question_answer

A locomotive exerts a tractive effort of 40,000 N in pulling a rain at 60 kmph on a level track. If the same train is to be mauled at the same speed but on gradient, the tractive effort required will be 60,000 N. The output delivered by the motor will be more if it is driven by

A)  a 3 -phase induction motor

B)  a dc series motor

C)  an ac series motor

D)  equal in all the three cases