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 **I ^{2}R 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 E_{1} is nearly equal to V_{1 }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.

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