In direct cooled system using hydrogen both stator and rotor conductors are made____________?

Related Mcqs:

1. The noise produced by a ___________ cooled machine is less as the rotor moves in a medium of smaller density?

   A. air B. hydrogen C. either A. or B. D. none of the above...

2. 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...

3. Machines cooled by direct cooling method may be called_____________?

   A. “supercharged” B. “inner cooled” C. “conductor cooled” D. any of the above...

4. Direct water cooling of rotor winding presents_____________?

   A. no mechanical difficulties B. lesser mechanical difficulties C. greater mechanical difficulties D. none of the above...

5. The stator of a D.C. machine comprises of_____________?

   A. main poles B. interpoles C. frame D. all of the above...

6. The cylindrical windings using circular conductors are used for current rating of____________?

   A. upto 20 A B. upto 40 A C. upto 60 A D. upto 80 A...

7. Cylindrical windings using circular conductors, employed in transformers, are_____________?

   A. single layered B. double layered C. multi-layered D. none of the above...

8. In self cooled motors the cooling time constant is about ___________ than the heating time constant because cooling conditions are worse at standstill?

   A. 2 to 3 times greater B. 3 to 4 times greater C. 4 to 5 times greater D. none 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. Hydrogen has a heat transfer co-efficient __________ times that of air?

    A. 1.5 B. 2.5 C. 3.5 D. 4.5...