Enter the rated power (kW) and the rated speed (rpm) into the calculator to determine the Induction Motor Torque. 

Induction Motor Torque Formula

The following formula is used to calculate the Induction Motor Torque. 

Tim = 9550-rP*rS
  • Where Tim is the Induction Motor Torque (N-m)
  • rP is the rated power (kW) 
  • rs is the rated speed (rpm) 

To calculate the induction motor torque, subtract the product of the rated power and speed from 9550.

How to Calculate Induction Motor Torque?

The following two example problems outline how to calculate the Induction Motor Torque.

Example Problem #1:

  1. First, determine the rated power (kW). In this example, the rated power (kW) is given as 43.
  2. Next, determine the rated speed (rpm). For this problem, the rated speed (rpm) is given as 72.
  3. Finally, calculate the Induction Motor Torque using the equation above: 

Tim = 9550-rP*rS

Inserting the values from above and solving the equation with the imputed values gives: 

Tim = 9550-43*72 = 6454 (N-m)

FAQ

What factors can affect the torque of an induction motor?

The torque of an induction motor can be affected by several factors including the motor’s rated power and speed, the quality of the electrical supply (voltage and frequency), the design of the motor (such as the number of poles and the construction of the rotor), and the load characteristics. Variations in these factors can lead to changes in the motor’s performance and its ability to generate torque.

How does the rated speed of an induction motor influence its torque?

The rated speed of an induction motor is directly related to its torque. According to the formula Tim = 9550 – rP*rS, where Tim is the torque, rP is the rated power, and rS is the rated speed, it’s evident that as the rated speed increases, the product of rated power and rated speed increases, which in turn reduces the torque. This relationship shows that higher speeds can lead to lower torque outputs for the same power rating.

Can the torque of an induction motor be increased, and if so, how?

Yes, the torque of an induction motor can be increased in several ways. One method is by improving the motor’s efficiency through better design or materials, which can reduce losses and increase torque. Another method is by using a variable frequency drive (VFD) to control the motor’s speed and voltage, optimizing the torque output for specific load conditions. Additionally, increasing the rated power of the motor, while keeping the rated speed constant, can also result in higher torque according to the torque formula.