Question

Torque developed by a DC motor depends upon _____________

(a) magnetic field

(b) active length of the conductor

(c) current flow through the conductors

(d) Current, active length, no. of conductors, magnetic field all

The question was posed to me by my college director while I was bunking the class.

My doubt stems from DC Motor Basics -2 topic in section DC Motors of DC Machines

Answer 1

Right answer is (d) Current, active length, no. of conductors, magnetic field all

The explanation: Torque produced by a DC motor is directly proportional to an armature current flowing through the machine. While it also depends on some constant values like active length, no. od armature conductors and magnetic field which are constant for a given machine.