Download Model question papers & previous years question papers

Posted Date: 09 Dec 2010      Posted By:: VEERAIYAN BOSE    Member Level: Gold  Points: 5 (Rs. 1)

2010 Anna University Chennai B.E Computer Science and Engineering Ec2201 — electrical engineering Question paper

Course: B.E Computer Science and Engineering   University/board: Anna University Chennai

Third Semester

Electronics and Communication Engineering

(Regulation 2008)
Time: Three hours Maximum: 100 Marks
Answer ALL Questions

PART A — (10 × 2 = 20 Marks)

1. What are the conditions to be fulfilled for the self-excitation of a dc shunt
2. What are the functions of inter poles and how are the inter-poles windings
3. The emf per turn of a single phase, 6.6 kV/440 V, 50 Hz Transformer is
approximately 12 V.
(a) the number of turns in the HV and LV windings and
(b) the net cross-sectional area of the core for a maximum flux density of
1.5 T.
4. Define voltage regulation of a transformer.
5. Why cannot an induction motor run at synchronous speed?
6. Why are single phase induction motors not self-starting?
7. What are the causes of faulty starting of a synchronous motor?
8. What are the applications of stepper motors?
9. Why are insulators used with overhead lines?
10. Define skin effect.

PART B — (5 × 16 = 80 Marks)

11. (a) (i) Describe with a neat sketch, the construction of a d.c. machine.
(ii) A separately excited dc generator running at 1000 r.p.m. supplied
110 A at 220 V to a resistive load. If the load resistance remains
constant, what will the load current if the speed is reduced to
800 r.p.m? Armature resistance is 0.02 . Field current is
unaltered. Assume a voltage drop of 1 V per brush. Ignore the effect
of armature reaction. [Marks 16]
(b) (i) Derive from the first principle, an expression for the torque
developed in d.c. motor.
(ii) In a brake test on a dc shunt motor, the load on one side of the
brake was 35 kg and on the other side 5 kg. The motor was running
at 1500 r.p.m. its input being 34 A at 400 V. The diameter of the
pulley is 50 c.m. Determine the torque and efficiency of the motor. [Marks 16]

12. (a) (i) From first principles, derive the emf equation of a transformer. Also
show that the voltage induced per turn is the same, whether it is
primary or secondary.
(ii) A single phase transformer with a ratio of 6.6. kV/415 V takes a
no-load current of 0.75 A at 0.22 p.f. If the secondary supplies a
current of 120 A at 0.8 p.f. calculate the total current taken by the
primary. [Marks 16]
(b) (i) Develop an equivalent circuit for a single phase two winding
(ii) Calculate the full-load efficiency at 0.8 p.f. and the voltage at the
secondary terminals when supplying full load secondary current at
unity power factor, for a 4 kVA, 200/400 V, 50 Hz, single phase
transformer of which the following are the test results :
OC test (on primary) : V = 200 V ; I = 0.8 A ; W = 50 W
SC test (on secondary) : V = 17.5 V ; I = 9 A; W = 50 W [Marks 16]

13. (a) (i) Explain with neat sketches, the principle of operation of a three phase
induction motor.
(ii) A 6 pole, 3 phase, 50 Hz induction motor develops a maximum
torque of 30 Nm at 960 r.p.m. Determine the torque exerted by the
motor at 5% slip. The rotor resistance per phase is 0.6 . [Marks 16]
(b) Discuss briefly the various methods of speed control of three-phase
induction motors. [Marks 16]

14. (a) (i) Derive the emf equation of an alternator. Discuss the effect of
winding factor on the induced emf.
(ii) Explain the speed-torque characteristics of a reluctance motor. [Marks 16]
(b) (i) A 500 kVA, 3.3. kV, 3-phase, star-connected alternator is found to
give a short circuit current of 290 A at normal field current. Its
effective winding resistance per phase is 0.7 . Estimate the full
load of voltage regulation by EMF method for 0.8 pf lagging.
(ii) Explain the speed-torque characteristics of a hysteresis motor. [Marks 16]

15. (a) (i) Draw the single diagram of a typical a.c. power supply scheme.
(ii) With a neat sketch, explain the inter sheath grading of cables. [Marks 16]
(b) (i) Explain briefly the advantages of EHVAC transmission over
EHVDC transmission. [Marks 16]
(ii) Draw the layout of a substation with the main equipments. [Marks 16]

Return to question paper search

Next Question Paper: Cs2201 — data structures

Previous Question Paper: Orissa Board Half Yearly Exam(Hindi) 2010{9th Class}

Related Question Papers:

  • PH2111 Engineering Physics I

  • Ba9224 — human resource management

  • Me2253 — engineering materials and metallurgy

  • Ge2021 — environmental science and engineering

  • Ba9223 — marketing management

  • Categories

    Submit Previous Years University Question Papers and make money from adsense revenue sharing program

    Are you preparing for a university examination? Download model question papers and practise before you write the exam.

    Complete the action items below to enter to win an iPad Mini from India Study Channel! in India Study Channel - Locker on LockerDome
    Awards & Gifts
    Active Members
    TodayLast 7 Daysmore...

    ISC Technologies, Kochi - India. © All Rights Reserved.