D D7145

The transformer is loaded at unity power factor on secondary side with a voltage of

220V. Determine the maximum efficiency and load at which it occurs.

b) Explain the working of Off-Load tap changing transformer with help of neat (5)

diagram.
16 In detail explain scott connection in three phase transformer.

17 a) A220kVA single phase transformer is in circuit continuously. For 8 hours in a
day, the load is 60kW at 0.8 pf. For 6 hours, the load is 80kW at unity pf and
for the remaining period of 24 hours it runs on no load. Full load copper losses
are 3.02kW and the iron losses are 1.6kW. Find all day efficiency.

b) What are the advantages and disadvantages of delta-delta connection?
oR oR KK

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