A. shunt motor
B. synchronous motor
C. induction regulator
D. synchronous generator
0
In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as______________?
0
Which of the following statement is incorrect ?
A. maximum grid voltage
B. critical grid voltage
C. any of the above
D. none of the above
0
In phase-shift control method the control is carried out by varying the of grid voltage
A. Copper oxide rectifier is a linear device
B. Copper oxide rectifier is not a perfect rectifier
C. Copper oxide rectifier has a low efficiency
D. Copper oxide rectifier finds use in control circuits
E. Copper oxide rectifier is not stable during early life
0
The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?
A. magnitude
B. polarity
C. phase
D. any of the above
E. none of the above
0
Copper oxide rectifier is usually designed not to operate above___________?
A. They are mechanically strong
B. They do not require any voltage for filament heating
C. Both (A) and (B)
D. None of the above
0
Ageing of a selenium rectifier may change the output voltage by__________?
A. 10°C
B. 20°C
C. 30°C
D. 45°C
0
The efficiency of the copper oxide rectifier seldom exceeds____________?
A. 5 to 10 per cent
B. 15 to 20 per cent
C. 25 to 30 per cent
D. none of the above
0
Selenium rectifier can be operated at temperatures as high as____________?
A. 90 to 95%
B. 85 to 90%
C. 80 to 85%
D. 65 to 75%
0
The applications of selenium rectifiers are usually limited to potential of_____________?
A. 25°C
B. 40°C
C. 60°C
D. 75°C
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