Torque and force production and power

A core task for a rotating electric machine is to produce the torque needed to achieve the required rotation speed under load. In linear machines, correspondingly, force production is the key element. Torque production is based on forces affecting the stator and the rotor. There are several ways to study force and torque production. This chapter explores the most important ways from the electrical drive's point of view. Torque production can be examined by analysing the energy stored in the magnetic circuit of the machine. Ignoring losses, the torque equation correlates with power. The voltage of a double‐salient pole reluctance machine can be expressed by applying Faraday's induction law and Ohm's law. The saliency of an electric machine produces torque if rotor movement results in a reduction in the reluctance of the main flux path. When applying numerical methods, Maxwell's stress tensor is often used for the calculation of torque.