Department of Electrical and Electronics Engineering · 2019-02-06 · VIVA QUESTIONS: 1. Define...

St.PETER’S ENGINEERING COLLEGE

(Sponsored by Shantha Educational Society)

(Approved by AICTE, New Delhi, Affiliated to JNTUH)

Giving Wings to Thoughts

Department of Electrical and Electronics Engineering

1 Control System Laboratory, EEE

(For CSE, ECE & EEE)

MASTER MANUAL

CONTROL SYSTEMS LAB

II Year B.Tech. EEE II - Sem

Prepared By

Goutam Barma

Asst. Prof. EEE








INDEX

Sl. No Experiment Name Page No.

1 CHARACTERISTICS OF SYNCHRO TRANSMITTER AND

RECEIVER PAIR

3

2 CHARACTERISTICS OF AC SERVOMOTOR

9

3

EFECT OF FEEDBACK ONDC SERVOMOTOR

15

4 TEMPERATURE CONTROL USING PID 19

5 TIME RESPONSE OF SECOND ORDER SYSTEM 22

6

PROGRAMMABLE LOGIC CONTROLLER

27

7 ROOT LOCUS PLOT, BODE PLOT USING MATLAB.

36

8 STATE SPACE MODEL FOR A GIVEN CLASSICAL TRANSFER

FUNCTION

42

9 TRANSFER FUNCTION OF DC GENERATOR 45

10 TRANSFER FUNCTION OF DC MOTOR 49

11 EFFECT OF P, PI AND PID CONTROLLER ON

A SECOND ORDER SYSTEM

54

12 LAG AND LEAD COMPENSATION -

MAGNITUDE AND PHASE PLOT

58








EXPERIMENT NO.1

CHARACTERISTICS OF SYNCHRO TRANSMITTER AND

RECEIVER PAIR

AIM: a) To study the characteristics of synchro Transmitter.

b) To study the characteristics of synchro transmitter and receiver pair.

APPARATUS:

1. Synchro Transmitter and receiver pair trainer kit.

2. Patch cords.

Characteristics of Synchro Transmitter.

CIRCUIT DIAGRAM:








PROCEDURE:

1. Connect the main supply to the system with the help of cable provided. Do not connect

any patch cords to terminals marked S1, S2, and S3.

2. Switch on mains supply for the unit.

3. Starting from zero position, note down the voltage between stator winding terminals i.e.

VS1 S2, VS2 S3, and VS3 S1 in a sequential manner. Enter readings in a tabular form and

plot a graph of angular manner. Enter readings in tabular form and plot a graph of angular

position of rotor vs. stator voltages for all three phases.

4. Note that zero position of the stator, rotor coincides with VS3 S1 voltage equal to zero

voltage. Don’t disturb this condition.

OBSERVATIONS:

Sl.

No.

Rotor position in

degrees

STATOR TERMINAL VOLTAGE

VS3S1 VS1S2 VS2S3

1 0

2 30

3 60

4 90

5 120

6 150

7 180

8 210

9 240

10 270

11 300

12 330

13 360








MODEL GRAPH:

Study of synchro transmitter & receiver pair

CIRCUIT DIAGRAM:








PROCEDURE:

1. Connect the mains supply with the help of cable provided.

2. Connect S1, S2 and S3 terminals of transmitter to S′1, S′2 and S′3 of synchro receiver by

patch cords provided respectively.

3. Main supply Switch on transmitter and reciever and also switch on the.

4. Move the pointer i.e. rotor position of synchro transmitter Tx in steps of 300 and observe

the new rotor position on receiver side which follows its both the directions of rotations

and their positions are in good agreement.

5. Enter the input angular position and output angular position in the tabular form and plot a

graph.

OBSERVATIONS:

S.No Transmitter Rotor

angle ( deg )

Receiver Rotor

angle ( deg )

1 30

2 60

3 90

4 120

5 150

6 180

7 210

8 240

9 270

10 300

11 330








12 360

MODEL GRAPH :

RESULT:

VIVA QUESTIONS:

1. Define synchro transmitter?

2. Define synchro receiver?

3. What are applications of synchro transmitter and receiver?

4. where it is used?

5. Explain Working Principle of synchro transmitter and receiver?

6. Draw the Ckt of synchro transmitter and receiver?

7. How it is useful to do this experiment

8. Write the terminal Voltages of the stator for Synchro Transmitter?

9. What is a synchro?

10. What are the names of synchros?








EXPERIMENT NO. 2

CHARACTERISTICS OF AC SERVOMOTOR

AIM: To study the Characteristics of AC Servomotor & to draw its Speed – Torque

Characteristics.

APPARATUS:

1. AC Servo Motor Unit

2. Multimeter

CIRCUIT DIAGRAM:








SPEED Vs BACK EMF CHARACTERISTICS:

PROCEDURE:

1. Study all the labels on the front panel carefully.

2. Initially keep load and servo motor switch at OFF position.

3. Keep P1 (load control knob of DC motor) and P2 (speed control knob of ac servo motor)

at minimum position.

4. Now switch ON main supply to the unit and also AC Servo Motor supply switch.

5. With load switch in OFF position vary the speed of AC Servo Motor by moving the

control voltage. This is done by varying the knob P2.

6. For different speed note down back e.m.f (in mili-volt) generated by DC motor at TP1

terminal using DMM.

7. Bring P1 and P2 to minimum position. Switch of the servomotor and the main supply to

the kit.

8. Plot the graph speed Vs back emf

TABULATION:

Sl. No. Speed (RPM) Back emf (mili-volt)

1 550

2 650

3 750

4 850

5 950








MODEL GRAPH:

SPEED Vs TORQUE CHARACTERISTICS:

PROCEDURE:

1. Switch ON the supply to the kit and also switch ON the servomotor. Keep the load switch

at OFF position

2. Vary P2 to set the control winding at Vc1=45V. This voltage can be measured by using

DMM at the terminals labeled “Control winding voltage” on the front panel of

servomotor kit.

3. Vary the load control knob P1 in steps and in each step note down the back emf, armature

current and speed.

4. Vary P2 to set the control winding at Vc2=50V and Vc3=55V and repeat the step 3.

6. Bring P1 to its minimum position and then bring P2 to its minimum position. Switch OFF

load, servomotor and main supply switch on by one.

5. Calculate the power and torque and plot the speed Vs torque characteristic of motor.








TABULATION:

Vc1 = 45V

Vc2 = 50V

S.NO Ia(mA) Speed

N(rpm) Eb(mV)

Power

(mW) T(N-m)

1 0.1

2 0.15

3 0.2

4 0.25

5 0.3

6 0.35

7 0.4

8 0.45

9 0.5

S.NO Ia(mA) Speed

N(rpm) Eb(mV)

Power

(mW) T(N-m)

1 0.1

2 0.15

3 0.2

4 0.25

5 0.3

6 0.35

7 0.4

8 0.45








Vc2 = 55V

CALCULATIONS:

Power P = Eb×Ia

T=60×𝑃×1.094×104

2𝜋×𝑁 gm-cm

9 0.5

S.NO Ia(mA) Speed

N(rpm) Eb(mV)

Power

(mW) T(N-m)

1 0.1

2 0.15

3 0.2

4 0.25

5 0.3

6 0.35

7 0.4

8 0.45

9 0.5








MODEL GRAPHS:

RESULT:

VIVA QUESTIONS:

1. Define Motor classifications?

2. What are applications of A,C servo Motor?


4. Explain Working Principle of A,C servo Motor?

5. Draw the Ckt of A,C servo Motor?

6. How it is useful to do this experiment

7. Difference between normal A.C motor & A,C servo Motor?

8. Draw the characterstics of A,C servo Motor?

9. Write Difference between D.C Servo Motor & A,C servo Motor?

10. What is the overall efficiency of A,C servo Motor?

11. Write the Transfer function equation for A,C servo Motor?








EXPERIMENT NO. 3

EFECT OF FEEDBACK ONDC SERVOMOTOR

AIM: To study the effect of feedback on DC Servo Motor by its Torque-Speed characteristic

APPARATUS:

1. DC Servo Motor Kit

2. Multimeter

CIRCUIT DIAGRAM:








PROCEDURE:

1. Before switch ON the instrument, please see that armature control potentiometer and

field control potentiometer are at minimum position so that the armature voltage applied

to the armature from zero volts onwards and field voltage applied to the field from 25V

onwards.

2. Switch ON the instrument, observe that the field on indication LED glows, if not then

immediately switch OFF the instrument. Please note that for all DC motors field voltage

to be given initially before applying the armature voltage. Initially DC ammeter and

RPM meter indicates ZERO reading.

3. Connect the ammeter to the terminal of field voltage Adjust spring balance so that there

is minimum load on the DC Servo Motor. You may fix knob at any particular place to

apply a fixed load on the DC Servo Motor.

4. Adjust armature control potentiometer so that Va = 10V and field control potentiometer

so that Vf = 20V by using digital ammeter.

5. Note down T1, T2, Armature Current (Ia) and Speed.

6. Keeping Va = 10V, Vf = 20V, adjust T1 up to 500 gm in suitable steps and note down the

readings as in step 6.

7. Now repeat the step 7 for Va = 15, 20 and 25 by keeping Vf at 20V.

8. You may repeat the steps 7 & 8 for Vf = 15V, 10V.

TABLE:

Field Voltage (Vf) = 20 V

Sl. No. T1

(gms)

T2

(gms) T = T1 - T1

Torque = T *

3.5

Speed

(rpm)

I a

(mA)

Va =

10 V

1

2

3

4

5

6

Va

=15 V

1

2








MODEL GRAPH:

RESULT: Hence the effect of Feedback on DC Servomotor has been studied with the help of

Torque-sped characteristics.

Viva-Voice Questions

1. Draw the speed torque characteristics of D.C Servo motor?

2. What are the applications of D.C Servo motor?

3. What are the types of D.C. Servo motor?

4. Write the formula for the torque in case of d.c. servo motor?

5. Compare ac and dc servo motors

6. Define Motor classifications?








EXPERIMENT NO. 4

TEMPERATURE CONTROL USING PID

AIM: To study the performance of various types of controllers used to control the temperature

of an oven and to draw the characteristics.

APPARATUS:

1. Temperature Control System Kit

2. Oven

3. Patch chords.

4. Stop watch

BLOCK DIAGRAM:








PROCEDURE:

I Identification of Oven Parameters :

1. Connect P output to the actuator input.

2. Keep the Switch S1 to ‘WAIT ‘ & S2 to ‘SET’, Open the feedback terminals and Switch

ON the kit.

3. Set the P Potentiometer to 1 (max).

4. Adjust the reference Potentiometer to set 5°C on the DVM. This provides an input of 0.5 V

to the driver.

5. Connect the Oven.

6. Put the Switch S2 to ‘MEASURE’ position and note down the room temperature.

7. Put the switch S1 to ‘RUN’ position and note the temperature readings for every 15 sec till

the temperature becomes almost constant.

8. Plot the temperature – time curve on a graph paper. Calculate the Values of T1 & T2 from

the graph and the open loop temperature constant ( K ).

K = Oven Temperature at steady state

Input in Volts.

II Proportional – Integral – Derivative Controller :

1. Starting with a cool oven, put the switch S1 to WAIT position and connect P,D,I

outputs to the actuator input. Keep R output disconnected. Short the feedback

terminals.

OBSERVATIONS:

S.No. Time (sec) Temp (οC)

(Open Loop)

Temp (οC)

(Closed Loop)

1 0

2 30

3 60

4 90

5 120








6 150

7 180

8 210

9 240

10 270

11 300

12 330

13 360

14 390

15 420

16 450

17 480

18 510

19 540

20 570

21 600

MODEL GRAPHS:

Open Loop Respons








Temperature response for P, PI, PID control

RESULT: The performance of various types of controllers used to control the temperature of

an oven are studied and its performance characteristics have been plotted.

Viva-Voice Questions

1. Draw the PID CONTROLLER?

2. What are the applications of PID CONTROLLER?

3. Define PID CONTROLLER?

4. Where it is used?

5. Explain Working Principle of PID CONTROLLER?

6. How it is useful to do this experiment?

7. What are the types of controllers?

8. Explain each one with neat sketch?

9. Draw the characteristics of PID CONTROLLER?

10. What are the advantages of PID CONTROLLER?








EXPERIMENT NO. 5

TIME RESPONSE OF SECOND ORDER SYSTEM

AIM: To study the time response for a second order system and to determine the time domain

specifications for a unit step signal.

APPARATUS:

1. Time Response of a second order system Trainer Kit

2. C.R.O.

3. Patch cords.

CIRCUIT DIAGRAM:








PROCEDURE:

1. Give the connection as per the circuit diagram. Switch ON the Main supply and the

trainer kit.

2. Using CRO set the Square wave at 2 Volt peak to peak. Draw the input square wave

signal.

3. Connect the output of square wave signal source to the input of second order system.

4. Using CRO observe the output and draw (unit step response)

5. From the step response on CRO screen not down Td, Tr, Tp, Ts and %Mp

6. For different values of gain repeat step no. 4 and 5.

7. Find the transfer function of the second order system inside the trainer kit.

OBSERVATION:

Sl No Gain

(KA) Td Tr Tp %Mp Ts Ess

1

2

3

4








CALCULATIONS:








MODEL GRAPH:

ESULT:

VIVA QUESTIONS:

1. What is Time Response?

2. Define Delay Time, Rise Time, Peak Time, Peak Over Shoot, Settling Time?

3. Define type and order of a system?

4. Distinguish between Type and Order of a system?

5. What is Steady State Error?

6. The damping ratio of system is 0.6 and the natural frequency of oscillation is 8 rad per sec.

Determine the rise time.

7. Define Positional Error Constant and Velocity Error Constant?








EXPERIMENT NO. 6

PROGRAMMABLE LOGIC CONTROLLER

AIM: To verify truth tables of all logic gates.

APPARATUS:

1. PLC Kit

2. WLP(WEG Ladder Program) software

PROCEDURE:

1. Switch ON the PLC kit. Observe the input and output switches

2a. Open WLP2.06

b. File New Type File name

c. Draw the ladder diagram for the given Boolean function

d. Save Compile Ladder Diagram

e. To clear PLC memory:

Communications PLC Memory Clear

f. To write on to the PLC memory:

Communications PC↔PLC PLC Write

g. Communications PLC Run

3. Verify the Boolean function (or Truth table) implemented by using the input and output

switches








(A) NOT Gate:

PLC implementation:

(B) OR Gate:

PLC implementation using WLP:








(C) AND Gate:


(D) NAND Gate:









(E) NOR Gate:


(F) XOR Gate:









(G) XNOR Gate:









(H) HALF Adder:









(I) Full Adder:








RESULT:

Viva-Voice

1. What are the applications of PROGRAMMABLE LOGIC CONTROLLER?

2. Define PROGRAMMABLE LOGIC CONTROLLER?


4. Explain Working Principle of PROGRAMMABLE LOGIC CONTROLLER?


6. What are the types of PROGRAMMABLE LOGIC CONTROLLER?


8. Draw the characteristics of PROGRAMMABLE LOGIC CONTROLLER?

9. What are the advantages of PROGRAMMABLE LOGIC CONTROLLER?








EXPERIMENT NO. 7

ROOT LOCUS PLOT, BODE PLOT USING MATLAB.

AIM: To obtain Root Locus plot & Bode plot for a given Transfer Function using MATLAB.

APPARATUS: MATLAB Software

PROGRAM:

I) ROOT LOCUS PLOT

num = input (‘Enter the Numerator‘)

den = input (‘Enter the Denominator’)

sys = tf(num,den)

rlocus(sys)

disp(‘The root locus Plot is displayed.’);








II) BODE PLOT



sys = tf(num, den)

bode(sys)

disp(‘The bode Plot is displayed.’);

G(s)H(S)=(𝑺+𝟓)

𝑺(𝑺+𝟑)








G(s)H(S)=𝟐𝟒𝟐(𝑺+𝟓)

𝑺(𝑺+𝟏)(𝑺𝟐+𝟓𝑺+𝟏𝟐𝟏)

G(s)H(S)=𝟏𝟎𝟎(𝟎.𝟎𝟐𝑺+𝟏)

(𝑺+𝟏)(𝟏+𝟎.𝟏𝑺)(𝟎.𝟎𝟏𝑺+𝟏)








III) Nyquist PLOT



sys = tf(num,den)

nyquist(sys)

disp(‘The nyquist Plot is displayed.’);

G(s)H(S)=𝟒𝟎

(𝑺+𝟒)(𝑺𝟐+𝟐𝑺+𝟐)








G(s)H(S)=(𝟏+𝟎.𝟓𝑺)(𝟏+𝑺)

(𝑺−𝟏)(𝟏+𝟏𝟎𝑺)

Viva voce:

1. Define root locus?

2. Define bode plot?

3. Define centroid?

4. Define frequency domain specifications?

5. Define the angle of departure?

6. Define angle of arrival?

7. Define resonance peak?

8. How the break away point is calculated?

9. Write the formula for the angle of asymptotes?

10. Where the root locus originates, where it terminates?








EXPERIMENT NO. 8

STATE SPACE MODEL FOR A GIVEN CLASSICAL

TRANSFER FUNCTION

AIM: To obtain State Space Model for a given Transfer Function and to obtain the Transfer

Function for a given State Space Model

APPARATUS: MATLAB Software

PROGRAM:

State Space Model for a given Transfer Function

disp (‘Transformation from Transfer function to State Space Model’);

num = input(‘Enter the Numerator:’)

den = input (‘Enter the Denominator:’)

sys = tf(num,den)

disp( ‘State Space Model for the given Transfer Function is’)

[A B C D] = tf2ss(num,den)

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

Transfer Function of given system is

Transfer Function:

2s^2 + 3 s + 2

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

2 s^4 + s^3 + s^2 + 2s

Corresponding State Space Model A,B,C,D are:

A = -0.5000 -0.5000 -1.0000 0

1.0000 0 0 0

0 1.0000 0 0

0 0 1.0000 0








B = 1

0

0

0

C = 0 1.0000 1.5000 1.000

D = 0

Transfer Function for a given State Space Model

disp(‘Transformation from State space model to Transfer Function’);

A= input(‘Enter the values of matrix A: ‘)

B= input(‘Enter the values of matrix B: ‘)

C= input(‘Enter the values of matrix C: ‘)

D = input(‘Enter the values of matrix D: ‘)

disp(‘Transfer Function for the given state space model is’)

[num,den] = ss2tf(A,B,C,D)

Sys = tf(num,den)

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

A, B, C, D Matrices of given State Space Model are:

A = 1 2

3 4

B = 1

1

C = 1 0

D = 0

And corresponding Transfer Function is :

Transfer Function

S – 2

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

S^2 – 5 s - 2








Viva voce:

1. Write the state model?

2. What are the different methods to represent state model?

3. Write the formula for the transfer function?

4. Write the properties of state transition matrix?

5. Write the canonical representation?

6. What are the advantages of phase variable representation?

7. What are the advantages of physical variable representation?

8. What are the advantages of canonical variable representation?

9. What are the advantages of Jordan variable representation?








EXPERIMENT NO. 9

TRANSFER FUNCTION OF DC GENERATOR

AIM: To obtain the transfer function of D.C Generator

APPARATUS:

1. Transfer function study module

2. DC generator 1500 rpm, 220V, 0.37 Amp

3. DC motor 1500 rpm, 220V, 0.37 Amp

4. Multi-meter

5. Patch Chord

TRANSFER FUNCTION MODEL:

The transfer function of a d.c. generator is derived as follows:

The differential equations relating various variables are

Vf (t) = Lf ff

fiR

dt

di (t) and

Vg(t) = Kg if(t)

Taking Laplace transform of above equations:

Vf (s) = Lf s If (s) + Rf If (s)

If (s) = ff

f

sLR

sV

)(and If(s) * Kg = Vg (s)

The two eqns. can be represented by a block diagram as follows:








The overall transfer function is

)(

)(

sV

sV

f

g

ff sLR

Kg

The values of Kg, Rf and Lf are determined from the experiment.

CIRCUIT DIAGRAM:








PROCEDURE:

1. Study the front panel of TRANSFER FUNCTION MODULE clearly.

2. Give the connection as per the circuit diagram.

3. Use the variable dc voltage source (0-220V DC) to supply the armature voltage of motor and

keep it at minimum position.

4. Use the fixed voltage source of 220V dc to supply filed of the motor.

5. Use the variable dc voltage source (100-220V DC) to supply the field of the generator and

keep it at minimum position.

6. Switch ON the supply mains and TRANSFER FUNCTION MODULE.

7. Vary the armature voltage of motor until the motor reaches its rated speed.

8. Note down the If and Eg of the generator.

9. Vary the If by varying the field voltage of the generator and note down the corresponding Eg.

10. Keep varying If until Eg reaches its rated value.

11. Bring the filed voltage knob of generator to minimum position.

12. Bring the armature voltage knob of motor to minimum position.

13. Switch OFF TRANSFER FUNCTION MODULE.

14. Switch OOF the mains supply.

15. Plot Eg Vs If graph.

16. Use multimeter to measure field resistance of generator Rf.

17. Take filed inductance of generator Lf = 5.1 H

18. Find the transfer function of the given dc generator.

TABULATION:

S.No. Field Current IF (A) Generated Voltage EG ( V )








MODEL GRAPH:

RESULT:

The transfer function of the D.C Generator is found to be ------------------------------

Viva-Voice:

1. Draw the Ckt of Transfer function of D.C Generator?

2. What are the applications of function of D.C Generator?

3. Define function of D.C Generator?


5. Explain Working Principle of function of D.C Generator?


7. What are the types of function of D.C Generator?


9. Draw the characteristics of function of D.C Generator?

10. What are the advantages of function of D.C Generator?








EXPERIMENT NO. 10

TRANSFER FUNCTION OF DC MOTOR

Aim: To derive the transfer function of the given DC motor

APPARATUS:

1. DC Motor –generator study unit

2. Patching Chord

CIRCUIT DIAGRAM:

THEORY:

Various parameters of a dc motor are given below

Ra = Armature resistance (ohm) La =Armature inductance (Henry)








J = Motor Inertia (KG-m2) B = co-efficient of viscous friction (N-m/rad per

sec)

Ia = Armature current (Amp.) T = Electromagnetic torque developed (N-m)

Ea = Voltage supplied to armature of motor (Volt)

Eb = Back emf induced across armature of motor (Volt)

Kb = Back emf constant (V/rad per sec)

Kt = Torque constant (N-m/Amp)

The simplified form of transfer function of a dc motor is given by

𝜔(𝑠)

𝐸𝑎(𝑠) =

𝐾𝑚

1+𝑠𝜏𝑚

Where

Km = Motor constant and 𝜏𝑚 = electro-mechanical time constant

𝐾𝑚 = 𝐾𝑡

𝐾𝑡.𝐾𝑏+𝑅𝑎 .𝐵 and 𝜏𝑚 =

𝑅𝑎 .𝐽

𝐾𝑡.𝐾𝑏+𝑅𝑎 .𝐵

PROCEDURE:

(A) To determine Kb: DC motor characteristics

1. Keep the motor load in ‘0’ position.

2. Keep the RESET switch in ‘RESET’ position.

3. Connect the patch chord from Ea terminal to DVM terminal.

4. Set Ea at 3V, 4V, 5V, 6V, 7V, 8V, 9V, 10V and note down the speed from the RPM meter on

the motor unit panel.

5. Bring the Ea potentiometer to its minimum position. Switch OFF the kit.

6. Assuming Ea = Eb, determine the Kb for each speed using the following formula








Kb= 30×𝐸𝑏

𝜋×𝑁 Volt/ rad per second

7. Find the average value of Kb from the table no. 1

8. Plot Eb Vs ω

Table No. 1

Sl.

No

Ea

(Volts)

N

(RPM) ω =

2𝜋×𝑁

60

(rad/sec)

Kb= 30×𝐸𝑏

𝜋×𝑁

(Volt/ rad per second)

1 3

2 4

3 5

4 6

5 7

6 8

7 9

8 10

Average Kb

(B) To determine B: Speed-torque characteristics DC motor

1. Keep the motor load in ‘0’ position.

2. Keep the RESET switch in ‘RESET’ position.

3. Connect the patch chord from Ea terminal to DVM terminal.

4. Set Ea at 8V.

5. Note down speed (N), armature current (Ia). Calculate ω, T, and B.

6. Change the load position from ‘0’ to ‘5’ once at a time and for each load position repeat step

no. 4








7. Bring the load to its ‘0’ position. Bring the Ea potentiometer to its minimum position. Switch

OFF the kit.

8. Find the average value of B from table no. 2.

9. Plot T Vs ω

Table No. 2

Ea = 8V

Sl.

No.

Load

position

N

(RPM) ω =

2𝜋×𝑁

60

(rad/sec)

Ia

(Amp)

T = Kb × Ia

(N-m) B =

𝜔

𝑇

(N-m/rad per sec)

1 0

2 1

3 2

4 3

5 4

6 5

Average B

(B) To determine 𝝉𝒎 : Step response of DC motor

1. Keep the motor switch in OFF position. Keep the load switch in ‘0’ position. Keep the RESET

switch in ‘RESET’ position.

2. Connect Ea and digital voltmeter terminals. Switch on the kit. Set Ea = 6 volts.

3. Note down the speed (N) of the motor and emf generated (Eg) across the armature of the

generator. These are the steady state values.

4. Using Es potentiometer, set Es = 0.632×Eg. This is the generator voltage at which the counter

will stop counting.

5. Switch OFF the motor. Keep the ‘RESET’ switch at READY position.

6. Now switch the motor ON and note down the counter reading as time constant in mili second.

7. For Ea = 8V and 10V repeat step no. 2, 3, 4, 5 and 6.








8. Bring the Ea potentiometer to its minimum position. Switch OFF the kit.

9. Find the average 𝝉𝒎 from the table no. 3

CALCULATION:

Ra = 4.5 Ohm, B=____________ N-m/rad per sec, 𝝉𝒎= _________ × 𝟏𝟎−𝟑 Sec

𝐾𝑚 = 𝐾𝑡

𝐾𝑡.𝐾𝑏+𝑅𝑎 .𝐵

The transfer function of the dc motor is

𝜔(𝑠)

𝐸𝑎(𝑠) =

𝐾𝑚

1+𝑠𝜏𝑚

Where

RESULT:

Transfer function of DC motor is given by ___________________________

VIVA:

1. What are the types of methods available to control the speed of a dc motor?

2. Why mechanical time constant is more than electrical time constant?

3. How speed and viscosity are related?

4. Can you justify that back emf constant = torque constant?

5. What is nature of relationship between torque and armature current in dc motor?

6. What is a PMDC motor?

7. Why small motors have high armature resistances compared to large motors?

8. Why large motors have high inductance resistances compared to small motors?

9. How to measure inductance of a dc motor?

10. What is the order of a dc motor?








EXPERIMENT NO. 11

EFFECT OF P, PI AND PID CONTROLLER ON A SECOND ORDER SYSTEM

AIM: To study the effect of P, PI and PID controller on a response of a second order system.

APPARATUS:

1. PID controller kit

2. C.R.O.

3. Patch chords

CIRCUIT DIAGRAM:








PROCEDURE:

Proportional [P] Controller

1. Make the connections as given in the circuit diagram. Keep I and D controllers at OFF

position.

2. Connect Second Order System in the loop and also connect Square Wave input and keep

the Damping factor of Second order system constant and observe the wave form at Vf by

varying P-Gain.

3. You can observe that as the P-Gain increases error decreases but oscillations increases. If

P gain is less, error is more but oscillations are less.

4. We can observe that the error voltage = G

Vs

1

5. Check with the Theoretical value and the practical result.

Proportional – Integral [PI] Controller

1. Make the connections as given in the circuit diagram - Keep D Controller at OFF

position.

2. Connect Square wave input to Second Order System for different Values of P and I gain

by keeping the damping factor constant by adjusting R value provided on the front panel

by varying both P gain and I gain.

3. Enter the results in the tabular column.

4. You can observe that study state error is zero with PI controller.








Proportional + Integral + Derivative [PID] Controller

1. Make the connections as given in the circuit diagram.

2. Connect square wave input to the Second order system and adjust damping factor by

adjusting R.

3. Observe the wave form at Input and VF. You can observe that by increasing the D gain

over shoots are minimizing.

CONNECTION DIAGRAM:








TABULAR COLUMN:

P – Controller

Sl.

No

P-

Gain

(G)

Set

voltage –

Vs

Feedback

voltage – VF

Error

voltage -

er

Calculated

error

=Vs/1+G

PI Controller

Sl.

No

P-

Gain

(G)

I-Gain

(G)

Set

voltage –

Vs

Feedback

voltage –

VF

Error

voltage -

er

Calculated

error

=Vs/1+G

PID Controller

Sl.

No

P-

Gain

(G)

I-Gain

(G)

D-Gain

(G)

Set

voltage –

Vs

Feedback

voltage

– VF

Error

voltag

e -er

Calculated

error

=Vs/1+G

RESULT:

VIVA QUESTIONS:

1. What is the effect of PI controller on the system performance?

2. What is the effect of P controller on the system performance?

3. What is the effect of PID controller on the system performance?

4. What are the disadvantages of P controller?

5. Define damping ratio?








EXPERIMENT NO. 12

LAG AND LEAD COMPENSATION –

MAGNITUDE AND PHASE PLOT

AIM: To obtain magnitude and phase plots of the given compensation networks and verify the

responses.

APPARATUS:

1. Lead-Lag Compensation Trainer Kit

2. Resistors

3. Capacitors

4. Patch Cords

CIRCUIT DIAGRAM:

Lag Compensator Lead Compensator








Lead - Lag Compensator

PROCEDURE:

1. Switch ON the Mains supply to the unit. Observe the sine wave signal by varying

frequency and amplitude potentiometer.

2. Now make the networks connections depending on Lag – Lead or Lag – Lead networks.

Connect sine wave output to networks input.

3. Note down the peak detector input using digital voltmeter provided. Now the frequency

and note down the frequency, Phase angle difference and output Vp for different

frequencies and enter the readings in the tabular column.

4. Now calculate the theoretical values of phase angle difference and gain. Compare this

with the measured values.

5. Plot the graph of Phase Angle Vs Frequency (Phase plot) and Gain Vs Frequency

(Magnitude plot).

6. Repeat the same for different frequencies.








TABULATION:

Sl.No. Frequency

(Hz)

Indicated Calculated

Φ Vout/Vin Φ

Vout/Vin

TABULATION:

Sl.No. Frequency

(Hz)

Indicated Calculated

Φ Vout/Vin Φ

Vout/Vin

MODEL CALCULATIONS:

In case of lag compensation network

G(S) = 1)(

1

21

2

csRR

csR =

Ts

Ts

1

1 =

)/1(

)/1(1

TS

TS

R2c = T; R1 + R2 = >1

G(jw) = 1

1222

22

T

T

- = Tan-1 wt – tan-1 wt

In case of lead compensation network








G (S) = 21

12 )1(

RR

csRR

21

21 1

RR

csRR

=)1(

)1(

TS

ST

=

)/1(

)/1(

TS

TS

G(jw) =

1

1222

22

T

T

G(jW) = tan-1 (wT) – tan-1 (wT)

CONNECTION DIAGRAM:

LAG COMPENSATION

LEAD

COMPEN

SATION








LEAD – LAG COMPENSATION








RESULT:

VIVA QUESTIONS:

1. What is compensator?

2. What is the difference between Lead and Lag compensator?

3. Bode plot for Lag network?

4. Which compensator used to improve study state response of system?

5. Which compensator used to improve transient response of system?

6. Which type of filter acts as a lead compensator?

7. Which compensator acts as a band pass filter?

8. Which compensator acts as a high pass filter?

Department of Electrical and Electronics Engineering · 2019-02-06 · VIVA QUESTIONS: 1. Define...

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Transcript of Department of Electrical and Electronics Engineering · 2019-02-06 · VIVA QUESTIONS: 1. Define...