Minimum Position.

EXPERIMENTAL PROCEDURE FOR MOTOR CONSTANT 1.) Switch on the Power Supply

2.) Switch On The Main Winding power supply 3.) After giving the power supply to the main winding, switch ON the control winding power supply switch . 4.) Vary the control voltage to set a rated voltage of the control winding (180V).

5.) Apply the load in step by step up to the motor run at zero rpm and note down the speed of the motor and applied

load.

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6.) After taking the readings, fully remove the load from the motor and bring the variable AC source in minimum

position.

7.) Switch off the control winding switch . 8.) Finally switch off the main winding switch and power supply switch. 9.) Tabulate the speed and load values and calculate torque.

10.) Draw the Graph between Control speeds Vs. Torque and find the motor constant .

FORMULA:

Torque T=(9.81*r*s)Nm

Motor constant K1= Where,

R=radius of the shaft

T=change in torque, Nm V=change in control winding voltage, Vdt S=applied load in kg

Torque T = (9.81*r*s) Nm

Motor constant K2= T=change in torque, Nm N=change in speed, rpm S=applied load in kg.

OBSERVATION TABLE:

For motor constant K1

S.No Load (S) Control voltage (V)volts Torque(T)Nm

For motor constant K2

S.No Speed(Rpm) Load(S)kg Torque(T)Nm

PRECAUTIONS:

1.) Make Connections As Shown In Circuit Diagram

2.) Readings should be taken without any parallax error.

APPLICATIONS: process control equipment, machine tools, sewing machines, robotics and portable drilling

machines.

RESULT: The Transfer Function of the AC servomotor was obtained to be --------

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EXPERIMENT NO-07

CHARACTERISTICS OF THE STEPPER MOTOR

AIM: To Find Out The Speed Vs. Torque Characteristics Of The Stepper Motor.

APPARATUS REQUIRED:

1.) Trainer kit (VSMIT-02)

2.) Weights

THEORY:

The Stepper Motor Is A Special Type, As That Of The Synchronous Motor, Which Is Designed To Rotate Through

A Specific Angle (Called A Step) For Each Electrical Pulse Received From Its Control Unit. Typical Step Sizes Are

7.5,15 Are Larger .The Stepper Motor Is Used in Digitally Controlled Position Control System in Open-Loop Mode.

The Input Command Is In The Form Of A Train Of Pulses To Turn A Shaft Through Specific Angle..Two Main

digital Systems and That No Sensors Are Needed by Counting Input Pulses and Periodic Counting If Speed

Information is Needed.

CIRCUIT DIAGRAM:

PROCEDURE:

1.) Switch On The Power Switch And Keep Int/Ext Switch To The Int Mode.

2.) Keep The Switch S1 To Position 1 [Down] 3.) Keep The Switch S2 To Position 0 [Up] 4.) Keep The Switch S3 To Position 0 For Decreasing The Speed And To Position 1 For Increasing The Speed. 5.) Now Fix The Weight Stand To The Disc Connected To The Shaft Of The Motor.

6.) By Using The Push Button Set The Speed Of The Motor To A Certain Value.

7.) Now Add Weight To The Weight Stand Until The Speed Does Not Decrease.

8.) If The Speed Slips From The Set Value, Then Decrease The Weight.

9.) Now Note The Set Speed In Rpm And Weight In Kg.

10.) Repeat The Steps 6,7,8,9 For Different Values Of Speed And Weights.

11.) Measure the Distance between the Centres

Of The Shaft and Load Point, Say R In Cm. 12.) Calculate The Torque By Multiplying The Weight In Kg And Measured Distance R In Cm. 13.) Plot the Speed vs. Torque Characteristics of the Stepper Motor

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OBSERVATION TABLE: where (r=4.2cm)

S.No Speed(N)Rpm Weight In Kg(W) Torque In Kgcmt=W*R

PRECAUTIONS:

1.) Make Connections As Shown In Circuit Diagram

2.) Readings should be taken without any parallax error.

APPLICATIONS: printers, tape drivers, capston drives, memory access mechanisms.

RESULT: Hence We Have Studied The Characteristics Of A Stepper Motor.

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EXPERIMENT-08

STUDY OF LAG COMPENSATOR AND LEAD COMPENSATOR

AIM: Study of Lag Compensator And Lead Compensator

APPARATUS REQUIRED: Trainer Kit, Patch Chords, CRO, Multimeter

Trainer Kit Is Used in Learning Passive Lag and Lead Compensator .Lag And Lead Compensator Is Designed Using

R-C Combinations. The Input Given Is Generally 3v Through A Function Generator.

THEORY:

Passive Electric Components-Resistors, Capacitors and Inductors Are Used For the Implementation of A

Compensator. However Since The Inductor Is Very Bulky Component At Low Frequencies Passive Networks Are

Made Up Of Only Resistors And Capacitors .Conditions For Reliazability Of Transfer Function D(S) With Passive

Resistor-Capacitor(Rc) Networks In That All Finite Poles Of G(S) Must Be Simple And Lie On The Negative Real

Axis The Zeros Of G(S) May Lie Anywhere In The S-Plane .

The Transfer Function Of A Simple First Order Compensator That Can Be Implemented By Passive Rc Network Is

G(S)=

---------Eq(A)

Where K Is A Constant; S= -Z And S= -P Represents The Zero And Pole Of The Compensator.

The Lag Network Has A Single Pole And A Single Zero With The Pole Lying To The Right Of The Zero On

Negative Real Axis Of The Complex Plane. Thus First Order Compensator Given By Above Equation Is A Lag

Compensator Of P

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PROCEDURE :

For Lag Compensator:

A.) 1.) Make The Connections As Per The Circuit Diagram I.E.Fig (2).

2.) Select The Components R=10k And C=0.1f 3.) Switch On The Supply

4.) Connect The Audio Frequency Generator At Input Excitation To 3volts R.Ms

5.) Now Change The Audio Oscillator Output Frequency In The Range 20hz To 1000hz In Proper Steps And Note

The Output Voltage. Enter The Result In Table.

6.) Calculate The Theoretical Value Of And Against Frequency Find The Corner Frequency.

B.) 1.) Make The Connections As Shown In Fig (3)

2.) Select The Components R1,R2,C.

3.) Switch On The Supply

4.) Connect Audio Frequency Generator At Input. Adjust Input Excitation To 3v R.M.S

5.) Now Change The Audio Oscillator Output Frequency In The Range 20hz To 1000hz In Proper Steps And Note

The Output Voltage .Enter The Result In Table

6.) Calculate The Theoretical Value Of And Against Frequency Find The Corner Frequency. 7.) Plot The Graph Of And Against Frequency And Find The Corner Frequency.

For Lead Compensator:

A.) 1.) Make the Connections As Per The Circuit Diagram I.E. Fig (4).

2.) Select the Components R=10k and C=0.1f 3.) Switch on the Supply

4.) Adjust the Input Excitation To 3v R.M.S

5.) Now Change The Audio Oscillator Output Frequency In The Range 20 Hz To 1000 Hz In Proper Steps And Note

The Output Voltage Vo For Given Input Frequency And Tabulate The Results.

6.) Calculate The Theoretical Value Of And Against Frequency Find The Corner Frequency.

B.)

1.) Make the Connections As Shown In Fig (3)

2.) Select The Components R1, R2, C.

3.) Switch on the Supply

4.) Connect Audio Frequency Generator At Input. Adjust Input Excitation to 3V R.M.S

5.) Now Change The Audio Oscillator Output Frequency In The Range 20Hz To 1000Hz In Proper Steps And Note

The Output Voltage. Enter the Result in Table

6.) Plot the Graph Of and Against Frequency and Find the Corner Frequency

25 | P a g e

OBSERVATION TABLE:

Input Frequency Is 20 To 1000Hz

Input Voltage Is 3 V R.M.S

For Lag Compensator

S.No Frequency(Hz) Vo(Volts) Vi(Volts) Observed

For Lead Compensator

S.No Frequency(Hz) Vo(Volts) Vi(Volts) Observed

PRECAUTIONS:

1.) In Determining Angle From Lissajous Fig A Proper Range Of Frequency Should Be Selected.

2.) Connections Should Be Neat And Clean.

APPLICATIONS: Used In Design Of Laser Guided Missiles, Automobile Diagnostics, Laser Frequency

Stabilizations.

RESULTS:

Hence We Have Studied the Operation of Lag Compensator and Lead Compensator