EC 2201 Electrical Engineering Important Questions for Anna University Nov/Dec Exams 2012

Electrical Engineering Important Questions

Type     : Questions

Sem       : 3rd Semester

Branch  : ECE

Subject  : Electrical Engineering

> Data Structures Questions

EC 2201 Electrical Engineering

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  expression for  the  induced   emf   of  a synchronous
      generator.  

(8)

(ii)      Explain the construction and operation of a reluctance motor.       (8)

 

Or

 

(b) (i) Explain   the  method   of  obtaining   the  voltage   regulation of  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  indicating the
      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.

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