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

Related Mcqs:

1. In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made____________?

   A. equal to that of armature mmf B. less in comparison with the armature mmf C. large in comparison with the armature mmf D. none of the above...

2. 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...

3. cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall______________?

   A. Direct B. Indirect C. Conventional D. Any of the above...

4. The weight of copper of both armature and field windings decreases with __________ in number of poles?

   A. increase B. decrease C. either of the above D. none of the above...

5. The laminations of the armature of a D.C. machine are usually ___________ thick?

   A. 0.1 to 0.2 mm B. 0.2 to 0.3 mm C. 0.3 to 0.4 mm D. 0.4 to 0.5 mm...

6. The efficiency of a machine should be as ____________ as possible to reduce the operating cost?

   A. high B. low C. either of the above D. none of the above...

7. 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...

8. 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...

9. 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...

10. Which of the following methods is most accurate ?

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