A.C. servomotors with concentrated stator windings

An investigation is made into the possibility of making a.c. servomotors with concentrated windings in the stator, e.g. 2-phase salient-pole servomotors and shaded-pole servomotors. A specific equivalent circuit for induction motors is used to obtain the voltage and torque equations of the motors. The effects of space harmonics on the motor torques are taken into account. The equations are evaluated and the performance characteristics of the two motors are obtained and found to have shapes necessary for the functions for which a servomotor is required. Test results of an experimental 2-phase salient-pole servomotor show that they agree closely with their corresponding values obtained by computation and that the response, characteristic of the motor practically coincides with that of a similar servomotor with distributed stator windings.