B.Tech. DEGREE EXAMINATION, MAY (Examination at the end of Second Year) ELECTRICALS AND ELECTRONICS. Paper I MATHEMATICS III

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1 B.Tech. DEGREE EXAMINATION, MAY 01. (DEE 11) Time : Three hours (Examination at the end of Second Year) ELECTRICALS AND ELECTRONICS Paper I MATHEMATICS III Answer Question No. 1 is compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define even and add function with example. Define periodic function. (c) Find the Fourier series expansion of on the interval [ C C l] 1 +. (d) Write the formula for half range cosine series on the interval [ 0,π]. Maximum : 75 marks (e) (f) (g) State the Fourier integral rhm. State shifting property for Fourier transform. Find the Fourier cosine transform of x e. (h) Prove that 1 µ = 1+ S. 4 (i) Evaluate tan 1 x. (j) (k) (l) Explain transcendental n eq. Write the method of Falsi position formula. State Gauss forward diff interpolation formula. (m) State Bassel s formula. (n) (o) State trapezoidal rule. Write the second order Runge-Kutta formula.

2 UNIT I. (a) Find the Fourier series representating f ( x) = x, 0< x < π. Sketch the graph of f ( x) from 4π to 4 π. Find the Fourier series of the periodic function defined as f( x) 3. (a) Find the half range sine series for f( x) x( x) π = π, π < x < 0 =. x 0< x < π = π on 0 <x < π. Deduce that Evaluate the following using parsvalitity identity, 0 x ( a + x ) dx ( a> 0). UNIT II ax bx ( b a ) λsinλx 4. (a) Using Fourier integral, show that e e = π ( λ + a )( λ + b ) ( > 0, b> 0) a. Find the Fourier transform of f ( x) defined by f( x) = e x, < x 5. (a) Find out the square root of 5. Given x 0 =.0, x 1 =7. 0 using bisection method. 4 Find a positive root of x x 10= 0 by Iteration method. 0 <. dx

3 UNIT III 6. Find f (.5) using Newton's forward and central backward formula from the following table. x y dy d y 7. From the following table of x and y obtaine and for x = 1.5, x = dx dx 8. (a) Find ( 0.1 ), y( 0. ), y( 0.3) x y UNIT IV dy y given that y + x dx Using Euler s method solve for y at = 9. Find y ( 0.1) and ( 0.) y = x y, y ( 0 ) = 1. y = and ( 0 ) = 1 dy dx x from = 3x + 1, y( 1) =. Using Taylor s series. taking h = y using Runga-Kutta Fourth order formula. Given that

4 (DEE 1) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper II NETWORK ANALYSIS I Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Describe Active element Define Dependent sources (c) Give the energy stored in an ideal Inductor. (d) Explain the kirchoff's current law. (e) State the thevenius theorem. (f) State the Nortou's theorem. (g) Give the application of maximum power transfer theorem. (h) Define Rms value (i) Define crest factor (j) Define form factor (k) Explain phase (l) Define power factor (m) Define selectivity (n) Define Bandwidth (o) Why power factor of a pure resistance is one?

5 UNIT I. (a) Explain the star-delta transformation. Find the single equivalent resistance between A and B is the circuit of the fig by network reduction. 3. (a) Explain the mesh analysis. Find V in the circuit of fig by modal analysis. UNIT II 4. (a) State the explain the superposition theorem. Find the current in 75 Ω resistor in the circuit shown in fig using superposition theorem. 5. (a) Find the effective (or) RMS value of the given voltage waveform. π u = sin(314t + ) 3 Find the RMS value, average value, form factor and peak factor of the waveform shown in fig.

6 UNIT III 6. An RLC series circuit has R = 10N, L = 0.5 H, and C =10 MF. Connected across a 00 v, 50Hz supply. Find (a) (c) (d) (e) (f) Reactance Impedance Current Phase angle Power factor Voltage across (g) Voltage across R, L and C. 7. (a) A series RLC circuit has R = 1n, L=1H, C = 1MF. Find the resonance frequency, voltage magnification at resonance and band width in rad/sec. Compare the series and parallel resonance circuit. UNIT IV 8. (a) State and prove initial value theorem. Discuss the time constant of R-L, R-C circuits. 9. Write short notes on the following: (a) (c) (d) (e) Title Control Comment Operating Print and end statements.

7 (DEE 13) B.Tech. DEGREE EXAMINATION, MAY 01 (Examination at the end of Second Year) Electricals and Electronics Paper III ELECTRONIC DEVICES Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) What is aquadog coaling? Why it is used in CRO? Define horizontal sensitivity of CRT. (c) What is thermal generation? (d) Why doping is required? (e) Draw photo diode control circuit. (f) State the disadvantages of LCD. (g) What is a Ohmic contact? (h) What is the expression for dynamic resistence of diode? (i) Why collector region is greater than emitter region? (j) What is the relationship between α and β? (k) What FET is called unipolardevice? (l) Give application of SCR. (m) Give the equivalent circuit of UJT. (n) Define pinch off voltage. (o) What is intrinsic stand of radio (n)?

8 UNIT I. (a) Derive the expression for acceleration, velocity and displacement of a charged particle placed in an electric field E. Draw and explain the based structure of PN junction. 3. (a) Derive the expression for the conductivity of exterinsic n-type p-types semiconductor. Derive the expression for the electromagnetic deflection sensitivity in the case of CRT. UNIT II 4. (a) Explain the V-I characteristics of a diode? Explain the basic operating principle of LED. 5. (a) Explain the tunneling effect with the help of neat diagram. Derive the expression for transition capacitance of a diode. UNIT III 6. (a) Explain the operation of n-p-n and p-n-p transistors? Define stability factor and what is the need of this in BTT circuit. 7. (a) Draw the circuit diagram of self bics circuit and derive the expression for S? Derive the relationship between α and ρ. UNIT IV 8. (a) Explain how FET works as voltage varibale resistor. Draw the fixing characteristics of SCR and briefly explain. 9. (a) Draw and explain the characteristics of UJT. Sketch the drain characterstics of MOSFET for different values of VAS and mark different regions of operation.

9 (DEE 14) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper IV ELECTRICAL AND ELECTRONICS ENGINEERING MATERIALS Time : Three hours Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) Maximum : 75 marks 1. (a) Give few examples of insulators. Explain the nano wires. (c) State Weidmann-Franz law. (d) Define fermi level. (e) Why is Brillouim zone. (f) Explain the fabrication of IC chip. (g) Define super conductivity. (h) Write the expression of Londois equation. (i) Define Isotope effect. (j) Define Meissner effect. (k) Explain domain theory. (l) Define piezo electricity. (m) Define B-H curve. (n) Explain the polarization mechanisms. (o) What are the applications of piezo electricity.

10 . Explain the following (a) Properties of carbon nano tubes. UNIT I Applications of nano-structured materials. 3. Write short notes on the following (a) Synthesis of nano structured materials. Electrical characteristics of carbon nano tubes. UNIT II 4. (a) Explain the classical free electron theory of metals. Explain the direct and indirect band gap semiconductors. 5. Derive an expression for the fermi energy interms of the number of electrons per unit volume. Explain the I.C. technology. UNIT III 6. (a) Explain in detail about type I and type II super conductors. Explain the BCS theory and copper pairs. 7. (a) Explain the critical parameters and penetration depth. Explain the high temperature super conductors and their applications. UNIT IV 8. (a) Briefly explain the classification of dielectrics. Write short notes on electric polarization and polarisability. 9. (a) Explain the different types of dielectric break down. Briefly explain the dielectric materials and their applications.

11 (DEE 15) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper V DIGITAL ELECTRONICS Time : Three hours Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) Maximum : 75 marks 1. (a) Convert the given number in to binary ( 134 ) 9. (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) What is meant by the base of a number system? Perform the subtraction using s complement. (i) (ii) Write De-Morgan law s. What does the abbreviation BCD stand for? What is a flip flop? How many outputs a magnitude comparator generates? What is meant by decoder? Realize full adder using half adder. Draw the characteristic table of J-K flip flop. What is the difference between flip flop and latch? Define fundamental mode operations. (m) What do you understand by race avoidance? (n) (o) What are the advantages of TTL family? What is a PAL?

12 UNIT I. (a) Simplify the Boolean function using K-maps ( wx,, y, z) = Σ( 1,3,7, 11, 15) don t care conditions d ( wx,, y, z) = Σ( 0,,5). Construct a logic diagram for the Boolean expression f AB. + C( A+ BD. ) only NOR gates. 3. (a) Deduce the Boolean expressions (i) AB + AC+ AB + C( AB+ C) (ii) A C+ AB+ ABC+ BC (iii) ( AB + A + AB) f that has the = using Simplify the Boolean function using tabulation method =Σ( 01,,,8, 10, 11, 14, 15) UNIT II f. 4. (a) Implement the following function with a mutiplexer. ( ABCD) =Σ( 0,3,4,8,9, 15) f. Draw the basic diagram of -to-4 line decoder with only NOR gates. Include an enable input. 5. (a) Design a excess-3 adder using 4-bit parallel adder and logic gates. Show that a full subtractor can be constructed with two half subtractors and an OR gate. UNIT III 6. (a) A sequential circuit with two D-flip flops A and B; two inputs x and y ; and one output z is specified by the following next state and output equations. (i) (ii) ( + 1) = At ( ) x( t) + Bt ( ) x( t) ( + 1) = A ( t) x( t) At Bt z = ( A+ B)x Draw the logic diagram of the circuit. Derive the state table. (iii) Derive the state diagram?

13 Convert a given JK flip flop to RS flip flop. 7. (a) Design a 4-bit binary ripple counter with n-flip flops. Explain 4-bit shift resister. UNIT IV 8. (a) Draw the circuit of a 3 i/p TTL totem pole NAND gate and explain its operation. Draw the circuit of ECC NAND gate and explain. 9. (a) Implement a PLA structure for a full adder. Draw the circuit of RTL NOR gate and explain.

14 (DEE 16) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper VI ELECTRO MECHANICS I Time : Three hours Maximum : 75 marks Answer question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define mechanical force. Define electric field energy. (c) Explain electric field energy. (d) What is the rotating part is a DC generator? (e) What is lap winding? (f) What is the function of armature system? (g) Define commutation. (h) Define efficiency of a DC machines. (i) What are the applications of DC compound generator? (j) What is the useful feature of back emf? (k) Draw the configuration of DC Shunt Generator. (l) Write the principle of Rosenberg generator. (m) What is the limitations of Swinburue s test? (n) What are the advantages of field test? (o) Explain parallel operation of DC generator.

15 UNIT I. (a) Explain the field energy and mechanical energy. Write short notes on torques in systems with permanent magnets. 3. (a) Explain the energy conversion through electric fields. Write short notes on energy in magnetic system. UNIT II 4. Draw a neat sketch of a dc machine and label the component parts name the material used for each component part. 5. (a) Deduce the equation for the emf induced in a DC machine. Explain armature reaction in a dc machine. UNIT III 6. (a) Explain the various methods of speed control of dc motors. Mention the limitations of each method. State with reasons applications of various types of dc motors. 7. (a) Draw the characteristics of a dc service motor and from the nature of the curve explain the applications of dc series motor. Explain why a dc motor should not be started direct-on-line. UNIT IV 8. Write short notes on principle and working of metadyne. 9. Explain Swinburue s test in detail.

16 (DEE 17) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper VII ENVIRONMENTAL STUDIES Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsory. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. Explain the following in 1 or sentences : (a) What is environmental science? What are the organisms of biotic components? (c) Define echology. (d) What are the alternative sources of energy? (e) Define Dam. (f) What is water logging? (g) What are the causes for positive soil pollution? (h) Define biodiversity. (i) What are the qualitative pollutants? (j) What is cloud deeding? (k) What are the different environmental Acts? (l) What is mortality? (m) What are causes of air pollution? (n) What are non-degradable pollutants? (o) Define pollution.

17 UNIT I. Explain the structure and functions of eco-system. 3. Explain in detail about the water resources. UNIT II 4. Explain briefly : (a) In-situ conservation of biodiversity. Ex-situ conservation of biodiversity. 5. Describe the sources and effects of noise pollution. UNIT III 6. Explain in detail about the water scarcity and green revolution. 7. Explain in detail about environmental impact assessment. UNIT IV 8. Discuss the basic features of air (pollution and control of pollution) act. 9. What are the basic features of water (Prevention and control of pollution) act?

18 (DEE 1) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper I MATHEMATICS IV Time : Three hours Maximum : 75 marks Answer Question No. 1 is compulsory (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define analytic function. Write the C-R equations in Cartesian form. 1 z (c) If f ( t) = u( x, y) + iv( x, y) is analytic then f ( ) is. (d) Find all values of K, such that f( z) = e (cosky + isinky) is analytic. x (e) (f) State Cauchy s integral formula. Define isolated singularity of the analytic function. z (g) Determine the poles of f ( z) =. ( z + 1)( z + ) (h) State Taylor s theorem for the analytic function f (z). (i) Find the residuce of the function 1 f( z) = at these poles. ( z + 1)( z + 3) (j) (k) (l) d Find dz z c z where C is z = 1. Write the orthogonal property for Bessel function. State Rodrigue s formula for Legendry polynomial. (m) Find J 1 ( x) = (n) Write the value of p ( ) in Legendry polynomial. 3 x (o) Write the formula for. J n x

19 . (a) P.T. x + y Real f UNIT I ( z) =. f ( z) where f( z) S.T. the function u log( x + y ) conjugate. w = is analytic. = is harmenic and find its harmonic 3. (a) Derive the necessary and sufficient condition for f ( z) to be analytic in Cartesian co-ordinates. Find the analytic function whose imaginary part is e x ( x y ycosy) UNIT II 4. (a) State and prove Cauchy s integral theorem. Evaluate using Cauchy s theorem z e C 3 z ( z 1) 3 dz where C is 1 z 1 =. 5. (a) State and prove Laurent s theorem for the analytic function f ( z). Find Taylor s Expansion for the function f( z) UNIT III 6. (a) State and prove Cauchy s Residure theorem. Find the Residue of ( z) z + 1 f = at these poles. r z ( z ) ( 1+ z) d y dy 7. (a) Solving series the differential equation x + y = 0. dx dx By using Cauchy s Residue theorem sin +. 1 = with centre i.

20 π 0 cosθ πa dθ = 1 a cos+ a 1 a n 8. (a) P.T. J ( x) = ( ) J ( x) ( a 1) < UNIT IV n 1 n where n is a +ve integer. Write J ( ) in finite form. 5 x 3 9. (a) Express x + x x 3 interms of Legendre Polynomials. State and prove the orthogonality of Legendre polynomials..

21 Time : Three hours B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of the Second Year) Electricals and Electronics Paper II ELECTRONIC CIRCUITS I (DEE ) Maximum : 75 marks 1. (a) What is a rectifier? Answer Question No.1 compulsorily. (15 1 = 15) Answer ONE question from each unit. (4 15 = 60) What is the necessity of bleeder resistor? (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) What do you mean by exponential input? What is clamping theorem? Why we representing gain in decibel? What is the need of cascading amplifier? Define current gain of amplifier. What do you under stand by frequency response of amplifier? Draw the small signal high frequency CE model of a transistor? What is meant by loot strapping? What is the effect of cascading on frequency response? Give the expression of gain bend width product for current. (m) Define input impedance of FET. (n) (o) What is 3db frequency? Define the output impedance of FET?

22 UNIT I. (a) Draw and explain the circuit diagram of full wave rectifier with T-section filter. Obtain the Rc high pess filter response for pulse in put. 3. (a) Derive the expression for ripple factor in full wave rectifier using an inductor filter. Explain clamping circuit theorem. UNIT II 4. (a) Draw the circuit diagram of emitter follower and derive the expression for Ai, Av, Rp, Ro using hybrid model. Explain about various operating points with in the limits of operation of transistor. 5. (a) Compare CE and ce configuration with regards i, R Ai Av. R 0,, Draw and explain the block diagram of two stage cascade amplifier. UNIT III 6. (a) Draw the small signal high frequency co model of transistor. Define f α, fβ and fτand derive the relation between fβ and f? τ 7. (a) Derive the expressions for gainband width product for voltage and current. Prove that (i) (ii) hfe = gmrb' e hie = rbb' + rb' e.

23 UNIT IV 8. (a) Explain the CS/CD amplifier operation of high frequencies. Explain the selection of configuration for multistage amplifiers. 9. (a) What is the effect of coupling and bypass capacitor on the frequency response of Rc coupled amplifier? Derive the expressions for Av, Ri and Ro for TFET CS configuration.

24 (DEE 3) B.Tech. DEGREE EXAMINATION, MAY 01 (Examination at the end of Second Year) Electricals and Electronics Paper III ELECTROMAGNETIC FIELD THEORY Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Give the limitations of Gauss s law. (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) Write down expression for the electric field due to a point charge. Find the expression for electric flux density. Write the relation between electric field and electric potential in rectangular coordinates. What is electric dipole? State any two methods of producing magnetic field. Define magnetic dipole. Write the expression for Lorentz force equation. What is mutual inductance? Define magnetic field intensity. Define magnetic flux density. What is magnetic moment? (m) Explain poynting vector. (n) (o) Define skin effect. What is a perfect dielectric?

25 UNIT I. (a) State and explain Gauss s law of electromagnetics in differential form. Explain the concept of electric field and write down expression for the electric field due to a point charge. 3. (a) Find the potential function at any point between spherical shell in terms of applied potential using Laplace equation. Show that E = V. UNIT II 4. (a) Derive the expression for force between two current carrying conductors in the same direction. Derive the expression for self-inductance of solenoid. 5. (a) Derive the expression for mutual inductance M. Using the concept of vector magnetic potential find the magnetic flux density at a point due to a long straight filamentary conductor carrying a current I in â 3 direction. UNIT III 6. (a) Show that, in a capacitor, the conduction current and displacement current are equal. A parallel plane capacitor with plane area of has a voltage current assuming = t0. 5 cm and plate separation of 3 mm 3 50sin10 tv applied to its plates. Calculate the displacement 7. (a) Derive the expression of Maxwell s equation. r r D * H = J +. t

26 Write and explain differential and integral forms of Maxwell s equations. UNIT IV 8. (a) Write and explain the poynting theorem. Write short notes on power flow and power density in an electromagnetic field. 9. (a) Derive an expression for power density in perfect dielectric electromagnetic field. Derive an expression for wave equation in free space.

27 (DEE 4) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper IV NETWORK ANALYSIS II Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define graph. Define twig. (c) Define planner graph. (d) Define subgraph. (e) What is a port? (f) What are impedance parameters? (g) Define duality. (h) Explain image parameters. (i) Define operational impedances. (j) Define mutual inductance. (k) Explain constant k-filters. (l) State the Millman s method. (m) Explain the double tuned circuits. (n) Explain the term pole. (o) Define basic tie set.

28 UNIT I. (a) Explain the procedure to form tie-set matrix. Write down the fundamental loop matrix of the network shown in Fig. Find the number of branches, nodes and loops. R 3. Write short notes on : (a) (c) Z parameters Y parameters ABCD parameters. UNIT II 4. Write short notes on the following : (a) Ladder and Latice networks Two post bridged T network. 5. Briefly explain the response of R L, R c circuits for impulse and pulse excitations using Laplace transform method. UNIT III 6. (a) In the circuit shown in fig, find the drop across 3 Ω resistor and - j 6 Ω capacitor.

29 Two coupled coils of self inductances L1 = 1H, L = H are coupled in (i) series adding (ii) series opposite (iii) parallel aiding (iv) parallel opposition. If the mutual inductance is 0.5 H. Find the equivalent inductance in each case. 7. Explain the following : (a) Low pass filters High pass filters (c) Band pass filters. UNIT IV 8. (a) What are the advantages in 3 phase systems? Explain the 3ψ balanced and unbalanced circuits. 9. (a) Explain the star/delta transformation method. A balanced star connected load of (8 j4) Ω /phase is connected to a 3ψ, 400 V, 50 Hz supply. Find the line current, power factor and power.

30 B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper V PRIME MOVERS AND PUMPS (DEE 5) Time : Three hours Maximum : 75 marks Answer Question No. 1 Compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) What are devices used for measuring the pressure? (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) Define specific gravity. Define the term Impact of Jet. What are the important efficiencies of a Turbine? Define net head in turbine. What are the different types of turbines? What is the purpose of the casing? What are the main parts of a centrifugal pump? What is delivery head? What is overall efficiency of centrifugal pump? What is steady flow energy equation? What is first law of thermodynamics? (m) What are the different types of steam turbines? (n) (o) What is second law of thermodynamics? Draw the p-v diagram of diesel cycle. UNIT I

31 . (a) Calculate the density, specific weight and weight of one litre of petrol of specific gravity = 0.7. Derive the equation for force exerted by a jet on stationary inclined flat plate. 3. Define specific speed of a centrifugal pump. Derive an expression for the same. UNIT II 4. A Francis turbine with an overall efficiency of 75% is required to produce kw power. It is working under a head of 7.6 m. The pheripheral velocity = 0.6 the radial velocity of flow at inlet is 0.96 gh and gh. The wheel runs at 150 r.p.m. and the hydraulic losses in the turbine are % of the available energy. Assuming radial discharge, determine (a) (c) (d) The guide blade angle The wheel vane angle at inlet Diameter of the wheel at inlet and Width of the wheel at inlet. 5. Describe briefly the functions of various main component of pelton turbine with neat sketches. UNIT III 6. Air at a pressure of 50 bar and a volume of 0. m 3 is expanded at constant pressure until the volume is doubled. It is then expanded according to pv 1.3 = constant, until the volume is 0.8 m 3. Calculate the work done in each process. 7. Derive the equations for finding efficiency of Diesel cycle and Brayton cycle. UNIT IV 8. Explain with neat sketch working of u-stroke engine. 9. Explain with a neat sketch pressure and velocity compounding of stream turbines.

32 (DEE 6) Time : Three hours 1. Write briefly on the following : (a) (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) B.Tech. DEGREE EXAMINATION, MAY 01. (Examination at the end of Second Year) Electricals and Electronics Paper VI ELECTRO MECHANICS II Answer Question No. 1 compulsorily. (15 1 = 15) Answer ONE question from each Unit. (4 15 = 60) Explain the principle of working of a transformer. Write the emf equation of a transformer. Define form factor. Draw the no-load phasor diagram of a transformer. Define voltage regulation of a transformer. Write the expression for efficiency of a transformer. Define all day efficiency. Maximum : 75 marks State two specific uses of autotransformers in the field of electrical engineering. Define the term slip of induction motor. Write the expression for rotor current of an induction motor. List the various losses that take place in an induction motor. What is an induction generator? (m) Name the different methods of speed control of a polyphase squirrel-case type induction motor. (n) (o) Name the various type of single phase induction motors manufactured in fractional kilowatt radius. Is it possible to change the direction of rotation of a shaded-pole type induction motor?

33 UNIT I. Draw the complete phasor diagram of transformer on-load. 3. Draw the equivalent circuit of a transformer with (a) Primary qualities referred to the secondary side, and Secondary quantities referred to the primary side. UNIT II 4. (a) State the need for parallel operation of transformer. Explain the scott connection of transformer. 5. (a) Make a comparison in the weight of copper required in an autotransformer and a two-winding transformer of the same rating. Write short notes on Transformer tap changing. UNIT III 6. Using the torque equation, draw the nature of the torque-slip characteristic of a threephase induction motor. Show on the curve, starting torque, maximum torque and slip at which torque is maximum. 7. (a) Explain no-load and blocked rotor test on 3 phase induction motor. A 4 pole, 50 Hz, 30 V, 5 Hp squirrel case induction motor gave the following test data : No-load test : Power input = 75 w, No-load current = 6.3 A, No-load input voltage = 30 V, Blocked rotor test : Power input = 735 w, Blocked rotor full load current 15 A, Blocked rotor input voltage = 40 V. Determine the full load efficiency of the motor from the above test data.

34 UNIT IV 8. Write short notes on Crawling and Cogging. 9. Explain the working of principle of a single phase induction motor with the help of double revolving field theory.