The total torque is shown in Figure 1c . This torque is developed due to the interaction of stator and rotor magnetic fields and hence is known as interaction torque or electromagnetic torque . The magnitude of the electromagnetic torque (T_em) or interaction torque is given by

(1)

Another configuration of the motor, with the flux lines, is shown in Figure 2a . Since the magnetic flux has a tendency to follow a minimum reluctance path or has a tendency to shorten its flux path, the rotor experiences an anti-clockwise torque. From Figure 2a it can be seen that the flux lines will have a tendency to align the rotor so that the reluctance encountered by them is reduced. The least reluctance position of the rotor is shown in Figure 2b .