ELBCTRICAL ENGINBBRING
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Select any three of the following statements read them carefully and identify the correct and the incorrect ones. Justify your answer using not more than 200 words m each case 20x3=60

The magnitude of a transfer function whose poles are only m the left half plane and whose zeros are mirrOr images of the poles about the axiS increases with increase in frequency

For measurement of 34> power using two wattmeters one of the wattmeters reads negative when the power factor angl e is more than 60°

In a 1arge interconnecled power system, conSider three buses having short circuit capacities 1600 MVA 1200 MVA and 1000 MVA respectively, the voltages 0f all the buses are 1 p.u. If a 3fie fault takes place on bus the change in bus voltage is descnbed as delta V1 delta V2 delta V3

A satellite earth station must have as many reCe1ve chains as there are camers transmitted to it

2. A system 1S represented by state equation X AX


Delermine the state transiti on matrix
Station transmits 50 MW power to station through a tie-line Maximum steady stale capacity of the line 1S 100 MW. Deteffillne the allowable sudden load that can be switched on without loss of stability. Denve any fonnulae used

Explain clearly the construction of a p-n Junction and its use to convert sun-light directly into electricity. What distingUishes a solar cell from a conventional p-n Junction diode?

3. Discuss briefly the mlcroprocessor architecture with special reference to the following components­ Data bus, Address bus and Control bus

Explain bnefly vanous abnonnal operating conditions m a large altemator against which protechon 1s necessary Explain c1early with neat diagram the protection 0f altemator against failure of excitati on

What lS Wave power? Describe some of the devlces used for converting wave power into electri cal power Discuss bnefly its feasibility with reference to Indian sub-continent

Differentiate between para-magnetic, diamagnetic and ferro-magnetic matenals Discuss vanous factors which affect permeability and hystereSiS loss

4 Explain how television lS capable of displaymg complete moving plctures, despite the fact that at any lnstant 0f time, only a tiny portion 0f the plcture tube screen lS active

How do the functions ofa communication satellite compare with those of a nucro Wave link repeater? WhatlS the into st Slgnificant difference m thelr functions?


SECTION B

5. Select any three of the following statements read them carefully and ldentify the correct and the mcorrect ones. Justify your answer using not more than 200 words in each case 20x3=60
The steady state errors for unit step lnput to type-O, type-I and type-2, unity feedback systemsare finite non-zero,zero and infinite respectively

"Tan 5" of an insulating matenallS an indication of its health

For the same rupturing capaaty the actual current to be intenupted by an HRC fuse lS much greater than that 0f any circuit breaker

PCM lS conSldered very well, but other modulation systems are also used

Explain with suitable diagrams, how one single phase wattmeter can be used to measure 34> active and reactive power. Discuss the linu tation of this method

Find the Signal-to-quantization nOise ratio m a bmary PCM system, lf the number of quantization levels lS 64

In a TV reveiving system the ple-ampl1fier (mounted on the aenal) has a gain of20 dB and a nOise factor of 6 dB and the cable between the pre-ampl1fier and the recelver has an attenuation factor of 3 dB. While the RF and IF stages or the reCelver heNe a total gain of 90 dB and a nOl se figures 0f 3 dB (RF stage) and I 3 dB (IF stage) Detemune the system overall nOise figure

7 Show that the feedback reduces the effect of parameter vanation on the perfonnance of the control system, but adversely affects the gam of the systems Also discuss bnefly the effect of feedback on the tranSient perfonnance 0f the control system

Denve a Simple expressiOn for the orbital penod of satellite in terms of the mecharucal constants of the satellite and the earth

A multimode fiber has a core refractive mdex 1 5 and the relative refractive lndex difference is 3 per cent and the operating wavelength is 0.8 m Calculate the critical radius of curvature at which large bending losses 0ccur

8 First manually pI ace OOs m the accumulator and all general purp ose regiSters Then write aprogramme which Wlll
place the hex number FE in the accumulator copy the contents 0f the accumulalor into reSiSter' copy the contents of the accumulator into register stop Show the progranune m 8085 nmemorucs

Derive swing equation and discuss its appl1cation in the study of power system stability

Discuss one scheme each 0f constant speed constant frequency (CS CF) vanable speed constant frequency (VSCF) 0f a Wlnd-electncal energy conversiOn system