Power and Torque Relations of Three Phase Induction Motor

Power and Torque Relations of Three Phase Induction Motor

The transformer equivalent circuit of an induction motor is quite helpful in analyzing the various power relations in the motor. Fig. 3.13 shows the equivalent circuit per phase of an induction motor where all values have been referred to primary (i.e., stator).

This is quite apparent from the equivalent circuit shown in Fig: 3.13. 

 Note that shaft torque T_sh will be less than T_g by the torque required to meet windage and frictional losses.