The developed Torque in a machine is defined as the Torque generated by the electric to mechanical power conversion. The torque is also known as Electromagnetic Torque.

The electrical power generated in the rotor is given by

These electrical powers are dissipated as I²R losses or copper loss in the rotor circuit.

Input power to the rotor is given as:

Where,

Equation (3) is called the Torque Equation Of the phase Induction Motor.

Starting Torque Of Induction Motor

At the start condition the value of s = 1. Therefore, the starting is obtained by putting the value of s = 1 in the equation (2), we get

The starting torque is also known as the Standstill Torque.

Torque Equation at Synchronous Speed

At synchronous speed, s = 0 and hence developed torque Ʈd = 0. At synchronous speed, the developed torque is zero.

Since E₁ is nearly equal to V₁ the equation (8) becomes

The Starting torque is obtained by putting, s = 1 in equation (9)

Therefore, it is clear from the above equation that the starting torque is proportional to the square of the stator applied voltage.

I hope the above note can help you understand the Torque Equation Of Three Phase Induction Motor properly. Stay with us for more educational video lectures and handwritten notes with free job alerts as well.

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