Cth Write Up

8/2/2019 Cth Write Up

1/42

V.V.P. Engineering College,Rajkot

CERTIFICATEThis is to certify that the

Mr./Ms.____________________________________________________________RollNo._______________EnrollmentNo.___________________________Branch__________________________________Semester_______________HassatisfactoryCompletedthecourse intheSubject___________________________________withinthefourwallof V.V.P.EngineeringCollege,Rajkot.

DateofSubmission:______________________________________________

Staff in Charge Head of the Department


2/42

V.V.P.ENGG.COLLEGE

ELECTRONICS &COMMUNICATION

ENGG.DEPARTMENT

CONTROL THEORY

LAB MANUAL

Electronics&CommunicationDepartment


3/42

LIST OF EXPERIMENT

B.E .4th

EC( CONTROL THEORY)

Sr.No.

LISTOF

EXPERIMENT

1 Tounderstandvarioustypesoftestingsignal.

2 TostudytheOperationof type0Controlsystem.

3 TostudytheOperationof type1ControlSystem.

4 TostudytheOperationof type2ControlSystem.

5

Tostudy

the

Speed

Torque

Characteristics

of

the

AC

Servo.

6 ToPerformtheworkingofStepperMotor.

7 DCServoMotor.

8ToPlottheCharactersticsofPotentiometerandstudythe

EffectOfLoading.

9 TostudytheSynchrosMotor.

10

Tostudy

the

Amplydyne

Generator.

11 TostudyImpulse,StapRampResponseUsingMATLAB.

12 Ploting the Bode Plot of a Transfer Function using MATLAB.13 PlotingtheRootLocusofaTransferFunctionusingMATLAB.

14 PlotingtheNyquistPlotofaTransferFunctionusingMATLAB.

Lab I/C HOD

(EC)

VVP/EC/CT-1


4/42

INDEXSr. No. Title Page Date Of

Start

Date Of

Completion

Initials of

Staff

Remarks

From To1 To understand various types of

testing signal.

2 To study the Operation of type 0

Control system.


Control System.


Control System.

5 To study the Speed Torque

Characteristics of the AC Servo.

6 To Perform the working of StepperMotor.

7 DC Servo Motor.

8 To Plot the Characterstics of

Potentiometer and study the Effect

Of Loading.

9TostudytheSynchrosMotor.

10 To study the Amplydyne Generator.

11 To study Impulse,Stap Ramp

Response Using MATLAB.

12 Ploting the Bode Plot of a Transfer

Function using MATLAB.

13 Ploting the Root Locus of a Transfer

Function using MATLAB.

14 Ploting the Nyquist Plot of a

Transfer Function using MATLAB.


5/42

EXPERIMENT NO 1

TEST SIGNAL GENERATOR

Aim:- To understand various types of Testing Signal.

APPARATUS:- TRAINER KIT- DIGITAL MULTIMETR

THEORY:

As the name suggests the test signal generator, generates

various test signals, which are required to test the working of various

control engineering systems, namely, Type 0 System, Type 1 controlsystem, Type 2 control system, Proportional (P) control system, PD

control system, PI control system, PID control system etc.

Various Signals such as, step ramp and parabolic aregenerated and made available at the output terminals as desired.

The step signals can be started from minimum as and when

desired by the Discharge/Restart toggle switch.Any of the three outputs viz, step, ramp, and parabolic can be

selected and made variable ate output terminals.

FUNCTIONS OF VARIOUS BLOCKS :-

POWER ON : It consists of the mains ON/OFF switch which energizes

the .Test Signal generator and the LED indicates that supply i.e ON.

PROCESS SELECT : The process select switch selects the output

available at output terminals viz., step signal, ramp signal of parabolic

signal.

STEP LEVEL ADJ. : The step level adjust is a fine control to vary thelevel of step signal.

DISCHARGE/RESTART : The discharge/ restart toggle switch is used

for either ramp or parabolic signal. This switch should be toggled to

discharge momentarily and then back to restart mode for

normal operation.

VVP/EC/CT2


6/42

SIMULATED OUTPUT : The simulated signal output either step, ramp

or parabolic (as selected) is available at these terminals for use as signal

input to trainers.

PROCEDURE:1. Connect the mains cord to 230V AC,1 phase and switch ON the

'POWER ON' switch.

2. See that the power on LED glows indicating that the test signalgenerator is energies.

3. Select the required signal (Out of step, ramp or parabolic) by using theprocess select switch.

4. The selected output is available at the output terminal markedsimulated output and can be observed on C.R.O .

5. The step level can be precisely adjusted using the step adjust control.(When step signal is selected ).

6. The Discharge/Restart switch is used for ramp or parabolic todischarge and restart the signal (when selected).

7. The selected output signal available at the simulated output terminalscan be connected to the trainer, which requires test signal input.

VVP/EC/CT3


7/42

(A) STEP SIGNAL

(Fig-1)

(B) RAMP SIGNAL

(Fig-2)

(C) PARABOLIC SIGNAL

(Fig-3)

VVP/EC/CT4


8/42

OBSERVATION TABLE:

STEP SIGNAL

SR.NO Input R(S)mV Output C(S)mV ERROR R(S)-C(S)

RAMP SIGNAL


PARABOLIC SIGNAL


CONCLUSION:-

VVP/EC/CT5


9/42

EXPERIMENT NO 2

TYPE 0 CONTROL SYSTEM

AIM: To study the operation of a type 'o' control system

APPARATUS:-1. ADTRON TRAINER KIT.2. ADTRON TEST SIGNAL GENERATOR3. DIGITAL MULTIMETER - 2 Nos.

THEROY:System error is an important feature of control system.

Errors in control system can be attributed to many factors. Change

in the reference input will cause unavoidable errors during transientperiods and May also cause steady state errors. Imperfection in

system components, such as static friction, backlash and amplifier

drift, as well as aging or distortion, will cause errors at steady state

Type o control system offers constant steady state error for step

input and infinite error for ramp input.

PROCEDURE:-1. Connect the required supply and switch on the unit. See that supply

LED glows ON.

I :- TIME RESPONSE ANALYSIS:-

A. STEP SIGNAL ANALYSIS :-

1. Connect test signal generator output to the I/P terminals of the trainer.2. Connect Digital Multimeter each at the Input and Output terminals.3. Switch ON the Test Signal Generator and select 'Step' signal of the

Output.

4. Adjust Step signal by 'Step ADJ' Potentiometer for 1V, 2V, 3V..........and for each reading, observe and record the output voltage in the

observation table-I.

5. Repeat the above procedure for different setting of T.6. From the readings calculate steady state error per unit step input and

plot input, Output graphs.

VVP/EC/CT6


10/42

B.RAMP SIGNAL ANALYSIS :-1. Selected Ramp signal from test signal generator. Keep toggle switch

in discharge' Position.

2. Keep Digital multimeter at the i/p & o/p terminals for 0-300 mvrange, or 0-2v range.3. Put toggle switch in restart position and ramp signal will be available

at the input terminals of the trainer.

4. Input voltage will go on increasing at a predetermined rate. Observeinput and output meters simultaneously an record the output voltage

for different input voltage for different input voltage at 10 mv, 20mv,

30mv,............ 250mv. Record your observations in table-II.

5. From the readings, analyze steady state error and plot input/outputgraphs.

C.PARABOLIC SIGNAL ANALYSIS :-1. Select parabolic signal from the test signal generator. Keep the toggle

switch in discharge position.

2. Connect digital multimeter (Voltage) at the input and output terminalsof the trainer kit.

3. Also connect the test signal generator output to the input of the trainer

Kit.4.Now keep the toggle switch of Test Generator in to Restart the

position the Parabolic Signal is available at the output.

5. Observe the input and Output meters simultaneously and record theOutput Voltage for different input voltage. Record your Observation

in table-III

6. From the reading, analyze the result and "Plot Input / Output graph".

VVP/EC/CT7


11/42

DIAGRAM:

STEP INPUT

RAMP INPUT

PARABOLIC INPUT

VVP/EC/CT8

R(t)

C(t)

0.2

0.4

0.6

1.0

V

OLT

S

0.8 ERROR PER UNIT STEP

TIME

TIME

20

40

60

80

100

120

ERROR

E1

E2

E3

R(S)

C(S)

140


12/42

OBSERVATION TABLE:

STEP SIGNAL


RAMP SIGNAL


PARABOLIC SIGNAL


CONCLUSION:

VVP/EC/CT9


13/42

EXPERIMENT NO - 3


Aim :- To Study the operation of a Type 1 control system.

Apparatus :-1)Adtron Trainer Kit.

2)Adtron test Signal.

3)Digital Multimeter 02 Nos.

THEORY:The Control system is that by means of which any quality of

interest in machine, mechanism or other equipment is

maintained or altered in accordance with a desire manner

system. The steady state performance of control system is

generally judged by the steady state error due to step, ramp

or acceleration inputs, which are considered to be the

standard signal.

Type 1control system offers Zero error for step input and

Constant error for ramp input.

Procedure :-1. Connect the required supply and switch on the unit. See supply that

LED glows.

I. TIME RESPONSE ANALYSIS

A. Step Signal Analysis :

2. Connect the test signal generator output to i/p terminals of the trainer.3. Connect Digital Multimeters each at the input and output terminals.

4. Switch on the test signal generator and select STEP signal for theoutput.

5. Adjust step signal by STEP ADJ potentiometer for 1V, 2V, 3V ..and for each reading observe and record the output voltage in the

observation table I.

6. Repeat the above procedure for different settings of T.7. From the readings calculate steady state error per unit step input and

plot input, output graphs.

VVP/EC/CT10


14/42


B. Ramp Signals Analysis :-

8. Select Ramp Signal from test signal generator. Keep toggle switch indischarge position.

9. Keep Digital Multimeters at the i/p and o/p terminals for 0-300mVrange. Or 0-2V range.

10.Make toggle switch in restart position and ramp signal will beavailable at the input terminals of the trainer.

11.Input voltage will go on increasing at a predefined rate. Observe input

and output meters simultaneously and record the output voltage fordifferent input voltage at 10mV, 20mV, 30mV..250mV.

Record your observations in Table II.

12.From the readings, analyse the steady state error and plot input /output

graphs.

C. Parabolic Signals Analysis :-

13. Select parabolic signal from test signal generator. Keep the toggle

switch in discharge position.

14. Connect digital Multimeter at the input and output terminals of thetrainer kit.

15. Also connect the test signal generator output to the input terminals of

the trainer kit.

16.Now keep the toggle of test signal generator in the restart position.

The parabolic signal is available at the output.

17.Observe the input and output meters simultaneously and record the

output voltage for different input voltages. Record your observation in

Table III.

18.From the readings, analyse the result and plot input/output graphs.

VVP/EC/CT11


15/42

STEP INPUT

R(S)

C(S)

0.2

0.4

0.6

1.0

VOLTAGE

0.8

TIME

ERROR=0

RAMP INPUT

PARABOLIC INPUT

VVP/EC/CT12


16/42

OBSERVATION TABLE

STEP SIGNAL


RAMP SIGNAL


PARABOLIC SIGNAL

CONCLUSION:

VVP/EC/CT13



17/42

EXPERIMENT NO. - 4


AIM:-TO STUDY THE OPERATION OF A TYPE 2 CONTROL SYSTEM.

APPARATUS:-1. Adtron trainer kit2. Adtron test signal generator3. Digital multimeter-2 nos.

THEORY:-Control system may be classified according to their ability to

follow step inputs, ramp inputs etc.This is a reasonable

classification scheme because actual inputs may frequently be

considered as combinations of such inputs. The magnitudes of the

steady state error due to these individual inputs are indicative of the

goodness of the system.

Where as type 2 offers zero error for both step and ramp inputs

PROCEDURE:-

1. Connect the required supply and switch on the unit.See that supply LED glows on.

1.TIME RESPONSE ANALYSIS

A.STEP SIGNAL ANALYSIS :-

1. Connect test signal generator o/p to the i/p terminals of the trainers.2. Connect the digital multi-meter each at the i/p and o/p terminals .3. Switch on the test signal generator and select STEP signal for the

o/p.4. Adjust step signal by STEP ADJ potentiometer for 1V, 2V,

3V. and for each reading observe and record the output voltage

in the observation table I.

5. Repeat the above procedures for different settings of Kit. . .6. From the reading calculate steady state error per unit step input and

plot input, output graphs.

VVP/EC/CT14


18/42

B. RAMP SIGNAL ANALYSIS :-

1. Select Ramp signal from test signal generator. Keep toggle switchin discharge position.2. Keep Digital Multimeter at the i/p & o/p terminals for 0-300mV

range or 0-2V range.

3. Make toggle switch in restart position and ramp signal will beavailable at the

4. Input voltage will go on increasing at a prefined rate. Observeinput and output meters simultaneously and record the output

voltage for different input voltage at 10mV, 20mV,

30mV,250mV. Record your observations in table II.

5. From the readings, analyze steady state error and plot input outputgraphs.

C. PARABOLIC SIGNAL ANALYSIS:-

1. Select parabolic signal from the test signal generator . Keep thetoggle switch

2. in discharge position.3. Connect digital multimeter (voltage) at the input and output

terminals of the trainer kit.

4. Also connect the test signal generator output to the input of thetrainer kit.

5.Now keep the toggle switch of Test Signal Generator in the Restartposition the parabolic signal is available at the output.

6. Observer the input and output meters simultaneously and recordthe output voltage for different input voltages. Record yourobservations in table III.

7. From the readings analyses the result and plot input/output graphs.

VVP/EC/CT15


19/42

STEP INPUT

RAMP INPUT

20

40

60

80

100

120

140

TIME

R(t)

C(t)

ERROR=0

160

180

200

mv

olt

s

PARABOLIC INPUT

VVP/EC/CT16


20/42

OBSERVATION TABLE:

STEP SIGNAL


RAMP SIGNAL


PARABOLIC SIGNAL


CONCLUSION:

VVP/EC/CT17


21/42

EXPERIMENT NO. - 5

A.C. SERVO MOTOR

AIM: -To study the speed torque characteristics of the A.C. servo motor.

APPARATUS: -Adtron trainer kit.

Digital voltmeter.

THEORY:-

The power devices commonly used in electrical control system areA.C.and D.C. servomotors.A.C. servomotors are best suited for low

power applications.they are rugged,light in weight and have no brush

contacts as is the case with D.C.servomotors.

An A.C.servomotor is basically a two phase induction motor except for

cetain special design features.A two phase induction motor consist of two

stator windings oriented 90 electrical apart in space and excited by AC

voltage which differ in time phase by 90.Fig.1 shows the schematic

diagram for balanced operation of the motor,i.e. voltages of equal rms

magnitude and 90 phase difference are applied to the two stator phases,

thus making their respective fields 90.apart in both time and space,

resulting in a magnetic field of constant magnitude rotating at

synchronous speed the direction of rotation depends upon phase

relationship of voltages V1 andV2.As the field sweeps over the motor,

voltages are induced in it producing current in the short circuit motor.

The rotating magnetic field interacts with these currents producing a

torque on the motor in the direction of the motor.

The general shape of the torque speed charac.of a two phase induction

motor is shown by curve. The use of such all motor in control system is

intolerable because of the positive slope that prevails over most of theoperating speed range.the positive slope represents negative damping in

the control system, which in turn can lead to a condition of instability.

therefore for control system applications the motor must be modified in a

way that ensure positive damping over the full speed range. A convenient

way to achieve this result is to design the motor with very high resistance.

the toque speed characteristic then assumes the shape shown by curve.

VVP/EC/CT18


22/42

PROCEDURE: -

1. Switch off the switches S1,S2. Keep potentiometer P1, P2 in fully

anti-clockwise direction.

2. Connect the supply and switch ON the unit,and see that power lampglows.

3. Switch on A.C. servo motor by putting ON switch S1. Let S2 be in

the OFF position.

4. Slowly increase P1 so that A.C. servo motor starts rotating.You may

have to give higher voltages to start the A.C. servo motor, then you may

decrease the voltage for lower voltage.

5. Connect D.C. voltmeter TP3 and record this back E.M.F. in the OT1

corresponding to the speed as indicated by R.P.M. meter.

6. Vary the speed of the A.C. servo motor as indicated by the

potentiometer P1 in step and record the corresponding back E.M.F. in

table I.

7. Now switch ON S2 . Let S1 be also in the ON position. Keep P2 in

the anti- clockwise position and increase P1 to get maximum speed.

8.Observe and record the current meter rounding on the panel with

respect to the corresponding speed.

9.Slowly increase potentiometer P2 steps and record speed and current

meter reading in table II.

10.Complete the table II and plot the speed v/s torque characteristics

Rewrite the back E.M.F. readings in table II from table I.

VVP/EC/CT19


23/42

DIAGRAM

SCHEMATIC DIAGRAM OF A TWO- PHASE SERVO MOTOR

SERVOMOTOR CHARACTERISTICS

VVP/EC/CT20


24/42

A.C.SERVOMOTORS

S1----- ON-OFF SWITCH for A.C.Servomotor

S2----- ON-OFF SWITCH for Load

P1----- A.C.Servomotor Speed controlP2----- Load Control

TP1----- Fixed 110V A.C.voltage for A.C..servo motor.

TP2----- Variable control voltage of A.C..servo motor.

TP3----- Load Voltage.

OBSERVATION TABLE-1

SR.NO SPEED (RPM) Back EMF Eb(Volt)

1.

2.

3.

4.

5.

VVP/EC/CT21


25/42

OBSERVATION TABLE-2

SR.

NOIa(mA) N(RPM)

Back

EMF

Eb(Volt)

P=Ia Eb

T(torque)=

cmcmN

p

2

6010019.1 4

1

2

3

4

5

CONCLUSION:

VVP/EC/CT22


26/42

EXPERI MENT NO :- 6

STEPPER MOTOR

AIM:-To perform the working of stepper motor.

APPARATUS:-1.Stepper motor demonstration unit

2.Power supply for stepper motor

3.Stepper motor

4.Analog interface unit or V/F convert

5.C.R.O.

6.Digital Multimeter

THEORY:-There are many kind of stepper motors. Unipolar type, Bipolar type,

Single-phase type, Multi-phase type... Single-phase stepper motor is

often used for quartz watch.

In the PM type stepper motor, a permanent magnet is used for rotor

and coils are put on stator. The stepper motor model which has 4-poles

is shown in the figure on the left. In case of this motor, step angle of

the rotor is 90 degrees.

The characteristic of stepper motor is the angle can be correctly

controlled and to be stable rotates ( It is due to the reliability of thecontrol signal ). Moreover, because the rotor is fixed by the magnetism

in the stationary condition as shown in the principle, the stationary

power(Stationary torque) is large. It suits the use to make stop at some

angle.

VVP/EC/CT23


27/42

PROCEDURE:-1.Short the terminals marked 1-2,3-4,5-6,7-8 with Jumper links.

2.Connect built in clock generator with the translator ckt by

shorting terminals clk out with in.

3.Plug in stepper motor to the i/p.4.Keep clock selector switch in the low mode direction switch in

clockwise and clock adjust potentiometer in the minimum

position./

5.Connect power supply to the unit and switch on the power

supply.

6.Observe and record the sequence of glowing L.E.D.s. Observe

the advancing steps of motor.

7.Observe the clock frequency at the clock i/p terminals by C.R.O.

8.Observe the control actions of clock selector switch, directionselector and clock adjust potentiometer.

VVP/EC/CT24


28/42

INTERFACE WITH MANUAL PULSES:-9.To interface the translator with the manual pulser, remove the

jumper link between clk out and in of the translator .connect

manual pulser o/p to the in terminals of the translator.

10. Give one pulse to the transistor by togging the pulser switchand observe one step advancement of the stepper motor. This

corresponds to 1.8

11. For each manual pulse, observe and record the L.E.D.sequence. Tabulate it in the observation table. Observe the

effect of direction selector switch in the L.E.D. sequence.

ANALOG INTERFACE :-12.To interface translator with the analogy voltages remove in

terminal connection from manual pulser and connect it with V/P

converter

unit (to be purchased separately)

13.Vary the i/p voltage by i/p adjust potentiometer and observe its

effect on the speed of the stepper motor

14.Observe the o/p frequency of V/F converter on C.R.O.and

tabulate it function of i/p voltage.

VVP/EC/CT25


29/42

TRUTH TABLE:

CLOKWISE DIRECTION

STEP A1 B1 A2 B2

1 1 1 0 0

2 0 1 1 03 0 0 1 1

4 1 0 0 1

5 1 1 0 0

ANTICLOKWISE DIRECTION

STEP A1 B1 A2 B2

1 1 1 0 0

2 1 0 0 1

3 0 0 1 1

4 0 1 1 0

5 1 1 0 0

CONCLUSION:-

VVP/EC/CT26


30/42

EXPERIMENT NO :- 7

D.C. SERVO MOTOR

AIM :- To study and plot the Speed Torque characteristics of D.C.servo motor.

APPARATUS :-1. ADTRON Trainer kit2. Digital Multimeter3. Mains 230V, 50 Hz AC supply

THEORY:-

In general,servo system can be described as a system in

which output is linearty independent on output. In uses

negative feedback principle. the D.C.servo system functions

in the following way refer to the following diagram

(1) Input is fed to the error amplifier

(2) Difference between V1& VF(error votage)is amplified.Theoutput of this stage is say positive.

(3) This voltage is power amplified. The output of the poweramplifier drives the D.C.servo motor

VVP/EC/CT27


31/42

(4) The D.C.servo motor mechanically copied with the variable areof the rebalance(feedback pot)

(5) The motor drives the feedback pot in such a way that feedbackvoltage equal the input voltage.

(6) When the feedback voltage equals the input the differencebetween the two voltages become zero.This is null point of thesystem.

(7) Hence the output of power amplifier would be 0 volt which willmake the motor stop.

Note:-D.C.Servo motor rotates in both the directions depending upon the

voltage polarity applied to it. Also its speed is very high(around 5000

rpm)

PROCEDURE :-

1. Switch OFF the switches S1,S2 and keep potentionmeter P1 and P2in fully anti-clockwise direction.

2. Connect the required supply and switch on the unit. See that thesupply neon glows.

3. Switch ON S1. i.e. supply is given to the motor and let S2 be in theOFF position.

4. Slowly vary P1 in clockwise position, so that A.C. servo motor startsrotating and note the speed as shown by the RPM meter provided on

the panel.5. Connect a D.C. voltmeter (Multimeter) across TP3 and record the

back EMF corresponding to the speed as indicated by the RPM

meter.6. Vary the speed of the DC servo motor and record the corresponding

back EMF in the table.

7.Now, with pot P1 in fully clockwise direction P2 in fully anti-

clockwiise direction switch on S2.8.Note the armature current Ia as shown by the current meter.9. Slowly vary the pot P2 in anticlockwise directon and for each speed

(same as the speed in table 1) and each corresponding reading note

the armature current Ia.

10.Calculate the torque as per the given formula and plot a graph ofspeed V/S torque characteristics.

VVP/EC/CT28


32/42

OBSERVATION TABLE

No. Master dial PotentiometerDirection of the slave pointer

in degrees

1 0

2 90

3 135

4 180

5 270

CONCLUSION:-

VVP/EC/CT29


33/42

EXPERIMENT NO :- 8POTENTI O M ETER

AI M :-To plot the characteristics of a potentiometerand study the effects of loading. APPARATUS:-

1. Adtron trainer kit2. Digital Multimeter3. Patch cords

THEORY:-

The Potentiometer is one of the most widely word electrical

components found in control system. It consists of resistance

element with a slider capable of being moved along its length. It isfrequently used in automatic control system to convert a

Mechanical signal in the form of shaft rotation to an electrical in

the form of a voltage, the magnitude of which is directlyproportional to the original mechanical signal

PROCEDURE:-

1. Connect the required supply and ON the unit.See that the supply

LED glows.

2. Rotate the knob of potentiometer P1 so that it will display 0.

3. Connect the +9V DC supply to the two ends of potentiometer P1.

4. Connect a multimeter (voltage) across the variable arm and ground.

5. Rotate the potentiometer P1 through 35 so that the indicator will

display 1.Note the o/p voltage in the observation table 1

6. Again rotate the potentiometer through P1 through another 36(720)

so that the indicator will show 2.Note the o/p voltage in the

observation table-1. Repeat the process till the display shows 10

and for each turn, note the redian in the observation table.

VVPE/EC/CT30


34/42

7. Plot the graph of 0 V/S o/p voltage.

8. Repeat the same procedure and the plot graph of potentiometer P1

and 9V DC supply.

9. Now repeat the above procedure for both potentiometer P1 and P2

with +12V DC supply.

10. Rotate the knob of potentiometer P1 so that it will display 0.

Connect +9V DC supply to the two ends of the potentiometer.

11. Connect load RL1 across the variable arm of potentiometer P1 and

the ground terminal.

12. Connect the Multimeter across the load.

13. Note the reading in the observation table-2.

14. Rotate the potentiometer P1 through 360 so that the indicator will

display 1. Note the o/p voltage in the observation table-2.

15. Again rotate the potentiometer P1 through another 360(720) so that

the indicator will show 2. Note the o/p voltage in the observation

table-2. Repeat the procedure till the display show10 and for eachturn note the reading in the observation table-

16. Calculate from the readings the loading error S using the formula

S = X2(1-X)

X(1-X)2 + RL/Rp

where X=/m ,m=360o

RL= Load resistance RL1 or RL2

Rp= Potentiometer resistance

17. Plot the graph of v/s S for load RL2.

18. Plot the same graph of v/s S for load RL2

19. Also plot the graph of v/s S o/p voltage with RL1 as load and

then with RL2 as load.

VVPE/EC/CT31


35/42

20. Repeat the above procedure and plot the graph for potentiometer

21. P2, load RL1 and load RL2.

22. Compare your results.

Potentiometer and effect of loading

VVPE/EC/CT32


36/42

OBSERVATION TABLE

With Load

No.of turns Indicated onthe Display

Rotation in Digrees0

Output Voltage V0

1 360

2 720

3 -

4 -

5 -

6 -

7 -

8 -9 -

10 3600

Without Load

No.of turns Indicated on

the Display

Rotation in Digrees

0

Output Voltage V0

1 360 2 720

3 -

4 -

5 -

6 -

7 -

8 -

9 -

10 3600

CONCLUSION

VVPE/EC/CT33


37/42


38/42

Let, Vs1, Vs2 & Vs3 be the voltages induced in the stator coil,

than for the rotor position of the synchro transmitter, where the rotor axis

makes an angle a with the axis of the starter coil S2 ,

Vs1 = KVr. Sinwet cos(+120)

Vs2 = KVr. Sinwet cosVs3 = KVr. Sinwet cos(+240)And the terminal voltages are :-

Vs1Vs2 = Vs1- Vs2 = 3KVr Sin(+240) SinwetVs2Vs3 = Vs2- Vs3 = 3KVr Sin(+120) SinwetVs3Vs1 = Vs3- Vs1 = 3KVr Sin.Sinwet

Thus it is seen that the input to the synchro transmitter is the

angular postion of its rotor shaft & the output is given by terminal voltage

equations. The magnitude of these voltages are functions of the shaft

postion.

The output of the synchro transmitter is applied to the stator

winding of a synchro control transformer. The control transformer is

similar in construction to a synchro transformer except for the fact that

the rotor of the control transformer is made cylindrical in shape. So that

the air gape is practically uniform. The system acts as an error detector.

Circulating currents of the same phase but of different magnitudes flow

through the two sets of stator coils. The result is the establishment of an

identical flux pattern in the air gape of the control system transformer.

The control transformer flux axis thus being in the same position as that

of synchro transmitter rotor, the voltage induced in the controltransformer rotor is proportional to the cosine angle between the two

rotors & Rs is given by,e(t) = KVr Cos Sinwet.

Where, is the angular displacement between two rotors. When = 90o , ie. The two rotors are at the right angles then the voltageinduced in the control transformer rotor is zero. This position is known as

electrical zero position of the control transformer. By making

combination of transmitter control transformer. The synchro transmitter

control transformer pairs acts as an error detector giving a voltage signalat the rotor terminals of the control transformer proportional to the

angular difference between the transmitter & the control transformer shaftpositions the voltage at the rotor terminals of the control transformer is;

e(t) = K1Vr(-) sinwet

This equation derived for constant ( - ) is valid for verifyingconditions as well so long as the rate of angle change small enough for

the speed voltages induced in the device to be negligible.

VVP/EC/CT35


39/42

This equation is represented graphically in ifig.4 for an arbitrary

time variation of ( - ).We see from this diagram that the output of synchro error detection

is a modulated signal; the modulating signal wave has the information

reading the lack of correspondence between the two rotor positions & thecarrier wave is the ac. Input to the rotor of the synchro transmitter. This

type of modulation is known as suppressed carrier modulation.

CONCLUSION:

VVP/EC/CT36


40/42

EXPERIMENT NO :- 10

AMPLYDYNE GENERATOR

AIM :To study the Amplydyne Generator.

THEORY:

INTRODUCTION :-

The amplydyne is basically a power amplifying device which

can generate output in the high range from 1 to 50 Kw. It is used to drive

a D.C. motor. The amplydyne is akind of motor which runs on a constantspeed of a suitable motor which serves as a source of energy to the unit.

The outout voltage of the amplydyne is controlled by the field current.The schematic diagram of the amplydyne generator with D.C. motor loadis shown in fig.

The current is the control voltage i.e. Ic produces a fine ,because of the full speed rotation of armature. The voltage e, is generatedacross brushes AA1. The resistance of the armature coil is very small.

Thus, a large current is made to flow due to the voltage. This large

current causes the strong armature reaction, which in turn generates avery high flux, which is 90o to o. The flux generated & rotation ofamplydyne armature produces a high voltage E2(t) at the brushes BB

1,

which are placed perpendicular to brushes AA1. This voltage is suppliedtp power the d.c. motor & connected load.A small change in the field

current causes a very high voltage generation at the output of the

amplydyne.

VVP/EC/CT37


41/42

FIG.AN AMPYDYNE GENERATOR WITH D.C.MOTOR AS THE LOAD

CONCLUSION :-

VVP/EC/CT38


42/42

Documents

Cth Write Up