Practice Test: Question Set - 08
1. The surge phenomenon is particularly important in case of
- (A) Low voltage transformers
- (B) Medium voltage transformers
- (C) High voltage transformers
- (D) Any of the above
2. For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used?
- (A) 1.0 Wb/m2
- (B) 1.1 Wb/m2
- (C) 1.3 Wb/m2
- (D) 1.6 Wb/m2
3. The distance between the starts of two consecutive coils measured in terms of coil sides is called
- (A) Front pitch
- (B) Winding pitch
- (C) Commutator pitch
- (D) Back pitch
4. With direct water cooling it is possible to have ratings of about
- (A) 200 MW
- (B) 300 MW
- (C) 400 MW
- (D) 600 MW
5. _________is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties?
- (A) Grey cast-iron
- (B) Cast steel
- (C) High carbon steel
- (D) Stainless steel
6. 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
7. If an insulating material is operated beyond the maximum allowable temperature, its life is
- (A) Drastically increased
- (B) Drastically reduced
- (C) Unaffected
- (D) None of the above
8. Hydrogen has a heat transfer coefficient _________ times that of air
- (A) 1.5
- (B) 2.5
- (C) 3.5
- (D) 4.5
9. The operation of a D.C. machine with large air gap lengths is comparatively
- (A) Quiet
- (B) Noisy
- (C) Either of the above
- (D) None of the above
10. 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
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