ii yr -ee - anucde.info - i 2) a) obtain the expressions for star-delta equivalence of resistive...

(DEE 211)

B.Tech. DEGREE EXAMINATION, NOV./DEC. – 2014

(Second Year)

ELECTRICALS & ELECTRONICS

Paper - I : Mathematics - III

Time : 3 Hours Maximum Marks: 75

Answer Question No.1 is compulsory (15×1 =15)

Answer ONE Question from each unit (4×15 = 60)

1) a) Define Periodic function.

b) Define odd function and give an example.

c) Find ao in the Fourier series of f(x) = in the interval –π < x < π.

d) Define Sine Series.

e) Write any two properties of Fourier transform.

f) Define Fourier transform.

g) Define Fourier cosine transform.

h) Define the integral transform.

i) Show that .

j) Evaluate ∆2 cos 2x.

k) State the Newton’s forward interpolation formula.

l) Write Stirlings formula.

m) Define numerical differentiation.

n) State Trapezoidal rule.

o) State Simpson’s three-eight rule.

UNIT - I

2) a) Find the Fourier series expansion of f(x) = 2x – x2, in the interval (0, 3) and hence

deduce that + …….. = .

b) Find the Fourier Cosine series for the function in 0 < x <

OR

c) Obtain Fourier series for the function f(x) given by

, −π ≤ x < 0

= , 0 ≤ x ≤ π

Deduce that + .

d) Find the complex form of the Fourier series of in −1≤ x ≤ 1.

UNIT - II

3) a) Solve the integral equation

=

Hence evaluate .

b) Find the root of the equation xex = cosx using the regula-falsi method correct to

three decimal places.

OR

c) Find the Fourier cosine transform of

.

d) Solve the following equations by Gauss elimination method:

UNIT - III

4) a) Apply Newton’s backward difference formula to the data below to obtain a

polynomial of degree 4 in x:

x: 1 2 3 4 5

y: 1 -1 1 -1 1

b) Apply Bessel’s formula to obtain y25, given y20 = 2854, y24 = 3162, y28 = 3544, y32 =

3992.

OR

c) Using Newton’s devided difference formula, evaluate f(8), given

x: 4 5 7 10 11

f(x): 48 100 294 900 1210

d) Find the first and second derivatives of the function tabulated below, at the point x =

1.1:

x: 1.0 1.2 1.4 1.6 1.8 2.0

f(x): 0 0.128 0.544 1.296 2.432 4.00

UNIT - IV

5) a) Evaluate by using Simpson’s rule.

b) Find an approximate value of y when x = 0.1, if and y = 1 at x = 0,

using Picard’s method.

OR

c) Evaluate y(0.1) correct to four decimal places using Taylor’s series method if

d) Apply Runge-Kutta method of fourth order to find the value of y for x = 0.2, in steps

of 0.1, if , given that y = 1 where x = 0.

(DEE212)


(Examination at the end of Second Year)

ELECTRICALS AND ELECTRONICS

Paper - II : Network Analysis -I


Answer Question No.1 compulsory (15)

Answer any One question from each unit (4 × 15=60)

1) a) Define potential difference.

b) What type of energy is stored by Inductor?

c) What is resonance?

d) What are half-power frequencies?

e) Based on which law mesh analysis is carried out?

f) What is the phase difference between voltage and current in a pure capacitor?

g) Why transient occurs in electric circuits?

h) What are the units of Apparent power?

i) For which type of circuits superposition theorem is valid?

j) How thevenin impedance is found?

k) What is the total reactance of a series RLC circuit at resonance?

l) How many cycles does a sinewave go through in 10s when its frequency is 50Hz?

m) What is the condition to be satisfied for Tellegen’s theorem?

n) What is an ideal voltage source?

o) Define average power.

UNIT - I

2) a) Obtain the expressions for star-delta equivalence of resistive networks.

b) Find out the equivalent resistance for the network shown in fig – 1.

OR

3) a) Derive the expressions for energy stored in Inductors and capacitors.

b) Find the power delivered by the 4V source and voltage across 2Ω resistor shown in

fig2.

UNIT - II

4) a) State and prove millman’s theorem.

b) Using Thevenin’s theorem find the current in 3Ω resistor shown in fig 3.

OR

5) a) Obtain the expressions for power and energy in R, L and C elements with sinusoidal

excitation.

b) Determine the r.m.s. value of the voltages defined by

V1 = 5 + 5 sin (314t + π/6)

V2 = 100 + 50 sinωt.

UNIT – III

6) a) Obtain the complex impedance expression for series RC circuit with phasor diagram.

b) For the series parallel circuit shown in fig4, determine

i) total impedance between the terminals a, b and state if is inductive or capacitive.

ii) the phase angle.

OR

7) a) Explain the band width of RLC circuit and derive the ‘Q’ – factor from it.

b) In the circuit shown in fig 5 the current at its maximum value with capacitor

value C = 20μF and 0.707 times its maximum value with C = 30 μF. Find the value

of Q at ω = 500 rad/sec and circuit constants.

UNIT - IV

8) a) Define laplace transforms and explain final value theorem.

b) Use the initial and final value theorems find the initial and final value of f(t) for the

following.

i) ( )

2

2

4 7 1F( )

1

s ss

s s

+ +=+

ii) ( ) ( )( )

27 63 134F( )

3 4 5

s ss

s s s

+ +=+ + +

OR

9) a) Determine the current i if the circuit driven by a voltage source as shown in fig6. The

initial value of the voltage across the capacitor and the initial current through the

inductor are both zero.

b) Derive the expression for current i(f) for RL circuit in fig 7.

(DEE 213)




Paper - III : Electronic Devices


Answer Question No.1 is compulsory (15)

Answer one question from each unit (4×15 = 60)

1) a) What are intrinsic & extrinsic semiconductors.

b) What is diffusion current.

c) What is meant by ‘Depletion region’.

d) What is ‘‘Tunneling’’.

e) What is Avalanche break down.

f) Give principle of photo diode.

g) Define α, β and γ of BJT.

h) Why is FET called a unipolar device.

UNIT - I

2) a) Explain carrier concentration in an Intrinsic semi conductor.

b) Explain the motion of an electron in electric field.

OR

3) a) State and explain Hall effect.

b) Derive the Fermi-level equation for an Intrinsic semi conductor with energy band

diagram.

UNIT - II

4) a) Draw the V-I characteristics of P-N junction diode and explain.

b) Draw a neat figure of Tunnel diode and explain its operation using VI

characteristics.

OR

5) a) Explain the action of a Zener diode as voltage regulator.

b) Explain the principle of operation of LCD and give its applications.

UNIT - III

6) a) Explain the working of a transistor in common base configuration.

b) Write short notes on Thermal stability.

OR

7) a) Derive the current components of BJT.

b) What is the principle of photo transistor with a neat figure explain the operation of

a photo transistor.

UNIT - IV

8) a) With a neat figure explain the working of a Depletion MOSFET.

b) Draw characteristics of DIAC and explain its operation.

OR

9) a) Derive an expression for amplification factor in FET.

b) Draw the electrical equivalent circuit and explain the operation of UJT.

(DEE 214)




Paper - IV : Electrical & Electronics Engineering Materials


Answer Question No.1 is compulsory (15× 1=15)

Answer ONE question from each unit (4×15 = 60)

1) a) What is a Nano tube.

b) What is Isotope effect.

c) Draw B-H Curve.

d) Differentiate type I and type II super conductors.

e) Define electrical conductivity.

f) What do you mean by penetration depth.

g) Define ferro electricity.

h) Give the examples of dielectric materials.

i) What is an insulator.

j) Write any two applications of nano-structure materials.

k) Define Fermi level.

l) Explain domain theory.

m) Define Meissner effect.

n) Explain the fabrication of IC chip.

o) Explain the nano wires.

UNIT - I

2) a) Explain briefly the synthesis of nano structured materials.

b) Write short notes on carbon Nano tubes.

OR

3) a) Discuss about the properties of carbon Nano tubes.

b) Give the applications of Nano structured materials.

UNIT - II

4) a) Explain briefly about free electron theory of metals.

b) Explain the direct and indirect band gap semi conductors.

OR

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) Explain about Type I and Type II super conductors.

OR

7) What is Piezoelectricity. Explain by giving applications.

UNIT - IV

8) a) Briefly explain the classification of dielectrics.

b) Write short notes on electric polarization and polarisability.

OR

9) Explain dielectric materials and their applications.

(DEE 215)


[Examination at the end of Second Year]


Paper - V : Digital Electronics


Question No.1 is compulsory (15)

Answer one question from each unit (4×15 = 60)

1) a) Convert (745)8 to Binary.

b) (3789)10 = ( ) 16.

c) What is 2’s complement.

d) 11101 × 110.1.

e) What is Excess – 3 code.

f) What is an universal gate.

g) Draw a Two variable k-map.

h) Define SOP.

i) Draw the truth table of EX - NOR.

j) Draw the truth table of half adder.

k) What is a Decoder.

l) Define ‘‘Carry’’.

m) What is a Latch.

n) Draw a JK flip flop.

o) List the applications of shift registers.

UNIT - I

2) a) Using an example explain Excess – 3 code.

b) How do you implement a two level NAND gate.

OR

3) a) Write short notes on Alphanumeric codes.

b) Simplify using k- map. F (A, B, C, D) = π (3, 2, 6, 7, 9, 13) + d (1).

UNIT - II

4) a) With neat figure explain comparator.

b) Design a BCD to 7 segment decoder.

OR

5) a) Explain the working of a carry lood ahead adder.

b) Write short notes on MUX and DEMUX.

UNIT - III

6) a) Give the significance of state table and state diagrams.

b) Design a 4 bit counter using ‘T’ flip flops.

OR

7) a) Draw and explain Master – Slave flip flop.

b) Design a synchronous counter. Write down the steps involved.

UNIT - IV

8) a) Explain ECL logic.

b) Discuss the features of PLA.

OR

9) a) Compare RTL, DTL and TTL families.

b) Explain sequential programmable Devices.

(DEE 216)

B.Tech. DEGREE EXAMINATION, NOV./DEC. - 2014


ELECTRICALS AND ELECTRONICS Paper – VI: Electro Mechanics - I

Time : 3 Hours Maximum Marks : 75

Answer question No.1 is compulsory (15)

Answer one question from each unit (4x15=60)

1) a) Write any two properties of the rotating electric machines.

b) Define Co-energy.

c) What are the factors on which the torque developed in an electromechanical energy

conversion device depends upon?

d) What are the essential parts of an electrical generator?

e) What is statically induced emf?

f) What are the functions of a pole shoe?

g) Define commutator pitch.

h) Draw the circuit for a long shunt compound generator.

i) List any two necessary conditions for parallel operation of D.C generators.

j) Write any two applications of D.C series generators.

k) What is the purpose of providing compensating windings in a D.C generator.

l) How may the direction of rotation of a d.c motor be reversed?

m) Write the principle of a Rosenberg generator.

n) What is Amplidyne?

o) Why starter is required for a D.C motor?

UNIT-I

2) a) Derive the expression for the magnetic force developed in linear electromagnetic

system.

b) Derive an expression for the energy stored in a magnetic field system? OR

3) a) Describe the principle of energy conversion. From a consideration of the various

energies involved, develop the model of an electromechanical conversion device.

b) Derive the expression for force between the plates of a parallel plate capacitor using

energy and co-energy method.

UNIT-II

4) a) With neat diagram, give the constructional features of a d.c machine.

b) The armature of a 6 – pole d.c generator having 650 conductors generates an induced

emf of 536.25 volts when running at 300 rpm, flux per pole being 55 m wb. What is

the type of simplex winding used?

OR

5) a) Define reactance voltage. What is its effect? Why is it necessary to neutralize it?

How can it be done? Also discuss about the function of interpoles.

b) Explain the no load and load characteristics of a D.C shunt generator with the help of

diagrams.

UNIT-III

6) a) What is parallel operation? How do you connect the two shunt generators in parallel.

b) Draw and explain the speed–torque characteristics and torque characteristics of dc

shunt motor.

OR

7) a) Why is a starter necessary for a d.c motor? What is the difference between 3 point

and 4 point starters?

b) Explain the rheostatic and voltage control of a d.c series motor?

UNIT-IV

8) a) How can stray losses of machine be determined with the help of a retardation test

with and without moment of inertia.

b) In a retardation test on d.c separately excited motor the induced emf in the armature

falls from 220V to 190V in 30 seconds disconnecting the armature from the supply.

The same fall takes place in 20 seconds if immediately after disconnection armature

is connected to a resistance which takes 10A (average) during this fall. Find the stray

losses of motor.

OR

9) a) Derive the condition for maximum efficiency in a d.c machine.

b) Explain the principle of operation and working of Rosenberg generator.

E E E

(DEE 217)

B. Tech. DEGREE EXAMINATION, NOV./DEC. – 2014



Paper - VII : Environmental Studies



Answer ONE Question from each unit (4 ×15 = 60)

1) Write short notes on:

a) Air Pollution.

b) Soil Erosion.

c) Global Warming.

d) Chipko Movement

e) Environmental Protection Act

UNIT – I

2) a) Discuss the concept of an ecosystem.

b) Discuss about a desert ecosystem.

OR

3) a) Write about forest resources use and over exploitation.

b) Discuss environmental issues concerning extracting and using mineral resources.

UNIT – II

4) a) Explain in-situ and ex-situ conservation of biodiversity.

b) Give the biogeographical classification of India.

OR

5) a) Define nuclear hazard. Give cause, effects and control measures of nuclear hazards.

b) Discuss solid waste management of industrial waste.

UNIT – III

6) a) Discuss how rainwater can be harvested in rural and urban areas.

b) Write a detailed note on watershed management.

OR

7) What is water conservation? How can we conserve water in domestic areas, industrial

areas and agricultural areas? Explain.

UNIT – IV

8) a) Write the salient points of ‘Forest Conservation Act’.

b) What functions are performed by the Central and State Boards?

OR

9) Discuss the constitution, duties and powers of the wild life advisory board under the

provisions of the wild life protection act, 1972.

(DEE 221)



ELECTRICALS AND ELECTRONICS Paper – I: Mathematics - IV



Answer ONE question from each unit (4x15=60)

1) a) Define singular point.

b) When do you say that a function is harmonic.

c) Write the Cauchy-Riemann equations in polar form.

d) Define derivative of a function f(z).

e) Define zero’s of a function.

f) State Cauchy’s integral formula.

g) Define Taylor’s series.

h) Define Removable singularity.

i) Define Residue of f(z).

j) Determine the poles of 2 3

1( )

( 1)f z

z z=

−.

k) Write Legendre’s equation.

l) Write the expression for P3(x).

m) Write the orthogonal property of Legendre polynomial.

n) Write Bessel’s equation.

o) Define Gama function.

UNIT-I

2) a) Show that the function ( )f z xy= is not analytic at the origin even though C-R

equations are satisfied thereof.

b) Find the regular function whose imaginary part is e-x(x cosy +y siny).

OR

3) a) State and prove Cauchy – Riemann equations in Cartesian form.

b) Find the orthogonal trajectories of the family curves x3 – 3xy2 = C.

UNIT-II 4) a) Evaluate, using Cauchy’s integral formula:

2, where C is 1 3

( 1)

z

C

e dzz

z− =

+∫ .

b) State and prove Taylor’s series.

OR

5) a) Find the Laurent’s expansion of 7 2

(z)( 1) ( 2)

zf

z z z

−=+ −

in the region 1 < z + 1 < 3.

b) What type of singularity have the function 2

4(z)

( 1)

zef

z=

−.

UNIT-III

6) a) Determine the poles of the function 2

2(z)

( 1) ( 2)

zf

z z=

− + and the residue at each pole.

b) Solve in series the equation 2

22

(1 ) 4 0d y dy

x x ydx dx

− − + = .

OR

7) a) Show that 2 2

22 2

0

cos 2 2,( 1)

1 2 cos 1

d aa

a a a

π θ θ πθ

= <− + −∫ .

b) Solve the equation 2

24 2 0

d y dyx y

dx dx+ + = in power series.

UNIT-IV

8) a) Show that 0

1( ) cos( sin ) ,nJ x n x d

π

θ θ θπ

= −∫ n being an integer.

b) State and prove Rodrigue’s formula.

OR

9) a) Prove that 1

0

( ) ( ) 0, for ,n nx J x J x dxα β α β= ≠∫ where ,α β are the roots of Jn (x) = 0.

b) Express 4x3 – 2x2 – 3x + 8 in terms of Legendre polynomials.

E E E

(DEE 222)

B. Tech. DEGREE EXAMINATION, NOV./DEC. – 2014



Paper - II : Electronic Circuits-1



Answer ONE Question from each unit (4 ×15 = 60)

1) a) Define Ripple Factor.

b) What is a filter.

c) What is a clipper.

d) Define h-parameter.

e) Define clamping theorem.

f) What is a cascode connection.

g) What is a bypass capacitor.

h) Define µ, rd and gm of FET.

UNIT – I

2) a) Draw a Bridge rectifier and obtain an expression for ripple factor. [With inductor

filter].

b) Draw and explain the response of a RC low pass filter to pulse and ramp inputs.

OR

3) a) Draw a circuit of a clipping circuit with diodes and explain.

b) Give the significance of capacitor and inductor filters.

UNIT – II

4) a) Explain the operation of a cascade transistor configuration.

b) Justify the validity of approximate hybrid model.

OR

5) a) Draw a single state transistor amplifier circuit at low frequency and obtain Ai, Av

and Ri, Ro.

b) Determine the input impedance, output impedance, Voltage gain and

current gain of the CE amplifier using h-parameter for the transistor with hie =3.2kΩ

and hfe = 100 at Vcc =16V

UNIT – III

6) a) Explain the features of BJT at high frequencies.

b) Obtain the gain bandwidth product of a CE amplifier at high frequencies. Draw the

circuit of the same.

OR

7) a) Draw the hybrid Π model of BJT in CE connection and derive the equation for

current gain.

b) A BJT has gm =25m mhos, rb′e = 4.9k Ω , hie = 5kΩ rbb′ = 100 Ω, Cb′c =10PF,

Cb′e =60PF and hfe = 224 at 1KHz Calculate α and β cutoff frequencies and fT.

UNIT – IV

8) a) Draw bandpass of cascaded stages of CE amp and derive Av and Ai of the

same .

b) Explain the operation of FET amplifier in CS configurations at low

frequencies.

OR

9) a) Explain the effect of coupling capacitors on multistage amplifier.

b) Explain the FET amplifier at high frequencies in CD configuration.

(DEE 223)




Paper – III: Electromagnetic Field Theory Time : 3 Hours Maximum Marks : 75

Answer Question No.1 is compulsory (15)

Answer ONE question from each unit (4xxxx15=60)

1) a) Does the potential V=10xy satisfy Laplace equation?

b) When a dielectric material is said to be linear and homogeneous?

c) Express relaxation time?

d) Express emf produced by stationary loop in a time varying B field?

e) Express torque on a current loop with magnetic moment in a magnetic field?

f) State Ampere’s circuital law and obtain third Maxwell’s equation?

g) Explain the concept of Skin Depth?

h) Derive Poisson’s equation from Gauss law?

UNIT-I 2) a) Derive the electric flux density for a line charge using Coulomb’s law with relevant

coordinate system?

b) i) Prove . D = v?

ii) A point charge 100 pC is located at (4, 1, -3) while the x–axis carries charge 2

nC/m. If the plane z =3 also carries 5 nC/m2. Find E at (1,1,1)?

OR

3) a) Derive the expression for a capacitance of two wire transmission line with neat

schematic?

b) Define electric dipole? Derive expression for electric field due to dipole?

UNIT-II 4) a) Derive H for infinite sheet of current using Ampere’s circuital law?

b) A circular loop located on x2 + y2 = 9, z = 0 carries a direct current of 10A along aø.

Determine H at (0, 0, 4) and (0, 0, -4)?

OR

5) a) Derive an expression for energy density in magnetic field?

b) Explain the different forces due to magnetic fields?

UNIT-III

6) a) Derive law of refraction of the magnetic field at a boundary form Maxwell’s

equations?

b) A current element of length 2 cm is located at the origin in free space and carries

current 12mA along az, A filamentary current of 15 az A is located along x =3, y=4.

Find the force on a current filament?

OR

7) a) Derive equation of continuity for time-varying fields? Explain about the

inconsistency in Ampere’s circuital law?

b) Determine i) Jd and ii) H, for given E =20 cos (t -50z) ay V/m in free space?

UNIT-IV

8) a) Derive the expressions of E & H of plane waves in a lossy medium?

b) In a medium E = 16e -0.05x sin (2x108t – 2x)az V/m. Find

i) the propagation constant ii) the wavelength iii) the speed of the wave

iv) the skin depth?

OR

9) a) Define power? Explain and derive poynting vector, poynting theorem and average

power?

b) In a nonmagnetic medium E = 4 sin (2 + 107 t – 0.8x)az V/m. Find

i) r,

ii) time average power carried out by the wave.

iii) the total power crossing 100cm2 of plane 2x + y = 5?

E E E

(DEE 224)


(Examination at the end of the Second Year)

ELECTRICALS AND ELECTRONICS Paper – IV: Network Analysis - II



Answer any one question from each unit (4x15=60)

1) a) Define graph.

b) What is a port?

c) What is meant by duality?

d) Define driving point impedance and admittance.

e) What are the applications of hybrid parameters?

f) What is the condition for reciprocity and symmetry?

g) Under what conditions pass band exists for constant k – band pass filter.

h) What is the purpose of a filter network?

i) Mention any two advantages of Laplace transformation.

j) What is the effect of critical co-efficient of coupling?

k) In star connection. What is the relationship between line voltage and phase voltage?

l) What is the expression for power factor in two wattmeter method of power

measurement?

m) Mention the application of Laplace transform.

n) Define a two – port network.

o) What is meant by All – pass filter?

UNIT-I

2) a) How tie – set matrix constructed? Explain with an example.

b) Determine the mesh current I1 in the circuit shown in figure 1.

OR

3) a) Obtain short circuit admittance parameters of a two–port network and draw its

equivalent circuit.

b) The hybrid parameters of a two port network shown in fig 2 are h11 = 1kΩ , h12

=0,003, h21 = 100, h22 = 50µ mho. Find V2 and Z parameters of the network.

UNIT-II 4) a) Obtain the step response of a parallel R L C circuit using Laplace transform method.

b) Determine voltage for the circuit shown in fig 4. c(0) = 4V, i(0) = 2A .

OR

5) a) Explain the network functions for two port networks.

b) Determine the transfer functions G21(s), Y21(s) and L21(s) for the network shown in

figure 5.

UNIT-III

6) a) Explain dot convention.

b) Derive the expression for critical valve of mutual inductance in double tuned coupled

circuits

OR

7) a) Explain m – derived - section filter with necessary equations.

b) Design constant K low pass T and section filters to be terminated in 600Ω, having

cut–off frequency 3 kHz. Determine (i) the frequency at which the filters offer

attenuation of 17.372 dB.

UNIT-IV

8) a) Explain with relevant diagrams the measurement of 3ø power with 2 wattmeter

method.

b) If the phase voltage of a 3–phase star connected generator is 200V, what will be the

line voltages

i) when the phases are connected correctly and

ii) when the connections to one of the phases are reversed?

OR

9) a) Explain the analysis of 3 – phase balanced circuits.

b) Two wattmeters connected to measure the input to a balanced three–phase circuit

indicate 2500W and 500W respectively. Find the power factor of the circuit when

both the readings are positive.

E E E

(DEE 225)



ELECTRICALS AND ELECTRONICS Paper – V: Prime Movers and Pumps



Answer one question from each unit (4x15=60)

1) a) Define fluids?

b) Define compressibility?

c) How pumps are classified?

d) Define centrifugal pump?

e) Define Reaction turbine?

f) What does velocity triangles indicates?

g) Mention the type of characteristic curves for turbines.

h) Define CP? Mention SI units.

i) Draw the P-V & T-S diagram for the Diesel cycle?

j) What is PMM-II?

k) Mention any two methods to improve the efficiency of a gas turbine.

l) Differentiative between closed and open cycle gas turbine.

m) Write down the Application of gas turbine.

n) What are the performance parameters of I.C. engines.

o) What are the types of steam turbines.

UNIT-I

2) a) What is the significance of viscosity and surface tension in fluid flow phenomenon?

Explain in detail with required equations.

b) A piston of 7.95 cm diameter and 30 cm long works in a cylinder of 8.0 cm diameter.

The annular space of the piston is filled with an oil of viscosity 2 poise. If an axial

load of 10 N is applied to the piston, calculate the speed of movement of the piston.

OR

3) a) What do you understand by characteristic curves of a pump? What is the significance

of the characteristic curves?

b) Define cavitation. What are the effects of cavitation.

UNIT-II

4) A pelton wheel is to be designed for a head of 60 m when running at 200 rpm. The pelton

wheel develops 95.6475 kw shaft power. The velocity of the buckets = 0.45 times the

velocity of the get, overall efficiency = 0.85 and co-efficient of the velocity is equal to

0.98.

OR

5) a) Differentiate between kapplan and propeller turbine.

b) Define the terms:

i) Hydraulic efficiency

ii) Mechanical efficiency

iii) Overall efficiency of a turbine.

UNIT-III

6) a) What are the advantages associated with diesel cycle as compared to the Otto cycle.

b) A gas engine working on Otto cycle has a cylinder of diameter 220 mm and stroke

300 mm. The clearance volume is 1800 cc. Find the air – standard efficiency.

Assume CP = 1.004 KJ/Kg. K and Cv = 0.718 KJ/Kg.K for air.

OR

7) Explain the Carnot engine cycle and its efficiency?

UNIT-IV

8) a) Explain the working principle of two stroke Otto cycle engine with neat sketch.

b) Differentiate between S.I. and C.I. engines .

OR

9) a) Discuss briefly the methods employed for improvement of thermal efficiency of open

cycle gas turbine.

b) What do you mean by steam turbine? Explain its function.

E E E

(DEE226)

B.Tech. DEGREE EXAMINATION, NOV./ DEC. 2014



Paper - VI : Electro Mechanics-II


Question no.1 is compulsory (1×15 = 15)

Answer one question from each unit (4× 15=60)

1) a) What is a transformer?

b) List out any two advantages of a spiral core transformer.

c) What is voltage transformation ratio?

d) What are the two components of a noload primary current?

e) Draw the vector diagram for a transformer on capacitive load.

f) Write the expression for total effective resistance of a transformer when referred to

primary.

g) Write the expression for exciting susceptance in a transformer.

h) What is voltage regulation?

i) Draw the circuit diagram of a step up auto transformer.

j) Is copper loss affected by power factor? How it varies?

k) How are eddy current losses minimised?

l) Define slip.

m) When is open – Delta connection of transformer employed?

n) What is crawling?

o) Write any two methods for starting squirrel cage induction motors.

UNIT - I

2) a) Derive the emf equation of a transformer.

b) A single phase transformer has 500 turns in the primary and 1200 turns in the

secondary. The cross – sectional area of the core is 80 sq.cm. If the primary winding

is connected to a 50 Hz supply at 500v, calculate (i) peak flux density and (ii) voltage

induced in the secondary.

OR

3) a) What is all-day efficiency? Derive the expression for all-day efficiency & regulation.

b) A 5- KVA, 2300/ 230V, 50Hz transformer was tested for the iron losses with normal

excitation and copper losses at full load and these were found to be 40w and 112w

respectively. Calculate the efficiencies of transformer at 0.8 power factor for the

following KVA outputs: 1.25, 2.5, 3.75, 5.0, 6.25, 7.5 KVA

UNIT - II

4) a) Explain how 3- phase to two phase conversion is done in transformer.

b) What are the necessary conditions for parallel operation of 3-phase transformers.

OR

5) a) Derive the expressions for load shared by transformers with unequal voltage ratios.

b) Two single- phase transformers with equal turns have impedance of (0.5+j3) ohm &

(0.6+j10) ohm with respect to secondary. If they operate in parallel, determine how

they share a total load of 100KW at 0.8 PF lagging?

UNIT - III

6) a) Discuss the constructional features and principle of operation of slip ring

3-phase induction motor.

b) Explain how a rotating magnetic field is produced in a three phase supply with the

help of neat diagrams.

OR

7) a) Derive the expressions for starting, rotor and breakdown torques in an induction

motor.

b) A 12- pole, 3- phase, 600v, 50Hz, star connected induction motor has rotor resistance

and stand still reactance of 0.03 and 0.5 ohm per phase respectively. Calculate

(i) speed of maximum torque

(ii) ratio of full load torque to maximum torque, if full load speed is 495 rpm.

UNIT - IV

8) a) Explain the double field revolving theory in a single phase induction motor.

b) Explain the methods for making single phase induction motor self starting.

OR 9) a) Explain Crawling and magnetic locking effects in induction motors.

b) A double case induction motor has the following equivalent circuit parameter, all of

which are phase values referred to primary:

Primary 1 1R 1 &X 3= Ω = Ω

outer case 1

0R 3= Ω and 1

0X 1= Ω

Inner case 1

iR 0.6= Ω and 1

iX 5= Ω

The primary is delta connected and supplied from 440V. Calculate the starting torque

and torque when running at a slip of 4%

The magnetising current may be neglected.

ii yr -ee - anucde.info - i 2) a) obtain the expressions for star-delta equivalence of resistive...

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