DC series motors are best suited for traction work because

• A. Its torque is proportional to the square of the armature current and speed is inversely proportional to torque
• B. Torque and speed are proportional to the square of the armature current
• C. Torque and speed are inversely proportional to the square of the armature current
• D. Its torque is proportional to the square of the armature current and speed is directional proporational to torque

Answer: (A)

Torque in d.c motor = k* φ * Ia
In series motor φ α Ia
Tα I²
N α 1/φ
N α 1/T