(a) Determine the efficiency of a 400 kVA transformer operating at half load if the full load copper loss equals its iron loss, which is 5 kW, and the power factor of the load is 0.85 lagging. (8 marks)
(b) A DC supply of 240 V is connected across the armature resistance of 4 Ω of a self-excited DC shunt motor, which causes the armature to rotate at a speed of 15 revolutions/second while drawing a total current of 50 A. If the field resistance is 10 Ω, the iron loss is 0.5 kW, and the friction and windage losses amount to 0.8 kW, determine the overall efficiency and torque developed at the armature. (17 marks)