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

Related Mcqs:

1. The insulation between windings and grounded core and the insulation between the windings of the same phase is called__________________?

   A. minor insulation B. major insulation C. either of the above 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. 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...

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. 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...

6. Transformers with a capacity of up to __________ have a cooling radiator system with natural cooling?

   A. 2 MVA B. 5 MVA C. 7.5 MVA D. 10 MVA...

7. 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...

8. A practical formula for determining the thickness of insulation between low voltage and high voltage windings is__________________?

   A. 1 + 0.2 kVmm B. 2 + 0.5 kVmm C. 4 + 0.7 kV mm D. 5 + 0.9 kV mm...

9. Which of the following is the basic consideration in the design of insulation ?

   A. Electrical considerations B. Mechanical considerations C. Thermal considerations D. All of the above...

10. 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...