Practice Test: Question Set - 04
1. The high voltage winding is usually which of the following type?
- (A) Cylindrical winding with circular conductors
- (B) Crossover winding with either circular or small
rectangular conductors
- (C) Continuous disc type winding with rectangular
conductors
- (D) All of the above types
2. Which of the following brushes can be used for high values of current density?
- (A) Metal graphite brushes
- (B) Hard carbon brushes
- (C) Electro-graphitic brushes
- (D) Natural graphite brushes
3. In D.C. machines, the ________ infield mmf results in increase in size and cost of machines.
- (A) Increase
- (B) Decrease
- (C) Either of the above
- (D) None of the above
4. Which of the following is the major consideration to evolve a good design?
- (A) Cost
- (B) Durability
- (C) Compliance with performance criteria as laid down
in specifications
- (D) All of the above
5. Electrical machines having power outputs ranging from a few kW up to approximately 250 kW may be classified as
- (A) Small size machines
- (B) Medium size machines
- (C) Large size machines
- (D) Any of the above
6. The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation?
- (A) Conduction
- (B) Convection
- (C) Radiation
- (D) All of the above
7. In direct cooled system using hydrogen both stator and rotor conductors are made
- (A) Solid
- (B) Hollow
- (C) Perforated
- (D) Any of the above
8. The value of exciting or magnetizing current depends upon which of the following factors?
- (A) Total mmf required
- (B) The number of turns in the exciting winding
- (C) The way in which the winding is distributed
- (D) All of the above
9. In transformers using hot rolled steel, the cross-section of the yoke is made about _________ greater than that of the core
- (A) 5 percent
- (B) 10 percent
- (C) 15 percent
- (D) 30 percent
10. 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
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