A 20KVA, 20,000/480V, 60 Hz distribution transformer is tested with the following results: Open-Circuit test (on Secondary) Short-circuit test (on Primary) Voc = 480 V VSc = 1130 V loc = 1.60 A Isc = 1.0 A Poc = 305 W Pac = 260 W a) Find the per-unit equivalent circuit for this transformer at 60 Hz. b) What would the rating of this transformer be if it were operated on a 50Hz power system? Sketch the equivalent circuito f the transformer referred to the primary side if it is operating at 50Hz