| 1. | In phase-shift control method the control is carried out by varying the of grid voltage ? | |
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magnitude
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polarity
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phase
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any of the above
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Report Question| 2. | Which of the following mercury arc rectifier will deliver least undulating current ? | |
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Six-phase
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Three-phase
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Two-phase
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Single-phase
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| 3. | The advantage of mercury arc rectifier is that ? | |
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it is light in weight and occupies small floor space
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it has high efficiency
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it has high overload capacity
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all of the above
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| 4. | The potential drop in the arc, in a mercury arc rectifier, varies ? | |
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0.05 V to 0.2 V per-cm length of the arc
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0.5 V to 1.6 V per cm length of the arc
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2 V to 3.5 V per cm length of the arc
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none of the above
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| 5. | The voltage chop between the anode and cathode, of a mercury arc rectifier comprises of the following ? | |
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anode drop and cathode drop
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anode drop and arc drop
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cathode drop and arc drop
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anode drop, cathode drop and arc drop
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| 6. | Mercury, in arc rectifiers, is chosen for cathode because ? | |
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its ionization potential is relatively low
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its atomic weight is quite high
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its boiling point and specific heat are low
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all of the above
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| 7. | In which of the following equipment direct current is needed ? | |
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Telephones
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Relays
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Time switches
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All of the above
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| 8. | Normally, which of the following is used, when a large-scale conversion from A.C. to D.C. power is required ? | |
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Motor-generator set
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Motor converter
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Rotary converter
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Mercury arc rectifier
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| 9. | In a single phase rotary converter the number of slip rings will be ? | |
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two
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three
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four
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six
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| 10. | Asynchronous converter can be started ? | |
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by means of a small auxiliary motor
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from AC. side as induction motor
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from D.C side as D.C motor
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any of the above methods
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