If the applied voltage of a DC motor is 230 V, then back emf, for maximum power developed is
Right Answer is:
For maximum power output, the back emf is equal to half of the applied voltage.
Hence, Eb = V/2 = 230/2 ⇒115 V. where V is the terminal voltage.
For maximum power transfer load resistance should be the same as series field resistance. So applied voltage 230 V will be divided equally 115 V on each section i.e. series field resistance and load resistance. Hence for maximum power development back emf should be 115 V.