Which of the following graphs represent a DC series motor?

The correct answer is option 3):(d)

Concept:

Speed (N) vs Torque (Ta) Characteristic:

• The Speed (N) vs Torque (Ta) Characteristic is similar to the Speed (N) vs Current (Ia).
• Characteristic because of torque is proportional to the square of current up to magnetic saturation and proportional to the current after magnetic saturation.

​

• The series motor develops high torque at low speed and vice-versa.
• It is because an increase in torque requires an increase in armature current, which is also the field current.
• The torque speed characteristics of the different motor can be given as