(dee 311) - anucde · (dee 311) b.tech. degree ... what are the advantages and disadvantages ......

(DEE 311)

B.Tech. DEGREE EXAMINATION, DECEMBER 2010. (Examination at the end of Third Year)

Electricals and Electronics Paper I — LINEAR CONTROL SYSTEMS

Time : Three hours Maximum : 75 marks

Answer ALL questions. Answer Q. No. 1 Compulsory.

All questions carry equal marks.

1. (a) Why compensation is necessary for feedback control system?

(b) What is the effect of adding a pole to open loop transfer function of a system?

(c) How the root loci are modified when a pole is added to open loop transfer function of the system?

(d) What are the advantages and disadvantages in frequency domain design?

(e) What is lag compensation? (f) Write the transfer function of lag

compensation. (g) Write the two equations that relates and

m of lag compensator. (h) Write the transfer function of lead

compensation and draw its pole-zero plot. (i) What is p-controller and its characteristics?

(j) What is the advantage of Nyquist plot?

(DEE 311) 2

(k) Write the transfer function of PI controller.

(l) What are the applications of bode plot?

(m) When lag/lead/lag-lead compensation is employed?

(n) What is series compensation?

UNIT I

2. (a) The state model of a linear time invariant system is given by tuBtAXtX ' tDutCXtY . Obtain the expression for

transfer function of the system.

(b) Draw the signal flow graph of the system described by the state model.

uXXXaa

XXX

001

0101010

3

2

121

3

2

1

and 3XY .

Or

3. (a) List the advantages and utilities of the state diagram.

(b) A system is represented by the following set of equations. Construct the signal flow graph and find the closed loop transfer function

utxxqxutxx 2211131 ,

utxqx 1122 .

(DEE 311) 3

UNIT II

4. (a) The characteristic equation of a feedback control system is

S4 + 20 KS3 + 5S2+10S+15 = 0

find range of K for which system is stable.

(b) The closed loop transfer function of a units feedback control system is given by

54SS

10tRtC

2 . Determine damping ratio

and expression for error response.

Or

5. (a) Using Routh’s stability critain ascertain stability for S6 + 2 S5+8 S4 +12 S3 + 20 S2 + 16 S + 16 =0.

(b) List the advantages of Roult-Hurwitz criterion.

UNIT III

6. (a) Give the general rules and procedure for constructing a root - Loci.

(b) Construct Nyquist plot for a feedback control system whose open-loop transfer function is

given by G(S) H(S) = S1S5

. Comment on

the stability of open-loop and closed system.

Or

(DEE 311) 4

7. (a) Sketch the bode plots and determine the again crossover and phase crossover frequencies

G(S) = S0.1H0.5SSS10

.

(b) Explain the salient features of Nichols chart.

UNIT IV

8. Consider a linear system described by the transfer

function 2S1SS

10SuSY

. Design a feedback

controller with a state feedback so that the closed loop poles are placed at –, –1 j1.

Or

9. A linear time invariant system is described by the following state model.

6116100010

3

2

1

XXX

uXXX

200

3

2

1

and

3

2

1

001XXX

Y .

Transform this model into a canonical state model.

—————

(DEE 312)

B.Tech. DEGREE EXAMINATION, DECEMBER 2010.

(Examination at the end of Third Year)

Electricals and Electronics

Paper II — ELECTRONIC CIRCUITS — II


Answer ALL questions. All questions carry equal marks.

1. (a) Give the efficiency of all power amplifier.

(b) What do you mean by push-pull amplifier?

(c) What is a chopper amplifier?

(d) Define quality factor and what is its ideal value.

(e) Define figure of merit.

(f) What is the characteristic feature of a tuned circuit?

(g) List the advantages of tuned amplifier.

(h) What do you mean by feed back?

(i) Define loop gain.

(j) What is meant by gain stability?

(DEE 312) 2

(k) What do you mean by an oscillator?

(l) Give the equation for frequency of oscillations in an oscillator.

(m) Define ripple rejection.

(n) Give the applications of sweep circuits.

(o) Explain the functions of multivibrator.

UNIT I

2. (a) Draw the circuit of a class A large signal amplifier and explain its operation.

(b) Discuss the temperature effect on the function of power amplifier.

Or

3. (a) Discuss the operation of a DC amplifier.

(b) Draw the circuit of a push-pull amplifier without transformer and explain its operation.

UNIT II

4. (a) Compare the negative feed back and positive feed back.

(b) Discuss different topologies in feed back amplifiers.

Or

(DEE 312) 3

5. (a) Draw the circuit diagram of a Wein-Bridge oscillator and briefly explain the operation.

(b) Explain the operation of a crystal oscillator.

UNIT III

6. (a) Derive an expression for the resonance frequency of a parallel circuit.

(b) Explain the operation of a class C amplifier.

Or

7. (a) Compare the three types of multivibrator.

(b) With a neat circuit explain the principle of operation of a Schmitt trigger.

UNIT IV

8. (a) Explain about load and line regulation.

(b) Explain the salient features of UPS.

Or

9. (a) Explain the operation of current sweep circuits.

(b) Explain how linearity correction is obtained and what are its advantages.

————————

(DEE 313)


(Examination at the end of Third Year Third Semester)


Paper III — GENERATION OF ELECTRICAL POWER



Answer Question No. 1 compulsorily. (1 15 = 15)

Answer ONE question from each Unit. (4 15 = 60)

1. (a) What are the different types of power stations?

(b) On what factors size of generators units depend?

(c) What is the function of economizer?

(d) List any one safety precaution for Nuclear power station.

(e) What are the different components in Nuclear power station?

(DEE 313) 2

(f) What is the difference between fission and fusion?

(g) Write the expression for the reaction in Nuclear reactor.

(h) Write the expression for thermal efficiency in a gas plant.

(i) What is a solar cell?

(j) List out the different types of wind generator.

(k) Draw fuel cell diagram.

(l) What is load factor?

(m) What is the maximum value of diversity factor?

(n) Classify Tariffs.

(o) What are causes for low power factor?

UNIT I

2. (a) Discuss load duration curve in detail.

(b) Explain fire tube boiler used in thermal power station.

Or

(DEE 313) 3

3. (a) What are the various factors that govern the location of a thermal power station?

(b) Briefly explain the working of a thermal power station with the help of neat diagram.

UNIT II

4. (a) How do you classify hydroelectric plants?

(b) Discuss about the hydroelectric plants with the help of neat diagram in detail and also discuss function of each component.

Or

5. (a) What is a moderator? Name some important moderators and discuss their advantages and disadvantages.

(b) Discuss the basic factors in designing of reactors.

UNIT III

6. (a) Briefly explain the open cycle and closed cycle gas turbine plants.

(b) Discuss solar thermal plant in detail with the help of neat diagram.

Or

(DEE 313) 4

7. (a) What are different types of wind generators? Discuss in detail.

(b) Explain briefly the fuel cell with the help of neat diagram.

UNIT IV

8. (a) Discuss the factors which affect the cost of generation and explain their division into fixed, semifixed and running costs.

(b) The maximum demand of a pwoer station is 150 MW. If the annual load factor is 45%, calculate the total energy generated in an year.

Or

9. (a) Discuss the different types of tariffs in detail.

(b) A consumer has a maximum demand of 200 kW at 40% load factor. If the tariff is Rs. 100 per kWH. Find the over all cost per kWH.

–––––––––––––––

(DEE 314)


(Examination at the end of Third Year Third Semester)


Paper IV — ELECTRICAL MEASUREMENTS


Answer ALL questions. Answer Q.No. 1 Compulsory.


1. (a) What is swamping resistance?

(b) List any two advantages of PMMC instruments.

(c) Why eddy current damping can not be used for Electrodynamometer type instrument?

(d) How do you measure the power in a 3- 4 – wire circuit?

(e) How do you reduce the creeping error in an energymeter?

(f) What is the purpose of a synchromoscope?

(g) Which bridge is used for measuring frequency?

(h) Which bridge is used for measuring low resistance?

(DEE 314) 2

(i) Write the expressions for capacitance and resistance in Schering’s bridge.

(j) What is the purpose of Ballistic Tests?

(k) Why is Epstein square used?

(l) List any two disadvantages of LCD.

(m) What is the frequency range in chopped operating mode?

(n) What is the range of the resistance in Thermistor?

(o) What is peizoresistive effect?

UNIT I

2. (a) Explain the working and constructional details of attraction type moving iron instruments.

(b) List out the advantages, disadvantages and errors of a PMMC instrument.

Or

3. (a) Explain the principle of operation and construction of electrodynamometer type instrument.

(b) What is synchronizing? Describe under what condition a 3- alternator can by

synchronized to 3- busbars.

(DEE 314) 3

UNIT II

4. (a) Explain the advantages and disadvantages of Instrument transformers.

(b) A current transformer has a single-tern primary and 200 turns secondary coddling. The secondary winding supplies a current of 5A to non inductive burden of 1 resistance. The requisite flux is set up in the core by an mmf of 80A. The frequency is 50Hz and the net cross-section of core is 1000mm2. Calculate the ratio and phase angle of the transformer. Neglect the effects of magnetic

leakage, iron losses and RI2 losses.

Or

5. (a) Describe the working of carry-foster slide-wire bridge.

(b) A 1000Hz bridge has the following constants arm ab, 1000R1 in parallel with

F1 5.0C arm bc, 10002R3 in series

with F3 5.0C arm cd mtt30L4 in series

with 200R4 . Find the constants of arm

da to balance to bridge Express the result as a pure resistance L or capacitance C.

(DEE 314) 4

UNIT III

6. (a) Explain the method of reversals for determination of B–H loop.

(b) Explain the method of measuring core loses by using Epstein’s square method.

Or

7. (a) How do you measure leakage factor using flux meter?

(b) What are the different methods adopted for measuring permeability.

UNIT IV

8. What is an LED? Explain the principle of operation of LED? List out the advantages and disadvantages.

Or

9. Describe the construction and working of

(a) thumococouple.

(b) strain guage.

——————

(DEE 315)




Paper V — TRANSMISSION AND DISTRIBUTION


Answer Question No. 1 compulsorily.

(1 15 = 15)

Answer ONE question from each Unit.

(4 15 = 60)

1. (a) Write the expression for GMR in bundled conductors.

(b) What is transposition of overhead lines?

(c) What is the purpose of self GMD in overhead lines?

(d) Why are bundled conductors used in EHV lines?

(e) What are the methods adopted to obtain the performance of medium transmission line?

(f) Write the expression for % regulation.

(g) What is corona?

(h) Which materials are generally used for conductors?

(i) Write the sag expression when supports are at equal level.

(j) 3 , 4 wire Ac system of distribution is used for why type of loads?

(k) What is the purpose of circuit breaks?

(l) What are the different types of insulations?

(m) What is the purpose of guard ring?

(n) What is material used for armouring on the cable?

(o) Why are intersheaths used in the cables?

(DEE 315) 2

UNIT I

2. (a) Derive expression for inductance of a 3 unsymmetrical lines.

(b) In a 1 double circuit transmission lines as shown in figure, conductors a and a are

parallel to each other in one conductor, while conductors b and b are parallel to each other in the other conductor. Each conductor is 2 cm. Determine the loop inductance of the line per kilometer assuming 2 parallel conductors equally share the current.

Or

3. (a) Derive the expression for capacitance of a 3 line by considering the effect of earth.

(b) Explain inductive interference.

UNIT II

4. (a) Derive the expressions for A, B, C and D constants for nominal- circuit of a medium transmission line.

(b) A 3 overhead line conductor has the following data :

Resistance = 13 /phase, Inductive reactance = 35 /phase, Capacitive susceptance = 0.0004 whos/phase. The receiving end load is 12500 KVA at 66 KV, 0.85 pf lagging. Determine the regulation and efficiency of transmission line using nominal-T method.

Or

5. (a) Describe the phenomenon of corona. Explain the various factors affecting corona.

(b) Derive the expression for sag and tension when supports are at unequal heights.

UNIT III

6. (a) Derive the expression for voltage regulation in an uniformly distributed loads on feeders.

(b) A uniformly-loaded DC 2-wire distribution 500 m long is loaded at 3 A/m run. Resistance of the loop is 0.01 /km. Determine the maximum voltage drop if the distributed is fed at both ends at same voltage.

Or

7. (a) Explain the single bus bar system with sectionalization and list their merits and demerits.

(b) What is a lightening arrestor? Explain in detail.

UNIT IV

(DEE 315) 3

8. (a) What is an insulator? Where and why insulators are used power systems? Explain pin type insulators in detail.

(b) A string insulator consists of five units. The capacitance from each joint to tower is 12% of capacitance of each unit. Determine the voltage across the lowest unit as percentage of total voltage. Also calculate string efficiency.

Or

9. (a) Derive expression for capacitance of a 3 core cable.

(b) A 3-core, 3 metal sheathed cable has following data :

Capacitance between three cores bunched together and earthed sheath is 6.6 F. Capacitance between the conductor and other two connected together to the sheath is 4 F. Determine the capacitance to neutral and total charging current drawn by cable, when the cable is connected to a 66 KV, 50 Hz, 3 supply.

———————–––

(DEE 316)




Paper VI — ELECTRO MECHANICS — III


Answer question No. 1 compulsorily.



1. Answer the following.

(a) What is meant by Distribution factor?

(b) Name the type of alternators depending on the type of prime mover.

(c) Why alternators are rated in KVA rather than in KW?

(d) Name the tests by which synchronous reactance of a synchronous machine in determined.

(e) Why two reaction theory is applied only to salient pole machines?

(f) Define Infinite bus bar?

(g) State the use of slip-test of an alternator.

(h) What is meant by synchronizing of alternators?

(i) Specify whether a synchronous motor is self-starting or Not?

(j) Define excitation circle.

(k) What is the purpose of damper winding?

(l) What are the advantages of synchronous motor?

(m) Why should a motor be named as universal motor?

(n) What are the two types of stepper motor?

(o) Why the reluctance motor has low efficiency.

UNIT I

2. (a) Describe the constructional details of a cylindrical motor and salient pole alternators.(7)

(b) A 500 V, 50 KVA, 1-phase alternator has an effective resistance of 0.2 . A field current of 10 A produces an armature current of 200 A on short circuit and an emt of 450 V on open circuit. Calculate

(i) Synchronous Impedance and reactance.

(ii) Full load Regulation with 0.8 p.f lagging. (8)

Or

(DEE 316) 2

3. (a) A 3-phase, 4 pole star connected alternator has 72 slots with two conductors per slot. The pitch of the coil has 4 slots less than the pole-pitch. The flux per pole is 0.163 wb. Calculate the no-load terminal voltage, of the speed of the alternator is 1500 rpm. (8)

(b) What is Armature reaction? Explain the effect of Armature reaction on terminal voltage with relevant phasor diagrams at

(i) UPF

(ii) Purely lagging p.f.

(iii) Purely leading p.f. (7)

UNIT II

4. (a) Describe the slip test method for the measurement of Xd and Xq of synchronous machine. (7)

(b) A 3-phase synchronous generator has per phase a direct axis synchronous reactance of 1.0 P.V. and a quadrature axis synchronous reactance of 0.65 P.V. Draw a phasor diagram of the machine when operating at full load at a p.f. of 0.8 lagging and estimate form these

(i) The load angle

(ii) P.V. no-load emf. (8)

Or

5. (a) What are the various methods of synchronizing alternators? Explain them briefly with neat diagrams. (7)

(b) A 3 mva, 6-pole alternator runs at 1000 rpm on 3.3 kv busbars. The synchronous reactance is 25%. Calculate the synchronizing power and torque per mechanical degree of displacement when the alternator is supplying full load at 0.8 p.f. lagging. (8)

UNIT III

6. (a) Explain the principle of operation of a 3-phase synchronous motor. (8)

(b) What is synchronous condenser? Explain with the help of phasor diagram how synchronous condenser can be used to improve the power factor. (7)

Or

7. (a) Explain the operation of a synchronous motor with neat phasor diagrams under

(i) Constant load, Varying excitation.

(ii) Constant excitation, varying Load. (8)

(b) Write short notes on the following

(i) functions of damper winding

(ii) V curves of synchronous motor. (7)

(DEE 316) 3

UNIT IV

8. (a) Explain the construction and principle of working of universal motor. (8)

(b) Explain the constructional features and working principle of variable reluctance motor. (7)

Or

9. (a) Describe the construction, working principle of variable stepper motor. (8)

(b) Explain the principle of operation and characteristics of hysteresis motor. (7)

——————

(DEE 321)




Paper I — LINEAR IC’s AND APPLICATIONS


Answer Question No. 1 Compulsorily.


1. (a) Define lock range.

(b) What is the difference between active filters and passive filters?

(c) What is a window detector?

(d) Draw the circuit diagram of a scalar.

(e) What is an Op amp?

(f) Why an active load is used in Op amp.

(g) Define common mode rejection ratio.

(h) What frequencies does a state variable filter allow?

(DEE 321) 2

(i) What are the applications of 555 timer?

(j) What are the uses of active filters?

(k) Give the applications of comparators.

(l) Draw the circuit of a Op amp voltage follower.

(m) Define slew rate.

(n) What are the limitations of Op amp

comparators?

(o) Write the functions of OP amplifier.

UNIT I

2. (a) Define frequency compensation. Suggest one

method for external frequency compensation.

(b) Show that an Op amp can be used as an

instrumentation amplifier.

Or

3. (a) Explain the principle of operation of a

precision rectifier.

(b) Draw a circuit to show that Op amp can be

used to convert current to voltage.

(DEE 321) 3

UNIT II

4. (a) Draw the I/P and O/P waveforms of a triangular waveform generator and explain its operation.

(b) Draw the circuit and explain the operation of a Wein bridge oscillator.

Or

5. (a) Draw the circuit of a Schmitt trigger and draw the transfer characteristics also explain the operation of same.

(b) Discuss the working of a Quadrature oscillator.

UNIT III

6. (a) Draw a positive clipper circuit and explain its operation with input and output waveforms.

(b) Explain the working of a R-2R ladder D/A converter.

Or

7. (a) Explain the principle of operation of a successive approximation A/D converter.

(b) Draw the circuit of a clamper and explain its operation.

(DEE 321) 4

UNIT IV

8. (a) Show that a 555 timer can work as a monostable multivibrator.

(b) Discuss 565 PLL applications.

Or

9. (a) Discuss the operation of sallen key HP filters.

(b) Discuss the salient features of All pass filters.

———————

(DEE 322)




Paper II — MICROPROCESSORS AND INTERFACING




1. (a) What is the purpose of RESET instruction?

(b) From which address the 8086 starts execution after reset.

(c) What are the address and data lines in 8086?

(d) What is the difference between the respective shift and rotate instructions?

(e) What is ALP?

(f) What is REP prefix, what is its use?

(DEE 322) 2

(g) What are the pseudo - ops?

(h) What is the function 4 CH under INT 21 H?

(i) What is a linker?

(j) What are the DOS function call?

(k) What is meant by dynamic RAM?

(l) What does the signal description RXC of

8251 perform?

(m) What are the different methods of data communication in 8251 VSART?

(n) What are the functional type of control words of 8251 A?

(o) What is set register?

UNIT I

2. (a) What do you mean by pipelined architecture? How is it implemented in 8086?

(b) Explain the concept of segmented memory and what are its advantages.

Or

3. (a) What are the different addressing modes supported by 8086? Explain each of them with an example.

(b) What are the assembler directives and pseudo-ops?

(DEE 322) 3

UNIT II

4. (a) Describe the procedure for coding the inter segment jump and call instruction.

(b) Write an ALP to change an already available

ascending order byte string to decending

order.

Or

5. (a) Write an ALP to convert decimal number to

binary equivalent.

(b) Explain various DEBUG commands, for

trouble shooting executable program.

UNIT III

6. (a) Explain the interrupt structure of 8086.

(b) Explain the term ‘‘Nested interrupt’’.

Or

7. (a) Explain the control word format of 8255 in

I/O and BSR mode.

(b) Explain the concept of Handshake of

input/output.

(DEE 322) 4

UNIT IV

8. (a) Draw and discuss briefly the internal

architecture of 8253.

(b) Explain the difference between 8259 and 8259 A.

Or

9. (a) Explain the mode set register of 8279.

(b) Explain RS 232 C serial data standard.

—————————

(DEE 323)




Paper III — DIGITAL SIGNAL PROCESSING


Answer question No.1 compulsorily. (1 15 = 15)


1. (a) What is meant by linear property of DTFT.

(b) Define Fourier transform of a sequence.

(c) What is the scaling property of the Z-transform

(d) State the initial value theorem.

(e) List four properties of DFT.

(f) When is the DFT X (k) of a sequence )(nx is imaginary?

(g) What is the circular frequency shifting property of DFT?

(h) What is meant by periodic convolution?

(i) Give two properties of Butter worth low-pass filter.

(DEE 323) 2

(j) What do you understand by backward difference?

(k) What is the main advantage of direct-form II realization when compared to direct – form I realization?

(l) What are the different types of filters based on impulse response?

(m) What is the most general form of IIR filter?

(n) What are the well-known methods for designing FIR filters with linear phase.

(o) Define Discrete Fourier series.

UNIT I

2. (a) List the properties of DTFT.

(b) Consider rectangular pulse

1

1)(

NnO

NnAnx find )( jweX .

Or

3. (a) Find the z-transform of )()cos()( nunrnx n .

(b) Find the inverse z-transform of

3223

)( 2

2

zzzz

ZX using long division

method for ROC 1z .

(DEE 323) 3

UNIT II

4. Find the DFT of a sequence 0,0,1,1)( nx and

find the IDFT of 0,1,0,1)( ky .

Or

5. (a) Find the DFT of the causal 3-sample averages.

(b) Draw the flow graph of 8-point DIT-FFT.

UNIT III

6. (a) What are the steps involved in the design of digital filters from analog filter?

(b) Design a chebyshev filter with a maximum passband attenuation of 2.5 dB at

20 p rad/sec and the stop band

attenuation of 30 dB at 50s rad/sec.

Or

7. (a) Compare butterworth and Chebyschov filter.

(b) An analog filter has a transfer function

10710

)( 2

ssSH . Design a digital filter

equivalent to this using impulse invariant method.

(DEE 323) 4

UNIT IV

8. (a) Compare Hamming window and Kaiser windows. List few advantages of Kaiser windows.

(b) Design a filter with

wweeHd wjjw

4044( 3)

Using a Hanning window with N = 7.

Or

9. (a) Obtain the cascade realization of system function )21()( 21 zzzH

)1( 21 zz .

(b) What is the basis for Fourier series method of design? Why truncation is necessary.

——————

(DEE 324)




Paper IV — POWER ELECTRONICS




1. (a) What are the three terminals of a MOSFET?

(b) Draw the circuit symbol of IGBT.

(c) What is SCR?

(d) Mention any protection method for SCR.

(e) What is a cycloconverter?

(f) What are the different modes of operation of 3 character?

(g) What is the difference between SCR and TRIAC?

(h) What is natural commutation?

(DEE 324) 2

(i) What are the different type of cycloconvention?

(j) What is a phase controlled rectifier?

(k) What is the principle of operation of dual converter?

(l) How does a speed control in DC motors can be achieved?

(m) What is voltage source inverter?

(n) List various turn off methods for SCR.

(o) What is digital firing scheme?

UNIT I

2. (a) Discuss briefly about SCR turn on and turn off methods.

(b) Explain briefly about MOSFET by showing its characteristics.

Or

3. (a) Discuss briefly about the characteristics of IGBT with neat diagrams.

(b) Discuss in detail about the working of UJT.

(DEE 324) 3

UNIT II

4. (a) Explain the operation of single phase dual converter in four quadrants.

(b) Explain the operation of 3 dual converter

with R load.

Or

5. (a) Explain briefly about the pulse width modulation control used for power factor correction.

(b) Discuss in detail about 1 halfwave

converter.

UNIT III

6. Explain the operation of MC Murray Bedford half bridge inverter with neat circuit diagram.

Or

7. (a) Explain the operation of current source inverter.

(b) Explain in detail about pulse width modulated inverter.

UNIT IV

(DEE 324) 4

8. Bring out the analysis of step down chopper with neat waveforms.

Or

9. (a) Explain the principle of operation of 1 cycloconverters.

(b) Mention the applications of 1 cycloconverter.

———————–––

(DEE 325)




Paper V — UTILIZATION OF ELECTRICAL POWER




1. (a) What is plugging?

(b) Draw the equivalent circuit.

(c) What is plugging?

(d) Draw the speed-time curve.

(e) What is the advantage of rheostatic braking?

(f) Define specific energy output.

(g) What is the machine employed for electric traction?

(h) What is the purpose of arc furnace?

(i) What are the different types of welding?

(j) What is the principle of operation of arc lamp?

(DEE 325) 2

(k) Define polar curve.

(l) Define solid angle.

(m) What is the purpose of flywheel?

(n) List the characteristics of carbon welding.

(o) List out the types of lamps.

UNIT I

2. (a) Discuss briefly about heating and cooling of motors.

(b) Draw the equivalent circuit and explain briefly. Describe Torque method.

Or

3. (a) Describe the plugging applied to DC motors.

(b) Explain briefly how the motor capacity is selected for continuous duty.

UNIT II

4. (a) What are the different types of electric braking are employed for the motors?

(b) Write a short notes on reversal of shunt motors.

Or

5. (a) Discuss about systems of electric traction.

(b) Write short notes on mechanics of train movement.

(DEE 325) 3

UNIT III

6. (a) Discuss briefly about working of any one induction furnace.

(b) What are the elementary principles for transfer of heat?

Or

7. (a) Explain about different types of welding.

(b) Discuss about the characteristics of metallic arc welding.

UNIT IV

8. Write short notes on :

(a) Polar curves

(b) Ultraviolet lamps.

Or

9. (a) Discuss about effect of voltage variation.

(b) Explain briefly about polar curves. Also discuss about factory lighting.

———————

(DEE 326)



Electrical and Electronics

Paper VI — SWITCH GEAR AND PROTECTION


Answer question No. 1 compulsorily.


All questions carry equal marks. 1. (a) What is a Relay? (b) What are the different zones of protection? (c) Define restricting voltage. (d) What is difference in principle of operation of

directional and non directional relays? (e) What is static relay? (f) Which type of protection is good for feeders? (g) Define soil resistivity. (h) What is the principle of operation of oil filled

circuit breaker? (i) Mention the application where Arc

suppression coil is used. (j) What is the purpose of grounding?

(DEE 326) 2

(k) What is the advantage of low current chopping resistance switching?

(l) What is purpose of amplitude compensation?

(m) What is the principle of operation of air blast circuit breaker?

(n) What is earth resistance?

(o) Explain the types of relays.

UNIT I

2. (a) Explain the principle of operation of mho relay.

(b) Explain briefly the instantaneous over current relay by showing the definite characteristics.

Or

3. (a) Briefly explain the operation of directional relay with neat phasor diagrams. Also derive torque equation.

(b) With the help of block diagram of inverse time over current relay, explain briefly about the operation of each component.

UNIT II

4. (a) Discuss briefly about interruption of capacitive currents with neat circuit diagram.

(b) What is current chopping? Explain in detail by showing diagrametically.

Or

(DEE 326) 3

5. (a) Explain the principle of operation of SF6 circuit breaker.

(b) What are merits of SF6 circuit breakers over other types of CBs?

UNIT III

6. (a) Enumerate the relaying schemes which are employed for the protection of a modern alternator. Describe with a neat sketch, the percentage differential protection of a modern alternator.

(b) Discuss briefly about Neutral grounding.

Or

7. What are the various methods of neutral grounding? Compare their performance with respect to (a) protective relaying (b) fault levels (c) stability (d) voltage levels of power systems.

UNIT IV

8. (a) Explain the operation of inverse time over current relays.

(b) What are the basic components of static relays?

Or

(DEE 326) 4

9. (a) Briefly explain the amplitude comparator.

(b) Discuss about the various types of differential relays.

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(dee 311) - anucde · (dee 311) b.tech. degree ... what are the advantages and disadvantages ......

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