2. DC machines (a) A separately excited DC generator with an armature circuit resistance Ra is operating at a terminal voltage V, while delivering an armature current la and has a constant loss P. (including the rotational losses and core losses). Find the value of la for which the generator efficiency is a maximum. b) A shunt DC generator delivers 195 A at terminal voltage of 250 V. The armature resistance and shunt field resistance are 0.02 2 and 50 2 respectively. The iron and friction losses equal to 950 W. Please find the following: (i) EMF generated; (ii) Copper Losses; (iii) Output power of the prime mover; (iv) Efficiency of the generator.