The forced oil and air circulation method is usual one for transformers of capacities____________?

Related Mcqs:

1. A current density of __________ is ilsed for large power transformers with forced circulation of oil or with water cooling coils?

   A. 1.5 to 2.5 A/mm2 B. 3.5 to 4.5 A/mm2 C. 4.0 to 5.0 A/mm2 D. 5.4 to 6.2 A/mm2...

2. The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are______________?

   A. 0.5 to 0.8 Wb/m2 B. 0.8 to 1.0 Wb/m2 C. 1.1 to 1.35 Wb/m2 D. 1.4 to 1.8 Wb/m2...

3. 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...

4. In D.C. machines the usual limit of slot pitch is________________?

   A. between 5 to 10 mm B. between 10 to 15 mm C. between 15 to 20 mm D. between 25 to 35 mm...

5. Aluminium when adopted as a conductor material in __________ transformers, decreases the overall cost of the transformer?

   A. small size B. medium size C. large size D. any of the above size...

6. Power transformers should be designed to have maximum efficiency________________?

   A. at one-fourth load B. at one-half load C. at or near full load D. any of the above...

7. Power transformers have rating_______________?

   A. equal to 50 kVA B. equal to 100 kVA C. above 200 kVA D. none of the above...

8. 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...

9. Multi-layer helical windings are commonly used in the transformers as high voltage windings_______________?

   A. upto 20 kV B. upto 50 kV C. upto 80 kV D. for 110 kV and above...

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

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