i've got stuck in this electricity problem and cant find a solution for it. I've attached you my workings. I'm not sure if I'm using the right formula for this as two valuables missing here.
Any help would be much appreciated.
A d.c. self-excited shunt generator has a field resistance of 160Ω. The generated emf is 420V and it supplies a load of 55kW Calculate the armature resistance when the generator terminal voltage is 408V