6.3

Qz:20-21

Ass:

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Question 1
Maximum efficiency of a transformer is achieved when
Select one:

1. Iron Losses = Copper Losses
2. Iron Losses > Copper Losses
3. Copper Losses> Iron Losses
4. None of the above

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Question 2

Vector/phasor diagrams of voltages and currents at no load and load conditions give a better idea of what actually happens inside a transformer (True/False)
Select one:
True
False

True

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Question 3

Secondary voltage cannot be reduced or increased by changing the turns ratio between the primary and secondary winding (True/False)
Select one:
True
False

False

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Question 4

In a delta connection, line voltage and phase voltage are the same (True/False)
Select one:
True
False

True

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Question 5

Delta-delta connections are employed in large power rated transformers used in low voltage applications(True/False)
Select one:
True
False

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Question 6

Mark the incorrect statement: Characteristics of air blast circuit Breakers include:
Select one:

1. High speed operation
2. Short arcing times
3. Does not allow current chopping
4. Rapid auto reclosing
5. Low maintenance of the breaker

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Question 7

Current chopping is used to describe the sudden reduction of current in a circuit breaker to zero at a time other than the natural instant of current zero (True/False)
Select one:
True
False

True

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Question 8
Improper battery sizing can lead to
Select one:

1. Low load voltage
2. Permanent damage to battery cells
3. Poor autonomy times
4. All of the above

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Question 9

Which of these statements is true for ACBs?
Select one:

1. Used for circuits rated at less than 1000 V
2. Can be installed in multi-tiers in LV switchboards or switchgear cabinets
3. Maybe placed in draw-out enclosures that permit removal without dismantling the switchgear
4. All of the above

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Question 10
Vacuum and air circuit breakers are medium voltage switchgear types(True/False)

Select one:
True
False

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