The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This allows us to estimate the torque developed by a motor without knowing the details of its circuitry.
@article{arxiv.1109.4203,
title = {Analysis of a Three Phase Induction Motor Directly from Maxwell's Equations},
author = {Shayak Bhattacharjee},
journal= {arXiv preprint arXiv:1109.4203},
year = {2015}
}