A dc motor develops the maximum mechanical power when the armature current is such that
A. the back emf is equal to 3/4th of the applied emf.
B. the back emf is equal to one-half of the applied emf.
C. the back emf is equal to 1/4th of the applied emf.
D. the back emf is equal to 2/3rd of the applied emf.
Answer:B
A dc motor develops the maximum mechanical power when the armature current is such that
A. the back emf is equal to 3/4th of the applied emf. B. the back emf is equal to one-half of the applied emf. C. the back emf is equal to 1/4th of the applied emf. D. the back emf is equal to 2/3rd of the applied emf.