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.Management Sciences
Category: Rectifiers and Converters
In selenium rectifiers efficiencies ranging from _______ to _______ percent are attainable?
A. 25, 35
B. 40, 50
C. 60, 70
D. 75, 85
Selenium rectifier can be operated at temperatures as high as____________?
A. 25°C
B. 40°C
C. 60°C
D. 75°C
In phase-shift control method the control is carried out by varying the of grid voltage
A. magnitude
B. polarity
C. phase
D. any of the above
E. none of the above
The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following_____________?
A. anode drop and cathode drop
B. anode drop and arc drop
C. cathode drop and arc drop
D. anode drop, cathode drop and arc drop
When a rectifier is loaded which of the following voltage drops take place ?
A. Voltage drop in transformer reactance
B. Voltage drop in resistance of transformer and smoothing chokes
C. Arc voltage drop
D. All of the above
The advantage of mercury arc rectifier is that________________?
A. it is light in weight and occupies small floor space
B. it has high efficiency
C. it has high overload capacity
D. it is comparatively noiseless
E. all of the above
Which of the following are the applications of D.C. system ?
A. Battery charging work
B. Arc welding
C. Electrolytic and electro-chemical processes
D. Arc lamps for search lights
E. All of the above
In a mercury arc rectifier positive ions are attracted towards______________?
A. anode
B. cathode
C. shell bottom
D. mercury pool
A rotary converter combines the function of____________?
A. an induction motor and a D.C. generator
B. a synchronous motor and a D.C. generator
C. a D.C. series motor and a D.C. generator
D. none of the above
Which of the following is reversible in action ?
A. Motor generator set
B. Motor converter
C. Rotary converter
D. Any of the above
E. None of the above
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