B.Tech. DEGREE EXAMINATION, DECEMBER (Examination at the end of Second Year) Electricals and Electronics. Paper I MATHEMATICS III

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1 (DEE 11) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper I MATHEMATICS III Time : Three hours Maximum : 75 marks Answer Question No. 1 Compulsorily. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Determine the period of the function f sinx sin3x 3 sin 4x 4 x sin x... Define periodic function. (c) Write the Fourier series for x (d) (e) (f) (g) State parseval s formula for Fourier series. f in the interval c x c l. Write the inversion formula for the Fourier cosine transform. 1 Show that 1 E. Write Newton-Raphison iteration formula. (h) Write the Fourier integral of f x. (j) (k) (l) Define interpolation. Write Lagranges interpolation formula. Write Bessel s formula. Define numerical integration. (m) Write Trapezoidal rule. (n) (o) Write Simson s 3/8 th rule. State Stirling's formula. UNIT I. (a) If f x cos x, expand f x as a fourier series in the interval,. f x Expand 1 4 x x, if 0 x 3, 4 if 1 1, x 1

2 as the Fourier series of sine terms. 3. (a) Find the complex form of the Fourier series of real constant. ax e in, Find a Fourier series with period 3 to represent f x x x 0, 3. UNIT II where a is a in the range 4. (a) Find the Fourier sine transform of e x, Hence show that 0 m x sinmx e dx, m 0. 1 x Solve the equations 10x y z 1 ; x 10y z 13 ; x y 10z 14 by using Gauss-Seidal method. 5. (a) Find the Fourier integral representation of f t 0, t 0 1, e at t 0, t 0 Verify the representation directly at the point t 0. Find a real root of the equation cos x 3x 1 correct to three decimal places using interation method. UNIT III 6. (a) Apply Bessel s formula to obtain y 5 given y 0 854, y4 316, y8 3544, y For the following values of x and y, find the first derivative at x 4. x : y : (a) Given the values x : f (x) : evaluate f 9, using Lagrange s formula. Construct Newton s forward interpolation polynomial for the following data : x : y : UNIT IV

3 8. Using Runge-Kutta method of order, 4 find y 0.3 for the equation dy dx y y x, y x 0 1, dx 9. (a) Evaluate 1 x dx Evaluate 1 x take h 0%. using trapezoidal rule taking h 1 / 4. taking 7 ordinates by applying Simpson s 3/8 th rule.

4 (DEE 1) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper II NETWORK ANALYSIS I Time : Three hours Maximum : 75 marks 1. (a) State Tellegan s theorem. Answer Question No. 1 Compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) (c) (d) (e) (f) (g) (h) (j) (k) (l) What is crest factor? Define Reactive power. Give the expression, for energy stored in inductor. Differentiate ideal and practical sources. Define Bandwidth. Define complex power. State Reciprocity theorem. Define self inductance. What is peak value? Define Final-value theorem. Differentiate dependent and Independent sources. (m) What is the time constant of a series R-L-C circuit? (n) (o) Define probe command. Define phase and phase difference in sinusoidal waveforms. UNIT I. (a) Find the power absorbed by each of the elements.

5 below. Determine the currents in bridge circuit by using mesh analysis in figure 3. (a) Determine the current drawn by the circuit given using star-delta transformation. Find the voltage across 40 and the power supplied by the 5 A source for the circuit below using nodal analysis.

6 UNIT II 4. (a) Determine the current through resistor by using Thevenchi theorem in the circuit below. (7) Find the Norton s equivalent circuit of the network shown.

7 5. (a) A sine wave of v t = 00 sin 50 t is applied to a 10 resistor in series with a coil. The reading of voltmeter is 10 V and across the coil, 75 V. Calculate power and reactive volt-amperes in the coil and power factor of the circuit. (7) Find the power in impedance j5 Nortons theorem for the given circuit. (8) connected between A and B using UNIT III 6. (a) Determine the load resistance to receive maximum power from the source ; also find the maximum power delivered to the load in the circuit below. (8) Find the form factor of the square wave as shown below. (7)

8 7. (a) A voltage v t = 10 sin wt is applied to a series RLC circuit. At the resonant frequency of the circuit, the maximum voltage across the capacitor is found to be 500 V. Moreover, the band width is known to be 400 rad/sec and the impedance at resonance is 100. Find the resonant frequency. Also find the values of L and C of the circuit. (7) (8) Determine the maximum power delivered to the load in the circuit shown. UNIT IV 8. (a) Find the complete response V c and then i for t 0 in the following circuit. (7) In the network shown below, the switch is closed at t 0 and there is no initial charge on either of the capacitor. Find the current i by Laplace Transform method.

9 9. (a) Calculate the voltage t shown below. v 1 across the inductance for t 0 in the circuit For the circuit shown in figure, determine the current when the switch is moved from position 1 to position at t 0. The switch has been in position 1 for a longtime to get steady state values.

10 (DEE 13) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (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. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Define Hall effect. All questions carry equal marks. (c) (d) (e) (f) (g) (h) (j) (k) (l) Define mass-action law. Define valance band. Define fermi level. Define diffusion capacitance of a forward biased diode. Write the applications of LED. What is meant by Avalanche effect? What is meant by depletion region in a PN junction? What is meant by Q-point? What are the different configurations of BJI? Define stability factor. What is meant by thermal run away? (m) What is pinch-off region in a JFET? (n) (o) What are the applications of TRIAC? Draw the characteristics of UJT. UNIT I. (a) Derive an equation electrostatic deflection in a CRT.

11 List the applications of CRT and explain any one application in detail. 3. (a) Explain the concept of fermi level in intrinsic semiconductor. Prove that the conductivity of a semiconductor is given by p n ). ( p n UNIT II 4. (a) Discuss the effect of temperature on the VI characteristics of a diode. Explain diffusion and transition capacitance. 5. (a) Explain the operation of a varactor diode and list few applications. Explain the principle of construction and working of a LCD. UNIT III 6. (a) Draw a circuit of a transistor in CE configuration and explain the characteristic curves. Explain how the instability in a transistor can be avoided. 7. (a) Explain the requirement of a biasing circuit. For a fixed bias circuit using NPN transistor the value of is 80. If R B = 390 k, R = 1.5 k and V cc 30 V, find the coordinates of the Q point. C UNIT IV 8. (a) Illustrate with neat circuit diagrams the technique of biasing an enhancement MOSFET. With the help of characteristic curves how do you find the FET parameters and also define FET parameters. 9. (a) Explain the electrical equivalent circuit and operation of UJT. Draw the characteristics of a SCR and explain.

12 (DEE 14) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper IV ELECTRICAL AND ELECTRONICS ENGINEERING MATERIALS 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 a Nano tube? (c) (d) (e) (f) (g) (h) Write any two application of nano-structure materials. Differentiate intrinsic and extrinsic semiconductor. What are the properties possessed by Carbon Nano tubes? What is an insultor? Differentiate type I and type II super conductors. What is Isotope effect? Draw B-H curve. List any two applications of hard magnetic materials. (j) (k) (l) Give any two applications where ferrites are used? What are different types of dielectric breakdown? Define electrical conductivity. (m) What do you mean by penetration depth? (n) (o) Give examples of dielectric materials. Define Ferro electricity. UNIT I. (a) Explain the electrical characteristics of Carbon Nano tubes. Discuss briefly about the properties of Carbon Nano-tubes. 3. (a) Discuss the applications of nano-structured materials. What are Carbon Nano tubes? Discuss briefly the structure of Carbon Nano tubes.

13 UNIT II 4. (a) What is electrical conductivity? Explain Weidmann-Franz law. Distinguish metals, insulators and intrinsic semiconductors. Also write short notes on I-C technology. 5. (a) Discuss the fabrication of IC chip. Also explain I-C technology. What are Brillouch zones? How are they related to the energy of an electron in a metal. UNIT III 6. (a) Explain briefly about Type I and Type II super conductors. Explain Meissner effect? Also discuss London s equation. 7. (a) Explain Ferromagnetism-Weiss theory briefly. What is Piezoelectricity? Explain by giving applications. UNIT IV 8. (a) Explain terms dielectric loss and dielectric breakdown briefly. Derive the Clausius-Mossotti relation. 9. (a) Explain the structure of BaT io3, briefly. What are different types of dielectric breakdown? Explain each one briefly.

14 (DEE 15) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electrical and Electronics Paper V DIGITAL ELECTRONICS Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsory. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Draw the symbols of universal gate. Define De-Morgan s theorem. (c) Convert ( ) to (X)8. (d) (A896)8 = ( )10. Solve. (e) What is byte and bit? (f) Draw the symbol of EX-NOR gate and its truth table. (g) (h) (j) (k) (l) What are the applications of multiplexers? What do you mean by parity generator? Draw the truth table of a full adder. Define a flip flop. Give the truth table of JK flip flop. Define a ripple counter. (m) What is a shift register? (n) (o) Convert T flip flop to D flip flop. Draw only the symbols. What is a BCD code? UNIT I. (a) Divide by 101. (ii) Subtract 1101 from 1001 using the 1 s complement method. Also show the direct subtraction for comparisons. Gives the rules for binary multiplicate. Explain with an example. 3. (a) Define SOP and POS. Explain minterm and maxterms.

15 Minimize the following expression ring K-map and implement it using logic gate Y m (0, 1, 5, 9, 13, 14, 15) + d (3, 4, 7, 10, 11) UNIT II 4. Explain the operation of a full subtractor implement with two half subtractors and other gates. 5. (a) Design a 4 input priority encoder with the D 0 having the high priority and D0 the low priority. Write short notes on decoder. UNIT III 6. (a) What do you mean by race-around condition? How it can be eliminated? Design a Mod-6 asynchronous counter using T-flip flops. 7. (a) Explain about Ring counter. With a neat circuit diagram explain the operation of J-K flip flop. UNIT IV 8. (a) Sketch the circuits of PMOS NAND and NOR gates. Discuss the characteristics. Sketch an IIL NAND and NOR gates and explain how it operates. 9. (a) Differentiate PAL and PAL s. Implement the following Boolean function using PLA F 1( A, B, C) (0, 1,, 4) F ( A, B, C) (0, 5, 6, 7)

16 (DEE 16) B.Tech. DEGREE EXAMINATION, DECEMBER 009. Time : Three hours 1. (a) What are permanent magnets? (c) (d) (e) (f) (g) (h) (j) (k) (l) What is coercivity? (Examination at the end of Second Year) Electricals and Electronics Paper VI ELECTRO MECHANICS I Answer Question No. 1 Compulsorily. Answer ONE question from each Unit. What are the two types of windings used in DC machines? What is commutation? Write the expression for generated EMF in a DC machine. What is armature reaction? List any two conditions for parallel operation of DC generators. Mention the conditions for voltage build-up of a shunt generator. What is condition for maximum power developed by the motor? What is Swinburne s test conducted on DC machines? What is the other name for Hopkinson s Test? What are the various losses occurring in DC machines? (m) What is Metadyne? (n) (o) On what factors does Eddy current losses depend? What is principle of operation of Rosenberg generator? UNIT I Maximum : 75 marks. (a) Explain briefly about the energy conversions with suitable figures. (1 15 = 15) (4 15 = 60) An electrochemical device has the following stator and rotor will inductances : L11 L 1.6 cos H; L L cos H. 1 1 Neglecting coil resistances, find the torque developed as a function of angle when both coils are connected in parallel to a voltage source 10 sin 314t volts. 3. (a) Discuss about the torques in system with permanent magnets. Explain in detail about mechanical field energy and electric field energy with suitable figures. UNIT II 4. (a) Explain the principle of operation of DC generator with neat diagrams.

17 A shunt generator delivers 450 A at 30 V and the resistance of shunt field and armature are 50 and 0.0 respectively. Calculate the generated emf. 5. (a) Discuss in detail about Armature reaction with suitable figures. A 30 hp, 440 V, 4 pole wave wound dc shunt motor has 840 armature conductors and 140 commutator segments. Its full load efficiency is 88% and the shunt field current is 1.8 A. If brushes are shifted backwards through 1.5 segment from the geometrical neutral axis, find the demagnetising and distorting ampturns/pole. UNIT III 6. (a) Discuss in detail about characteristics of DC motors with neat figures. A 460 V series motor runs at 500 rpm. Taking a current of 40 A. Calculate the speed and % change in torque if the load is reduced so that the motor is taking 30 A. Total resistance of armature and field circuits is 0.8. Assume flux is proportional to field current. 7. (a) Explain in detail about the working of a 3 point starter with neat diagram. A 500-V dc shunt motor is to have a starter with five sections. The maximum permissible current is 100 A and the armature resistance is 0.5. Determine the resistance sections. UNIT IV 8. (a) Explain field test conducted on DC machine. A 500 V, shunt motor takes a total current of 5 A when running unloaded. The resistance of armature circuit is 0.5 and field resistance is 15. Calculate the efficiency and output when the motor is loaded and taking a current of 100 A. 9. (a) Explain the Swinburne s test conducted on DC machine and mention its advantages. Explain the operation of Rosenberg generator.

18 (DEE 17) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper VII ENVIRONMENTAL STUDIES Time : Three hours Maximum : 75 marks Answer Question No. 1 is compulsorily. (1 15 = 15) 1. (a) Define Ecosystem. Answer ONE question from each Unit. What are autrotrophic components and heterotrophic components? (c) Enumerate the abiotic characteristics of an ecosystem. (d) What are autrotrophs? (e) What is the importance of ozone in stratosphere? (f) (g) (h) (j) (k) What is WCED? Define watershed. Mention two water conservation practices. What are the impacts of modern agriculture? What are the sources of indoor air pollution? What is the importance of forests? (l) What are advantages and disadvantages of nuclear power? (m) What is the significance of Relegaon Siddhi? (n) What are green house gases? (o) What are the pollutants responsible for ozone depletion in stratosphere? UNIT I (4 15 = 60). Explain the structure and function of the ecosystem with help of a forest ecosystem. Explain the various components of the Ecosystem and their importance. 3. Distinguish between renewable and non-renewable energy resources. UNIT II 4. What is meant by biodiversity? Explain different concepts involved in biodiversity.

19 5. What are the effects of air pollution on human beings, plants and materials? UNIT III 6. Explain the following : (a) Hazardous wastes and their disposal methods Global issues of Environmental pollution (c) Name different types of municipal solid wastes and their disposal methods. 7. What are the sources of air, water and soil pollution that effect the human health? UNIT IV 8. Discuss the salient features of forest conservation act. 9. Write short notes on : (a) Tehri Dam Florosis (c) Chipko Movement.

20 (DEE 1) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) ELECTRICALS AND ELECTRONICS Paper I MATHEMATICS IV Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Define a harmonic function. Examine the analyticity of f z z. x y (c) Find the analytic function whose imaginary part is. x y (d) Write the real and imaginary part of log z. (e) State the Cauchy's integral theorem. (f) Classify the different singularities of a function f z. (g) What is meant by a residue of f z at z a? (h) Find the residue corresponding to the poles of f z z. cosz Define an isolated essential singularity of f z. z z 1 (j) Evaluate dz z 1 C where c is the circle z 1. (k) (l) Define a regular singular point of a differential equation. Give an example of such a point. State the orthogonality property of Bessel functions.

21 (m) Write the Bessel differential equation of order n. (n) Write the generating function for P n x. (o) Express 5 x 3 x in terms of Legendry Polynomials.. (a) Show that the function f z UNIT I i y 1 i x, 0 x y Cauchy Riemann equations at the origin. But z and 0 0 f 0 does not exists. Determine the analytic function whose real part is cos x cosh y. 3. (a) Determine the analytic function w uiv If u v x yx 4xy y z x iy and f z uiv, find f z in terms of z. UNIT II. if v logx y x y f satisfies the is an analytic function of 4. (a) Using Cauchys integral formula, evaluate z where C is circle dz1 C x y 4. Find the first three terms of the Taylor series expansion of z z i. 1 f about z 4 5. (a) Evaluate z dz, where C is the contour given by the circle z 1 1 described c in that anti-clockwise sense. Expand z z 1 f in Taylor series about z 1 the point z 0 and (ii) about z 1. UNIT III cos 6. (a) Apply the calculus of residues and show that d. 54cos 6 0 Obtain a series solution of the equation

22 d y dy x 1 x 1 3x y 0. dx dx 7. (a) Solve the equation in series : d y dy x y 0. dx dx Show that : 0 cos a d, a 1acos a 1a 1. UNIT IV 8. (a) Show that np x xpx P x n n n 1. Prove that x cosn x sin 9. (a) Show that : d dx J n 1 0 xj x xj x 1 1. (ii) x J xj x Prove that : 1 1 P m J 0 x P n x dx 0, 0 m n, m n n 1 d, n being an integer.

23 (DEE ) B.Tech DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals And Electronics Paper II ELECTRONIC CIRCUITS I Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Define ripple factor of a diode. (c) (d) (e) (f) (g) (h) (j) What are the advantages of bridge rectifier. Draw the circuit of a clipper. What is an operating point of a BJT? What do you mean by single stage transistor amplifier? Why does ac load differ from dc load? Define r d and gm of a FET. What is the difference between shunt and series clipper? What effect does a clamper have on the rms voltage of a sine-wave output? What type of distortion is harmonic distortion? (k) (l) Define cut-off frequency. Why gain of amplifier is expressed in logarithmic scale? (m) What is Hi Fi amplifier system? (n) (o) Why do you require multi-stage amplifiers? What is crystal oscillator? UNIT I. (a) Define regulation and derive the same for a bridge rectifier. Compare the three types of filters used in rectifier. 3. (a) Obtain the response of a low pass RC circuit to sine input. Explain the operation of double ended clipper.

24 UNIT II 4. (a) Draw the circuit of a practical single stage transistor amplifier and explain its function. Sketch the Ebers-Moll model of transistor and write the relevant equation. 5. Derive the expression for the CE short circuit current gain as a function of frequency. UNIT III 6. (a) Derive the high frequency equivalent circuit of emitter follower. Derive the expression for the overall voltage gain. Justify the validity of approximate hybrid model applicable in high frequency region. 7. (a) Derive an expression for gain band width product of a short circuit model of CE configuration in a BJT. Draw the hybrid - model of BJT in CE connection and derive the equation for current gain. UNIT IV 8. (a) Draw the circuit of a CE-CB cascade amplifier and explain its operation. Discuss the effect of bypass capacitors. 9. (a) Derive voltage gain, input impedance and output impedance of a common source FET amplifier. Explain the significance of FET amplifier at high frequencies.

25 (DEE 3) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (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. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) What is the definition of electromagnetic field? (c) (d) (e) (f) (g) (h) (j) (k) (l) What is Coulomb s law? State Poisson's equation. State Ampere s circuital law in integral form. Define Ohm s law in point form. What is the relation between magnetic flux, magnetic flux density and magnetic field intensity? What is energy density in magnetic field? What is magnetic flux density? What is Scott connection? Define displacement current. State modified Ampere s circuital law in differential form. What is power density in an electromagnetic field? (m) State the poynting theorem. (n) (o) Define skin depth. State magnetic boundary conditions. UNIT I. (a) Derive an expression for capacitances of a pair of co-axial cylinders of radii a and b and length l the dielectric being air the outside cylinder is earthed. 9 is located in vaccum at P 0.03, 0.01, 0.04 A charge Q C. Find force on Q due to Q1 100C at P 0.03, 0.08, all distances in meters.

26 3. (a) Using Laplace s equation, derive an expression for the potential difference at any point between spherical Shell s interms of the applied voltage. Explain the conditions at a boundary between two dielectrics. UNIT II 4. (a) Explain the concept of scalar and vector magnetic potentials. State and explain the biot-savart law. 5. (a) State and explain the Ampere s law in integral form as used in magnetic field. r,, z due to an intensity long Find magnetic field intensity at a point straight filament carrying a current I in the z -direction. UNIT III 6. (a) State and explain the Maxwell s equations in integral form and in differential form. An a.c. voltage source V V0 sinwt is connected across a parallel plate capacitor C. Verify that the displacement current in the capacitor is the same as the conduction current in the wires. 7. (a) Explain the Maxwell s first curl equation for the electromagnetic field. Explain the inconsistency in Ampere s circuital law. UNIT IV 8. (a) Explain uniform planewave motion in free space. Show that in empty space 0, P 0 1 B B. c t J satisfies the wave equation 9. (a) Derive the expression for poynting vector. Show that this can be used to calculate the power. Find the average poynting vector for a plane wave of amplitude H 1A / mt in a homogenous isotropic medium for which 1, r 4. r 0

27 (DEE 4) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper IV NETWORK ANALYSIS II Time : Three hours Maximum : 75 marks 1. (a) Define oriented graph. Answer Question No. 1 Compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) (c) Define a tree. Give the relation between y and z parameter. (d) What is a cut-set matrix? (e) What is dual network? (f) State final value theorem. (g) What is a band pass filter? (h) Give the expression for coefficient coupling. Draw the circuit for two-port bridged-t network. (j) List any two advantages of 3-phase systems. (k) What is a constant k-filter? (l) Show the configuration of star and delta connections of a 3-phase system. (m) Write the expression for finding the number of links of a graph. (n) List any two properties of incidence matrix. (o) Define mutual inductance. UNIT I. (a) Draw the dual network for the given network.

28 analysis. Find the power dissipated in the 6 resistor the circuit shown using nodal 3. (a) Find the h-parameters of the network shown. Find the transmission parameters for the circuit shown. UNIT II 4. (a) Find the voltage across the capacitor in the network shown below.

29 Obtain the lattice equivalent of a symmetrical T-network shown. 5. (a) Find the Z parameters of the RC ladder network shown. Find the expression for the voltage across the capacity with application of the step voltage in the following circuit. Let the initial voltage in the capacitor be 1 volt. 6. (a) Discuss about constant M-filters. UNIT III Design a high pass filter having a cut-off frequency of 1kHz with a load resistance of 600.

30 7. (a) For the circuit shown in figure, find the ratio of output voltage to source voltage. Derive the expression for coefficient of coupling. 8. (a) Three impedances UNIT IV Z 0 30, Z and Z are 1 delta-connected to a 400V, phase currents (ii) line currents and (iii) total power consumed by the load. 3 system as shown in figure. Determine the 3 A symmetrical 3, 3-wire 400V, supply is connected to a delta connected load. Impedances in each branch are Z BR.5 60 sequence is RYB. Z 30, Z and RY 10 YB. Find its equivalent star-connected load; the phase 9. (a) Two wattmeter method is used to measure power in a 3 load. The wattmeter readings are 400W and 5W. Calculate total active power (ii) power factor and (iii) reactive power.

31 V RN V ions A balanced 3, star connected voltage source has with RYB phase sequence, and it supplies a balanced delta connected 3 load. The total power drawn by the load is 15kW at 0.8 lagging power factor. Find the line currents, load and phase currents.

32 (DEE 5) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper V PRIME MOVERS AND PUMPS Time : Three hours Maximum : 75 marks Answer Question No. 1 is compulsory. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Define the mass density (units). (c) (d) (e) (f) (g) (h) (j) (k) (l) Write down the any two examples of reaction turbine. Define the term impact of jets. What is the difference between pump and turbine? Define centrifugal pump. What is cavitation? Define Enthalphy. Draw the P-V diagram of Brayton cycle. Give the Kelvin-Plank statement of second law. Give the two points of difference between a petrol engine and diesel engine. Draw a line diagram of closed cycle gas turbine plant. Define specific speed of a centrifugal pump. (m) Define mean effective pressure. (n) (o) What is steady flow process? Differentiate the impulse turbine and reaction turbine. UNIT I. (a) Derive the equation for force exerted by a jet on stationary inclined flat plate. A jet of water of diameter 50 mm moving with a velocity of 0 m/s strikes a fixed plate in such a way that the angle between the jet and the plate is 60. Find the force exerted by the jet on the plate. In the direction normal to the plate and

33 (ii) In the direction of jet. 3. (a) Draw and discuss the operating characteristics of a centrifugal pump. Find the number of pumps required to take water from a deep well under a total head of 89 m. All the pumps are identical and running at 800 rpm. The specific speed of each pump is given as 5 while the rated capacity of each pump is 0.16 m 3 /sec. UNIT II 4. (a) Prove that the work done per second per unit weight of water is a reaction 1 g turbine is given as Vwu Vw u 1 where Vw 1 and Vw = Velocities of whirl at inlet and outlet. u 1 and u = peripheral velocities at inlet and outlet. An inward flow reaction turbine has an exit diameter of 1 meter and its breadth at inlet in 50 mm. If the velocity of flow at inlet is meters/sec. Find the mass of water passing through the turbine per second. Assume 10% of the area of flow is blocked by blade thickness. If the speed of the runner is 10 r.p.m. and guide blades make an angle of 10 to the wheel tangent, draw the inlet velocity triangle and find : the runner vane angle at inlet. (ii) velocity of wheel at inlet. 5. (a) Draw inlet and outlet velocity triangles for a pelton wheel turbine and indicates the directions of various velocities. A pelton wheel is to be designed for the following specifications power = kW, S.P. Head = 00 m, Speed = 800 rpm, 0 = 0.86 and jet diameter is not exceed one tenth the wheel diameter. Determine : (ii) Wheel diameter. The number of jets required and (iii) Diameter of the jet. Take C and speed ratio = V UNIT III 6. (a) Show that the efficiency of the Ottocycle depend only compression ratio. All engine working on the Ottocycle is supplied with air at 0.1 Mpa, 35C. The compression ratio is 8. Heat supplied is 100 kj/kg. Calculate the

34 maximum pressure and temperature of the cycle, the cycle efficiency and the mean effective pressure. For air C P = 1.005, C and R kj/kgk. V 7. (a) What do you understand by macroscopic and microscopic view points? (c) Define an isolated system. A piston and cylinder machine contains a fluid system which passes through a complete cycle of four processes. During a cycle, the sum of all heat transfer is 170 kj. The system completes 100 cycles per minute. Complete the following table showing the method for each item and compute the net rate of work output in kw Process Q (kj/min.) W (kj/min.) E (kj/min.) a b 0 1,170 b c 0,000 0 c d 3,100 37,600 d a UNIT IV (a) Explain the working of a four stroke cycle diesel engine by drawing neat sketch. Give the advantages of gas turbines over steam turbines. 8. (a) Derive an expression for force, work done diagram efficiency stage efficiency and axial thrust in case of steam turbines. Steam issues from the nozzle of a single impulse wheel turbine at 800 m/sec. The nozzle angle is 0 and the blade angles are 30 at inlet and outlet. Determine the blade velocity and the work done per kg of steam. Neglect the effect of friction.

35 (DEE 6) B.Tech. DEGREE EXAMINATION, DECEMBER 009. (Examination at the end of Second Year) Electricals and Electronics Paper VI ELECTRO MECHANICS II Time : Three hours Maximum : 75 marks 1. (a) What is a transformer? (c) (d) (e) (f) (g) (h) (j) (k) (l) All questions carry equal marks. Define voltage transformation ratio. Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) Classify the tranformers based on voltage and number of turns. Draw the phasor diagram of a transformer on load. Define voltage regulation of a transformer. Give the expression for Maximum efficiency conditon. List any application of autotransformer. Draw the phasor diagram representing identical impedance voltage triangle. List any two disadvantages of open connection. What is scott connection? What is the principle of involved in rotation of the rotor? Write the torque equation of an Induction Motor. (m) What is cogging? (n) (o) Mention the applications of an Induction generator. What is condition for Maximum Power Output of an Induction Motor? UNIT I. (a) A 5 kva transformer has 500 turns on the primary and 50 turns on the secondary winding. The primary is connected to 3000 V, 50 Hz supply. Find the full load primary and secondary currents, the secondary emf and the maximum flux in the core. Neglect leakage drops and no load primary current. The no load of a transformer is 50A at 0.3 power factor when supplied at 30V, 50Hz. The number of turns on the primary winding is 00. Calculate (ii) Maximum value of fluse in the core The core loss (iii) Magnetism current.

36 3. (a) The parameters of a 300/30V, 50 Hz transformer are given below : R R R 0 50 X X 0.73 X The secondary load impedance Z ej 0.9. Solve the exact equivalent circuit with normal voltage across the primary. The efficiency of a 400 kva, 1 transformer is 98.77% when delivering full load at 0.8 pf. and 99.13% at half load and unity p.f. Calculate : (ii) iron loss full load copper loss. UNIT II 4. (a) Explain briefly about the open data connections. 000V, A balanced 3 load of 150 kva at 1000V, lagging p.f. is supplied from 3 mains through 1 transformers connected in (ii) Delta delta Open delta. Find the current in the windings of each transformer and power factor at which they operate in each case. Explain calculations with circuit and vector diagrams. 5. (a) Explain briefly about Scott connection. Two transformers are required for a scott connection operating from a 440V, 3 supply for supplying two 1 furnaces at 00V on the side. If the total output is 150 kva, Calculate the secondary to primary turn ratio and the winding currents of each transformers. UNIT III 6. (a) Discuss about the Block rotor Test on 3 induction motor and derive the necessary equations.

37 A 110V, 3 star connected induction motor takes 5A at a line voltage of 30V with rotor locked. With this line voltage, power input to motor is 440w and core loss of 40w. The d.c. resistance between a pair of stator terminal is 0.1. If the ratio of ac to dc resistance is 1.6, Find the equivalent leakage reactance/phase of the motor and the stator and motor resistance per phase. 7. (a) A 50 Hz, 8 pole induction motor has a full load slip 4%. The rotor resistance is /phase and standstill reactance is /phase. Find the ratio of maximum to full load torque and the speed at which the maximum torque occurs. The power input to the rotor of a 440V, 50 Hz, 6 pole, 3 IM is 0 kw. The slip is 3% (ii) Calculate : Frequency of rotor currents Rotor speed (iii) Rotor copper losses (iv) Mechanical power developed (v) Rotor resistance per phase if rotor current is 60A. UNIT IV 8. (a) Explain in detail about Crawling and Cogging. A double case induction motor has the following equivalent circuit parameters, all of which are phase values referred to the primary Primary R 1 X 3 1 Outercase R 3 X Inner case R 0.6 X 5 t 0 t The primary is connected and supplied from 440V. Calculate starting torque and the torque when running at a slip of 40%. The magnetising current may be neglected. 9. (a) Discuss in detail about the double field revolving theory. Discuss about various starting methods of 1 Induction Motor.