12 kW, 100V DC machine runs at 1000 rpm at no load (Ia=6A) and at 932rpm at full load when operated as a shunt motor. Take armature resistance as 0.1 ohms. Which of the following are true?
a) The speed regulation of the machine is 6%.
b) The field current required for the rated load operation is 5A.
c) The back EMF at full load is approximately 95V.
d) The efficiency of the machine at full load is approximately 90%.
