Calculating of torque

Hi

I have COMSOL 4.2a and I'm new in COMSOL. I'm simulating in AC/DC module Switched Reluctance Motor and I need to calculate torque of rotor and build plot of torque depending on angle of rotation. In user guide I found only equations how to calculate torque using Maxwell’s stress tensor and any example how to do it. Does someone have an example or user guide how to calculate torque.

Thank you in advance,
Artem