# Electrical Engineering 3rd ND10 EC2201

ANNA UNIVERSITY OF TECHNOLOGY
B.E / B.TECH DEGREE EXAMINATIONS : NOV/DEC 2010
REGULATIONS : 2008
EC 2201 Electrical Engineering

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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)
Develop the equivalent circuit of a transformer.(8)
(ii)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  indicating the generation, transmission and distribution section.(10)
(ii)Draw and explain the layout of a single bus bar substation.(6)
Or