# Electrical Engineering Objective Questions { Transformers }

302.  The equivalent resistance andequivalent reactance of a transformer are respectively 0.5 SI and 0.8 12. The voltage regulation will be zero when the load power factor is

303.  A symmetrical 3-phase supply is applied to theprimary terminals A1, B and C1 of the Y-Y transformer asshown in the given figure. The secondary terminals A2, B2 and C2 give a symmetrical 3-phase voltage. If the terminals H1 and H2 of phase I of the primary are reversed without changing the supply at A1, B1 and C1, thenthe phase angle between the line voltage VA2B2 and c2A2 on the secondary side will be

304.  For the system shown in given figure, the phase relation of current 'I' with respect to the voltage VAB is Ideal transformer

305.  A 3-phase Y/A transformer has per phase turn ratio 'K' and line voltage ratio `K1'. If the voltage of A winding lags the voltage of Y winding by an angle 4), then K, K1 and (pare related as

306. Two transformers X and Y with identical ratings and dimensions have 0.8 mm and 1.2 mm thick laminations respectively. If Rm and Xm are the magnetizing branch parameters in the equivalent circuit, then

307.  Hysteresis loss of a transformer designed at voltage 'V' and frequency 'f' is Ph. If the transformer is operated from a voltage `x?/' and frequency `xf' the hysteresis loss for a Steinmetz constant of 2 will be

308.  Three single-phase transformers, each of 100 kVA rating are connected in delta. If one of the transformers is taken out of service, the capacity of the system will be

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