1. Two single-phase transformers A and B of equal voltage ratio are running in parallel and supplying a load requiring 500 A at 0.8 power factor lagging at a terminal voltage of 400 V. The equivalent impedances of the transformers, as referred to secondary windings, are (2 +j3) and (2.5 + j5) ohm. Calculate the current supplied by each transformer. (Note. The student is advised to try by arithmetic method also). [I = 304 A ; I = 197 A] %3D

2. Given three identical ideal single-phase transformers with each rated at 100KVA and 7kV/3.5kV, they are connected as a three-phase transformer bank. The three-phase transformer has high voltage side connected in delta and the low voltage side is connected in wye. A three-phase 200KVA, wye connected load is connected at the low voltage side of the transformer. Calculate the following: a. Rated line-to-line voltage on each side b. Line current on each side of the transformer

A short-circuit test has been carried out with a three-phase transformer of 30/6.5 kV. By experiment, the high-voltage side was short-circuited and it was read: Ik=30A, Uk=234V and Pk=5.24kW a) Find the nominal voltage drop in % for this transformer where a was measured power factor of 0.8 ind.Under a certain load of the transformer, we measure a voltage drop of 5%, when the primary side is at 30kV. b) Find the secondary clamping voltage at this particular load

In a transformer that has 10 times more turns on the secondary side (side 2) than on the primary side (side 1), the magnitude of the voltage/EMF across the windings on the secondary side, E₂ will be... O a.... 10 times lower than the voltage/emf on the primary side, E₁. O b.... the same as the voltage/emf on the primary side. O c.... always zero regardless of the voltage on the primary side, E₁. O d.... 10 times higher than the voltage/emf on the primary side, E₁.