Practice Test: Question Set - 03
1. 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
2. The heat dissipated by from a surface depends upon its temperature and its characteristics like color, roughness etc.
- (A) Conduction
- (B) Convection
- (C) Radiation
- (D) Any of the above
3. Materials exhibiting zero value of resistivity are known as ________.
- (A) Conductors
- (B) Semiconductors
- (C) Insulators
- (D) Superconductors
4. Commercial available medium size machines have a speed range of _________.
- (A) 200 to 400 r.p.m.
- (B) 600 to 1000 r.p.m.
- (C) 1000 to 1500 r.p.m.
- (D) 2000 to 2500 r.p.m.
5. __________ has a low-relative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable.
- (A) Cast steel
- (B) Aluminium
- (C) Soft steel
- (D) Cast iron
6. With conventional hydrogen cooling it is possible to increase the rating of a single unit to
- (A) 50 MW
- (B) 100 MW
- (C) 200 MW
- (D) None of the above
7. 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
8. In induction motors, the length of air gap in kept as small as mechanically possible is order to have
- (A) Low power factor
- (B) High power factor
- (C) High over load capacity
- (D) Any of the above
9. Power transformers have rating
- (A) Equal to 50 kVA
- (B) Equal to 100 kVA
- (C) Above 200 kVA
- (D) None of the above
10. Disc windings are primarily used in
- (A) Short capacity transformers
- (B) Medium capacity transformers
- (C) High capacity transformers
- (D) Any of the above
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