Electical Engineering ( EE ) - Anna University Prev Year Question papers for 3rd semester ECE ( Electronics and Communication Engineering ) regulation 2008...

Electical Engineering ( EE ) - Anna University Prev Year Question papers for 3rd semester ECE ( Electronics and Communication Engineering ) regulation 2008...



Posted by R.Anirudhan



B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2009
Third Semester

Electronics and Communication Engineering
 EC 2201 — ELECTRICAL ENGINEERING (Regulation 2008)
Time : Three hours                                                                     Maximum : 100 Marks

Answer ALL Questions
PART A — (10 × 2 = 20 Marks)

1.       What are the functions of yoke in a D.C. machine?
 2.       List the methods of speed control of a D.C. shunt motor.
 3.       Write down the emf equations of a single phase transformer.
 4.       Give  the  expression   for  percentage   voltage  regulation   of  a  single  phase transformer.
 5.      Define the slip of a three phase induction motor.
 6.       List the types of starters used to start three phase induction motors.
 7.       What are the two types of synchronous machines?
 8.       Give the applications of stepper motors.
 9.       Why are high voltages preferred for the transmission of electrical power?
 10.     List the components in a substation.

PART B — (5 × 16 = 80 Marks)
 11.     (a)      (i)       With  a  neat  sketch  explain  the  constructional  details  of  a  D.C. machine.             (12)
 (ii)      Draw  and  explain  the  internal  and  external  characteristics  of  a
D.C. shunt generator.                                                                       (4) Or
 (b)      (i)       Derive the torque equation of a D.C. motor.                                    (6)
 (ii)      With a neat sketch explain the operation of a three point starter for a D.C. motor.      (10)
 12.     (a)      Explain the principle of operation of a single phase transformer  and its behaviour on loaded condition with phasor diagram.                                                              (16) Or

(b)(i) 
(ii)
Develop the equivalent circuit of a transformer.                             (8) 
Explain the O.C. and S.C. tests done on a single phase transformer.
(8)
13.(a)(i)With neat sketches explain the construction of three phase slip ring and squirrel cage induction motors.                                               (10)
(ii)Compare the slip ring and squirrel cage rotors.                              (6)

Or
(b)      (i)       Explain the auto transformer  and star delta starters used to start the three phase induction motors.                                                                                             (8)
(ii)      Explain  the  principle  of operation  of a shaded  pole  single  phase induction motor.                                                                                                         (8)
14.(a)(i)Derive   the  expressionfor  the  induced   emf   of  asynchronous
generator.
(8)
(ii)      Explain the construction and operation of a reluctance motor.       (8)
 Or
(b)(i)Explain   the  method   of  obtaining   the  voltage   regulationof  a
synchronous generator using EMF method.(10)
(ii)Explain the construction and operation of a hysterisis motor.(6)

15.(a)(i)Explain  the structure  of a electrical  power  system  indicatingthe
generation, transmission and distribution section.(10)
(ii)Draw and explain the layout of a single bus bar substation.(6)
 Or
 (b)      (i)       Discuss the advantages and disadvantages  of EHVAC and EHVDC
systems.                                                                                          (10)
 (ii)      Explain  the construction  of any one type of cables  used for EHV
systems.                                                                                           (6)

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