Correct Answer - Option 2 : Rotor input in watts

Torque developed:

- The developed Torque or Induced Torque Equation 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 developed torque equation is given as

Td = mechanical power developed / mechanical angular velocity developed

Td = Pm / ωr

Since, Pm = (1 - s) Pg, ωr = (1 - s) ωs

⇒ Td = (1 - s) Pg / (1 - s) ωs

⇒ Td = Pg / ωs

- The above equation expresses the developed torque directly in terms of the air gap power
- Pg and the synchronous speed ωs. Since ωs is constant and independent of the load conditions.
- If the value of the Pg is known then, the developed torque can be found directly.
- The air gap power Pg is also called as the Torque in Synchronous Watts.

Synchronous Watt is the torque that develops the power of 1 Watt when the machine is running at synchronous speed.

In an induction motor, synchronous wattage indicates the rotor input in the units of watts.