Practice Test: Question Set - 07
1. Yokes with rectangular cross-section are used for
- (A) Small capacity transformers
- (B) Medium capacity transformers
- (C) Large capacity transformers
- (D) Any of the above
2. Which of the following methods is most accurate?
- (A) Equivalent current method
- (B) Equivalent power method
- (C) Equivalent torque method
- (D) Method of average losses
3. The increase in heat dissipation by air blasts is due to increase in
- (A) Conduction
- (B) Convection
- (C) Radiation
- (D) Any of the above
4. Electrical machines having a power output up to about 750 W may be called _________machines.
- (A) Small size
- (B) Medium size
- (C) Large size
- (D) Any of the above
5. The efficiency of a machine should be as _________ as possible to reduce the operating cost.
- (A) High
- (B) Low
- (C) Either of the above
- (D) None of the above
6. The thermal conductivity of hydrogen is ______ times that of air
- (A) 2
- (B) 3
- (C) 5
- (D) 7
7. The flash point of transformer oil should be higher than
- (A) 40°C
- (B) 60°C
- (C) 80°C
- (D) 104°C
8. Is usually used for brush rockers
- (A) Mild steel
- (B) Copper
- (C) Aluminium
- (D) Cast-iron
9. 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
10. In a D.C. machine, the value of peripheral speed should not, normally, exceed
- (A) 10 m/s
- (B) 20 m/s
- (C) 30 m/s
- (D) 40 m/s
0 blogger:
Post a Comment