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.Management Sciences
Category: Rectifiers and Converters
On which of the following factors the number of phases for which a rectifier should be designed depend ?
A. The voltage regulation of the rec¬tifier should be low
B. In the output circuit there should be no harmonics
C. The power factor of the system should be high
D. The rectifier supply transformer should be utilized to the best ad-vantage
E. all of the above
In a rotary converter I2R losses as compared to a D.C. generator of the same size will be___________?
A. same
B. less
C. double
D. three times
The efficiency of the copper oxide rectifier seldom exceeds____________?
A. 90 to 95%
B. 85 to 90%
C. 80 to 85%
D. 65 to 75%
In a mercury arc rectifier, the anode is usually made of_____________?
A. copper
B. aluminium
C. silver
D. graphite
E. tungsten
Normally, which of the following is used, when a large-scale conversion from AC. to D.C. power is required ?
A. Motor-generator set
B. Motor converter
C. Rotary converter
D. Mercury arc rectifier
To produce cathode spot in a mercury arc rectifier______________?
A. anode is heated
B. tube is evacuated
C. an auxiliary electrode is used
D. low mercury vapour pressures are used
Which of the following metals is generally manufactured by electrolysis process ?
A. Load
B. Aluminium
C. Copper
D. Zinc
E. None of the above
In a glass bulb mercury arc rectifier the maximum current rating is restricted to___________?
A. 2000 A
B. 1500 A
C. 1000 A
D. 500 A
Which of the following is the loss within the mercury arc rectifier chamber ?
A. Voltage drop in arc
B. Voltage drop at the anode
C. Voltage drop at the cathode
D. All of the above
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