A 500 W, 200 V compound motor has two field windings, one has a resistance of 0.03? and the other a resistance of 50 ?.

i) Draw and label a circuit diagram. Which winding should be connected to the Z-ZZ terminal?

ii) If the armature resistance is 0.15 ?, calculate the emf when it draws an armature current of 5A whilst running at 3000 rpm.

iii) When the load increases so that the motor draws a current of 10A, what is the new speed of the machine? (assume the field shunt current does not change – just the series field)