CS MAINS ELECTRICAL ENGINEERING 2014
Paper II
Maximum Marks: 250

Question Paper Specific Instructions
Please read eaeh ofthe following instructions carefully before attempting questions
There are EIGHT questions divided in TWO SECTIONS and printed both in HINDI and in
ENGLISH.
Candidate has to attempt FIVE questions in all.
Questions no. 1 and 5 are compulsory and out of the remaining, THREE are to be attempted
choosing at least ONE from each section.
The number ofmarks carried by a question part is indicated against it.
Answers must be written in the medium authorized in the Admission Certificate which must be
stated clearly on the cover of this Question-cum-Answer Booklet in the space provided. No
marks will be given for answers written in a medium other than the authorized one.
Assume suitable data, ifconsidered necessary, and indicate the same clearly.
Unless otherwise mentioned, symbols and notations carry their usual standard meanings.
Attempts of questions shall be counted in chronological order. Unless struck off, attempt of a
question shall be counted even' if attempted partly. Any page or portion ofthe page left blank in the
Question-cum-Answer Booklet must be clearly struck off.

SECTION A
1. Answer all of the following: lOx 5=50
An approximate Bode plot of magnitude for a system was obtained and .is shown, below. Identify the system in terms of-minimum phase transfer function. <img src='./qimages/269-1a.jpg'> 10
Write the various interrupts available in the microprocessor 8085 in the order of decreasing priority. 6
Specify multiplexed and non-multiplexed bus lines ill 8085microprocessor.4
Explain the function of piezoelectric crystal as transducer. Specify its use in ,'Kitchen lighter Ultrasound diagnostic equipments Industrial cleaning machines. 10
Draw the typical characteristics of an IDMT Relay and how to use these curves. . 10
Using symmetrical component theory for analysing an unbalanced fault, show that under certain circumstances, it is possible that the fault current for a fault can exceed the fault current for a 3-phase fault in the same system. 10

What is the effect of introducing derivative control action on the response of a system A system has open-loop transfer function given by Evaluate the parameters of a PD controller with this system with unity feedback so that the closed loop system has poles located at 3 ± j4. Indicate the nature of closed loop time response to unit step input change. "20
For a 2-bus system shown below, derive expressions for Real Power and Reactive Power at receiving end and sending end. <img src='./qimages/269-2b.jpg'>
An IDMT Relay has a current setting of 150% and has a time multiple setting of 0·5. The relay is connected in a circuit through a C.T. having a ratio of 500 5 amps. Calculate the time of operation of the relay if the circuit carries a fault current of6,000 A. Use the table given below: 10
P.S.M. 2 3·6 5 8 10 15 20
Time in seconds
for T.M.S. of 1·0 10 6 3·9 3·15 2·8 2·2 2·1

Q3.(a) Draw the approximate time response of an underdamped second order system subjected to unit step input disturbance in desired value for the following cases of complex conjugate poles:
with constant real part
with constant imaginary part
with constant damping ratio
In each case consider at least 2 sets of values and mention the most important feature of the response. 20

Draw the equivalent of a medium length transmission line using pie-model. Assume that the receiving end is supplying a lagging power factor load. Draw the Phasqr diagram showing all voltages and currents. Derive the C and D con'stants of this line in terms of line parameters Z and Y. 20
Explairiwhat is meant by Bewley-Lattice diagram. What is,the use of this diagram'? 10

Q4. Describe with a block diagram the Ramp type analog-to-digital conversion.Alsodraw the block diagram ofRamp type digital voltmeter. 20
Describe the various addressing modes in the microprocessor 8085. Give suitable examples for each addressing mode. 10
A sinusoidal signal is transmitted using P.C.M. The output signal to quantization noise is required to be 55·8 dB. Find the minimum number of quantization levels. Derive the equation used. 20

SECTIONB
Q5. Answer all of the following:
A plant has open-loop transfer function
2 O·Is) 0·5s)
Determine the complete stability information of. thoe unity feedback Closed loop system by sketching Nyquist path and Nyquist.plot. 10

Derive an expression for the.Bandwidth of 'P.C.M.' system.
A channel with bit rate, Rb =36 "kbps is available for 'P.e.M.' voice transmission. Find the appropriate val.ues of binary digits the number of quantization and the sampling rate asswiiing fm =3·2 kHz.
(d)Explain the importance of adding impedance· in the neutral path of an alternator.

analog transducer with a 0 10_V input is able to distinguish a change of 1 mV in its signal. Calculate its resolution the minimum number of bits of ADC so that the digital output has almost the -same resolution as transducer. Also calculate the quantization interval and number of decision levels. 1.0
Q6. LVDT with bellow is used for measuring the pressure. Draw the circuit diagram of LVDT-bellow system. 6
The sensitivity of LVDT-bellow system is 40 V per mm. The bellows are deflected by 0·15 mm by a pressure of 1·0 x 106 N per m2. the pressure when the output voltage of LVDT is 3·9V. 14

Explain Direct addressing Register indirect addressing Immediate addressing Register addressing. 20
The parity check matrix H of a linear block code is given by

1 0 1 1 1 0 0
1 1 0 1 0 1 0
0 1 1 1 0 1 1
Determine the coded word for the data 0101. 10
Q7. For a position control system as shown in the figure below, determine the range of compensator gain K and the location of zero in left half for which the system is stable. <img src='./qimages/269-7a.jpg'> 20

Explain hardware single stepping used in 8085 microprocessor. 20

Derive the expression for maximum signal to quantization noise ratio for sinusoidal message input when waveform coding is done by D.M. under overload condition. 10

Q8. A system is modelled in state-space form as <img src='./qimages/269-8a.jpg'> Draw the signal flow graph and obtain the transfer function. 10
Define state controllability of a system. Apply the controllability test to determine the controllability ofa modelled by the state-space model as <img src='./qimages/269-8a2.jpg'> 10

In a 220 kV, 50 ds power system, the reactance and capacitance upto the circuit breaker are 8 ohms and 0·025 J!F respectively. A resistance of 600 ohms is connected across the circuit breaker contacts. Determine the following: 20
Natural frequency of oscillation
Damped frequency of oscillation
Value of Critical Resistance which will give no transient oscillations
The value of resistance which when connected across circuit breaker contacts will give damped frequency of oscillation of one-fourth of the natural frequency of oscillation.
Show how unit protection principle can be employed in balanced voltage system. 10