Which of the following methods is most accurate ?

Related Mcqs:

1. Which of the following methods is used for air cooling of turbo-alternators ?

   A. One sided axial ventilation
   B. Two sided axial ventilation
   C. Multiple inlet system
   D. All of the above

2. Which of the following methods does not take into account the maximum temperature rise under variable load conditions ?

   A. Equivalent power method
   B. Equivalent current method
   C. Method of average losses
   D. Equivalent torque method

3. By which of the following methods motor rating for variable load drives can be determined ?

   A. Method of average losses
   B. Equivalent current method
   C. Equivalent torque method
   D. Equivalent power method
   E. All of the above

4. By which of the following methods the temperature rise of windings and other parts may be determined ?

   A. Thermometer method
   B. Resistance method
   C. Embedded temperature detector method
   D. Any of the above

5. Which of the following methods may be adopted to reduce the effects of armature reaction ?

   A. Increase in length of air gap at pole tips
   B. Increasing reluctance of pole tips
   C. Compensating windings
   D. Interpoles
   E. All of the above

6. Which of the following is the major consideration to evolve a good design ?

   A. Cost
   B. Durability
   C. Compliance with performance criteria as laid down in specifications
   D. All of the above

7. The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ?

   A. Conduction
   B. Convection
   C. Radiation
   D. All of the above

8. The slot leakage can be calculated by making which of the following assumptions ?

   A. The current in the slot conductors is uniformly distributed over their cross-section
   B. The leakage path is straight across the slot and around the iron at the bottom
   C. The permanence of air paths is only considered. The reluctance of iron paths is assumed as zero
   D. All of the above

9. For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?

   A. 1.0 to 1.2 A/mm2
   B. 1.5 to 2.0 A/mm2
   C. 2.2 to 3.2 A/mm2
   D. 3.2 to 4.2 A/mm2

10. The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following ?

    A. Corrugations
    B. Fins
    C. Tubes
    D. Radiator tanks
    E. All of the above