Anna University Chennai 2007-3rd Sem B.E Electronics & Tele-Communication Engineering ./B.Tech , /- Question Paper

B.E./B.Tech. DEGREE EXAMINATION, MAY/ JUNE 2007.
Third Semester
Electronics and Communication Engineering
ELECTRICAL ENGINEERING
Time: 3 hours
Maximum: 100 marks

PART A - (10x two = 20 marks)
ans ALL ques..
1. Write the expression for determining real, reactive and apparent power in a 3 phase circuit.
2. Define voltage regulation.
3. Write the speed formula of a dc machine.
4. Name any 2 non-loading method of testing dc machines.
5. What are all the advantages of induction motor over other motors?
6. Draw an approximate equivalent circuit of an induction motor.
7. Mention a few of the special features on synchronous machine.
8. Write any 2 applications of reluctance motor.
9. Name the divisions of electric power system.
10. What are the options of site for the coal fired thermal power station?

PART B - (5x16 = 80 marks)
11. (a) (i) The voltage across the lines of s 3 phase star connected generator is 11 KV. The generator supplies a six MW load at 0.8 lagging power factor. compute the active and reactive components in every of the generator? (8)
(ii) Draw the circuit diagram and discuss the theory of 3 phase power measurement by 2 wattmeter method. (8)
Or
(b) (i) discuss the principle of operation of Single phase Transformer (8)
(ii) A 150 KVA, 2400/240 V Transformer has R2 = 0.002 ohm, X two = 0.45 ohm. compute the primary induce emf. (8)

12. (a) (i) discuss the principle of operation of DC motor. (8)
(ii) Draw the schematic diagram of all kinds of DC machines. (8)
Or
(b) discuss the Swinburne’s test of predetermination of efficiency of a DC Machine as generator and motor. (16)

13. (a) Develop an equivalent circuit of an induction motor from 1st principle. (16)
Or
(b) discuss the different starting methods of squirrel cage induction motor. (16)

14. (a) With the help of schematic diagrams, discuss the constructional details of synchronous machine.
Or
(b) compute the percentage voltage regulation for a 3 phase star connected 2500 KVA, 6600V alternator operating at full load and (i) 0.8 power factor lagging, (ii) 0.8 power factor leading. The per-phase synchronous reactance is 10.4 ohm. Neglect armature resistance. (16)

15. (a) Draw the schematic diagram depicting the structure of a power system and discuss every major divisions. (16)
Or
(b) Write short notes on: (16)
(i) HVDC transmission
(ii) Underground cables.

Earning:   Approval pending.