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Department of Electrical Engineering
E Machine
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Question 1 : The p.f at which the transformer operates.
Option-1 :is unity
Option-2 :is 0.8 lag
Option-3 :0.8 lead
Option-4 :depends upon the p.f of the load.
Question 2 : the various losses occurring in a power transformer are___________ losses.
Option-1 :copper and iron
Option-2 :friction and winding.
Option-3 : iron , friction and windage losses
Option-4 :both A and B
Question 3 : A transformer can have zero regulation at
Option-1 :zero p.f
Option-2 :unity p.f
Option-3 :lagging p.f
Option-4 :leading p.f
Question 4 : The iron core in a transformer provides a __________ path to the main flux.
Option-1 :low reluctance
Option-2 :high reluctance
Option-3 :low resistance
Option-4 :high conductivity
Question 5 : If rated dc voltage is applied instead of ac to the primary of a transformer
Option-1 :secondary of transformer will burn.
Option-2 :primary of transformer will burn.
Option-3 :secondary voltage will be excessively high
Option-4 :thre will be no secondary voltage.
Question 6 : The nominal short circuit voltage of a transformer is defined as the percentage of the rated___________ voltage.
Option-1 :primary
Option-2 :secondary
Option-3 :none of these.
Question 7 : If rated ac voltage is applied to the primary with secondary short-circuited.
Option-1 :transformation action will not take place.
Option-2 :high flux will be produced.
Option-3 :enormous high current will flow through the winding and.therefore,they will burn.
Option-4 :only primary winding will burn.
Question 8 : The open-circuit test on a transformer gives
Option-1 :equivalent resistance and leakage reactance.
Option-2 :magnetizing current and core loss at rated voltage.
Option-3 :copper losses.
Option-4 :both B and C.
Question 9 : If thick laminations are used in construction of a transformer core, the losses which will increase are
Option-1 :eddy current.
Option-2 :hysteresis.
Option-3 :copper.
Option-4 :both A and B.
Question 10 : The open circuit test on a transformer is usually performed by exciting the low voltage winding. This is becouse
Option-1 :it draws sufficiently large no-load current which can be conveniently measured.
Option-2 :the required power input is low.
Option-3 :it is not advisible to work on high voltage side.
Option-4 :the voltage required is low.
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