Torque Speed Characteristic of an Induction Motor

The Torque - Speed Characteristic is a curve that plots the relationship between the torque and the speed of an induction motor. In the topic "Torque Equation of an Induction Motor", we've already delved into the torque of the induction motor. The torque equation is presented as follows:

At the maximum torque, the speed of the rotor is expressed by the equation shown below:

The curve below shows the Torque Speed Characteristic:

The magnitude of the maximum torque is independent of rotor resistance. However, the specific slip value at which the maximum torque τmax occurs is indeed influenced by it. Specifically, the larger the value of rotor resistance R2, the higher the slip value at which the maximum torque is achieved. As the rotor resistance increases, the motor's pull - out speed decreases, while the maximum torque itself remains unchanged.