The self-inductance of a stator winding of a salient electric machine, shown in Fig. P3.4, is given by
![2479_930d6964-fdf3-4f83-9279-5bf30b558194.png](https://secure.tutorsglobe.com/CMSImages/2479_930d6964-fdf3-4f83-9279-5bf30b558194.png)
Answer the following questions [9].
(1) Derive the field energy of the machine.
(2) Derive the coenergy of the machine.
(3) Derive the torque equation.
![1073_2131a3c1-5b7c-4995-aecd-2310a728bd24.png](https://secure.tutorsglobe.com/CMSImages/1073_2131a3c1-5b7c-4995-aecd-2310a728bd24.png)