 # Electrical Engineering Objective Questions { Transformers }

274. The percentage resistance and percentage reactance of a 10 kVA, 400 V/ 200 V, 3-phase transformer are 2% and 10% respectively. If the constant losses in the machine are 1%, the maximum possible percentage efficiency of the transformer is

275.  A 400 V/100 V, 10 kVA two-winding transformer is reconnected as an auto-transformer across a suitable voltage source. The maximum rating of such an arrangement could be

276.  In a constant voltage transformer (CVT), the output voltage remains constant due to

277. 1n the protection of transformers, harmonic restraint is used to guard against

278. The main reason for connecting a pulse transformer at the output stage of a thyristor triggering circuit is to

279.  A 3-phase transformer has rating of 20 MVA, 220 kV (star) ? 33 kV (delta) with leakage reactance of 12%. The transformer reactance (in ohms) referred to each phase of the L.V. delta-connected side is

280.  A lkVA, 230 V/100V, single phase, 50 Hz transformer having negligible winding resistance and leakage inductance is operating under saturation, while 250 V, 50 Hz sinusoidal supply is connected to the high voltage winding. A resistive load is connected to the low voltage winding which draws rated current. Which one of the following quantities will not be sinusoidal?

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